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Wang X, Cui Y, Wang Y, Liu S, Meng N, Wei W, Bai Y, Shen Y, Guo J, Guo Z, Wang M. Assessment of Lung Nodule Detection and Lung CT Screening Reporting and Data System Classification Using Zero Echo Time Pulmonary MRI. J Magn Reson Imaging 2024. [PMID: 38602245 DOI: 10.1002/jmri.29388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
BACKGROUND The detection rate of lung nodules has increased considerably with CT as the primary method of examination, and the repeated CT examinations at 3 months, 6 months or annually, based on nodule characteristics, have increased the radiation exposure of patients. So, it is urgent to explore a radiation-free MRI examination method that can effectively address the challenges posed by low proton density and magnetic field inhomogeneities. PURPOSE To evaluate the potential of zero echo time (ZTE) MRI in lung nodule detection and lung CT screening reporting and data system (lung-RADS) classification, and to explore the value of ZTE-MRI in the assessment of lung nodules. STUDY TYPE Prospective. POPULATION 54 patients, including 21 men and 33 women. FIELD STRENGTH/SEQUENCE Chest CT using a 16-slice scanner and ZTE-MRI at 3.0T based on fast gradient echo. ASSESSMENT Nodule type (ground-glass nodules, part-solid nodules, and solid nodules), lung-RADS classification, and nodule diameter (manual measurement) on CT and ZTE-MRI images were recorded. STATISTICAL TESTS The percent of concordant cases, Kappa value, intraclass correlation coefficient (ICC), Wilcoxon signed-rank test, Spearman's correlation, and Bland-Altman. The p-value <0.05 is considered significant. RESULTS A total of 54 patients (age, 54.8 ± 11.9 years; 21 men) with 63 nodules were enrolled. Compared with CT, the total nodule detection rate of ZTE-MRI was 85.7%. The intermodality agreement of ZTE-MRI and CT lung nodules type evaluation was substantial (Kappa = 0.761), and the intermodality agreement of ZTE-MRI and CT lung-RADS classification was moderate (Kappa = 0.592). The diameter measurements between ZTE-MRI and CT showed no significant difference and demonstrated a high degree of interobserver (ICC = 0.997-0.999) and intermodality (ICC = 0.956-0.985) agreements. DATA CONCLUSION The measurement of nodule diameter by pulmonary ZTE-MRI is similar to that by CT, but the ability of lung-RADS to classify nodes from MRI images still requires further research. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Xinhui Wang
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Yingying Cui
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Ying Wang
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Shuo Liu
- Department of Medical Imaging, Xinxiang Medical University and Henan Provincial People's Hospital, Zhengzhou, China
| | - Nan Meng
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Wei Wei
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Yan Bai
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | - Yu Shen
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
| | | | - Zhiping Guo
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
- Health Management Center of Henan Province, Zhengzhou University People's Hospital and FuWai Central China Cardiovascular Hospital, Zhengzhou, China
| | - Meiyun Wang
- Department of Medical Imaging, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Zhengzhou, China
- Laboratory of Brain Science and Brain-Like Intelligence Technology, Biomedical Research Institute, Henan Academy of Sciences, Zhengzhou, China
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Meng N, Feng P, Yu X, Wu Y, Fu F, Li Z, Luo Y, Tan H, Yuan J, Yang Y, Wang Z, Wang M. An [ 18F]FDG PET/3D-ultrashort echo time MRI-based radiomics model established by machine learning facilitates preoperative assessment of lymph node status in non-small cell lung cancer. Eur Radiol 2024; 34:318-329. [PMID: 37530809 DOI: 10.1007/s00330-023-09978-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 04/09/2023] [Accepted: 04/21/2023] [Indexed: 08/03/2023]
Abstract
OBJECTIVES To develop an [18F]FDG PET/3D-UTE model based on clinical factors, three-dimensional ultrashort echo time (3D-UTE), and PET radiomics features via machine learning for the assessment of lymph node (LN) status in non-small cell lung cancer (NSCLC). METHODS A total of 145 NSCLC patients (training, 101 cases; test, 44 cases) underwent whole-body [18F]FDG PET/CT and chest [18F]FDG PET/MRI were enrolled. Preoperative clinical factors and 3D-UTE, CT, and PET radiomics features were analyzed. The Mann-Whitney U test, LASSO regression, and SelectKBest were used for feature extraction. Five machine learning algorithms were used to establish prediction models, which were evaluated by the area under receiver-operator characteristic (ROC), DeLong test, calibration curves, and decision curve analysis (DCA). RESULTS A prediction model based on random forest, consisting of four clinical factors, six 3D-UTE, and six PET radiomics features, was used as the final model for PET/3D-UTE. The AUCs of this model were 0.912 and 0.791 in the training and test sets, respectively, which not only showed different degrees of improvement over individual models such as clinical, 3D-UTE, and PET (AUC-training = 0.838, 0.834, and 0.828, AUC-test = 0.756, 0.745, and 0.768, respectively) but also achieved the similar diagnostic efficacy as the optimal PET/CT model (AUC-training = 0.890, AUC-test = 0.793). The calibration curves and DCA indicated good consistency (C-index, 0.912) and clinical utility of this model, respectively. CONCLUSION The [18F]FDG PET/3D-UTE model based on clinical factors, 3D-UTE, and PET radiomics features using machine learning methods could noninvasively assess the LN status of NSCLC. CLINICAL RELEVANCE STATEMENT A machine learning model of 18F-fluorodeoxyglucose positron emission tomography/ three-dimensional ultrashort echo time could noninvasively assess the lymph node status of non-small cell lung cancer, which provides a novel method with less radiation burden for clinical practice. KEY POINTS • The 3D-UTE radiomics model using the PLS-DA classifier was significantly associated with LN status in NSCLC and has similar diagnostic performance as the clinical, CT, and PET models. • The [18F]FDG PET/3D-UTE model based on clinical factors, 3D-UTE, and PET radiomics features using the RF classifier could noninvasively assess the LN status of NSCLC and showed improved diagnostic performance compared to the clinical, 3D-UTE, and PET models. • In the assessment of LN status in NSCLC, the [18F]FDG PET/3D-UTE model has similar diagnostic efficacy as the [18F]FDG PET/CT model that incorporates clinical factors and CT and PET radiomics features.
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Affiliation(s)
- Nan Meng
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
- Laboratory of Brain Science and Brain-Like Intelligence Technology, Biomedical Research Institute, Henan Academy of Science, Zhengzhou, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Pengyang Feng
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
- Department of Medical Imaging, Henan University People's Hospital & Henan Provincial People's Hospital, Zhengzhou, China
| | - Xuan Yu
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
| | - Yaping Wu
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
| | - Fangfang Fu
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
| | - Ziqiang Li
- Department of Medical Imaging, Xinxiang Medical University People's Hospital & Henan Provincial People's Hospital, Zhengzhou, China
| | - Yu Luo
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
| | - Hongna Tan
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China
| | - Jianmin Yuan
- Central Research Institute, United Imaging Healthcare Group, Shanghai, China
| | - Yang Yang
- Beijing United Imaging Research Institute of Intelligent Imaging, United Imaging Healthcare Group, Beijing, China
| | - Zhe Wang
- Central Research Institute, United Imaging Healthcare Group, Shanghai, China
| | - Meiyun Wang
- Department of Medical Imaging, Henan Provincial People's Hospital & Zhengzhou University People's Hospital, 7 Weiwu Road, Zhengzhou, 450000, China.
- Laboratory of Brain Science and Brain-Like Intelligence Technology, Biomedical Research Institute, Henan Academy of Science, Zhengzhou, China.
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China.
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Ohno Y, Ozawa Y, Nagata H, Ueda T, Yoshikawa T, Takenaka D, Koyama H. Lung Magnetic Resonance Imaging: Technical Advancements and Clinical Applications. Invest Radiol 2024; 59:38-52. [PMID: 37707840 DOI: 10.1097/rli.0000000000001017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
ABSTRACT Since lung magnetic resonance imaging (MRI) became clinically available, limited clinical utility has been suggested for applying MRI to lung diseases. Moreover, clinical applications of MRI for patients with lung diseases or thoracic oncology may vary from country to country due to clinical indications, type of health insurance, or number of MR units available. Because of this situation, members of the Fleischner Society and of the Japanese Society for Magnetic Resonance in Medicine have published new reports to provide appropriate clinical indications for lung MRI. This review article presents a brief history of lung MRI in terms of its technical aspects and major clinical indications, such as (1) what is currently available, (2) what is promising but requires further validation or evaluation, and (3) which developments warrant research-based evaluations in preclinical or patient studies. We hope this article will provide Investigative Radiology readers with further knowledge of the current status of lung MRI and will assist them with the application of appropriate protocols in routine clinical practice.
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Affiliation(s)
- Yoshiharu Ohno
- From the Department of Diagnostic Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ohno); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ohno and H.N.); Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ozawa and T.U.); Department of Diagnostic Radiology, Hyogo Cancer Center, Akashi, Hyogo, Japan (T.Y., D.T.); and Department of Radiology, Advanced Diagnostic Medical Imaging, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (H.K.)
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Sodhi KS, Bhatia A, Rana P, Mathew JL. Impact of Radial Percentage K-Space Filling and Signal Averaging on Native Lung MRI Image Quality in 3D Radial UTE Acquisition: A Pilot Study. Acad Radiol 2023; 30:2557-2565. [PMID: 36931950 DOI: 10.1016/j.acra.2023.01.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 01/08/2023] [Accepted: 01/23/2023] [Indexed: 03/18/2023]
Abstract
RATIONALE AND OBJECTIVE To assess the impact of radial percentage k-space filling and signal averaging on lung MRI image quality in 3D radial ultrashort echo-time (UTE) acquisition. MATERIALS AND METHODS In this IRB approved prospective study, 25 patients (10-30 years) referred for MRI examination for indications other than related to lungs were enrolled from January 2021 to November 2021. All the patients underwent lung MRI, using three different UTE sequence parameters with radial (R) percentage of 100 or 200 and number of signal averages (NSA) of one or two. Two radiologists independently assessed the images for the outline of pleural and mediastinal surface, visibility of lung parenchyma, major bronchi, and segmental bronchi. The quality of the images was assessed based on the degree of motion artifacts. For objective assessment, signal-to-noise ratio, contrast-to-noise ratio, and contrast ratio were calculated. RESULTS The outline of pleural and mediastinal surface, lung parenchyma, and segmental bronchi were best demonstrated on R100_NSA2 sequence. The major bronchi were best demonstrated on R100_NSA2 and R100_NSA1 sequences. The intersequence difference was statistically significant for evaluating the pleural and mediastinal surface and segmental bronchi only (p < 0.05). Overall, the best image quality with least artifacts was seen with R100_NSA2 sequence. The objective assessment showed no statistically significant difference between the three sequences (p > 0.05). Interobserver agreement for different findings was substantial to almost perfect for R100_NSA2 and R200_NSA1 sequences. CONCLUSION R100_NSA2 UTE sequence performed best for the evaluation of the different findings and showed the best image quality.
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Affiliation(s)
- Kushaljit Singh Sodhi
- Mallinckrodt Institute of Radiology, Washington University in St. Louis School of Medicine, St.Louis, Missouri, USA; Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
| | - Anmol Bhatia
- Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Pratyaksha Rana
- Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Joseph L Mathew
- Department of Pediatrics, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Papp D, Elders B, Wielopolski PA, Kotek G, Vogel M, Tiddens HAWM, Ciet P, Hernandez-Tamames JA. Lung parenchyma and structure visualisation in paediatric chest MRI: a comparison of different short and ultra-short echo time protocols. Clin Radiol 2023; 78:e319-e327. [PMID: 36746723 DOI: 10.1016/j.crad.2022.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/23/2022] [Indexed: 01/22/2023]
Abstract
AIM To evaluate image quality acquired at lung imaging using magnetic resonance imaging (MRI) sequences using short and ultra-short (UTE) echo times (TEs) with different acquisition strategies (breath-hold, prospective, and retrospective gating) in paediatric patients and in healthy volunteers. MATERIALS AND METHODS End-inspiratory and end-expiratory three-dimensional (3D) spoiled gradient (SPGR3D) and 3D zero echo-time (ZTE3D), and 3D UTE free-breathing (UTE3D), prospective projection navigated radial ZTE3D (ZTE3D vnav), and four-dimensional ZTE (ZTE4D) were performed using a 1.5 T MRI system. For quantitative assessment, the contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) values were calculated. To evaluate image quality, qualitative scoring was undertaken on all sequences to evaluate depiction of intrapulmonary vessels, fissures, bronchi, imaging noise, artefacts, and overall acceptability. RESULTS Eight cystic fibrosis (CF) patients (median age 14 years, range 13-17 years), seven children with history of prematurity with or without bronchopulmonary dysplasia (BPD; median 10 years, range 10-11 years), and 10 healthy volunteers (median 32 years, range 20-52 years) were included in the study. ZTE3D vnav provided the most reliable output in terms of image quality, although scan time was highly dependent on navigator triggering efficiency and respiratory pattern. CONCLUSIONS Best image quality was achieved with prospective ZTE3D and UTE3D readouts both in children and volunteers. The current implementation of retrospective ZTE3D readout (ZTE4D) did not provide diagnostic image quality but rather introduced artefacts over the entire imaging volume mimicking lung pathology.
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Affiliation(s)
- D Papp
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands.
| | - B Elders
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands; Department of Paediatric Pulmonology and Allergology, Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, the Netherlands
| | - P A Wielopolski
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands
| | - G Kotek
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands
| | - M Vogel
- General Electric Healthcare, Waukesha, WI, USA
| | - H A W M Tiddens
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands; Department of Paediatric Pulmonology and Allergology, Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, the Netherlands
| | - P Ciet
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands; Department of Paediatric Pulmonology and Allergology, Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, the Netherlands
| | - J A Hernandez-Tamames
- Department of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, the Netherlands
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Pavlova OS, Gulyaev MV, Gervits LL, Hurshkainen AA, Nikulin AV, Puchnin VM, Teploukhova ED, Kuropatkina TA, Anisimov NV, Medvedeva NA, Pirogov YA. Т 1 mapping of rat lungs in 19 F MRI using octafluorocyclobutane. Magn Reson Med 2023; 89:2318-2331. [PMID: 36744719 DOI: 10.1002/mrm.29606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 02/07/2023]
Abstract
PURPOSE To demonstrate the feasibility of using octafluorocyclobutane (OFCB, c-C4 F8 ) for T1 mapping of lungs in 19 F MRI. METHODS The study was performed at 7 T in three healthy rats and three rats with pulmonary hypertension. To increase the sensitivity of 19 F MRI, a bent-shaped RF coil with periodic metal strips structure was used. The double flip angle method was used to calculate normalized transmitting RF field (B1n + ) maps and for correcting T1 maps built with the variable flip angle (VFA) method. The ultrashort TE pulse sequence was applied for acquiring MR images throughout the study. RESULTS The dependencies of OFCB relaxation times on its partial pressure in mixtures with oxygen, air, helium, and argon were obtained. T1 of OFCB linearly depended on its partial pressure with the slope of about 0.35 ms/kPa in the case of free diffusion. RF field inhomogeneity leads to distortion of T1 maps built with the VFA method, and therefore to high standard deviation of T1 in these maps. To improve the accuracy of the T1 maps, the B1n + maps were applied for VFA correction. This contributed to a 2-3-fold decrease in the SD of T1 values in the corresponding maps compared with T1 maps calculated without the correction. Three-dimensional T1 maps were obtained, and the mean T1 in healthy rat lungs was 35 ± 10 ms, and in rat lungs with pulmonary hypertension - 41 ± 9 ms. CONCLUSION OFCB has a spin-rotational relaxation mechanism and can be used for 19 F T1 mapping of lungs. The calculated OFCB maps captured ventilation defects induced by edema.
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Affiliation(s)
- Olga S Pavlova
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, Russia.,Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Mikhail V Gulyaev
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, Russia
| | - Lev L Gervits
- Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Moscow, Russia
| | - Anna A Hurshkainen
- School of Physics and Engineering, ITMO University, St. Petersburg, Russia
| | - Anton V Nikulin
- Center of Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Viktor M Puchnin
- School of Physics and Engineering, ITMO University, St. Petersburg, Russia
| | | | | | | | | | - Yury A Pirogov
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
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Zou Q, Torres LA, Fain SB, Higano NS, Bates AJ, Jacob M. Dynamic imaging using motion-compensated smoothness regularization on manifolds (MoCo-SToRM). Phys Med Biol 2022; 67:10.1088/1361-6560/ac79fc. [PMID: 35714617 PMCID: PMC9677930 DOI: 10.1088/1361-6560/ac79fc] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 06/17/2022] [Indexed: 01/07/2023]
Abstract
Objective. We introduce an unsupervised motion-compensated reconstruction scheme for high-resolution free-breathing pulmonary magnetic resonance imaging.Approach. We model the image frames in the time series as the deformed version of the 3D template image volume. We assume the deformation maps to be points on a smooth manifold in high-dimensional space. Specifically, we model the deformation map at each time instant as the output of a CNN-based generator that has the same weight for all time-frames, driven by a low-dimensional latent vector. The time series of latent vectors account for the dynamics in the dataset, including respiratory motion and bulk motion. The template image volume, the parameters of the generator, and the latent vectors are learned directly from the k-t space data in an unsupervised fashion.Main results. Our experimental results show improved reconstructions compared to state-of-the-art methods, especially in the context of bulk motion during the scans.Significance. The proposed unsupervised motion-compensated scheme jointly estimates the latent vectors that capture the motion dynamics, the corresponding deformation maps, and the reconstructed motion-compensated images from the raw k-t space data of each subject. Unlike current motion-resolved strategies, the proposed scheme is more robust to bulk motion events during the scan.
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Affiliation(s)
- Qing Zou
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA
| | - Luis A. Torres
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Sean B. Fain
- Department of Radiology, The University of Iowa, Iowa City, IA, USA
| | - Nara S. Higano
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children’s Hospital, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Alister J. Bates
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children’s Hospital, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Mathews Jacob
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA
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Unsupervised-learning-based method for chest MRI-CT transformation using structure constrained unsupervised generative attention networks. Sci Rep 2022; 12:11090. [PMID: 35773366 PMCID: PMC9247083 DOI: 10.1038/s41598-022-14677-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 06/10/2022] [Indexed: 01/04/2023] Open
Abstract
The integrated positron emission tomography/magnetic resonance imaging (PET/MRI) scanner simultaneously acquires metabolic information via PET and morphological information using MRI. However, attenuation correction, which is necessary for quantitative PET evaluation, is difficult as it requires the generation of attenuation-correction maps from MRI, which has no direct relationship with the gamma-ray attenuation information. MRI-based bone tissue segmentation is potentially available for attenuation correction in relatively rigid and fixed organs such as the head and pelvis regions. However, this is challenging for the chest region because of respiratory and cardiac motions in the chest, its anatomically complicated structure, and the thin bone cortex. We propose a new method using unsupervised generative attentional networks with adaptive layer-instance normalisation for image-to-image translation (U-GAT-IT), which specialised in unpaired image transformation based on attention maps for image transformation. We added the modality-independent neighbourhood descriptor (MIND) to the loss of U-GAT-IT to guarantee anatomical consistency in the image transformation between different domains. Our proposed method obtained a synthesised computed tomography of the chest. Experimental results showed that our method outperforms current approaches. The study findings suggest the possibility of synthesising clinically acceptable computed tomography images from chest MRI with minimal changes in anatomical structures without human annotation.
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Liu Q, Feng Z, Liu WV, Fu W, He L, Cheng X, Mao Z, Zhou W. Assessment of Solid Pulmonary Nodules or Masses Using Zero Echo Time MR Lung Imaging: A Prospective Head-to-Head Comparison With CT. Front Oncol 2022; 12:812014. [PMID: 35558517 PMCID: PMC9088008 DOI: 10.3389/fonc.2022.812014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/24/2022] [Indexed: 11/13/2022] Open
Abstract
Objective The aim of this study is to determine the potential of zero echo time (ZTE) MR lung imaging in the assessment of solid pulmonary nodules or masses and diagnostic consistency to CT in terms of morphologic characterization. Methods Our Institutional Review Board approved this prospective study. Seventy-one patients with solid pulmonary nodules or masses larger than 1 cm in diameter confirmed by chest CT were enrolled and underwent further lung ZTE-MRI scans within 7 days. ZTE-MRI and CT images were compared in terms of image quality and imaging features. Unidimensional diameter and three-dimensional volume measurements on both modalities were manually measured and compared using the Wilcoxon signed-rank test, intraclass correlation coefficient (ICC), Pearson's correlation analysis, and Bland-Altman analysis. Multivariable logistic regression analysis was used to identify the factors associated with significant inter-modality variation of volume. Results Fifty-four of 71 (76.1%) patients were diagnosed with lung cancer. Subjective image quality was superior in CT compared with ZTE-MRI (p < 0.001). Inter-modality agreement for the imaging features was moderate for emphysema (kappa = 0.50), substantial for fibrosis (kappa = 0.76), and almost perfect (kappa = 0.88-1.00) for the remaining features. The size measurements including diameter and volume between ZTE-MRI and CT showed no significant difference (p = 0.36 for diameter and 0.60 for volume) and revealed perfect inter-observer (ICC = 0.975-0.980) and inter-modality (ICC = 0.942-0.992) agreements. Multivariable analysis showed that non-smooth margin [odds ratio (OR) = 6.008, p = 0.015] was an independent predictor for the significant inter-modality variation of volume. Conclusion ZTE lung imaging is feasible as a part of chest MRI in the assessment and surveillance for solid pulmonary nodules or masses larger than 1 cm, presenting perfect agreement with CT in terms of morphologic characterization.
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Affiliation(s)
- Qianyun Liu
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
| | - Zhichao Feng
- Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Weiyin Vivian Liu
- Magnetic Resonance (MR) Research, General Electric (GE) Healthcare, Beijing, China
| | - Weidong Fu
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
| | - Lei He
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
| | - Xiaosan Cheng
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
| | - Zhongliang Mao
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
| | - Wenming Zhou
- Department of Medical Imaging, Yueyang Central Hospital, Yueyang, China
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Ljungberg E, Wood TC, Solana AB, Williams SCR, Barker GJ, Wiesinger F. Motion corrected silent ZTE neuroimaging. Magn Reson Med 2022; 88:195-210. [PMID: 35381110 PMCID: PMC9321117 DOI: 10.1002/mrm.29201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/16/2022] [Accepted: 01/28/2022] [Indexed: 11/11/2022]
Abstract
Purpose To develop self‐navigated motion correction for 3D silent zero echo time (ZTE) based neuroimaging and characterize its performance for different types of head motion. Methods The proposed method termed MERLIN (Motion Estimation & Retrospective correction Leveraging Interleaved Navigators) achieves self‐navigation by using interleaved 3D phyllotaxis k‐space sampling. Low resolution navigator images are reconstructed continuously throughout the ZTE acquisition using a sliding window and co‐registered in image space relative to a fixed reference position. Rigid body motion corrections are then applied retrospectively to the k‐space trajectory and raw data and reconstructed into a final, high‐resolution ZTE image. Results MERLIN demonstrated successful and consistent motion correction for magnetization prepared ZTE images for a range of different instructed motion paradigms. The acoustic noise response of the self‐navigated phyllotaxis trajectory was found to be only slightly above ambient noise levels (<4 dBA). Conclusion Silent ZTE imaging combined with MERLIN addresses two major challenges intrinsic to MRI (i.e., subject motion and acoustic noise) in a synergistic and integrated manner without increase in scan time and thereby forms a versatile and powerful framework for clinical and research MR neuroimaging applications.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | | | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,GE Healthcare, Munich, Germany
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11
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Zeimpekis KG, Kellenberger CJ, Geiger J. Assessment of lung density in pediatric patients using three-dimensional ultrashort echo-time and four-dimensional zero echo-time sequences. Jpn J Radiol 2022; 40:722-729. [PMID: 35237890 PMCID: PMC8890957 DOI: 10.1007/s11604-022-01258-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 02/17/2022] [Indexed: 11/28/2022]
Abstract
Purpose Lung magnetic resonance imaging (MRI) using conventional sequences is limited due to strong signal loss by susceptibility effects of aerated lung. Our aim is to assess lung signal intensity in children on ultrashort echo-time (UTE) and zero echo-time (ZTE) sequences. We hypothesize that lung signal intensity can be correlated to lung physical density. Materials and methods Lung MRI was performed in 17 children with morphologically normal lungs (median age: 4.7 years, range 15 days to 17 years). Both lungs were manually segmented in UTE and ZTE images and the average signal intensities were extracted. Lung-to-background signal ratios (LBR) were compared for both sequences and between both patient groups using non-parametric tests and correlation analysis. Anatomical region-of-interest (ROI) analysis was performed for the normal cohort for assessment of the anteroposterior lung gradient. Results There was no significant difference between LBR of normal lungs using UTE and ZTE (p < 0.05). Both sequences revealed a LBR age-dependency with a high negative correlation for UTE (Rs = – 0.77; range 2.98–1.41) and ZTE (Rs = – 0.82; range 2.66–1.38)). Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were age-dependent for both sequences. SNR was higher for children up to 2 years old with 3D UTE Cones while for the rest it was higher with 4D ZTE. CNR was similar for both sequences. Posterior lung areas exhibited higher signal intensity compared to anterior ones (UTE 9.4% and ZTE 12% higher), both with high correlation coefficients (R2UTE = 0.94, R2ZTE = 0.97). Conclusion The ZTE sequence can measure signal intensity similarly to UTE in pediatric patients. Both sequences reveal an age- and gravity-dependency of LBR.
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Affiliation(s)
- Konstantinos G Zeimpekis
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, 3010, Bern, Switzerland.
| | - Christian J Kellenberger
- Department of Diagnostic Imaging, University Children's Hospital Zurich, Steinwiesstrasse 75, 8032, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Julia Geiger
- Department of Diagnostic Imaging, University Children's Hospital Zurich, Steinwiesstrasse 75, 8032, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
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12
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Froidevaux R, Weiger M, Pruessmann KP. Pulse encoding for ZTE imaging: RF excitation without dead-time penalty. Magn Reson Med 2021; 87:1360-1374. [PMID: 34775617 PMCID: PMC9299067 DOI: 10.1002/mrm.29056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/09/2021] [Accepted: 10/04/2021] [Indexed: 11/23/2022]
Abstract
Purpose To overcome limitations in the duration of RF excitation in zero‐TE (ZTE) MRI by exploiting intrinsic encoding properties of RF pulses to retrieve data missed during the dead time caused by the pulse. Methods An enhanced ZTE signal model was developed using multiple RF pulses, which enables accessing information hidden in the pulse‐induced dead time via encoding intrinsically applied by the RF pulses. Such ZTE with pulse encoding was implemented by acquisition of two ZTE data sets using excitation with similar frequency‐swept pulses differing only by a small off‐resonance in their center frequency. In this way, the minimum scan time is doubled but each acquisition contributes equally to the SNR, as with ordinary averaging. The method was demonstrated on long‐T2 and short‐T2 phantoms as well as in in vivo experiments. Results ZTE with pulse encoding provided good image quality at unprecedented dead‐time gaps, demonstrated here up to 6 Nyquist dwells. In head imaging, the ability to use longer excitation pulses led to approximately 2‐fold improvements in SNR efficiency as compared with conventional ZTE and allowed the creation of T1 contrast. Conclusion Exploiting intrinsic encoding properties of RF pulses in a new signal model enables algebraic reconstruction of ZTE data sets with large dead‐time gaps. This permits larger flip angles, which can be used to achieve enhanced T1 contrast and significant improvements in SNR efficiency in case the Ernst angle can be better approached, thus broadening the range of application of ZTE MRI.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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13
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Fractionated deep-inspiration breath-hold ZTE Compared with Free-breathing four-dimensional ZTE for detecting pulmonary nodules in oncological patients underwent PET/MRI. Sci Rep 2021; 11:17636. [PMID: 34480038 PMCID: PMC8417270 DOI: 10.1038/s41598-021-94702-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/16/2021] [Indexed: 12/04/2022] Open
Abstract
The zero echo time (ZTE) technique has improved the detection of lung nodules in PET/MRI but respiratory motion remains a challenge in lung scan. We investigated the feasibility and performance of fractionated deep-inspiration breath-hold (FDIBH) three-dimensional (3D) ZTE FDG PET/MRI for assessing lung nodules in patients with proved malignancy. Sixty patients who had undergone ZTE FDG PET/MRI and chest CT within a three-day interval were retrospectively included. Lung nodules less than 2 mm were excluded for analysis. Two physicians checked the adequacy of FDIBH ZTE and compared the lung nodule detection rates of FDIBH 3D ZTE and free-breathing (FB) four-dimensional (4D) ZTE, with chest CT as the reference standard. FDIBH resolved the effect of respiratory motion in 49 patients. The mean number and size of the pulmonary nodules identified in CT were 15 ± 31.3 per patient and 5.9 ± 4.6 mm in diameter. The overall nodule detection rate was 71% for FDIBH 3D ZTE and 70% for FB 4D ZTE (p = 0.73). FDIBH 3D ZTE significantly outperformed FB 4DZTE in detecting lung base nodules (72% and 68%; p = 0.03), especially for detecting those less than 6 mm (61% and 55%; p = 0.03). High inter-rater reliability for FDIBH 3D ZTE and FB 4D ZTE (k = 0.9 and 0.92) was noted. In conclusion, the capability of FDIBH 3D ZTE in respiratory motion resolution was limited with a technical failure rate of 18%. However, it could provide full expansion of the lung in a shorter scan time which enabled better detection of nodules (< 6 mm) in basal lungs, compared to FB 4D ZTE.
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14
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Geiger J, Zeimpekis KG, Jung A, Moeller A, Kellenberger CJ. Clinical application of ultrashort echo-time MRI for lung pathologies in children. Clin Radiol 2021; 76:708.e9-708.e17. [PMID: 34120734 DOI: 10.1016/j.crad.2021.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/20/2021] [Indexed: 01/05/2023]
Abstract
Lung magnetic resonance imaging (MRI) is considered to be challenging, because the low proton density of the tissue, fast signal decay, and respiratory artefacts hamper adequate image quality. MRI of the lungs and thorax is increasingly used in the paediatric population, because it is a radiation-free alternative to chest CT. Recently, ultrashort echo-time (UTE) sequences have been introduced into clinical MRI protocols, in order to improve the contrast-to-noise ratio due to reduced susceptibility artefacts and to depict structural alterations comparable to CT. The purpose of this review is to provide an overview of various clinical conditions and pathologies in the paediatric chest depicted by an UTE sequence, the so-called three-dimensional (3D) Cones sequence, in comparison with conventional MRI sequences. Besides describing typical features of cystic fibrosis, we present UTE application in other more or less common paediatric lung pathologies, for instance, interstitial pneumopathies, pulmonary infections, and congenital pulmonary malformations.
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Affiliation(s)
- J Geiger
- Department of Diagnostic Imaging, University Children's Hospital Zürich, Zürich, Switzerland; University of Zürich, University Children's Hospital Zürich, Zürich, Switzerland.
| | - K G Zeimpekis
- Department of Nuclear Medicine, University Hospital Zürich, Zürich, Switzerland; Department of Electrical Engineering and Information Technology, ETH Zürich, Zürich, Switzerland
| | - A Jung
- University of Zürich, University Children's Hospital Zürich, Zürich, Switzerland; Division of Respiratory Medicine and Cystic Fibrosis, University Children's Hospital Zürich, Zürich, Switzerland
| | - A Moeller
- University of Zürich, University Children's Hospital Zürich, Zürich, Switzerland; Division of Respiratory Medicine and Cystic Fibrosis, University Children's Hospital Zürich, Zürich, Switzerland
| | - C J Kellenberger
- Department of Diagnostic Imaging, University Children's Hospital Zürich, Zürich, Switzerland; University of Zürich, University Children's Hospital Zürich, Zürich, Switzerland
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15
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Yucel S, Aycicek T, Ceyhan Bilgici M, Dincer OS, Tomak L. 3 Tesla MRI in diagnosis and follow up of children with pneumonia. Clin Imaging 2021; 79:213-218. [PMID: 34116298 DOI: 10.1016/j.clinimag.2021.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 05/10/2021] [Accepted: 05/27/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the utilization of 3-Tesla (3 T) magnetic resonance imaging (MRI) in detection of pulmonary abnormalities in children with pneumonia. MATERIALS AND METHODS Forty-seven children with pneumonia prospectively underwent 3 T thoracic MRI and posteroanterior (PA) chest radiography (CR). Of these, 15 patients also underwent contrast-enhanced thorax computed tomography (CT) or high-resolution CT (HRCT). The MRI protocol included axial and coronal T2-weighted spectral presaturation with inversion recovery (SPIR) Multivane-XD and axial echo-planar diffusion-weighted imaging (EPI DWI) with respiratory gating. Kappa statistics, Cochran Q, and McNemar tests were used to investigate the results. RESULTS Agreement between CR and MRI was substantial in detecting consolidation/infiltration (k = 0.64), peribronchial thickening (k = 0.64), and bronchiectasis (k = 1); moderate in detecting cavity (k = 0.54) and pleural effusion (k = 0.44); and fair in detecting empyema (0.32) and bilateral involvement of lungs (k = 0.23). MRI was superior to CR in detecting bilateral involvement (p < 0.001), lymph node (p < 0.001), pleural effusion (p < 0.001), and empyema (p = 0.003). MRI detected all the consolidation/infiltration also detected on CT imaging. A kappa test showed moderate agreement between MRI and CT in detecting pleural effusion and ground-glass opacity (GGO), and substantial or almost perfect agreement for all other pathologies. No statistically significant difference was observed between MRI and CT for detecting pneumonia-associated pathologies by the McNemar test. CONCLUSION Thoracic 3 T MRI is an accurate and effective technique for evaluating children with pneumonia. MRI detected more pathologies than CR and had similar results to those of thorax CT.
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Affiliation(s)
- Serap Yucel
- Mus State Hospital, Department of Radiology, Mus, Turkey.
| | - Tugba Aycicek
- M.D. Prof. Ondokuz Mayıs University Faculty of Medicine, Department of Pediatric Disease, Samsun, Turkey
| | - Meltem Ceyhan Bilgici
- Ondokuz Mayıs University Faculty of Medicine, Department of Radiology, Samsun, Turkey
| | - Oguz Salih Dincer
- M.D. Prof. Ondokuz Mayıs University Faculty of Medicine, Department of Pediatric Disease, Samsun, Turkey
| | - Leman Tomak
- Ondokuz Mayis University Faculty of Medicine, Department of Biostatistics and Medical Informatics, Samsun, Turkey
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16
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Froidevaux R, Weiger M, Rösler MB, Brunner DO, Pruessmann KP. HYFI: Hybrid filling of the dead-time gap for faster zero echo time imaging. NMR IN BIOMEDICINE 2021; 34:e4493. [PMID: 33624305 PMCID: PMC8244056 DOI: 10.1002/nbm.4493] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 05/31/2023]
Abstract
The aim of this work was to improve the SNR efficiency of zero echo time (ZTE) MRI pulse sequences for faster imaging of short-T2 components at large dead-time gaps. ZTE MRI with hybrid filling (HYFI) is a strategy for retrieving inner k-space data missed during the dead-time gaps arising from radio-frequency excitation and switching in ZTE imaging. It performs hybrid filling of the inner k-space with a small single-point-imaging core surrounded by a stack of shells acquired on radial readouts in an onion-like fashion. The exposition of this concept is followed by translation into guidelines for parameter choice and implementation details. The imaging properties and performance of HYFI are studied in simulations as well as phantom, in vitro and in vivo imaging, with an emphasis on comparison with the pointwise encoding time reduction with radial acquisition (PETRA) technique. Simulations predict higher SNR efficiency for HYFI compared with PETRA at preserved image quality, with the advantage increasing with the size of the k-space gap. These results are confirmed by imaging experiments with gap sizes of 25 to 50 Nyquist dwells, in which scan times for similar image quality could be reduced by 25% to 60%. The HYFI technique provides both high SNR efficiency and image quality, thus outperforming previously known ZTE-based pulse sequences, in particular for large k-space gaps. Promising applications include direct imaging of ultrashort-T2 components, such as the myelin bilayer or collagen, T2 mapping of ultrafast relaxing signals, and ZTE imaging with reduced chemical shift artifacts.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela B Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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17
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Tanaka Y, Ohno Y, Hanamatsu S, Obama Y, Ueda T, Ikeda H, Iwase A, Fukuba T, Hattori H, Murayama K, Yoshikawa T, Takenaka D, Koyama H, Toyama H. State-of-the-art MR Imaging for Thoracic Diseases. Magn Reson Med Sci 2021; 21:212-234. [PMID: 33952785 PMCID: PMC9199970 DOI: 10.2463/mrms.rev.2020-0184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Since thoracic MR imaging was first used in a clinical setting, it has been suggested that MR imaging has limited clinical utility for thoracic diseases, especially lung diseases, in comparison with x-ray CT and positron emission tomography (PET)/CT. However, in many countries and states and for specific indications, MR imaging has recently become practicable. In addition, recently developed pulmonary MR imaging with ultra-short TE (UTE) and zero TE (ZTE) has enhanced the utility of MR imaging for thoracic diseases in routine clinical practice. Furthermore, MR imaging has been introduced as being capable of assessing pulmonary function. It should be borne in mind, however, that these applications have so far been academically and clinically used only for healthy volunteers, but not for patients with various pulmonary diseases in Japan or other countries. In 2020, the Fleischner Society published a new report, which provides consensus expert opinions regarding appropriate clinical indications of pulmonary MR imaging for not only oncologic but also pulmonary diseases. This review article presents a brief history of MR imaging for thoracic diseases regarding its technical aspects and major clinical indications in Japan 1) in terms of what is currently available, 2) promising but requiring further validation or evaluation, and 3) developments warranting research investigations in preclinical or patient studies. State-of-the-art MR imaging can non-invasively visualize lung structural and functional abnormalities without ionizing radiation and thus provide an alternative to CT. MR imaging is considered as a tool for providing unique information. Moreover, prospective, randomized, and multi-center trials should be conducted to directly compare MR imaging with conventional methods to determine whether the former has equal or superior clinical relevance. The results of these trials together with continued improvements are expected to update or modify recommendations for the use of MRI in near future.
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Affiliation(s)
- Yumi Tanaka
- Department of Radiology, Fujita Health University School of Medicine
| | - Yoshiharu Ohno
- Department of Radiology, Fujita Health University School of Medicine.,Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine
| | - Satomu Hanamatsu
- Department of Radiology, Fujita Health University School of Medicine
| | - Yuki Obama
- Department of Radiology, Fujita Health University School of Medicine
| | - Takahiro Ueda
- Department of Radiology, Fujita Health University School of Medicine
| | - Hirotaka Ikeda
- Department of Radiology, Fujita Health University School of Medicine
| | - Akiyoshi Iwase
- Department of Radiology, Fujita Health University Hospital
| | - Takashi Fukuba
- Department of Radiology, Fujita Health University Hospital
| | - Hidekazu Hattori
- Department of Radiology, Fujita Health University School of Medicine
| | - Kazuhiro Murayama
- Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine
| | | | | | | | - Hiroshi Toyama
- Department of Radiology, Fujita Health University School of Medicine
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18
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Abstract
OBJECTIVE. The purpose of this article is to review currently available and emerging techniques for pediatric lung MRI for general radiologists. CONCLUSION. MRI is a radiation-free alternative to CT, and clearly understanding the strengths and limitations of established and emerging techniques of pediatric lung MRI can allow practitioners to select and combine the optimal techniques, apply them in clinical practice, and potentially improve early diagnostic accuracy and patient management.
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19
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Zeimpekis KG, Geiger J, Wiesinger F, Delso G, Kellenberger CJ. Three-dimensional magnetic resonance imaging ultrashort echo-time cones for assessing lung density in pediatric patients. Pediatr Radiol 2021; 51:57-65. [PMID: 32860525 PMCID: PMC7796870 DOI: 10.1007/s00247-020-04791-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/18/2020] [Accepted: 07/29/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND MRI of lung parenchyma is challenging because of the rapid decay of signal by susceptibility effects of aerated lung on routine fast spin-echo sequences. OBJECTIVE To assess lung signal intensity in children on ultrashort echo-time sequences in comparison to a fast spin-echo technique. MATERIALS AND METHODS We conducted a retrospective study of lung MRI obtained in 30 patients (median age 5 years, range 2 months to 18 years) including 15 with normal lungs and 15 with cystic fibrosis. On a fast spin-echo sequence with radial readout and an ultrashort echo-time sequence, both lungs were segmented and signal intensities were extracted. We compared lung-to-background signal ratios and histogram analysis between the two patient cohorts using non-parametric tests and correlation analysis. RESULTS On ultrashort echo-time the lung-to-background ratio was age-dependent, ranging from 3.15 to 1.33 with high negative correlation (Rs = -0.86). Signal in posterior dependent portions of the lung was 18% and 11% higher than that of the anterior lung for age groups 0-2 and 2-18 years, respectively. The fast spin-echo sequence showed no variation of signal ratios by age or location, with a median of 0.99 (0.98-1.02). Histograms of ultrashort echo-time slices between controls and children with aggravated cystic fibrosis with mucus plugging and wall thickening exhibited significant discrepancies that differentiated between normal and pathological lungs. CONCLUSION Signal intensity of lung on ultrashort echo-time is higher than that on fast spin-echo sequences, is age-dependent and shows a gravity-dependent anterior to posterior gradient. This signal variation appears similar to lung density described on CT.
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Affiliation(s)
- Konstantinos G. Zeimpekis
- grid.412004.30000 0004 0478 9977Department of Nuclear Medicine, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland ,grid.5801.c0000 0001 2156 2780Department of Information Technology and Electrical Engineering, ETH, Zürich, Switzerland
| | - Julia Geiger
- grid.412341.10000 0001 0726 4330Department of Diagnostic Imaging, University Children’s Hospital Zürich, Zürich, Switzerland ,grid.412341.10000 0001 0726 4330Children’s Research Center, University Children’s Hospital Zürich, Zürich, Switzerland
| | | | - Gaspar Delso
- grid.418143.b0000 0001 0943 0267GE Healthcare, Waukesha, WI USA
| | - Christian J. Kellenberger
- grid.412341.10000 0001 0726 4330Department of Diagnostic Imaging, University Children’s Hospital Zürich, Zürich, Switzerland ,grid.412341.10000 0001 0726 4330Children’s Research Center, University Children’s Hospital Zürich, Zürich, Switzerland
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20
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Boucneau T, Fernandez B, Besson FL, Menini A, Wiesinger F, Durand E, Caramella C, Darrasse L, Maître X. AZTEK: Adaptive zero TE k-space trajectories. Magn Reson Med 2020; 85:926-935. [PMID: 32936490 DOI: 10.1002/mrm.28483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/28/2022]
Abstract
PURPOSE Because of short signal lifetimes and respiratory motion, 3D lung MRI is still challenging today. Zero-TE (ZTE) pulse sequences offer promising solutions as they overcome the issue of short T 2 ∗ . Nevertheless, as they rely on continuous readout gradients, the trajectories they follow in k-space are not adapted to retrospective gating and inferred motion correction. THEORY AND METHODS We propose AZTEK (adaptive ZTE k-space trajectories), a set of 3D radial trajectories featuring three tuning parameters, to adapt the acquisition to any moving organ while keeping seamless transitions between consecutive spokes. Standard ZTE and AZTEK trajectories were compared for static and moving phantom acquisitions as well as for human thoracic imaging performed on 3 volunteers (1 healthy and 2 patients with lung cancer). RESULTS For the static phantom, we observe comparable image qualities with standard and AZTEK trajectories. For the moving phantom, spatially coherent undersampling artifacts observed on gated images with the standard trajectory are alleviated with AZTEK. The same improvement in image quality is obtained in human, so details are more delineated in the lung with the use of the adaptive trajectory. CONCLUSION The AZTEK technique opens the possibility for 3D dynamic ZTE lung imaging with retrospective gating. It enables us to uniformly sample the k-space for any arbitrary respiratory motion gate, while preserving static image quality, improving dynamic image quality and guaranteeing continuous readout gradient transitions between spokes, which makes it appropriate to ZTE.
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Affiliation(s)
- Tanguy Boucneau
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | | | - Florent L Besson
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France.,Université Paris-Saclay, Department of Biophysics and Nuclear Medicine, Hopitaux Universitaires Paris-Saclay, Le Kremlin Bicêtre, France
| | - Anne Menini
- Applications & Workflow, GE Healthcare, Menlo Park, California, USA
| | | | - Emmanuel Durand
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France.,Université Paris-Saclay, Department of Biophysics and Nuclear Medicine, Hopitaux Universitaires Paris-Saclay, Le Kremlin Bicêtre, France
| | | | - Luc Darrasse
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | - Xavier Maître
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
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21
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Tiddens HAWM, Meerburg JJ, van der Eerden MM, Ciet P. The radiological diagnosis of bronchiectasis: what's in a name? Eur Respir Rev 2020; 29:29/156/190120. [PMID: 32554759 PMCID: PMC9489191 DOI: 10.1183/16000617.0120-2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 01/02/2020] [Indexed: 12/31/2022] Open
Abstract
Diagnosis of bronchiectasis is usually made using chest computed tomography (CT) scan, the current gold standard method. A bronchiectatic airway can show abnormal widening and thickening of its airway wall. In addition, it can show an irregular wall and lack of tapering, and/or can be visible in the periphery of the lung. Its diagnosis is still largely expert based. More recently, it has become clear that airway dimensions on CT and therefore the diagnosis of bronchiectasis are highly dependent on lung volume. Hence, control of lung volume is required during CT acquisition to standardise the evaluation of airways. Automated image analysis systems are in development for the objective analysis of airway dimensions and for the diagnosis of bronchiectasis. To use these systems, clear and objective definitions for the diagnosis of bronchiectasis are needed. Furthermore, the use of these systems requires standardisation of CT protocols and of lung volume during chest CT acquisition. In addition, sex- and age-specific reference values are needed for image analysis outcome parameters. This review focusses on today's issues relating to the radiological diagnosis of bronchiectasis using state-of-the-art CT imaging techniques. Bronchiectasis diagnosis is expert based. Clear definitions, standardisation of lung volume and CT protocols, and reference values are needed to allow automated image analysis for its diagnosis and to be used for clinical management and clinical studies.http://bit.ly/35vASqz
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Affiliation(s)
- Harm A W M Tiddens
- Dept of Paediatric Pulmonology and Allergology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Rotterdam, The Netherlands .,Dept of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Jennifer J Meerburg
- Dept of Paediatric Pulmonology and Allergology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Rotterdam, The Netherlands.,Dept of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
| | | | - Pierluigi Ciet
- Dept of Paediatric Pulmonology and Allergology, Erasmus Medical Centre (MC)-Sophia Children's Hospital, Rotterdam, The Netherlands.,Dept of Radiology and Nuclear Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
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Bae K, Jeon KN, Hwang MJ, Lee JS, Park SE, Kim HC, Menini A. Respiratory motion-resolved four-dimensional zero echo time (4D ZTE) lung MRI using retrospective soft gating: feasibility and image quality compared with 3D ZTE. Eur Radiol 2020; 30:5130-5138. [PMID: 32333146 DOI: 10.1007/s00330-020-06890-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/18/2020] [Accepted: 04/10/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To evaluate the feasibility and image quality of respiratory motion-resolved 4D zero echo time (ZTE) lung MRI compared with that of 3D ZTE. METHODS Our institutional review board approved this study. Twenty-one patients underwent lung scans using 3D ZTE and 4D ZTE sequences via prospective and retrospective soft gating techniques, respectively. Image qualities of 3D ZTE and 4D ZTE at end-expiration were compared through objective and subjective assessments. The quality of end-expiratory images of 3D ZTE and 4D ZTE of the two groups with different lung functions was also compared. RESULTS Images were successfully acquired in all patients without any adverse events. Signal-to-noise ratios (SNRs) of lung parenchyma and thoracic structures were significantly (all p < 0.001) higher in 4D ZTE. Contrast-to-noise ratios (CNRs) of peripheral bronchi, peripheral pulmonary vessels, and nodules or masses were significantly (all p < 0.001) higher in 4D ZTE. The subjective image quality assessed by two independent radiologists showed that intrapulmonary structures, noise and artifacts, and overall acceptability were superior in 4D ZTE (all p < 0.001). Image qualities of groups with normal and low lung functions differed significantly (all p < 0.05) in 3D ZTE, but not in 4D ZTE. The mean acquisition time was 136 s (127-143 s) in 3D ZTE and 325 s (308-352 s) in 4D ZTE. CONCLUSIONS Respiratory motion-resolved 4D ZTE lung imaging was feasible as part of routine chest MRI. The 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR than the 3D ZTE, regardless of patients' lung function. KEY POINTS • ZTE MRI captures rapidly decaying transverse magnetization in the lung parenchyma. • 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR compared with 3D ZTE. • Compared with 3D ZTE, the image quality of 4D ZTE lung MRI was affected less by patients' lung function and respiratory performance.
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Affiliation(s)
- Kyungsoo Bae
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea.,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea
| | - Kyung Nyeo Jeon
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea. .,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea.
| | | | - Joon Sung Lee
- General Electric (GE) Healthcare Korea, Seoul, South Korea
| | - Sung Eun Park
- Department of Radiology, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju, South Korea.,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, South Korea
| | - Ho Cheol Kim
- Department of Internal Medicine, School of Medicine, Gyeongsang National University, Jinju, South Korea
| | - Anne Menini
- Applied Science Lab, GE Healthcare, Menlo Park, CA, USA
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23
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Diagnostic performance of zero-TE lung MR imaging in FDG PET/MRI for pulmonary malignancies. Eur Radiol 2020; 30:4995-5003. [PMID: 32300969 PMCID: PMC7431435 DOI: 10.1007/s00330-020-06848-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/10/2020] [Accepted: 03/30/2020] [Indexed: 10/27/2022]
Abstract
OBJECTIVES This study aimed to evaluate the diagnostic performance of the lung zero-echo time (ZTE) sequence in FDG PET/MRI for detection and differentiation of lung lesions in oncologic patients in comparison with conventional two-point Dixon-based MR imaging. METHODS In this single-institution retrospective study approved by the institutional review board, 209 patients with malignancies (97 men and 112 women; age range, 17-89 years; mean age, 66.5 ± 12.9 years) underwent 18F-FDG PET/MRI between August 2017 and August 2018, with diagnostic Dixon and ZTE under respiratory gating acquired simultaneously with PET. Image analysis was performed for PET/Dixon and PET/ZTE fused images by two readers to assess the detectability and differentiation of lung lesions. The reference standard was pathological findings and/or the data from a chest CT. The detection and differentiation abilities were evaluated for all lesions and subgroups divided by lesion size and maximum standardized uptake value (SUVmax). RESULTS Based on the reference standard, 227 lung lesions were identified in 113 patients. The detectability of PET/ZTE was significantly better than that of PET/Dixon for overall lesions, lesions with a SUVmax less than 3.0 and lesions smaller than 4 mm (p < 0.01). The diagnostic performance of PET/ZTE was significantly better than that of PET/Dixon for overall lesions and lesions smaller than 4 mm (p < 0.01). CONCLUSIONS ZTE can improve diagnostic performance in the detection and differentiation of both FDG-avid and non-FDG-avid lung lesions smaller than 4 mm in size, yielding a promising tool to enhance the utility of FDG PET/MRI in oncology patients with lung lesions. KEY POINTS • The detection rate of PET/ZTE for lesions with a SUVmax of less than 1.0 was significantly better than that of PET/Dixon. • The performance for differentiation of PET/ZTE for lesions that were even smaller than 4 mm in size were significantly better than that of PET/Dixon. • Inter-rater agreement of PET/ZTE for the differentiation of lesions less than 4 mm in size was substantial and better than that of PET/Dixon.
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24
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Froidevaux R, Weiger M, Rösler MB, Brunner DO, Dietrich BE, Reber J, Pruessmann KP. High-resolution short-T 2 MRI using a high-performance gradient. Magn Reson Med 2020; 84:1933-1946. [PMID: 32176828 DOI: 10.1002/mrm.28254] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE To achieve high resolution in imaging of short-T2 materials and tissues by using a high-performance human-sized gradient insert with strength up to 200 mT/m and 100% duty cycle. METHODS Dedicated short-T2 methodology and hardware are used, such as the pointwise encoding time reduction with radial acquisition (PETRA) technique with modulated excitation pulses, optimized radio-frequency hardware, and a high-performance gradient insert. A theoretical analysis of actual spatial resolution and SNR is provided to support the choice of scan parameters and interpretation of the results. Imaging is performed in resolution phantoms, animal specimen, and human volunteers at both conventional and maximum available gradient strengths and compared using image subtraction. RESULTS Calculations suggest that increasing gradient strength beyond conventional values considerably improves both actual resolution and SNR efficiency in short-T2 imaging. Resolution improvements are confirmed in all investigated samples, in particular 2 mm slots were resolved in a hard-plastic plate with T2 ≈ 10 μs and in vivo musculoskeletal images were acquired at isotropic 200 μm resolution. Expected improvements in signal yield are realized in fine structures benefitting from high resolution but to less extent in regions of low contrast where decay-related blurring leads to signal overlap between neighboring locations. CONCLUSION Strong gradients with high duty cycle enable short-T2 imaging at unprecedentedly high resolution, holding the potential for improving MRI of, eg, bone, tendon, lung, or teeth. Moreover, it allows direct access of tissues with T2 of tens of microseconds such as myelin or collagen.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela B Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Benjamin E Dietrich
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Jonas Reber
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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25
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Obert AJ, Gutberlet M, Kern AL, Kaireit TF, Grimm R, Wacker F, Vogel-Claussen J. 1 H-guided reconstruction of 19 F gas MRI in COPD patients. Magn Reson Med 2020; 84:1336-1346. [PMID: 32060989 DOI: 10.1002/mrm.28209] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/20/2020] [Accepted: 01/20/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To reduce acquisition time and improve image quality and robustness of ventilation assessment in a single breath-hold using 1 H-guided reconstruction of fluorinated gas (19 F) MRI. METHODS Reconstructions constraining total variation in the image domain, L1 norm in the wavelet domain, and directional total variation between 19 F and 1 H images were compared in order to accelerate 19 F ventilation imaging using retrospectively undersampled data from a healthy volunteer. Using the optimal constrained reconstruction in 8 patients with chronic obstructive pulmonary disease (16-seconds breath-hold), ventilation maps of various acceleration factors (2-fold to 13-fold) were compared with maps of the full data set using the Dice coefficient, difference in volume defect percentage and overlap percentage, as well as hyperpolarized 129 Xe gas MRI. RESULTS The reconstruction constraining total variation and directional total variation simultaneously performed best in the healthy volunteer (RMS error = 0.07, structural similarity index = 0.77) for a measurement time of 2 seconds. Using the same reconstruction in the patients with chronic obstructive pulmonary disease, the Dice coefficient of defect volumes was 0.86 ± 0.05, the mean difference in volume defect percentage was -1.0 ± 1.7 percentage points, and the overlap percentage was 87% ± 2% for a measurement time of 6 seconds. Between volume defect percentage of 19 F and 129 Xe, a linear correlation (r = 0.75; P = .03) was found, with 19 F volume defect percentage being significantly higher (mean difference = 11%; P = .04). CONCLUSION 1 H-guided reconstruction of pulmonary 19 F gas MRI enables reduction of acquisition time while maintaining image quality and robustness of functional parameters.
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Affiliation(s)
- Arnd Jonathan Obert
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
| | - Marcel Gutberlet
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
| | - Agilo Luitger Kern
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
| | - Till Frederik Kaireit
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
| | | | - Frank Wacker
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
| | - Jens Vogel-Claussen
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover, German Center for Lung Research, Hannover, Germany
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26
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Ljungberg E, Wood T, Solana AB, Kolind S, Williams SCR, Wiesinger F, Barker GJ. Silent T
1
mapping using the variable flip angle method with B
1
correction. Magn Reson Med 2020; 84:813-824. [DOI: 10.1002/mrm.28178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/11/2019] [Accepted: 12/30/2019] [Indexed: 11/12/2022]
Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging Institute of Psychiatry, Psychology & Neuroscience, King's College London London UK
| | - Tobias Wood
- Department of Neuroimaging Institute of Psychiatry, Psychology & Neuroscience, King's College London London UK
| | | | - Shannon Kolind
- Department of Physics and Astronomy University of British Columbia Vancouver BC Canada
- Department of Radiology University of British Columbia Vancouver BC Canada
- International Collaboration on Repair Discoveries University of British Columbia Vancouver BC Canada
- Medicine (Neurology) University of British Columbia Vancouver BC Canada
| | - Steven C. R. Williams
- Department of Neuroimaging Institute of Psychiatry, Psychology & Neuroscience, King's College London London UK
| | - Florian Wiesinger
- Department of Neuroimaging Institute of Psychiatry, Psychology & Neuroscience, King's College London London UK
- ASL Europe, General Electric Healthcare Munich Germany
| | - Gareth J. Barker
- Department of Neuroimaging Institute of Psychiatry, Psychology & Neuroscience, King's College London London UK
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27
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Liszewski MC, Ciet P, Lee EY. Lung and Pleura. PEDIATRIC BODY MRI 2020. [PMCID: PMC7245516 DOI: 10.1007/978-3-030-31989-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Willmering MM, Robison RK, Wang H, Pipe JG, Woods JC. Implementation of the FLORET UTE sequence for lung imaging. Magn Reson Med 2019; 82:1091-1100. [PMID: 31081961 PMCID: PMC6559861 DOI: 10.1002/mrm.27800] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/21/2019] [Accepted: 04/15/2019] [Indexed: 12/28/2022]
Abstract
PURPOSE Magnetic resonance imaging of lungs is inherently challenging, but it has become more common with the use of UTE sequences and their relative insensitivity to motion. Spiral UTE sequences have been touted recently as having greater k-space sampling efficiencies than radial UTE, but few are designed for the shorter T2 * of the lung. In this study, FLORET (Fermat looped, orthogonally encoded trajectories), a recently developed spiral 3D-UTE sequence designed for the short T2 * species, was implemented in human lungs for the first time and the images were compared with traditional radial UTE images. METHODS The FLORET sequence was implemented with parameters optimized for lung imaging on healthy and diseased (cystic fibrosis) subjects. On healthy subjects, radial UTE images (3D-radial and 2D-radial with phase encoding) were acquired for comparison to FLORET. Various metrics including SNR, vasculature contrast, diaphragm sharpness, and parenchymal density ratios were acquired and compared among the separate UTE sequences. RESULTS The FLORET sequence performed similarly to traditional radial UTE methods with a much shorter total scan time for fully sampled images (FLORET: 1 minute 55 seconds, 3D-radial: 3 minutes 25 seconds, 2D-radial with phase encoding: 7 minutes 22 seconds). Additionally, the FLORET image obtained on the cystic fibrosis subject resulted in the observation of cystic fibrosis lung pathology similar or superior to that of the other UTE-MRI techniques. CONCLUSION The FLORET sequence allows for faster acquisition of high diagnostic-quality lung images and its short T2 * components without sacrificing SNR, image quality, or tissue/disease quantification.
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Affiliation(s)
- Matthew M. Willmering
- Center for Pulmonary Imaging Research, Divisions of Pulmonary Medicine and Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Ryan K. Robison
- Department of Radiology, Phoenix Children’s Hospital, Phoenix, AZ, 85016, USA
| | - Hui Wang
- Center for Pulmonary Imaging Research, Divisions of Pulmonary Medicine and Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, USA
- Clinical Science, Philips Healthcare, Gainesville, FL, 32608, USA
| | - James G. Pipe
- Imaging Research, Barrow Neurological Institute, Phoenix, AZ, 85013, USA
| | - Jason C. Woods
- Center for Pulmonary Imaging Research, Divisions of Pulmonary Medicine and Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, 45229, USA
- Departments of Pediatrics, Radiology, and Physics, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
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29
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Assessment of MR imaging during one-lung flooding in a large animal model. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 32:581-590. [PMID: 31152266 DOI: 10.1007/s10334-019-00759-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/23/2019] [Accepted: 05/20/2019] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Magnetic resonance imaging (MRI) of the lung remains challenging due to the low tissue density, susceptibility artefacts, unfavourable relaxation times and motion. Previously, we demonstrated in vivo that one-lung flooding (OLF) with saline is a viable and safe approach. This study investigates the feasibility of OLF in an MRI environment and evaluates the flooding process on MR images. METHODS OLF of the left lung was performed on five animals using a porcine model. Before, during and after OLF, standard T2w and T1w spin-echo (SE) and gradient-echo (GRE) sequences were applied at 3 T. RESULTS The procedure was successfully performed in all animals. On T1w MRI, the flooded lung appeared homogenous and isointense with muscle tissue. On T2w images, vascular structures were highly hypointense, while the bronchi were clearly demarcated with hypointense wall and hyperintense lumen. The anatomical demarcation of the flooded lung from the surrounding organs was superior on T2w images. No outflow effects were seen, and no respiration triggering was required. DISCUSSION OLF can be safely performed in an MR scanner with highly detailed visualization of the pulmonary structures on T2w images. The method provides new approaches to MRI-based image-guided pulmonary interventions using the presented experimental model.
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30
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Liszewski MC, Ciet P, Lee EY. MR Imaging of Lungs and Airways in Children:. Magn Reson Imaging Clin N Am 2019; 27:201-225. [DOI: 10.1016/j.mric.2019.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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31
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Bates AJ, Higano NS, Hysinger EB, Fleck RJ, Hahn AD, Fain SB, Kingma PS, Woods JC. Quantitative Assessment of Regional Dynamic Airway Collapse in Neonates via Retrospectively Respiratory-Gated 1 H Ultrashort Echo Time MRI. J Magn Reson Imaging 2019; 49:659-667. [PMID: 30252988 PMCID: PMC6375762 DOI: 10.1002/jmri.26296] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/27/2018] [Accepted: 07/27/2018] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Neonatal dynamic tracheal collapse (tracheomalacia, TM) is a common and serious comorbidity in infants, particularly those with chronic lung disease of prematurity (bronchopulmonary dysplasia, BPD) or congenital airway or lung-related conditions such as congenital diaphragmatic hernia (CDH), but the underlying pathology, impact on clinical outcomes, and response to therapy are not well understood. There is a pressing clinical need for an accurate, objective, and safe assessment of neonatal TM. PURPOSE To use retrospectively respiratory-gated ultrashort echo-time (UTE) MRI to noninvasively analyze moving tracheal anatomy for regional, quantitative evaluation of dynamic airway collapse in quiet-breathing, nonsedated neonates. STUDY TYPE Prospective. POPULATION/SUBJECTS Twenty-seven neonatal subjects with varying respiratory morbidities (control, BPD, CDH, abnormal polysomnogram). FIELD STRENGTH/SEQUENCE High-resolution 3D radial UTE MRI (0.7 mm isotropic) on 1.5T scanner sited in the neonatal intensive care unit. ASSESSMENT Images were retrospectively respiratory-gated using the motion-modulated time-course of the k-space center. Tracheal surfaces were generated from segmentations of end-expiration/inspiration images and analyzed geometrically along the tracheal length to calculate percent-change in luminal cross-sectional area (A % ) and ratio of minor-to-major diameters at end-expiration (r D,exp ). Geometric results were compared to clinically available bronchoscopic findings (n = 14). STATISTICAL TESTS Two-sample t-test. RESULTS Maximum A % significantly identified subjects with/without a bronchoscopic TM diagnosis (with: 46.9 ± 10.0%; without: 27.0 ± 5.8%; P < 0.001), as did minimum r D,exp (with: 0.346 ± 0.146; without: 0.671 ± 0.218; P = 0.008). Subjects with severe BPD exhibited a far larger range of minimum r D,exp than subjects with mild/moderate BPD or controls (0.631 ± 0.222, 0.782 ± 0.075, and 0.776 ± 0.030, respectively), while minimum r D,exp was reduced in CDH subjects (0.331 ± 0.171) compared with controls (P < 0.001). DATA CONCLUSION Respiratory-gated UTE MRI can quantitatively and safely evaluate neonatal dynamic tracheal collapse, as validated with the clinical standard of bronchoscopy, without requiring invasive procedures, anesthesia, or ionizing radiation. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:659-667.
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Affiliation(s)
- Alister J Bates
- Upper Airway Center, Division of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| | - Nara S Higano
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| | - Erik B Hysinger
- Upper Airway Center, Division of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Robert J Fleck
- Upper Airway Center, Division of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| | - Andrew D Hahn
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Sean B Fain
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Paul S Kingma
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| | - Jason C Woods
- Upper Airway Center, Division of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
- Departments of Radiology and Physics, University of Cincinnati, Cincinnati, Ohio, USA
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Gomes AL, Kinchesh P, Gilchrist S, Allen PD, Lourenço LM, Ryan AJ, Smart SC. Cardio-Respiratory synchronized bSSFP MRI for high throughput in vivo lung tumour quantification. PLoS One 2019; 14:e0212172. [PMID: 30753240 PMCID: PMC6372180 DOI: 10.1371/journal.pone.0212172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 01/29/2019] [Indexed: 11/18/2022] Open
Abstract
The identification and measurement of tumours is a key requirement in the study of tumour development in mouse models of human cancer. Disease burden in autochthonous tumours, such as those arising in the lung, can be seen with non-invasive imaging, but cannot be accurately measured using standard tools such as callipers. Lung imaging is further complicated in the mouse due to instabilities arising from the rapid but cyclic cardio-respiratory motions, and the desire to use free-breathing animals. Female A/JOlaHsd mice were either injected (i.p.) with PBS 0.1ml/10g body weight (n = 6), or 10% urethane/PBS 0.1ml/10g body weight (n = 12) to induce autochthonous lung tumours. Cardio-respiratory synchronised bSSFP MRI, at 200 μm isotropic resolution was performed at 8, 13 and 18 weeks post induction. Images from the same mouse at different time points were aligned using threshold-based segmented masks of the lungs (ITK-SNAP and MATLAB) and tumour volumes were determined via threshold-based segmentation (ITK-SNAP).Scan times were routinely below 10 minutes and tumours were readily identifiable. Image registration allowed serial measurement of tumour volumes as small as 0.056 mm3. Repetitive imaging did not lead to mouse welfare issues. We have developed a motion desensitised scan that enables high sensitivity MRI to be performed with high throughput capability of greater than 4 mice/hour. Image segmentation and registration allows serial measurement of individual, small tumours. This allows fast and highly efficient volumetric lung tumour monitoring in cohorts of 30 mice per imaging time point. As a result, adaptive trial study designs can be achieved, optimizing experimental and welfare outcomes.
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Affiliation(s)
- Ana L. Gomes
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Paul Kinchesh
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Stuart Gilchrist
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Philip D. Allen
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Luiza Madia Lourenço
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Anderson J. Ryan
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Sean C. Smart
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
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Bae K, Jeon KN, Hwang MJ, Lee JS, Ha JY, Ryu KH, Kim HC. Comparison of lung imaging using three-dimensional ultrashort echo time and zero echo time sequences: preliminary study. Eur Radiol 2018; 29:2253-2262. [PMID: 30547204 DOI: 10.1007/s00330-018-5889-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/29/2018] [Accepted: 11/13/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To determine the feasibility of using high-resolution volumetric zero echo time (ZTE) sequence in routine lung magnetic resonance imaging (MRI) and compare free breathing 3D ultrashort echo time (UTE) and ZTE lung MRI in terms of image quality and small-nodule detection. MATERIALS AND METHODS Our Institutional Review Board approved this study. Twenty patients underwent both UTE and ZTE sequences during routine lung MR. UTE and ZTE images were compared in terms of subjective image quality and detection of lung parenchymal signal, intrapulmonary structures, and sub-centimeter nodules. Differences between the two sequences were compared through statistical analysis. RESULTS Lung parenchyma showed significantly (p < 0.05) higher signal-to-noise ratio (SNR) in ZTE than in UTE. The SNR and contrast-to-noise ratio (CNR) of peripheral bronchus and small pulmonary arteries were significantly (all p < 0.05) higher in ZTE. Subjective image quality evaluated by two independent radiologists in terms of depicting normal structures and overall acceptability was superior in ZTE (p < 0.05). The diagnostic accuracy for sub-centimeter nodules was significantly higher for ZTE (reader 1: AUC, 0.972; p = 0.044; reader 2: AUC, 0.946; p = 0.045) than that for UTE (reader 1: AUC, 0.885; reader 2: AUC, 0.855). Mean scan time was 131 s (125-141 s) in ZTE and 467 s (453-508 s) in UTE. ZTE images were obtained with less acoustic noise. CONCLUSION Implementing ZTE as an additional sequence in routine lung MR is feasible. ZTE can provide high-resolution pulmonary structural information with better SNR and CNR using shorter time than UTE. KEY POINTS • Both UTE and ZTE techniques use very short TEs to capture signals from very short T2/T2* tissues. • ZTE is superior in capturing lung parenchymal signal than UTE. • ZTE provides high-resolution structural information with better SNR and CNR for normal intrapulmonary structures and small nodules using shorter scan time than UTE.
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Affiliation(s)
- Kyungsoo Bae
- Department of Radiology, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, South Korea.,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, 51472, South Korea
| | - Kyung Nyeo Jeon
- Department of Radiology, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, South Korea. .,Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, 51472, South Korea.
| | - Moon Jung Hwang
- General Electronics (GE) Healthcare Korea, Seoul, South Korea
| | - Joon Sung Lee
- General Electronics (GE) Healthcare Korea, Seoul, South Korea
| | - Ji Young Ha
- Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, 51472, South Korea
| | - Kyeong Hwa Ryu
- Department of Radiology, Gyeongsang National University Changwon Hospital, 555 Samjeongja-dong, Seongsan-gu, Changwon, 51472, South Korea
| | - Ho Cheol Kim
- Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, South Korea
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Mendes Pereira L, Wech T, Weng AM, Kestler C, Veldhoen S, Bley TA, Köstler H. UTE-SENCEFUL: first results for 3D high-resolution lung ventilation imaging. Magn Reson Med 2018; 81:2464-2473. [PMID: 30393947 DOI: 10.1002/mrm.27576] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/27/2018] [Accepted: 10/01/2018] [Indexed: 02/05/2023]
Abstract
PURPOSE This study aimed to develop a 3D MRI technique to assess lung ventilation in free-breathing and without the administration of contrast agent. METHODS A 3D-UTE sequence with a koosh ball trajectory was developed for a 3 Tesla scanner. An oversampled k-space was acquired, and the direct current signal from the k-space center was used as a navigator to sort the acquired data into 8 individual breathing phases. Gradient delays were corrected, and iterative SENSE was used to reconstruct the individual timeframes. Subsequently, the signal changes caused by motion were eliminated using a 3D image registration technique, and ventilation-weighted maps were created by analyzing the signal changes in the lung tissue. Six healthy volunteers and 1 patient with lung cancer were scanned with the new 3D-UTE and the standard 2D technique. Image quality and quantitative ventilation values were compared between both methods. RESULTS UTE-based self-gated noncontrast-enhanced functional lung (SENCEFUL) MRI provided a time-resolved reconstruction of the breathing motion, with a 49% increase of the SNR. Ventilation quantification for healthy subjects was in statistical agreement with 2D-SENCEFUL and the literature, with a mean value of 0.11 ± 0.08 mL/mL for the whole lung. UTE-SENCEFUL was able to visualize and quantify ventilation deficits in a patient with lung tumor that were not properly depicted by 2D-SENCEFUL. CONCLUSION UTE-SENCEFUL represents a robust MRI method to assess both morphological and functional information of the lungs in 3D. When compared to the 2D approach, 3D-UTE offered ventilation maps with higher resolution, improved SNR, and reduced ventilation artifacts.
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Affiliation(s)
- L Mendes Pereira
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - T Wech
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - A M Weng
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - C Kestler
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - S Veldhoen
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - T A Bley
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - H Köstler
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
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35
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Bauman G, Pusterla O, Bieri O. Functional lung imaging with transient spoiled gradient echo. Magn Reson Med 2018; 81:1915-1923. [DOI: 10.1002/mrm.27535] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/06/2018] [Accepted: 08/27/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Grzegorz Bauman
- Division of Radiological Physics, Department of Radiology University of Basel Hospital Basel Switzerland
- Department of Biomedical Engineering University of Basel Basel Switzerland
| | - Orso Pusterla
- Division of Radiological Physics, Department of Radiology University of Basel Hospital Basel Switzerland
- Department of Biomedical Engineering University of Basel Basel Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology University of Basel Hospital Basel Switzerland
- Department of Biomedical Engineering University of Basel Basel Switzerland
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36
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Couch MJ, Ball IK, Li T, Fox MS, Biman B, Albert MS. 19 F MRI of the Lungs Using Inert Fluorinated Gases: Challenges and New Developments. J Magn Reson Imaging 2018; 49:343-354. [PMID: 30248212 DOI: 10.1002/jmri.26292] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/23/2018] [Accepted: 07/26/2018] [Indexed: 12/27/2022] Open
Abstract
Fluorine-19 (19 F) MRI using inhaled inert fluorinated gases is an emerging technique that can provide functional images of the lungs. Inert fluorinated gases are nontoxic, abundant, relatively inexpensive, and the technique can be performed on any MRI scanner with broadband multinuclear imaging capabilities. Pulmonary 19 F MRI has been performed in animals, healthy human volunteers, and in patients with lung disease. In this review, the technical requirements of 19 F MRI are discussed, along with various imaging approaches used to optimize the image quality. Lung imaging is typically performed in humans using a gas mixture containing 79% perfluoropropane (PFP) or sulphur hexafluoride (SF6 ) and 21% oxygen. In lung diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF), ventilation defects are apparent in regions that the inhaled gas cannot access. 19 F lung images are typically acquired in a single breath-hold, or in a time-resolved, multiple breath fashion. The former provides measurements of the ventilation defect percent (VDP), while the latter provides measurements of gas replacement (ie, fractional ventilation). Finally, preliminary comparisons with other functional lung imaging techniques are discussed, such as Fourier decomposition MRI and hyperpolarized gas MRI. Overall, functional 19 F lung MRI is expected to complement existing proton-based structural imaging techniques, and the combination of structural and functional lung MRI will provide useful outcome measures in the future management of pulmonary diseases in the clinic. Level of Evidence: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:343-354.
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Affiliation(s)
- Marcus J Couch
- Translational Medicine Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Iain K Ball
- Philips Electronics Australia, North Ryde, Sydney, Australia
| | - Tao Li
- Department of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada
| | - Matthew S Fox
- Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Birubi Biman
- Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario, Canada.,Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada.,Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Mitchell S Albert
- Department of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada.,Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada.,Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
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Wiesinger F, Menini A, Solana AB. Looping Star. Magn Reson Med 2018; 81:57-68. [DOI: 10.1002/mrm.27440] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/29/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Florian Wiesinger
- ASL Europe, GE Healthcare; Munich Germany
- Department of Neuroimaging; Institute of Psychiatry, Psychology & Neuroscience, King's College London; London United Kingdom
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Tsuchiya N, Beek EJRV, Ohno Y, Hatabu H, Kauczor HU, Swift A, Vogel-Claussen J, Biederer J, Wild J, Wielpütz MO, Schiebler ML. Magnetic resonance angiography for the primary diagnosis of pulmonary embolism: A review from the international workshop for pulmonary functional imaging. World J Radiol 2018; 10:52-64. [PMID: 29988845 PMCID: PMC6033703 DOI: 10.4329/wjr.v10.i6.52] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/25/2018] [Accepted: 05/30/2018] [Indexed: 02/06/2023] Open
Abstract
Pulmonary contrast enhanced magnetic resonance angiography (CE-MRA) is useful for the primary diagnosis of pulmonary embolism (PE). Many sites have chosen not to use CE-MRA as a first line of diagnostic tool for PE because of the speed and higher efficacy of computerized tomographic angiography (CTA). In this review, we discuss the strengths and weaknesses of CE-MRA and the appropriate imaging scenarios for the primary diagnosis of PE derived from our unique multi-institutional experience in this area. The optimal patient for this test has a low to intermediate suspicion for PE based on clinical decision rules. Patients in extremis are not candidates for this test. Younger women (< 35 years of age) and patients with iodinated contrast allergies are best served by using this modality We discuss the history of the use of this test, recent technical innovations, artifacts, direct and indirect findings for PE, ancillary findings, and the effectiveness (patient outcomes) of CE-MRA for the exclusion of PE. Current outcomes data shows that CE-MRA and NM V/Q scans are effective alternative tests to CTA for the primary diagnosis of PE.
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Affiliation(s)
- Nanae Tsuchiya
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Okinawa 903-0215, Japan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI 53792, United States
| | - Edwin JR van Beek
- Edinburgh Imaging, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Yoshiharu Ohno
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hiroto Hatabu
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA 02115, United States
| | - Hans-Ulrich Kauczor
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg 69120, Germany
| | - Andrew Swift
- Department of Radiology, Royal Hallamshire Hospital, University of Sheffield, Sheffield S10 2JF, United Kingdom
| | - Jens Vogel-Claussen
- Department of Radiology, Carl-Neuberg Strasse 1, Hannover-Gr-Buchholz 30625, Germany
| | - Jürgen Biederer
- Radiology Darmstadt, Gross-Gerau County Hospital, Gross-Gerau 64521, Germany
| | - James Wild
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2JF, United Kingdom
| | - Mark O Wielpütz
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg 69120, Germany
| | - Mark L Schiebler
- Department of Radiology, University of Wisconsin-Madison, Madison, WI 53792, United States
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Yoon SH, Lee C, Park J, Goo JM, Park JY. Gradient-echo-based 3D submillisecond echo time pulmonary MR imaging: a preliminary usability study on clinical and preclinical MR scanners. Br J Radiol 2018; 91:20170796. [PMID: 29569463 DOI: 10.1259/bjr.20170796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE To preliminarily investigate a technical feasibility of a submillisecond echo time concurrent-dephasing-and-excitation (CODE) sequence for pulmonary MRI on clinical and preclinical MR scanners Methods: CODE imaging (echo time, 0.14 ~ 0.18 ms) was performed with American College of Radiology phantom at 3 T, 7 healthy volunteers at 1.5 and 3 T, 10 rabbits at 3 T, and 2 rodents at 9.4 T. Signal-to-noise ratio was compared in phantom. Image quality of human MRI was visually assessed on a 5-point scale for comparison between CODE and conventional lung MRI sequences. Visibility of bronchi, subcentimeter nodules, and MR air-bronchogram were assessed in animal studies. RESULTS In phantom study, signal-to-noise ratio was higher with CODE than with original three-dimensional ultrashort-echo time sequence (106.71 ± 4.32 vs 91.66 ± 3.54; p < 0.001). Image quality of human MRI was better with CODE than with conventional MRI sequences (p ≤ 0.002). Bronchi remained traceable up to the fifth bronchial generation in CODE images in rabbits and rodents. 95.2% of metastatic nodules (diameter, 1.5 ± 0.4 mm) and 93.8% of MR air-bronchogram (diameter, 0.9 ± 0.2 mm) in rabbits. CONCLUSION Submillisecond echo time pulmonary MRI was technically feasible by using CODE on various MR scanners. Advances in knowledge: CODE can be a practical alternative for lung MRI on both clinical and pre-clinical scanners, without challenges of free-induction-decay-based ultrashort-echo time sequences.
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Affiliation(s)
- Soon Ho Yoon
- 1 Department of Radiology, Seoul National University College of Medicine, Seoul National University Hospital , Seoul , South Korea
| | - Chanhee Lee
- 2 Department of Biomedical Engineering, Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University , Suwon-si , South Korea
| | - Jinil Park
- 2 Department of Biomedical Engineering, Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University , Suwon-si , South Korea
| | - Jin Mo Goo
- 1 Department of Radiology, Seoul National University College of Medicine, Seoul National University Hospital , Seoul , South Korea.,3 Institute of Radiation Medicine, Seoul National University Medical Research Center , Seoul , South Korea
| | - Jang-Yeon Park
- 2 Department of Biomedical Engineering, Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University , Suwon-si , South Korea
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Jiang W, Ong F, Johnson KM, Nagle SK, Hope TA, Lustig M, Larson PEZ. Motion robust high resolution 3D free-breathing pulmonary MRI using dynamic 3D image self-navigator. Magn Reson Med 2017; 79:2954-2967. [PMID: 29023975 DOI: 10.1002/mrm.26958] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 08/16/2017] [Accepted: 09/14/2017] [Indexed: 01/01/2023]
Abstract
PURPOSE To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. METHODS Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states. RESULTS Respiratory motion estimation derived from the proposed dynamic 3D self-navigator of 7.5 mm isotropic reconstruction resolution and a temporal resolution of 300 ms was successful for estimating complex respiratory motion patterns. This estimation improved image quality compared to respiratory belt and DC-based navigators. Respiratory motion compensation with soft-gating and respiratory motion-resolved techniques provided good image quality from highly undersampled data in volunteers and clinical patients. CONCLUSION An optimized 3D UTE sequence combined with the proposed reconstruction methods can provide high-resolution motion robust pulmonary MRI. Feasibility was shown in patients who had irregular breathing patterns in which our approach could depict clinically relevant pulmonary pathologies. Magn Reson Med 79:2954-2967, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Wenwen Jiang
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
| | - Frank Ong
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin, Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Scott K Nagle
- Department of Medical Physics, University of Wisconsin, Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Thomas A Hope
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Michael Lustig
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA.,Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Peder E Z Larson
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA.,Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
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41
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Froidevaux R, Weiger M, Brunner DO, Dietrich BE, Wilm BJ, Pruessmann KP. Filling the dead-time gap in zero echo time MRI: Principles compared. Magn Reson Med 2017; 79:2036-2045. [PMID: 28856717 DOI: 10.1002/mrm.26875] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/07/2022]
Abstract
PURPOSE MRI of tissues with short coherence lifetimes T2 or T2* can be performed efficiently using zero echo time (ZTE) techniques such as algebraic ZTE, pointwise encoding time reduction with radial acquisition (PETRA), and water- and fat-suppressed proton projection MRI (WASPI). They share the principal challenge of recovering data in central k-space missed due to an initial radiofrequency dead time. The purpose of this study was to compare the three techniques directly, with a particular focus on their behavior in the presence of ultra-short-lived spins. METHODS The most direct comparison was enabled by aligning acquisition and reconstruction strategies of the three techniques. Image quality and short- T2* performance were investigated using point spread functions, 3D simulations, and imaging of phantom and bone samples with short (<1 ms) and ultra-short (<100 μs) T2*. RESULTS Algebraic ZTE offers favorable properties but is limited to k-space gaps up to approximately three Nyquist dwells. At larger gaps, PETRA enables robust imaging with little compromise in image quality, whereas WASPI may be prone to artifacts from ultra-short T2* species. CONCLUSION For small k-space gaps (<4 dwells) and T2* much larger than the dead time, all techniques enable artifact-free short- T2* MRI. However, if these requirements are not fulfilled careful consideration is needed and PETRA will generally achieve better image quality. Magn Reson Med 79:2036-2045, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Benjamin E Dietrich
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Bertram J Wilm
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Delacoste J, Chaptinel J, Beigelman-Aubry C, Piccini D, Sauty A, Stuber M. A double echo ultra short echo time (UTE) acquisition for respiratory motion-suppressed high resolution imaging of the lung. Magn Reson Med 2017; 79:2297-2305. [PMID: 28856720 DOI: 10.1002/mrm.26891] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/04/2017] [Accepted: 08/08/2017] [Indexed: 12/24/2022]
Abstract
PURPOSE Magnetic resonance imaging is a promising alternative to computed tomography for lung imaging. However, organ motion and poor signal-to-noise ratio, arising from short T2*, impair image quality. To alleviate these issues, a new retrospective gating method was implemented and tested with an ultra-short echo time sequence. METHODS A 3D double-echo ultra-short echo time sequence was used to acquire data during free breathing in ten healthy adult subjects. A self-gating method was used to reconstruct respiratory motion suppressed expiratory and inspiratory images. These images were objectively compared to uncorrected data sets using quantitative end-points (pulmonary vessel sharpness, lung-liver interface definition, signal-to-noise ratio). The method was preliminarily tested in two cystic fibrosis patients who underwent computed tomography. RESULTS Vessel sharpness in expiratory ultra-short echo time data sets with second echo motion detection was significantly higher (13% relative increase) than in uncorrected images while the opposite was observed in inspiratory images. The method was successfully applied in patients and some findings (e.g., hypointense areas) were similar to those from computed tomography. CONCLUSION Free breathing ultra-short echo time was successfully implemented, allowing flexible image reconstruction of two different respiratory states. Objective improvements in image quality were obtained with the new method and initial feasibility in a clinical setting was demonstrated. Magn Reson Med 79:2297-2305, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jean Delacoste
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Jerome Chaptinel
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Catherine Beigelman-Aubry
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Davide Piccini
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.,Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland
| | - Alain Sauty
- Adult CF Multisites Unit, Hospital of Morges, Morges, Switzerland.,Service of Pneumology, Department of Medicine, University Hospital (CHUV), Lausanne, Switzerland
| | - Matthias Stuber
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
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Iwadate Y, Nozaki A, Nunokawa Y, Okuda S, Jinzaki M, Kabasawa H. Silent navigator-triggered silent MRI of the abdomen. Magn Reson Med 2017; 79:2170-2175. [PMID: 28782173 DOI: 10.1002/mrm.26869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 07/15/2017] [Accepted: 07/19/2017] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop and demonstrate the feasibility of a silent respiratory navigator technique for prospective triggering, which was incorporated into a three-dimensional radial zero-echo-time sequence for respiratory navigated silent abdominal imaging. METHODS A nonselective hard excitation radiofrequency pulse was used for the navigator sequence with a derated readout gradient, to avoid generation of high levels of acoustic noise. The acquired navigator signals were processed in real time and used for prospective triggering of the zero-echo-time sequence. Ten healthy volunteers were scanned using the proposed and conventional techniques at 1.5 T. An acoustic noise measurement with A-weighted continuous equivalent sound pressure level was also performed. RESULTS The sound pressure-level values of the background noise, zero-echo-time imaging, conventional, and silent navigators were 68.3, 68.4, 102.5, and 69.4 dBA, respectively. Excellent correlation with correlation coefficients greater than 0.9 was observed between the bellows signals and displacement values calculated from the navigators. Sharpness of the portal vein of both conventional and silent navigator-triggered images was significantly higher than those of nontriggered images. CONCLUSIONS The silent navigator-triggered zero-echo-time technique is feasible and might improve image quality and workflow of abdominal MRI of patients who are prone to acoustic noise. Magn Reson Med 79:2170-2175, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Yuji Iwadate
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
| | - Atsushi Nozaki
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
| | | | - Shigeo Okuda
- Department of Radiology, Keio University School of Medicine, Tokyo, Japan
| | - Masahiro Jinzaki
- Department of Radiology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroyuki Kabasawa
- Global MR Applications and Workflow, GE Healthcare Japan, Hino, Tokyo, Japan
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Hahn AD, Higano NS, Walkup LL, Thomen RP, Cao X, Merhar SL, Tkach JA, Woods JC, Fain SB. Pulmonary MRI of neonates in the intensive care unit using 3D ultrashort echo time and a small footprint MRI system. J Magn Reson Imaging 2016; 45:463-471. [PMID: 27458992 DOI: 10.1002/jmri.25394] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/01/2016] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To determine the feasibility of pulmonary magnetic resonance imaging (MRI) of neonatal lung structures enabled by combining two novel technologies: first, a 3D radial ultrashort echo time (UTE) pulse sequence capable of high spatial resolution full-chest imaging in nonsedated quiet-breathing neonates; and second, a unique, small-footprint 1.5T MRI scanner design adapted for neonatal imaging and installed within the neonatal intensive care unit (NICU). MATERIALS AND METHODS Ten patients underwent MRI within the NICU, in accordance with an approved Institutional Review Board protocol. Five had clinical diagnoses of bronchopulmonary dysplasia (BPD), and five had putatively normal lung function. Pulmonary imaging was performed at 1.5T using 3D radial UTE and standard 3D fast gradient recalled echo (FGRE). Diagnostic quality, presence of motion artifacts, and apparent severity of lung pathology were evaluated by two radiologists. Quantitative metrics were additionally used to evaluate lung parenchymal signal. RESULTS UTE images showed significantly higher signal in lung parenchyma (P < 0.0001) and fewer apparent motion artifacts compared to FGRE (P = 0.046). Pulmonary pathology was more severe in patients diagnosed with BPD relative to controls (P = 0.001). Infants diagnosed with BPD also had significantly higher signal in lung parenchyma, measured using UTE, relative to controls (P = 0.002). CONCLUSION These results demonstrate the technical feasibility of pulmonary MRI in free-breathing, nonsedated infants in the NICU at high, isotropic resolutions approaching that achievable with computed tomography (CT). There is potential for pulmonary MRI to play a role in improving how clinicians understand and manage care of neonatal and pediatric pulmonary diseases. J. Magn. Reson. Imaging 2016. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:463-471.
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Affiliation(s)
- Andrew D Hahn
- Department of Medical Physics, University of Wisconsin, Madison, WI
| | - Nara S Higano
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Physics, Washington University in St. Louis, St. Louis, MO
| | - Laura L Walkup
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Robert P Thomen
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Physics, Washington University in St. Louis, St. Louis, MO
| | - Xuefeng Cao
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Physics, University of Cincinnati, Cincinnati, OH
| | - Stephanie L Merhar
- Perinatal Institute, Division of Neonatology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Jean A Tkach
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Physics, Washington University in St. Louis, St. Louis, MO
| | - Sean B Fain
- Department of Medical Physics, University of Wisconsin, Madison, WI
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Abstract
BACKGROUND One disadvantage of magnetic resonance imaging (MRI) is the inability to adequately image the lungs. Recent advances in hyperpolarized gas technology [e.g., helium-3 ((3)He) and xenon-129 ((129)Xe)] have changed this. However, the required technology is expensive and often needing extra physics or engineering staff. Hence there is considerable interest in developing (1)H (proton)-based MRI approaches that can be readily implemented on standard clinical systems. Thus, the purpose of this work was to compare a newly developed free breathing proton-based MR lung imaging method to that of a standard gadolinium (Gd) based perfusion approach. METHODS Healthy volunteers [10] were scanned using a 3-T MRI with 8 parallel receivers, and a cardiac gated fast spin echo (FSE) sequence. Acquisition was cardiac triggered, with different time delays incremented to cover the entire cardiac cycle. Image k-space was filled rectilinearly. But to reduce motion artefacts k-space was retrospectively sorted using the minimal variance algorithm (MVA), based on physiologic data recorded from both the respiratory bellows and electrocardiogram (ECG). Resorted and reconstructed FSE images were compared to contrast enhanced lung images, obtained following intravenous injection of Gd-DTPA-BMA. RESULTS Biphasic variation in FSE lung signal intensity was observed across the cardiac cycle with a maximal signal change following rapid cardiac ejection (between S and T waves), and following rapid isovolumetric relaxation. A difference image between systolic and diastolic states in the cardiac cycle resulted in images with improved lung contrast to noise ratio (CNR). FSE image intensity was uniform over lung parenchyma while Gd-based enhancement of spoiled gradient recalled echo (SPGR) images showed gravitational dependence. CONCLUSIONS Here we show how 1H-MR images of lung can be obtained during free breathing. The image contrast obtained during this approach is likely the result of flow and oxygen modulation during the cardiac cycle. This free breathing method provides lung images comparable to those obtained using Gd-enhancement. Besides having the advantage of free breathing, this approach doesn't require any Gd-contrast or suffer from methodological problems associated with perfusion (e.g., poor bolus timing). However, as gravitational differences typically observed in lung perfusion are not visible with this method it is not providing exclusive microvascular perfusion information.
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Affiliation(s)
- Sergei I Obruchkov
- 1 Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada ; 2 Imaging Research Centre, St. Joseph's Healthcare, Hamilton, Ontario, Canada ; 3 Department of Electrical and Computer Engineering, 4 McMaster School of Biomedical Engineering, 5 Department of Radiology, McMaster University, Hamilton, Ontario, Canada
| | - Michael D Noseworthy
- 1 Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada ; 2 Imaging Research Centre, St. Joseph's Healthcare, Hamilton, Ontario, Canada ; 3 Department of Electrical and Computer Engineering, 4 McMaster School of Biomedical Engineering, 5 Department of Radiology, McMaster University, Hamilton, Ontario, Canada
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46
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Higano NS, Hahn AD, Tkach JA, Cao X, Walkup LL, Thomen RP, Merhar SL, Kingma PS, Fain SB, Woods JC. Retrospective respiratory self-gating and removal of bulk motion in pulmonary UTE MRI of neonates and adults. Magn Reson Med 2016; 77:1284-1295. [PMID: 26972576 DOI: 10.1002/mrm.26212] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/09/2016] [Accepted: 02/20/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE To implement pulmonary three-dimensional (3D) radial ultrashort echo-time (UTE) MRI in non-sedated, free-breathing neonates and adults with retrospective motion tracking of respiratory and intermittent bulk motion, to obtain diagnostic-quality, respiratory-gated images. METHODS Pulmonary 3D radial UTE MRI was performed at 1.5 tesla (T) during free breathing in neonates and adult volunteers for validation. Motion-tracking waveforms were obtained from the time course of each free induction decay's initial point (i.e., k-space center), allowing for respiratory-gated image reconstructions that excluded data acquired during bulk motion. Tidal volumes were calculated from end-expiration and end-inspiration images. Respiratory rates were calculated from the Fourier transform of the motion-tracking waveform during quiet breathing, with comparison to physiologic prediction in neonates and validation with spirometry in adults. RESULTS High-quality respiratory-gated anatomic images were obtained at inspiration and expiration, with less respiratory blurring at the expense of signal-to-noise for narrower gating windows. Inspiration-expiration volume differences agreed with physiologic predictions (neonates; Bland-Altman bias = 6.2 mL) and spirometric values (adults; bias = 0.11 L). MRI-measured respiratory rates compared well with the observed rates (biases = -0.5 and 0.2 breaths/min for neonates and adults, respectively). CONCLUSIONS Three-dimensional radial pulmonary UTE MRI allows for retrospective respiratory self-gating and removal of intermittent bulk motion in free-breathing, non-sedated neonates and adults. Magn Reson Med 77:1284-1295, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Nara S Higano
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Andrew D Hahn
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jean A Tkach
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Xuefeng Cao
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Laura L Walkup
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Robert P Thomen
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Stephanie L Merhar
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul S Kingma
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Sean B Fain
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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47
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Ultrashort echo time and zero echo time MRI at 7T. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 29:359-70. [PMID: 26702940 DOI: 10.1007/s10334-015-0509-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/23/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Zero echo time (ZTE) and ultrashort echo time (UTE) pulse sequences for MRI offer unique advantages of being able to detect signal from rapidly decaying short-T2 tissue components. In this paper, we applied 3D ZTE and UTE pulse sequences at 7T to assess differences between these methods. MATERIALS AND METHODS We matched the ZTE and UTE pulse sequences closely in terms of readout trajectories and image contrast. Our ZTE used the water- and fat-suppressed solid-state proton projection imaging method to fill the center of k-space. Images from healthy volunteers obtained at 7T were compared qualitatively, as well as with SNR and CNR measurements for various ultrashort, short, and long-T2 tissues. RESULTS We measured nearly identical contrast-to-noise and signal-to-noise ratios (CNR/SNR) in similar scan times between the two approaches for ultrashort, short, and long-T2 components in the brain, knee and ankle. In our protocol, we observed gradient fidelity artifacts in UTE, and our chosen flip angle and readout also resulted in shading artifacts in ZTE due to inadvertent spatial selectivity. These can be corrected by advanced reconstruction methods or with different chosen protocol parameters. CONCLUSION The applied ZTE and UTE pulse sequences achieved similar contrast and SNR efficiency for volumetric imaging of ultrashort-T2 components. Key differences include that ZTE is limited to volumetric imaging, but has substantially reduced acoustic noise levels during the scan. Meanwhile, UTE has higher acoustic noise levels and greater sensitivity to gradient fidelity, but offers more flexibility in image contrast and volume selection.
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48
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Jang H, Wiens CN, McMillan AB. Ramped hybrid encoding for improved ultrashort echo time imaging. Magn Reson Med 2015; 76:814-25. [PMID: 26381890 DOI: 10.1002/mrm.25977] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/15/2022]
Abstract
PURPOSE We propose a new acquisition to minimize the per-excitation encoding duration and improve the imaging capability for short T2 * species. METHODS In the proposed ramped hybrid encoding (RHE) technique, gradients are applied before the radiofrequency (RF) pulse as in pointwise encoding time reduction with radial acquisition (PETRA) and zero echo time (ZTE) imaging. However, in RHE, gradients are rapidly ramped after RF excitation to the maximum amplitude to minimize encoding duration. To acquire central k-space data not measured during RF deadtime, RHE uses a hybrid encoding scheme similar to PETRA. A new gradient calibration method based on single-point imaging was developed to estimate the k-space trajectory and enable robust and high quality reconstruction. RESULTS RHE enables a shorter per-excitation encoding time and provides the highest spatial resolution among ultrashort T2 * imaging methods. In phantom and in vivo experiments, RHE exhibited robust imaging with negligible chemical shift or blurriness caused by T2 * decay and unwanted slice selection. CONCLUSION RHE allows the shortest per-excitation encoding time for ultrashort T2 * imaging, which alleviates the impact of fast T2 * decay occurring during encoding, and enables improved spatial resolution. Magn Reson Med 76:814-825, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA.,Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin, USA
| | - Curtis N Wiens
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | - Alan B McMillan
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
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49
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Burris NS, Johnson KM, Larson PEZ, Hope MD, Nagle SK, Behr SC, Hope TA. Detection of Small Pulmonary Nodules with Ultrashort Echo Time Sequences in Oncology Patients by Using a PET/MR System. Radiology 2015; 278:239-46. [PMID: 26133050 DOI: 10.1148/radiol.2015150489] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To investigate the utility of a free-breathing ultrashort echo time (UTE) sequence for the evaluation of small pulmonary nodules in oncology patients by using a hybrid positron emission tomography (PET)/magnetic resonance (MR) imaging system and to compare the nodule detection rate between UTE and a conventional three-dimensional gradient-recalled-echo (GRE) technique. MATERIALS AND METHODS In this HIPAA-compliant, institutional review board-approved prospective study, 82 pulmonary nodules were identified in eight patients with extrathoracic malignancies. Patients underwent free-breathing UTE and dual-echo three-dimensional GRE imaging of the lungs in a hybrid PET/MR imaging unit immediately after clinical PET/computed tomography (CT). CT was considered the reference standard for nodule detection. Two reviewers identified nodules and obtained measurements on MR images. The McNemar test was used to evaluate differences in nodule detection rate between MR techniques, and interrater agreement was assessed by using Bland-Altman plots. RESULTS Mean nodule diameter ± standard deviation was 6.2 mm ± 2.7 (range, 3-17 mm). The detection rate was higher for UTE imaging than for dual-echo GRE imaging for nodules of at least 4 mm (82% vs 34%, respectively; P < .001), with the largest difference in detection noted in the 4-8-mm nodule group (79% vs 21%, P < .001). UTE imaging displayed a higher detection rate than dual-echo GRE imaging for nodules without fluorodeoxyglucose avidity (68% vs 22%, respectively; P < .001). Interrater reliability of nodule detection with MR imaging was high (κ = 0.90 for UTE imaging and κ = 0.92 for dual-echo GRE imaging). CONCLUSION A free-breathing UTE sequence has high sensitivity for the detection of small pulmonary nodules (4-8 mm) and outperformed a three-dimensional dual-echo GRE technique for the detection of small, non-fluorodeoxyglucose-avid nodules.
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Affiliation(s)
- Nicholas S Burris
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Kevin M Johnson
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Peder E Z Larson
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Michael D Hope
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Scott K Nagle
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Spencer C Behr
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
| | - Thomas A Hope
- From the Department of Radiology (N.S.B., P.E.Z.L., M.D.H., S.C.B., T.A.H.), University of California-San Francisco, 505 Parnassus Ave, Box 0628, San Francisco, CA 94143-0628; Departments of Medical Physics (K.M.J., S.K.N.), Radiology (S.K.N.), and Pediatrics (S.K.N.), University of Wisconsin, Madison, Wis; and UCSF Graduate Program in Bioengineering, University of California-Berkeley, Berkeley, Calif (P.E.Z.L.)
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50
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Rychert KM, Zhu G, Kmiec MM, Nemani VK, Williams BB, Flood AB, Swartz HM, Gimi B. Imaging tooth enamel using zero echo time (ZTE) magnetic resonance imaging. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2015; 9417:94171I. [PMID: 25914509 PMCID: PMC4405678 DOI: 10.1117/12.2083995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In an event where many thousands of people may have been exposed to levels of radiation that are sufficient to cause the acute radiation syndrome, we need technology that can estimate the absorbed dose on an individual basis for triage and meaningful medical decision making. Such dose estimates may be achieved using in vivo electron paramagnetic resonance (EPR) tooth biodosimetry, which measures the number of persistent free radicals that are generated in tooth enamel following irradiation. However, the accuracy of dose estimates may be impacted by individual variations in teeth, especially the amount and distribution of enamel in the inhomogeneous sensitive volume of the resonator used to detect the radicals. In order to study the relationship between interpersonal variations in enamel and EPR-based dose estimates, it is desirable to estimate these parameters nondestructively and without adding radiation to the teeth. Magnetic Resonance Imaging (MRI) is capable of acquiring structural and biochemical information without imparting additional radiation, which may be beneficial for many EPR dosimetry studies. However, the extremely short T2 relaxation time in tooth structures precludes tooth imaging using conventional MRI methods. Therefore, we used zero echo time (ZTE) MRI to image teeth ex vivo to assess enamel volumes and spatial distributions. Using these data in combination with the data on the distribution of the transverse radio frequency magnetic field from electromagnetic simulations, we then can identify possible sources of variations in radiation-induced signals detectable by EPR. Unlike conventional MRI, ZTE applies spatial encoding gradients during the RF excitation pulse, thereby facilitating signal acquisition almost immediately after excitation, minimizing signal loss from short T2 relaxation times. ZTE successfully provided volumetric measures of tooth enamel that may be related to variations that impact EPR dosimetry and facilitate the development of analytical procedures for individual dose estimates.
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Affiliation(s)
- Kevin M. Rychert
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Gang Zhu
- MRI Division, Bruker BioSpin Corporation, 15 Fortune Drive, Billerica, MA 01821
| | - Maciej M. Kmiec
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Venkata K. Nemani
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Benjamin B. Williams
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Ann Barry Flood
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Harold M. Swartz
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Barjor Gimi
- Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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