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Gao Y, Xiong Z, Shan S, Liu Y, Rong P, Li M, Wilman AH, Pike GB, Liu F, Sun H. Plug-and-Play latent feature editing for orientation-adaptive quantitative susceptibility mapping neural networks. Med Image Anal 2024; 94:103160. [PMID: 38552528 DOI: 10.1016/j.media.2024.103160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 03/09/2024] [Accepted: 03/23/2024] [Indexed: 04/16/2024]
Abstract
Quantitative susceptibility mapping (QSM) is a post-processing technique for deriving tissue magnetic susceptibility distribution from MRI phase measurements. Deep learning (DL) algorithms hold great potential for solving the ill-posed QSM reconstruction problem. However, a significant challenge facing current DL-QSM approaches is their limited adaptability to magnetic dipole field orientation variations during training and testing. In this work, we propose a novel Orientation-Adaptive Latent Feature Editing (OA-LFE) module to learn the encoding of acquisition orientation vectors and seamlessly integrate them into the latent features of deep networks. Importantly, it can be directly Plug-and-Play (PnP) into various existing DL-QSM architectures, enabling reconstructions of QSM from arbitrary magnetic dipole orientations. Its effectiveness is demonstrated by combining the OA-LFE module into our previously proposed phase-to-susceptibility single-step instant QSM (iQSM) network, which was initially tailored for pure-axial acquisitions. The proposed OA-LFE-empowered iQSM, which we refer to as iQSM+, is trained in a simulated-supervised manner on a specially-designed simulation brain dataset. Comprehensive experiments are conducted on simulated and in vivo human brain datasets, encompassing subjects ranging from healthy individuals to those with pathological conditions. These experiments involve various MRI platforms (3T and 7T) and aim to compare our proposed iQSM+ against several established QSM reconstruction frameworks, including the original iQSM. The iQSM+ yields QSM images with significantly improved accuracies and mitigates artifacts, surpassing other state-of-the-art DL-QSM algorithms. The PnP OA-LFE module's versatility was further demonstrated by its successful application to xQSM, a distinct DL-QSM network for dipole inversion. In conclusion, this work introduces a new DL paradigm, allowing researchers to develop innovative QSM methods without requiring a complete overhaul of their existing architectures.
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Affiliation(s)
- Yang Gao
- School of Computer Science and Engineering, Central South University, Changsha, China.
| | - Zhuang Xiong
- School of Electrical Engineering and Computer Science, University of Queensland, Brisbane, Australia
| | - Shanshan Shan
- State Key Laboratory of Radiation, Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, China
| | - Yin Liu
- Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Pengfei Rong
- Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Min Li
- School of Computer Science and Engineering, Central South University, Changsha, China
| | - Alan H Wilman
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada
| | - G Bruce Pike
- Departments of Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Feng Liu
- School of Electrical Engineering and Computer Science, University of Queensland, Brisbane, Australia
| | - Hongfu Sun
- School of Electrical Engineering and Computer Science, University of Queensland, Brisbane, Australia; School of Engineering, University of Newcastle, Newcastle, Australia
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2
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De A, Grenier J, Wilman AH. Simultaneous time-of-flight MR angiography and quantitative susceptibility mapping with key time-of-flight features. NMR Biomed 2024; 37:e5079. [PMID: 38054247 DOI: 10.1002/nbm.5079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 10/30/2023] [Accepted: 11/05/2023] [Indexed: 12/07/2023]
Abstract
A technique for combined time-of-flight (TOF) MR angiography (MRA) and quantitative susceptibility mapping (QSM) was developed with key features of standard three-dimensional (3D) TOF acquisitions, including multiple overlapping thin slab acquisition (MOTSA), ramped RF excitation, and venous saturation. The developed triple-echo 3D TOF-QSM sequence enabled TOF-MRA, susceptibility-weighted imaging (SWI), QSM, and R2* mapping. The effects of ramped RF, resolution, flip angle, venous saturation, and MOTSA were studied on QSM. Six volunteers were scanned at 3 T with the developed sequence, conventional TOF-MRA, and conventional SWI. Quantitative comparison of susceptibility values on QSM and normalized arterial and venous vessel-to-background contrasts on TOF and SWI were performed. The ramped RF excitation created an inherent phase variation in the raw phase. A generic correction factor was computed to remove the phase variation to obtain QSM without artifacts from the TOF-QSM sequence. No statistically significant difference was observed between the developed and standard QSM sequence for susceptibility values. However, maintaining standard TOF features led to compromises in signal-to-noise ratio for QSM and SWI, arising from the use of MOTSA rather than one large 3D slab, higher TOF spatial resolution, increased TOF background suppression due to larger flip angles, and reduced venous signal from venous saturation. In terms of vessel contrast, veins showed higher normalized contrast on SWI derived from TOF-QSM than the standard SWI sequence. While fast flowing arteries had reduced contrast compared with standard TOF-MRA, no statistical difference was observed for slow flowing arteries. Arterial contrast differences largely arise from the longer TR used in TOF-QSM over standard TOF-MRA to accommodate additional later echoes for SWI. In conclusion, although the sequence has a longer TR and slightly lower arterial contrast, provided an adequate correction is made for ramped RF excitation effects on phase, QSM may be performed from a multiecho sequence that includes all key TOF features, thus enabling simultaneous TOF-MRA, SWI, QSM, and R2* map computation.
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Affiliation(s)
- Ashmita De
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Justin Grenier
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada
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Naji N, Gee M, Jickling GC, Emery DJ, Saad F, McCreary CR, Smith EE, Camicioli R, Wilman AH. Quantifying cerebral microbleeds using quantitative susceptibility mapping from magnetization-prepared rapid gradient-echo. NMR Biomed 2024:e5139. [PMID: 38465729 DOI: 10.1002/nbm.5139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 03/12/2024]
Abstract
T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) is commonly included in brain studies for structural imaging using magnitude images; however, its phase images can provide an opportunity to assess microbleed burden using quantitative susceptibility mapping (QSM). This potential application for MPRAGE-based QSM was evaluated using in vivo and simulated measurements. Possible factors affecting image quality were also explored. Detection sensitivity was evaluated against standard multiecho gradient echo (MEGE) QSM using 3-T in vivo data of 15 subjects with a combined total of 108 confirmed microbleeds. The two methods were compared based on the microbleed size and susceptibility measurements. In addition, simulations explored the detection sensitivity of MPRAGE-QSM at different representative magnetic field strengths and echo times using microbleeds of different size, susceptibility, and location. Results showed that in vivo microbleeds appeared to be smaller (× 0.54) and of higher mean susceptibility (× 1.9) on MPRAGE-QSM than on MEGE-QSM, but total susceptibility estimates were in closer agreement (slope: 0.97, r2 : 0.94), and detection sensitivity was comparable. In simulations, QSM at 1.5 T had a low contrast-to-noise ratio that obscured the detection of many microbleeds. Signal-to-noise ratio (SNR) levels at 3 T and above resulted in better contrast and increased detection. The detection rates for microbleeds of minimum one-voxel diameter and 0.4-ppm susceptibility were 0.55, 0.80, and 0.88 at SNR levels of 1.5, 3, and 7 T, respectively. Size and total susceptibility estimates were more consistent than mean susceptibility estimates, which showed size-dependent underestimation. MPRAGE-QSM provides an opportunity to detect and quantify the size and susceptibility of microbleeds of at least one-voxel diameter at B0 of 3 T or higher with no additional time cost, when standard T2 *-weighted images are not available or have inadequate spatial resolution. The total susceptibility measure is more robust against sequence variations and might allow combining data from different protocols.
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Affiliation(s)
- Nashwan Naji
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Myrlene Gee
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| | - Glen C Jickling
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| | - Derek J Emery
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Feryal Saad
- Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Cheryl R McCreary
- Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
| | - Eric E Smith
- Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Richard Camicioli
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
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Zhu Z, Naji N, Esfahani JH, Snyder J, Seres P, Emery DJ, Noga M, Blevins G, Smyth P, Wilman AH. MR Susceptibility Separation for Quantifying Lesion Paramagnetic and Diamagnetic Evolution in Relapsing-Remitting Multiple Sclerosis. J Magn Reson Imaging 2024. [PMID: 38308397 DOI: 10.1002/jmri.29266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Multiple sclerosis (MS) lesion evolution may involve changes in diamagnetic myelin and paramagnetic iron. Conventional quantitative susceptibility mapping (QSM) can provide net susceptibility distribution, but not the discrete paramagnetic and diamagnetic components. PURPOSE To apply susceptibility separation (χ separation) to follow lesion evolution in MS with comparison to R2 */R2 ' /QSM. STUDY TYPE Longitudinal, prospective. SUBJECTS Twenty relapsing-remitting MS subjects (mean age: 42.5 ± 9.4 years, 13 females; mean years of symptoms: 4.3 ± 1.4 years). FIELD STRENGTH/SEQUENCE Three-dimensional multiple echo gradient echo (QSM and R2 * mapping), two-dimensional dual echo fast spin echo (R2 mapping), T2 -weighted fluid attenuated inversion recovery, and T1-weighted magnetization prepared gradient echo sequences at 3 T. ASSESSMENT Data were analyzed from two scans separated by a mean interval of 14.4 ± 2.0 months. White matter lesions on fluid-attenuated inversion recovery were defined by an automatic pipeline, then manually refined (by ZZ/AHW, 3/25 years' experience in MRI), and verified by a radiologist (MN, 25 years' experience in MS). Susceptibility separation yielded the paramagnetic and diamagnetic susceptibility content of each voxel. Lesions were classified into four groups based on the variation of QSM/R2 * or separated into positive/negative components from χ separation. STATISTICAL TESTS Two-sample paired t tests for assessment of longitudinal differences. Spearman correlation coefficients to assess associations between χ separation and R2 */R2 ' /QSM. Significant level: P < 0.005. RESULTS A total of 183 lesions were quantified. Categorizing lesions into groups based on χ separation demonstrated significant annual changes in QSM//R2 */R2 ' . When lesions were grouped based on changes in QSM and R2 *, both changing in unison yielded a significant dominant paramagnetic variation and both opposing yielded a dominant diamagnetic variation. Significant Spearman correlation coefficients were found between susceptibility-sensitive MRI indices and χ separation. DATA CONCLUSION Susceptibility separation changes in MS lesions may distinguish and quantify paramagnetic and diamagnetic evolution, potentially providing additional insight compared to R2 * and QSM alone. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Ziyan Zhu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Nashwan Naji
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Javad Hamidi Esfahani
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Jeff Snyder
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Peter Seres
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Derek J Emery
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Michelle Noga
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Gregg Blevins
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Penelope Smyth
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
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Zhuang C, Chen B, Wu S, Xu L, Zhang X, Zheng X, Chen Y, Geng Y, Guan J, Lin Y, Wilman AH, Wu R. Repurposing of the PET Probe Prototype PiB for Label and Radiation-Free CEST MRI Molecular Imaging of Amyloid. ACS Chem Neurosci 2023; 14:4344-4351. [PMID: 38061891 PMCID: PMC10741654 DOI: 10.1021/acschemneuro.3c00539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Positron emission tomography (PET) probes are specific and sensitive while suffering from radiation risk. It is worthwhile to explore the chemical emission saturation transfer (CEST) effects of the probe prototypes and repurpose them for CEST imaging to avoid radiation. In this study, we used 11C-PiB as an example of a PET probe for detecting amyloid and tested the feasibility of repurposing this PET probe prototype, PiB, for CEST imaging. After optimizing the parameters through preliminary phantom experiments, we used APP/PS1 transgenic mice and age-matched C57 mice for in vivo CEST magnetic resonance imaging (MRI) of amyloid. Furthermore, the pathological assessment was conducted on the same brain slices to evaluate the correlation between the CEST MRI signal abnormality and β-amyloid deposition detected by immunohistochemical staining. In our results, the Z-spectra revealed an apparent CEST effect that peaked at approximately 6 ppm. APP/PS1 mice as young as 9 months injected with PiB showed a significantly higher CEST effect compared to the control groups. The hyperintense region was correlated with the Aβ deposition shown by pathological staining. In conclusion, repurposing the PET probe prototype for CEST MRI imaging is feasible and enables label- and radiation-free detection of the amyloid while maintaining the sensitivity and specificity of the ligand. This study opens the door to developing CEST probes based on PET probe prototypes.
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Affiliation(s)
- Caiyu Zhuang
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Department
of Radiology, First Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Beibei Chen
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Shuohua Wu
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Liang Xu
- Department
of Medical Imaging, Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen 518107, China
| | - Xiaolei Zhang
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Xinhui Zheng
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yue Chen
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yiqun Geng
- Laboratory
of Molecular Pathology, Shantou University
Medical College, Shantou 515041, China
| | - Jitian Guan
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
| | - Yan Lin
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Provincial
Key Laboratory for Breast Cancer Diagnosis and Treatment, Shantou 515041, China
| | - Alan H. Wilman
- The Department
of Biomedical Engineering, University of
Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Renhua Wu
- Department
of Radiology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China
- Provincial
Key Laboratory for Breast Cancer Diagnosis and Treatment, Shantou 515041, China
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6
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Nathoo N, Gee M, Nelles K, Burt J, Sun H, Seres P, Wilman AH, Beaulieu C, Ba F, Camicioli R. Quantitative Susceptibility Mapping Changes Relate to Gait Issues in Parkinson's Disease. Can J Neurol Sci 2023; 50:853-860. [PMID: 36351571 DOI: 10.1017/cjn.2022.316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Quantitative susceptibility mapping (QSM) demonstrates elevated iron content in Parkinson's disease (PD) patients within the basal ganglia, though it has infrequently been studied in relation to gait difficulties including freezing of gait (FOG). Our purpose was to relate QSM of basal ganglia and extra-basal ganglia structures with qualitative and quantitative gait measures in PD. METHODS This case-control study included PD and cognitively unimpaired (CU) participants from the Comprehensive Assessment of Neurodegeneration and Dementia study. Whole brain QSM was acquired at 3T. Region of interests (ROIs) were drawn blinded manually in the caudate nucleus, putamen, globus pallidus, pulvinar nucleus of the thalamus, red nucleus, substantia nigra, and dentate nucleus. Susceptibilities of ROIs were compared between PD and CU. Items from the FOG questionnaire and quantitative gait measures from PD participants were compared to susceptibilities. RESULTS Twenty-nine participants with PD and 27 CU participants were included. There was no difference in susceptibility values in any ROI when comparing CU versus PD (p > 0.05 for all). PD participants with gait impairment (n = 23) had significantly higher susceptibility in the putamen (p = 0.008), red nucleus (p = 0.01), and caudate nucleus (p = 0.03) compared to those without gait impairment (n = 6). PD participants with FOG (n = 12) had significantly higher susceptibility in the globus pallidus (p = 0.03) compared to those without FOG (n = 17). Among quantitative gait measures, only stride time variability was significantly different between those with and without FOG (p = 0.04). CONCLUSION Susceptibilities in basal ganglia and extra-basal ganglia structures are related to qualitative measures of gait impairment and FOG in PD.
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Affiliation(s)
- Nabeela Nathoo
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Myrlene Gee
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Krista Nelles
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Jacqueline Burt
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Hongfu Sun
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Fang Ba
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Richard Camicioli
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
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7
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Kushol R, Parnianpour P, Wilman AH, Kalra S, Yang YH. Effects of MRI scanner manufacturers in classification tasks with deep learning models. Sci Rep 2023; 13:16791. [PMID: 37798392 PMCID: PMC10556074 DOI: 10.1038/s41598-023-43715-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 09/27/2023] [Indexed: 10/07/2023] Open
Abstract
Deep learning has become a leading subset of machine learning and has been successfully employed in diverse areas, ranging from natural language processing to medical image analysis. In medical imaging, researchers have progressively turned towards multi-center neuroimaging studies to address complex questions in neuroscience, leveraging larger sample sizes and aiming to enhance the accuracy of deep learning models. However, variations in image pixel/voxel characteristics can arise between centers due to factors including differences in magnetic resonance imaging scanners. Such variations create challenges, particularly inconsistent performance in machine learning-based approaches, often referred to as domain shift, where the trained models fail to achieve satisfactory or improved results when confronted with dissimilar test data. This study analyzes the performance of multiple disease classification tasks using multi-center MRI data obtained from three widely used scanner manufacturers (GE, Philips, and Siemens) across several deep learning-based networks. Furthermore, we investigate the efficacy of mitigating scanner vendor effects using ComBat-based harmonization techniques when applied to multi-center datasets of 3D structural MR images. Our experimental results reveal a substantial decline in classification performance when models trained on one type of scanner manufacturer are tested with data from different manufacturers. Moreover, despite applying ComBat-based harmonization, the harmonized images do not demonstrate any noticeable performance enhancement for disease classification tasks.
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Affiliation(s)
- Rafsanjany Kushol
- Department of Computing Science, University of Alberta, Edmonton, Canada.
| | - Pedram Parnianpour
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Departments of Radiology and Diagnostic Imaging and Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Sanjay Kalra
- Department of Computing Science, University of Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Yee-Hong Yang
- Department of Computing Science, University of Alberta, Edmonton, Canada
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8
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Kushol R, Wilman AH, Kalra S, Yang YH. DSMRI: Domain Shift Analyzer for Multi-Center MRI Datasets. Diagnostics (Basel) 2023; 13:2947. [PMID: 37761314 PMCID: PMC10527875 DOI: 10.3390/diagnostics13182947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 09/05/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
In medical research and clinical applications, the utilization of MRI datasets from multiple centers has become increasingly prevalent. However, inherent variability between these centers presents challenges due to domain shift, which can impact the quality and reliability of the analysis. Regrettably, the absence of adequate tools for domain shift analysis hinders the development and validation of domain adaptation and harmonization techniques. To address this issue, this paper presents a novel Domain Shift analyzer for MRI (DSMRI) framework designed explicitly for domain shift analysis in multi-center MRI datasets. The proposed model assesses the degree of domain shift within an MRI dataset by leveraging various MRI-quality-related metrics derived from the spatial domain. DSMRI also incorporates features from the frequency domain to capture low- and high-frequency information about the image. It further includes the wavelet domain features by effectively measuring the sparsity and energy present in the wavelet coefficients. Furthermore, DSMRI introduces several texture features, thereby enhancing the robustness of the domain shift analysis process. The proposed framework includes visualization techniques such as t-SNE and UMAP to demonstrate that similar data are grouped closely while dissimilar data are in separate clusters. Additionally, quantitative analysis is used to measure the domain shift distance, domain classification accuracy, and the ranking of significant features. The effectiveness of the proposed approach is demonstrated using experimental evaluations on seven large-scale multi-site neuroimaging datasets.
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Affiliation(s)
- Rafsanjany Kushol
- Department of Computing Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Alan H. Wilman
- Departments of Radiology and Diagnostic Imaging and Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Sanjay Kalra
- Department of Computing Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Yee-Hong Yang
- Department of Computing Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
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9
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Kushol R, Luk CC, Dey A, Benatar M, Briemberg H, Dionne A, Dupré N, Frayne R, Genge A, Gibson S, Graham SJ, Korngut L, Seres P, Welsh RC, Wilman AH, Zinman L, Kalra S, Yang YH. SF2Former: Amyotrophic lateral sclerosis identification from multi-center MRI data using spatial and frequency fusion transformer. Comput Med Imaging Graph 2023; 108:102279. [PMID: 37573646 DOI: 10.1016/j.compmedimag.2023.102279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 07/17/2023] [Accepted: 07/22/2023] [Indexed: 08/15/2023]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a complex neurodegenerative disorder characterized by motor neuron degeneration. Significant research has begun to establish brain magnetic resonance imaging (MRI) as a potential biomarker to diagnose and monitor the state of the disease. Deep learning has emerged as a prominent class of machine learning algorithms in computer vision and has shown successful applications in various medical image analysis tasks. However, deep learning methods applied to neuroimaging have not achieved superior performance in classifying ALS patients from healthy controls due to insignificant structural changes correlated with pathological features. Thus, a critical challenge in deep models is to identify discriminative features from limited training data. To address this challenge, this study introduces a framework called SF2Former, which leverages the power of the vision transformer architecture to distinguish ALS subjects from the control group by exploiting the long-range relationships among image features. Additionally, spatial and frequency domain information is combined to enhance the network's performance, as MRI scans are initially captured in the frequency domain and then converted to the spatial domain. The proposed framework is trained using a series of consecutive coronal slices and utilizes pre-trained weights from ImageNet through transfer learning. Finally, a majority voting scheme is employed on the coronal slices of each subject to generate the final classification decision. The proposed architecture is extensively evaluated with multi-modal neuroimaging data (i.e., T1-weighted, R2*, FLAIR) using two well-organized versions of the Canadian ALS Neuroimaging Consortium (CALSNIC) multi-center datasets. The experimental results demonstrate the superiority of the proposed strategy in terms of classification accuracy compared to several popular deep learning-based techniques.
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Affiliation(s)
- Rafsanjany Kushol
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada.
| | - Collin C Luk
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada; Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Avyarthana Dey
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael Benatar
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Hannah Briemberg
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Annie Dionne
- Axe Neurosciences, CHU de Québec, Université Laval, Québec, QC, Canada; Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Nicolas Dupré
- Axe Neurosciences, CHU de Québec, Université Laval, Québec, QC, Canada; Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Richard Frayne
- Departments of Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Angela Genge
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Summer Gibson
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Simon J Graham
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Lawrence Korngut
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Peter Seres
- Departments of Biomedical Engineering and Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada
| | - Robert C Welsh
- Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
| | - Alan H Wilman
- Departments of Biomedical Engineering and Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada
| | - Lorne Zinman
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Sanjay Kalra
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada; Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Yee-Hong Yang
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada
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10
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Snyder J, Seres P, Wilman AH. Signal-to-noise ratio penalties from a loss of stimulated echoes when using slab-selective excitation in three-dimensional fast spin echo imaging with long echo trains. NMR Biomed 2023; 36:e4881. [PMID: 36427186 DOI: 10.1002/nbm.4881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
Three-dimensional fast spin echo imaging with long echo trains combines high resolution with reasonable acquisition times and reduced specific absorption rate due to low refocusing flip angles. Typically, an entire volume is encoded (nonselective excitation) or localization can be performed with slab select excitation, which uses a long 90° pulse for precise localization, followed by a preliminary nonselective 180° pulse bounded by spoiler gradients to destroy signal outside of the volume of interest. Subsequent flip angles in the train are nonselective and identical between the two methods. The inclusion of the initial selective pulse and spoiler gradients results in a signal-to-noise ratio (SNR) penalty for slab selection, beyond the slice-averaging dependence, arising from a loss of stimulated echoes. SNR differences are explored using Bloch equation simulations of a T2-weighted 96 echo train sequence with varying parameters including T2, T1, and B1+ and compared with phantom and in vivo brain, neck, and knee experiments. In vivo SNR measurements in the three regions showed a maximum decrease of selective SNR by 29% (gastrocnemius muscle), 25% (pons), and 22% (globus pallidus), despite similar experimental parameters to nonselective experiments. Decreased SNR was compounded by B1+ variation affecting prescribed flip angles with further smaller reductions with T2 and T1 times. In conclusion, the elimination of coherences via the preliminary nominal 180° pulse and spoiler gradients in addition to the extended echo timing from the long excitation pulse resulted in a reduction in SNR compared with the nonselective case. Consideration of the required SNR and chosen anatomy as well as sequence restrictions should be weighed before choosing slab-selective excitation.
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Affiliation(s)
- Jeff Snyder
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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11
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Adel SAA, Treit S, Abd Wahab W, Little G, Schmitt L, Wilman AH, Beaulieu C, Gross DW. Longitudinal hippocampal diffusion-weighted imaging and T2 relaxometry demonstrate regional abnormalities which are stable and predict subfield pathology in temporal lobe epilepsy. Epilepsia Open 2023; 8:100-112. [PMID: 36461649 PMCID: PMC9977756 DOI: 10.1002/epi4.12679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/15/2022] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE High-resolution (1 mm isotropic) diffusion tensor imaging (DTI) of the hippocampus in temporal lobe epilepsy (TLE) patients has shown patterns of hippocampal subfield diffusion abnormalities, which were consistent with hippocampal sclerosis (HS) subtype on surgical histology. The objectives of this longitudinal imaging study were to determine the stability of focal hippocampus diffusion changes over time in TLE patients, compare diffusion and quantitative T2 abnormalities of the sclerotic hippocampus, and correlate presurgical mean diffusivity (MD) and T2 maps with postsurgical histology. METHODS Nineteen TLE patients and 19 controls underwent two high-resolution (1 mm isotropic) DTI and 1.1 × 1.1 × 1 mm3 T2 relaxometry scans (in a subset of 16 TLE patients and 9 controls) of the hippocampus at 3T, with a 2.6 ± 0.8 year inter-scan interval. Within-participant hippocampal volume, MD and T2 were compared between the scans. Contralateral hippocampal changes 2.3 ± 1.0 years after surgery and ipsilateral preoperative MD maps versus postoperative subfield histopathology were evaluated in eight patients who underwent surgical resection of the hippocampus. RESULTS Reduced volume and elevated MD and T2 of sclerotic hippocampi remained unchanged between longitudinal scans. Focal regions of elevated MD and T2 in bilateral hippocampi of HS TLE were detected consistently at both scans. Regions of high MD and T2 correlated and remained consistent over time. Volume, MD, and T2 remained unchanged in postoperative contralateral hippocampus. Regional elevations of MD identified subfield neuron loss on postsurgical histology with 88% sensitivity and 88% specificity. Focal T2 elevations identified subfield neuron loss with 75% sensitivity and 88% specificity. SIGNIFICANCE Diffusion and T2 abnormalities in ipsilateral and contralateral hippocampi remained unchanged between the scans suggesting permanent microstructural alterations. MD and T2 demonstrated good sensitivity and specificity to detect hippocampal subfield neuron loss on postsurgical histology, supporting the potential that high-resolution hippocampal DTI and T2 could be used to diagnose HS subtype before surgery.
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Affiliation(s)
- Seyed Amir Ali Adel
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah Treit
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Wasan Abd Wahab
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| | - Graham Little
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Department of Computer Science, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laura Schmitt
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Donald W Gross
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
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12
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Snyder J, Seres P, Stobbe RW, Grenier JG, Smyth P, Blevins G, Wilman AH. Inline dual-echo T2 quantification in brain using a fast mapping reconstruction technique. NMR Biomed 2023; 36:e4811. [PMID: 35934839 DOI: 10.1002/nbm.4811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 07/06/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
T2 mapping from 2D proton density and T2-weighted images (PD-T2) using Bloch equation simulations can be time consuming and introduces a latency between image acquisition and T2 map production. A fast T2 mapping reconstruction method is investigated and compared with a previous modeling approach to reduce computation time and allow inline T2 maps on the MRI console. Brain PD-T2 images from five multiple sclerosis patients were used to compare T2 map reconstruction times between the new subtraction method and the Euclidean norm minimization technique. Bloch equation simulations were used to create the lookup table for decay curve matching in both cases. Agreement of the two techniques used Bland-Altman analysis for investigating individual subsets of data and all image points in the five volumes (meta-analysis). The subtraction method resulted in an average reduction of computation time for single slices from 134 s (minimization method) to 0.44 s. Comparing T2 values between the subtraction and minimization methods resulted in a confidence interval ranging from -0.06 to 0.06 ms (95% of values were within ± 0.06 ms between the techniques). Using identical reconstruction code based on the subtraction method, inline T2 maps were produced from PD-T2 images directly on the scanner console. The excellent agreement between the two methods permits the subtraction technique to be interchanged with the previous method, reducing computation time and allowing inline T2 map reconstruction based on Bloch simulations directly on the scanner.
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Affiliation(s)
- Jeff Snyder
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Robert W Stobbe
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Justin G Grenier
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Penelope Smyth
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, Canada
| | - Gregg Blevins
- Department of Medicine, Division of Neurology, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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13
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Qiu J, Tan G, Lin Y, Guan J, Dai Z, Wang F, Zhuang C, Wilman AH, Huang H, Cao Z, Tang Y, Jia Y, Li Y, Zhou T, Wu R. Automated detection of intracranial artery stenosis and occlusion in magnetic resonance angiography: A preliminary study based on deep learning. Magn Reson Imaging 2022; 94:105-111. [PMID: 36174873 DOI: 10.1016/j.mri.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 09/12/2022] [Accepted: 09/22/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND OBJECTIVES Intracranial atherosclerotic stenosis of a major intracranial artery is the common cause of ischemic stroke. We evaluate the feasibility of using deep learning to automatically detect intracranial arterial steno-occlusive lesions from time-of-flight magnetic resonance angiography. METHODS In a retrospective study, magnetic resonance images with radiological reports of intracranial arterial stenosis and occlusion were extracted. The images were randomly divided into a training set and a test set. The manual annotation of lesions with a bounding box labeled "moderate stenosis," "severe stenosis," "occlusion," and "absence of signal" was considered as ground truth. A deep learning algorithm based on you only look once version 5 (YOLOv5) detection model was developed with the training set, and its sensitivity and positive predictive values to detect lesions were evaluated in the test set. RESULTS A dataset of 200 examinations consisted of a total of 411 lesions-242 moderate stenoses, 84 severe stenoses, 70 occlusions, and 15 absence of signal. The magnetic resonance images contained 291 lesions in the training set and 120 lesions in the test set. The sensitivity and positive predictive values were 64.2 and 83.7%, respectively. The detection sensitivity in relation to the location was greatest in the internal carotid artery (86.2%). CONCLUSIONS Applying deep learning algorithms in the automated detection of intracranial arterial steno-occlusive lesions from time-of-flight magnetic resonance angiography is feasible and has great potential.
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Affiliation(s)
- Jinming Qiu
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China; Department of Radiology, the Sixth Affiliated Hospital, South China University of Technology, Foshan 528000, Guangdong, PR China
| | - Guanru Tan
- Department of Computer Science, Shantou University, Shantou 515041, Guangdong, PR China
| | - Yan Lin
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Jitian Guan
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Zhuozhi Dai
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Fei Wang
- Department of Computer Science, Shantou University, Shantou 515041, Guangdong, PR China
| | - Caiyu Zhuang
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Huaidong Huang
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Zhen Cao
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Yanyan Tang
- Department of Medical Imaging, the Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, Guangdong, PR China
| | - Yanlong Jia
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Yan Li
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
| | - Teng Zhou
- Department of Computer Science, Shantou University, Shantou 515041, Guangdong, PR China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou 515800, China
| | - Renhua Wu
- Department of Radiology, the Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong, PR China
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14
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Naji N, Lauzon ML, Seres P, Stolz E, Frayne R, Lebel C, Beaulieu C, Wilman AH. Multisite reproducibility of quantitative susceptibility mapping and effective transverse relaxation rate in deep gray matter at 3 T using locally optimized sequences in 24 traveling heads. NMR Biomed 2022; 35:e4788. [PMID: 35704837 DOI: 10.1002/nbm.4788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/28/2022] [Accepted: 06/05/2022] [Indexed: 06/15/2023]
Abstract
Iron concentration in the human brain plays a crucial role in several neurodegenerative diseases and can be monitored noninvasively using quantitative susceptibility mapping (QSM) and effective transverse relaxation rate (R2 *) mapping from multiecho T2 *-weighted images. Large population studies enable better understanding of pathologies and can benefit from pooling multisite data. However, reproducibility may be compromised between sites and studies using different hardware and sequence protocols. This work investigates QSM and R2 * reproducibility at 3 T using locally optimized sequences from three centers and two vendors, and investigates possible reduction of cross-site variability through postprocessing approaches. Twenty-four healthy subjects traveled between three sites and were scanned twice at each site. Scan-rescan measurements from seven deep gray matter regions were used for assessing within-site and cross-site reproducibility using intraclass correlation coefficient (ICC) and within-subject standard deviation (SDw) measures. In addition, multiple QSM and R2 * postprocessing options were investigated with the aim to minimize cross-site sequence-related variations, including: mask generation approach, echo-timing selection, harmonizing spatial resolution, field map estimation, susceptibility inversion method, and linear field correction for magnitude images. The same-subject cross-site region of interest measurements for QSM and R2 * were highly correlated (R2 ≥ 0.94) and reproducible (mean ICC of 0.89 and 0.82 for QSM and R2 *, respectively). The mean cross-site SDw was 4.16 parts per billion (ppb) for QSM and 1.27 s-1 for R2 *. For within-site measurements of QSM and R2 *, the mean ICC was 0.97 and 0.87 and mean SDw was 2.36 ppb and 0.97 s-1 , respectively. The precision level is regionally dependent and is reduced in the frontal lobe, near brain edges, and in white matter regions. Cross-site QSM variability (mean SDw) was reduced up to 46% through postprocessing approaches, such as masking out less reliable regions, matching available echo timings and spatial resolution, avoiding the use of the nonconsistent magnitude contrast between scans in field estimation, and minimizing streaking artifacts.
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Affiliation(s)
- Nashwan Naji
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - M Louis Lauzon
- Departments of Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Emily Stolz
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Richard Frayne
- Departments of Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
| | - Catherine Lebel
- Department of Radiology, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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15
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De A, Sun H, Emery DJ, Butcher KS, Wilman AH. Quantitative susceptibility-weighted imaging in presence of strong susceptibility sources: Application to hemorrhage. Magn Reson Imaging 2022; 92:224-231. [PMID: 35772582 DOI: 10.1016/j.mri.2022.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/13/2022] [Accepted: 06/23/2022] [Indexed: 11/17/2022]
Abstract
PURPOSE To optimize quantitative susceptibility-weighted imaging also known as true susceptibility-weighted imaging (tSWI) for strong susceptibility sources like hemorrhage and compare to standard susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM). METHODS Ten patients with known intracerebral hemorrhage were scanned using a 3D SWI sequence. The magnitude and phase images were utilized to compute QSM, tSWI and SWI images. tSWI parameters including the upper threshold for creating susceptibility-weighted masks and the multiplication factor were optimized for hemorrhage depiction. Combined tSWI was also computed with independent optimized parameters for both veins and hemorrhagic regions. tSWI results were compared to SWI and QSM utilizing region-of-interest measurements, Pearson's correlation and Kruskal-Wallis test. RESULTS Fifteen hemorrhages were found, with mean susceptibility 0.81 ± 0.37 ppm. Unlike SWI which utilizes a phase mask, tSWI uses a mask computed from QSM. In tSWI, the weighted mask required an extended upper threshold far beyond the standard level for more effective visualization of hemorrhage texture. The upper threshold was set to the mean maximum susceptibility in the hemorrhagic region (3.24 ppm) with a multiplication factor of 2. The blooming effect, seen in SWI, was observed to be larger in hemorrhages with higher susceptibility values (r = 0.78, p < 0.001) with reduced blooming on tSWI. On SWI, 4 out of 15 hemorrhages showed phase wrap artifacts in the hemorrhagic region and all patients showed some phase wraps in the air-tissue interface near the auditory and frontal sinuses. These phase wrap artifacts were absent on tSWI. In hemorrhagic region, a higher correlation was observed between the actual susceptibility values and mean gray value for tSWI (r = -0.93, p < 0.001) than SWI (r = -0.87, p < 0.001). CONCLUSION In hemorrhage, tSWI minimizes both blooming effects and phase wrap artifacts observed in SWI. However, unlike SWI, tSWI requires an altered upper threshold for best hemorrhage depiction that greatly differs from the standard value. tSWI can be used as a complementary technique for visualizing hemorrhage along with SWI.
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Affiliation(s)
- Ashmita De
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada.
| | - Hongfu Sun
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Derek J Emery
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada
| | - Kenneth S Butcher
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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16
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Mehdizadeh N, Wilman AH. Myelin water fraction mapping from multiple echo spin echoes and an independent B 1 + map. Magn Reson Med 2022; 88:1380-1390. [PMID: 35576121 PMCID: PMC9321077 DOI: 10.1002/mrm.29286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/23/2022] [Accepted: 04/13/2022] [Indexed: 11/11/2022]
Abstract
Purpose Myelin water fraction (MWF) is often obtained from a multiple echo spin echo (MESE) sequence using multi‐component T2 fitting with non‐negative least squares. This process fits many unknowns including B1+ to produce a T2 spectrum for each voxel. Presented is an alternative using a rapid B1+ mapping sequence to supply B1+ for the MWF fitting procedure. Methods Effects of B1+ errors on MWF calculations were modeled for 2D and 3D MESE using Bloch and extended phase graph simulations, respectively. Variations in SNR and relative refocusing widths were tested. Human brain experiments at 3 T used 2D MESE and an independent B1+ map. MWF maps were produced with the standard approach and with the use of the independent B1+ map. Differences in B1+ and mean MWF in specific brain regions were compared. Results For 2D MESE, MWF with the standard method was strongly affected by B1+ misestimations arising from limited SNR and response asymmetry around 180°, which decreased with increasing relative refocusing width. Using an independent B1+ map increased mean MWF and decreased coefficient of variation. Notable differences in vivo in 2D MESE were in areas of high B1+ such as thalamus and splenium where mean MWF increased by 88% and 31%, respectively (P < 0.001). Simulations also demonstrated the advantages of this approach for 3D MESE when SNR is <500. Conclusion For 2D MESE, because of increased complexity of decay curves and limited SNR, supplying B1+ improves MWF results in peripheral and central brain regions where flip angles differ substantially from 180°.
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Affiliation(s)
- Nima Mehdizadeh
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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17
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Snyder J, McPhee KC, Wilman AH. T 2 quantification in brain using 3D fast spin-echo imaging with long echo trains. Magn Reson Med 2021; 87:2145-2160. [PMID: 34894641 PMCID: PMC9299830 DOI: 10.1002/mrm.29113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 11/15/2022]
Abstract
Purpose Three‐dimensional fast spin‐echo (FSE) sequences commonly use very long echo trains (>64 echoes) and severely reduced refocusing angles. They are increasingly used in brain exams due to high, isotropic resolution and reasonable scan time when using long trains and short interecho spacing. In this study, T2 quantification in 3D FSE is investigated to achieve increased resolution when comparing with established 2D (proton‐density dual‐echo and multi‐echo spin‐echo) methods. Methods The FSE sequence design was explored to use long echo trains while minimizing T2 fitting error and maintaining typical proton density and T2‐weighted contrasts. Constant and variable flip angle trains were investigated using extended phase graph and Bloch equation simulations. Optimized parameters were analyzed in phantom experiments and validated in vivo in comparison to 2D methods for eight regions of interest in brain, including deep gray‐matter structures and white‐matter tracts. Results Phantom and healthy in vivo brain T2 measurements showed that optimized variable echo‐train 3D FSE performs similarly to previous 2D methods, while achieving three‐fold‐higher slice resolution, evident visually in the 3D T2 maps. Optimization resulted in better T2 fitting and compared well with standard multi‐echo spin echo (within the 8‐ms confidence limits defined based on Bland‐Altman analysis). Conclusion T2 mapping using 3D FSE with long echo trains and variable refocusing angles provides T2 accuracy in agreement with 2D methods with additional high‐resolution benefits, allowing isotropic views while avoiding incidental magnetization transfer effects. Consequently, optimized 3D sequences should be considered when choosing T2 mapping methods for high anatomic detail.
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Affiliation(s)
- Jeff Snyder
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | | | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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18
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MacLennan T, Seres P, Rickard J, Stolz E, Beaulieu C, Wilman AH. Characterization of B 1 + field variation in brain at 3 T using 385 healthy individuals across the lifespan. Magn Reson Med 2021; 87:960-971. [PMID: 34545972 DOI: 10.1002/mrm.29011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/18/2021] [Accepted: 08/31/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE The transmit field B 1 + at 3 T in brain affects the spatial uniformity and contrast of most image acquisitions. Here, B 1 + spatial variation in brain at 3 T is characterized in a large healthy population. METHODS Bloch-Siegert B 1 + maps were acquired at 3 T from 385 healthy subjects aged 5-90 years on a single MRI system. After transforming all B 1 + maps to a standard brain atlas space, region-of-interest analysis was performed, and intersubject voxel-wise coefficient of variation was calculated across the whole brain. The B 1 + variability due to age and brain size was studied separately in males and females, along with B 1 + variability due to nonideal transmit calibration. RESULTS The voxel-based mean coefficient of variation was 4.0% across all subjects, and the difference in B 1 + between central (left thalamus) and outer regions (left frontal gray matter) was 24.2% ± 2.3%. The least intersubject variability occurred in central regions, whereas regions toward brain edges increased markedly in variation. The B 1 + variability with age was mostly attributed to lifespan changes in CSF volume (which alters brain conductivity) and head orientation. Larger brain size correlated with more B 1 + inhomogeneity (p < .001). Varying head position and anatomy resulted in an inaccurate transmit calibration. CONCLUSION In standard atlas space, intersubject B 1 + variability at 3 T was relatively small in a large population aged 5-90 years. The B 1 + varied with age-related changes of CSF volume and head orientation, as well as differences in brain size and transmit calibration.
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Affiliation(s)
- Thomas MacLennan
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Julia Rickard
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Emily Stolz
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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19
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Treit S, Naji N, Seres P, Rickard J, Stolz E, Wilman AH, Beaulieu C. R2* and quantitative susceptibility mapping in deep gray matter of 498 healthy controls from 5 to 90 years. Hum Brain Mapp 2021; 42:4597-4610. [PMID: 34184808 PMCID: PMC8410539 DOI: 10.1002/hbm.25569] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 12/17/2022] Open
Abstract
Putative MRI markers of iron in deep gray matter have demonstrated age related changes during discrete periods of healthy childhood or adulthood, but few studies have included subjects across the lifespan. This study reports both transverse relaxation rate (R2*) and quantitative susceptibility mapping (QSM) of four primary deep gray matter regions (thalamus, putamen, caudate, and globus pallidus) in 498 healthy individuals aged 5–90 years. In the caudate, putamen, and globus pallidus, increases of QSM and R2* were steepest during childhood continuing gradually throughout adulthood, except caudate susceptibility which reached a plateau in the late 30s. The thalamus had a unique profile with steeper changes of R2* (reflecting additive effects of myelin and iron) than QSM during childhood, both reaching a plateau in the mid‐30s to early 40s and decreasing thereafter. There were no hemispheric or sex differences for any region. Notably, both R2* and QSM values showed more inter‐subject variability with increasing age from 5 to 90 years, potentially reflecting a common starting point in iron/myelination during childhood that diverges as a result of lifestyle and genetic factors that accumulate with age.
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Affiliation(s)
- Sarah Treit
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nashwan Naji
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter Seres
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Julia Rickard
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Emily Stolz
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Kamtchum-Tatuene J, Noubiap JJ, Wilman AH, Saqqur M, Shuaib A, Jickling GC. Prevalence of High-risk Plaques and Risk of Stroke in Patients With Asymptomatic Carotid Stenosis: A Meta-analysis. JAMA Neurol 2021; 77:1524-1535. [PMID: 32744595 DOI: 10.1001/jamaneurol.2020.2658] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Importance There is an ongoing debate regarding the management of asymptomatic carotid stenosis. Previous studies have reported imaging features of high-risk plaques that could help to optimize the risk-benefit ratio of revascularization. However, such studies have not provided an accurate estimate of the prevalence of high-risk plaques and the associated annual incidence of ipsilateral ischemic cerebrovascular events to inform the design of clinical trials using a risk-oriented selection of patients before randomization. Objective To assess the relevance and feasibility of risk-oriented selection of patients for revascularization. Data Sources A systematic search of PubMed and Ovid Embase from database inception to July 31, 2019, was performed. Study Selection Prospective observational studies that reported prevalence of high-risk plaques and incidence of ipsilateral ischemic cerebrovascular events were included. Data Extraction and Synthesis Aggregated data were pooled using random-effects meta-analysis. Data were analyzed from December 16, 2019, to January 15, 2020. Main Outcomes and Measures Prevalence of high-risk plaques and annual incidence of ipsilateral ischemic events. Results Overall, 64 studies enrolling 20 751 participants aged 29 to 95 years (mean age range, 55.0-76.5 years; proportion of men, 45%-87%) were included in the meta-analysis. Among all participants, the pooled prevalence of high-risk plaques was 26.5% (95% CI, 22.9%-30.3%). The most prevalent high-risk plaque features were neovascularization (43.4%; 95% CI, 31.4%-55.8%) in 785 participants, echolucency (42.3%; 95% CI, 32.2%-52.8%) in 12 364 participants, and lipid-rich necrotic core (36.3%; 95% CI, 27.7%-45.2%) in 3728 participants. The overall incidence of ipsilateral ischemic cerebrovascular events was 3.2 events per 100 person-years (22 cohorts with 10 381 participants; mean follow-up period, 2.8 years; range, 0.7-6.5 years). The incidence of ipsilateral ischemic cerebrovascular events was higher in patients with high-risk plaques (4.3 events per 100 person-years; 95% CI, 2.5-6.5 events per 100 person-years) than in those without high-risk plaques (1.2 events per 100 person-years; 95% CI, 0.6-1.8 events per 100 person-years), with an odds ratio of 3.0 (95% CI, 2.1-4.3; I2 = 48.8%). In studies focusing on severe stenosis (9 cohorts with 2128 participants; mean follow-up period, 2.8 years; range, 1.4-6.5 years), the incidence of ipsilateral ischemic cerebrovascular events was 3.7 events per 100 person-years (95% CI, 1.9-6.0 events per 100 person-years). The incidence of ipsilateral ischemic cerebrovascular events was also higher in patients with high-risk plaques (7.3 events per 100 person-years; 95% CI, 2.0-15.0 events per 100 person-years) than in those without high-risk plaques (1.7 events per 100 person-years; 95% CI, 0.6-3.3 events per 100 person-years), with an odds ratio of 3.2 (95% CI, 1.7-5.9; I2 = 39.6%). Conclusions and Relevance High-risk plaques are common in patients with asymptomatic carotid stenosis, and the associated risk of an ipsilateral ischemic cerebrovascular event is higher than the currently accepted estimates. Extension of routine assessment of asymptomatic carotid stenosis beyond the grade of stenosis may help improve risk stratification and optimize therapy.
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Affiliation(s)
- Joseph Kamtchum-Tatuene
- Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jean Jacques Noubiap
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, Royal Adelaide Hospital, The University of Adelaide, Adelaide, South Australia, Australia
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Maher Saqqur
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ashfaq Shuaib
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Glen C Jickling
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Gao Y, Zhu X, Moffat BA, Glarin R, Wilman AH, Pike GB, Crozier S, Liu F, Sun H. xQSM: quantitative susceptibility mapping with octave convolutional and noise-regularized neural networks. NMR Biomed 2021; 34:e4461. [PMID: 33368705 DOI: 10.1002/nbm.4461] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/25/2020] [Indexed: 06/12/2023]
Abstract
Quantitative susceptibility mapping (QSM) provides a valuable MRI contrast mechanism that has demonstrated broad clinical applications. However, the image reconstruction of QSM is challenging due to its ill-posed dipole inversion process. In this study, a new deep learning method for QSM reconstruction, namely xQSM, was designed by introducing noise regularization and modified octave convolutional layers into a U-net backbone and trained with synthetic and in vivo datasets, respectively. The xQSM method was compared with two recent deep learning (QSMnet+ and DeepQSM) and two conventional dipole inversion (MEDI and iLSQR) methods, using both digital simulations and in vivo experiments. Reconstruction error metrics, including peak signal-to-noise ratio, structural similarity, normalized root mean squared error and deep gray matter susceptibility measurements, were evaluated for comparison of the different methods. The results showed that the proposed xQSM network trained with in vivo datasets achieved the best reconstructions of all the deep learning methods. In particular, it led to, on average, 32.3%, 25.4% and 11.7% improvement in the accuracy of globus pallidus susceptibility estimation for digital simulations and 39.3%, 21.8% and 6.3% improvements for in vivo acquisitions compared with DeepQSM, QSMnet+ and iLSQR, respectively. It also exhibited the highest linearity against different susceptibility intensity scales and demonstrated the most robust generalization capability to various spatial resolutions of all the deep learning methods. In addition, the xQSM method also substantially shortened the reconstruction time from minutes using MEDI to only a few seconds.
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Affiliation(s)
- Yang Gao
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
| | - Xuanyu Zhu
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
| | - Bradford A Moffat
- Melbourne Brain Centre Imaging Unit, Department of Medicine and Radiology, The University of Melbourne, Parkville, Australia
| | - Rebecca Glarin
- Melbourne Brain Centre Imaging Unit, Department of Medicine and Radiology, The University of Melbourne, Parkville, Australia
- Department of Radiology, Royal Melbourne Hospital, Parkville, Australia
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - G Bruce Pike
- Departments of Radiology and Clinical Neurosciences, University of Calgary, Calgary, Canada
| | - Stuart Crozier
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
| | - Feng Liu
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
| | - Hongfu Sun
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia
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22
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Dai Z, Kalra S, Mah D, Seres P, Sun H, Wu R, Wilman AH. Amide signal intensities may be reduced in the motor cortex and the corticospinal tract of ALS patients. Eur Radiol 2021; 31:1401-1409. [PMID: 32909054 DOI: 10.1007/s00330-020-07243-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/21/2020] [Accepted: 08/28/2020] [Indexed: 02/05/2023]
Abstract
OBJECTIVES The aim of the study is to assess amide concentration changes in ALS patients compared with healthy controls by using quantitative amide proton transfer (APT) and multiparameter magnetic resonance imaging, and testing its correlation with clinical scores. METHODS Sixteen ALS patients and sixteen healthy controls were recruited as part of the Canadian ALS Neuroimaging Consortium, and multimodal magnetic resonance imaging was performed at 3 T, including APT and diffusion imaging. Lorentz fitting was used to quantify the amide effect. Clinical disability was evaluated using the revised ALS functional rating scale (ALSFRS-R), and its correlation with image characteristics was assessed. The diagnostic performance of different imaging parameters was evaluated with receiver operating characteristic analysis. RESULTS Our results showed that the amide peak was significantly different between the motor cortex and other gray matter territories within the brain of ALS patients (p < 0.001). Compared with controls, amide signal intensities in ALS were significantly reduced in the motor cortex (p < 0.001) and corticospinal tract (p = 0.046), while abnormalities were not detected using routine imaging methods. There was no significant correlation between amide and ALSFRS-R score. The diagnostic accuracy of the amide peak was superior to that of diffusion imaging. CONCLUSIONS This study demonstrated changes of amide signal intensities in the motor cortex and corticospinal tract of ALS patients. KEY POINTS • The neurodegenerative disease amyotrophic lateral sclerosis (ALS) has a lack of objective imaging indicators for diagnosis and assessment. • Analysis of amide proton transfer imaging revealed changes in the motor cortex and corticospinal tract of ALS patients that were not visible on standard magnetic resonance imaging. • The diagnostic accuracy of the amide peak was superior to that of diffusion imaging.
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Affiliation(s)
- Zhuozhi Dai
- Department of Radiology, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, T6G 2V2, Canada
| | - Sanjay Kalra
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
| | - Dennell Mah
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, T6G 2V2, Canada
| | - Hongfu Sun
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Renhua Wu
- Department of Radiology, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China.
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, T6G 2V2, Canada.
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23
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Pietrosanu M, Zhang L, Seres P, Elkady A, Wilman AH, Kong L, Cobzas D. Stable Anatomy Detection in Multimodal Imaging Through Sparse Group Regularization: A Comparative Study of Iron Accumulation in the Aging Brain. Front Hum Neurosci 2021; 15:641616. [PMID: 33708081 PMCID: PMC7940836 DOI: 10.3389/fnhum.2021.641616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/28/2021] [Indexed: 11/13/2022] Open
Abstract
Multimodal neuroimaging provides a rich source of data for identifying brain regions associated with disease progression and aging. However, present studies still typically analyze modalities separately or aggregate voxel-wise measurements and analyses to the structural level, thus reducing statistical power. As a central example, previous works have used two quantitative MRI parameters-R2* and quantitative susceptibility (QS)-to study changes in iron associated with aging in healthy and multiple sclerosis subjects, but failed to simultaneously account for both. In this article, we propose a unified framework that combines information from multiple imaging modalities and regularizes estimates for increased interpretability, generalizability, and stability. Our work focuses on joint region detection problems where overlap between effect supports across modalities is encouraged but not strictly enforced. To achieve this, we combine L 1 (lasso), total variation (TV), and L 2 group lasso penalties. While the TV penalty encourages geometric regularization by controlling estimate variability and support boundary geometry, the group lasso penalty accounts for similarities in the support between imaging modalities. We address the computational difficulty in this regularization scheme with an alternating direction method of multipliers (ADMM) optimizer. In a neuroimaging application, we compare our method against independent sparse and joint sparse models using a dataset of R2* and QS maps derived from MRI scans of 113 healthy controls: our method produces clinically-interpretable regions where specific iron changes are associated with healthy aging. Together with results across multiple simulation studies, we conclude that our approach identifies regions that are more strongly associated with the variable of interest (e.g., age), more accurate, and more stable with respect to training data variability. This work makes progress toward a stable and interpretable multimodal imaging analysis framework for studying disease-related changes in brain structure and can be extended for classification and disease prediction tasks.
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Affiliation(s)
- Matthew Pietrosanu
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Li Zhang
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Ahmed Elkady
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Linglong Kong
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Dana Cobzas
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada.,Department of Computer Science, MacEwan University, Edmonton, AB, Canada
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24
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Klahr AC, Kosior JC, Dowlatshahi D, Buck BH, Beaulieu C, Gioia LC, Kalashyan H, Wilman AH, Jeerakathil T, Emery DJ, Shuaib A, Butcher KS. Lower Blood Pressure Is Not Associated With Decreased Arterial Spin Labeling Estimates of Perfusion in Intracerebral Hemorrhage. J Am Heart Assoc 2020; 8:e010904. [PMID: 31131671 PMCID: PMC6585347 DOI: 10.1161/jaha.118.010904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Background Subacute ischemic lesions in intracerebral hemorrhage (ICH) have been hypothesized to result from hypoperfusion. Although studies of cerebral blood flow (CBF) indicate modest hypoperfusion in ICH, these investigations have been limited to early time points. Arterial spin labeling (ASL), a magnetic resonance imaging technique, can be used to measure CBF without a contrast agent. We assessed CBF in patients with ICH using ASL and tested the hypothesis that CBF is related to systolic blood pressure (SBP). Methods and Results In this cross‐sectional study, patients with ICH were assessed with ASL at 48 hours, 7 days, and/or 30 days after onset. Relative CBF (rCBF; ratio of ipsilateral/contralateral perfusion) was measured in the perihematomal regions, hemispheres, border zones, and the perilesional area in patients with diffusion‐weighted imaging hyperintensities. Twenty‐patients (65% men; mean±SD age, 68.5±12.7 years) underwent imaging with ASL at 48 hours (N=12), day 7 (N=6), and day 30 (N=11). Median (interquartile range) hematoma volume was 13.1 (6.3–19.3) mL. Mean±SD baseline SBP was 185.4±25.5 mm Hg. Mean perihematomal rCBF was 0.9±0.2 at 48 hours at all time points. Baseline SBP and other SBP measurements were not associated with a decrease in rCBF in any of the regions of interest (P≥0.111). rCBF did not differ among time points in any of the regions of interest (P≥0.097). Mean perilesional rCBF was 1.04±0.65 and was unrelated to baseline SBP (P=0.105). Conclusions ASL can be used to measure rCBF in patients with acute and subacute ICH. Perihematomal CBF was not associated with SBP changes at any time point. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00963976.
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Affiliation(s)
- Ana C Klahr
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada
| | - Jayme C Kosior
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada
| | | | - Brian H Buck
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada
| | - Christian Beaulieu
- 2 Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
| | - Laura C Gioia
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada
| | | | - Alan H Wilman
- 2 Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
| | | | - Derek J Emery
- 3 Department of Radiology and Diagnostic Imaging University of Alberta Edmonton Alberta Canada
| | - Ashfaq Shuaib
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada
| | - Kenneth S Butcher
- 1 Division of Neurology University of Alberta Edmonton Alberta Canada.,5 Prince of Wales Clinical School University of New South Wales Sydney New South Wales Australia
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25
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Carter LN, Addison O, Naji N, Seres P, Wilman AH, Shepherd DE, Grover L, Cox S. Reducing MRI susceptibility artefacts in implants using additively manufactured porous Ti-6Al-4V structures. Acta Biomater 2020; 107:338-348. [PMID: 32119921 DOI: 10.1016/j.actbio.2020.02.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/03/2020] [Accepted: 02/24/2020] [Indexed: 01/28/2023]
Abstract
Magnetic Resonance Imaging (MRI) is critical in diagnosing post-operative complications following implant surgery and imaging anatomy adjacent to implants. Increasing field strengths and use of gradient-echo sequences have highlighted difficulties from susceptibility artefacts in scan data. Artefacts manifest around metal implants, including those made from titanium alloys, making detection of complications (e.g. bleeding, infection) difficult and hindering imaging of surrounding structures such as the brain or inner ear. Existing research focusses on post-processing and unorthodox scan sequences to better capture data around these devices. This study proposes a complementary up-stream design approach using lightweight structures produced via additive manufacturing (AM). Strategic implant mass reduction presents a potential tool in managing artefacts. Uniform specimens of Ti-6Al-4V structures, including lattices, were produced using the AM process, selective laser melting, with various unit cell designs and relative densities (3.1%-96.7%). Samples, submerged in water, were imaged in a 3T MRI system using clinically relevant sequences. Artefacts were quantified by image analysis revealing a strong linear relationship (RR2 = 0.99) between severity and relative sample density. Likewise, distortion due to slice selection errors showed a squared relationship (RR2 = 0.92) with sample density. Unique artefact features were identified surrounding honeycomb samples suggesting a complex relationship exists for larger unit cells. To demonstrate clinical utility, a honeycomb design was applied to a representative cranioplasty. Analysis revealed 10% artefact reduction compared to traditional solid material illustrating the feasibility of this approach. This study provides a basis to strategically design implants to reduce MRI artefacts and improve post-operative diagnosis capability. STATEMENT OF SIGNIFICANCE: MRI susceptibility artefacts surrounding metal implants present a clinical challenge for the diagnosis of post-operative complications relating to the implant itself or underlying anatomy. In this study for the first time we demonstrate that additive manufacturing may be exploited to create lattice structures that predictably reduce MRI image artefact severity surrounding titanium alloy implants. Specifically, a direct correlation of artefact severity, both total signal loss and distortion, with the relative material density of these functionalised materials has been demonstrated within clinically relevant MRI sequences. This approach opens the door for strategic implant design, utilising this structurally functionalised material, that may improve post-operative patient outcomes and compliments existing efforts in this area which focus on data acquisition and post-processing methods.
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Naji N, Sun H, Wilman AH. On the value of QSM from MPRAGE for segmenting and quantifying iron‐rich deep gray matter. Magn Reson Med 2020; 84:1486-1500. [DOI: 10.1002/mrm.28226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/20/2020] [Accepted: 02/03/2020] [Indexed: 01/10/2023]
Affiliation(s)
- Nashwan Naji
- Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
| | - Hongfu Sun
- School of Information Technology and Electrical Engineering University of Queensland Brisbane Queensland Australia
| | - Alan H. Wilman
- Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
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27
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Gross DW, Misaghi E, Steve TA, Wilman AH, Beaulieu C. Cover Image, Volume 30, Issue 2. Hippocampus 2020. [DOI: 10.1002/hipo.23192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Donald William Gross
- Division of Neurology, Department of MedicineUniversity of Alberta Edmonton Alberta Canada
| | - Ehsan Misaghi
- Division of Neurology, Department of MedicineUniversity of Alberta Edmonton Alberta Canada
| | - Trevor A. Steve
- Division of Neurology, Department of MedicineUniversity of Alberta Edmonton Alberta Canada
| | - Alan H. Wilman
- Department of Biomedical EngineeringUniversity of Alberta Edmonton Alberta Canada
| | - Christian Beaulieu
- Department of Biomedical EngineeringUniversity of Alberta Edmonton Alberta Canada
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28
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Gross DW, Misaghi E, Steve TA, Wilman AH, Beaulieu C. Curved multiplanar reformatting provides improved visualization of hippocampal anatomy. Hippocampus 2019; 30:156-161. [PMID: 31743546 PMCID: PMC7004122 DOI: 10.1002/hipo.23177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/18/2019] [Accepted: 11/01/2019] [Indexed: 01/30/2023]
Abstract
There is a growing body of literature studying changes in hippocampal subfields in a variety of different neurological conditions, but this work has mainly focused on the hippocampal body given challenges in visualization of hippocampal anatomy in the head and tail when sectioned in the typical coronal image plane. Curved multiplanar reformatting (CMPR) is an image reconstruction method that can improve visualization of complex three‐dimensional structures. The objective of this study was to determine whether CMPR could facilitate visualization of the human hippocampal anatomy along the entire caudal–rostral axis. CMPR was applied to high‐resolution magnetic resonance imaging acquired ex vivo on four cadaveric hippocampal specimens at 4.7 T (T2‐weighted, 0.2 × 0.2 × 0.5 mm3). CMPR provided clear visualization of the classic “interlocking C” appearance of the dentate gyrus and cornu ammonis along the entire caudal–rostral axis including the head and tail, which otherwise show complex anatomy on the standard coronal slices. CMPR facilitated visualization of hippocampal anatomy providing the impetus to develop simplified approaches to delineate subfields along the entire hippocampus including the usually neglected head and tail.
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Affiliation(s)
- Donald William Gross
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ehsan Misaghi
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Trevor A Steve
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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29
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De A, Sun H, Emery DJ, Butcher KS, Wilman AH. Rapid quantitative susceptibility mapping of intracerebral hemorrhage. J Magn Reson Imaging 2019; 51:712-718. [DOI: 10.1002/jmri.26850] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 06/17/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- Ashmita De
- The Department of Biomedical EngineeringUniversity of Alberta Edmonton Canada
| | - Hongfu Sun
- The Department of Biomedical EngineeringUniversity of Alberta Edmonton Canada
| | - Derek J. Emery
- Department of Radiology and Diagnostic ImagingUniversity of Alberta Edmonton Canada
| | - Kenneth S. Butcher
- Division of Neurology, Department of MedicineUniversity of Alberta Edmonton Canada
| | - Alan H. Wilman
- The Department of Biomedical EngineeringUniversity of Alberta Edmonton Canada
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30
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Johns SLM, Ishaque A, Khan M, Yang YH, Wilman AH, Kalra S. Quantifying changes on susceptibility weighted images in amyotrophic lateral sclerosis using MRI texture analysis. Amyotroph Lateral Scler Frontotemporal Degener 2019; 20:396-403. [PMID: 31025885 DOI: 10.1080/21678421.2019.1599024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Objective: Susceptibility-weighted imaging (SWI) has been used to identify neurodegeneration in amyotrophic lateral sclerosis (ALS) through qualitative gross visual comparison of signal intensity. The aim of this study was to quantitatively identify cerebral degeneration in ALS on SWI using texture analysis. Methods: SW images were acquired from 17 ALS patients (58.4 ± 10.3 years, 13M/4F, ALSFRS-R 41.2 ± 4.1) and 18 healthy controls (56.3 ± 17.6 years, 9M/9F) at 4.7 tesla. Textures were computed within the precentral gyrus and basal ganglia and compared between patients and controls using ANCOVA with age and gender as covariates. Texture features were correlated with clinical measures in patients. Texture features found to be significantly different between patients and controls in the precentral gyrus were then used in a whole-brain 3D texture analysis. Results: The texture feature autocorrelation was significantly higher in ALS patients compared to healthy controls in the precentral gyrus and basal ganglia (p < 0.05). Autocorrelation correlated significantly with clinical measures such as disease progression rate and finger tapping speed (p < 0.05). Whole brain 3D texture analysis using autocorrelation revealed differences between ALS patients and controls within the precentral gyrus on SWI images (p < 0.001). Conclusion: Texture analysis on SWI can quantitatively identify cerebral differences between ALS patients and controls.
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Affiliation(s)
- Scott L M Johns
- a Department of Biological Sciences , University of Alberta , Edmonton , Canada
| | - Abdullah Ishaque
- b Neuroscience and Mental Health Institute , University of Alberta , Edmonton , Canada.,c Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Canada
| | - Muhammad Khan
- c Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Canada
| | - Yee-Hong Yang
- d Department of Computing Science , University of Alberta , Edmonton , Canada
| | - Alan H Wilman
- e Department of Biomedical Engineering , University of Alberta , Edmonton , Canada, and
| | - Sanjay Kalra
- b Neuroscience and Mental Health Institute , University of Alberta , Edmonton , Canada.,d Department of Computing Science , University of Alberta , Edmonton , Canada.,e Department of Biomedical Engineering , University of Alberta , Edmonton , Canada, and.,f Department of Medicine, Division of Neurology , University of Alberta , Edmonton , Canada
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31
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McPhee KC, Wilman AH. T
1
and T
2
quantification from standard turbo spin echo images. Magn Reson Med 2018; 81:2052-2063. [DOI: 10.1002/mrm.27495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/10/2018] [Accepted: 07/23/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Kelly C. McPhee
- Department of Physics University of Alberta Edmonton Alberta Canada
- Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
| | - Alan H. Wilman
- Department of Physics University of Alberta Edmonton Alberta Canada
- Department of Biomedical Engineering University of Alberta Edmonton Alberta Canada
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32
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Sun H, Klahr AC, Kate M, Gioia LC, Emery DJ, Butcher KS, Wilman AH. Quantitative Susceptibility Mapping for Following Intracranial Hemorrhage. Radiology 2018; 288:830-839. [DOI: 10.1148/radiol.2018171918] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Hongfu Sun
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Ana C. Klahr
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Mahesh Kate
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Laura C. Gioia
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Derek J. Emery
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Kenneth S. Butcher
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
| | - Alan H. Wilman
- From the Department of Biomedical Engineering (H.S., A.H.W.), Division of Neurology, Department of Medicine (A.C.K., M.K., L.C.G., K.S.B.), and Department of Radiology and Diagnostic Imaging (D.J.E.), University of Alberta, 1098 RTF, Edmonton, AB, Canada T6G 2V2
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Walsh AJ, Sun H, Emery DJ, Wilman AH. Hematocrit Measurement with R2* and Quantitative Susceptibility Mapping in Postmortem Brain. AJNR Am J Neuroradiol 2018; 39:1260-1266. [PMID: 29794234 DOI: 10.3174/ajnr.a5677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/01/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE Noninvasive venous oxygenation quantification with MR imaging will improve the neurophysiologic investigation and the understanding of the pathophysiology in neurologic diseases. Available MR imaging methods are limited by sensitivity to flow and often require assumptions of the hematocrit level. In situ postmortem imaging enables evaluation of methods in a fully deoxygenated environment without flow artifacts, allowing direct calculation of hematocrit. This study compares 2 venous oxygenation quantification methods in in situ postmortem subjects. MATERIALS AND METHODS Transverse relaxation (R2*) mapping and quantitative susceptibility mapping were performed on a whole-body 4.7T MR imaging system. Intravenous measurements in major draining intracranial veins were compared between the 2 methods in 3 postmortem subjects. The quantitative susceptibility mapping technique was also applied in 10 healthy control subjects and compared with reference venous oxygenation values. RESULTS In 2 early postmortem subjects, R2* mapping and quantitative susceptibility mapping measurements within intracranial veins had a significant and strong correlation (R2 = 0.805, P = .004 and R2 = 0.836, P = .02). Higher R2* and susceptibility values were consistently demonstrated within gravitationally dependent venous segments during the early postmortem period. Hematocrit ranged from 0.102 to 0.580 in postmortem subjects, with R2* and susceptibility as large as 291 seconds-1 and 1.75 ppm, respectively. CONCLUSIONS Measurements of R2* and quantitative susceptibility mapping within large intracranial draining veins have a high correlation in early postmortem subjects. This study supports the use of quantitative susceptibility mapping for evaluation of in vivo venous oxygenation and postmortem hematocrit concentrations.
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Affiliation(s)
- A J Walsh
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
- Radiology and Diagnostic Imaging (A.J.W., D.J.E.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - H Sun
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
| | - D J Emery
- Radiology and Diagnostic Imaging (A.J.W., D.J.E.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - A H Wilman
- From the Departments of Biomedical Engineering (A.J.W., H.S., A.H.W.)
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McPhee KC, Wilman AH. Limitations of skipping echoes for exponential T2fitting. J Magn Reson Imaging 2018; 48:1432-1440. [DOI: 10.1002/jmri.26052] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/27/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Kelly C. McPhee
- Department of Physics; University of Alberta; Edmonton Alberta Canada
- Department of Biomedical Engineering; University of Alberta; Edmonton Alberta Canada
| | - Alan H. Wilman
- Department of Physics; University of Alberta; Edmonton Alberta Canada
- Department of Biomedical Engineering; University of Alberta; Edmonton Alberta Canada
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Elkady AM, Cobzas D, Sun H, Blevins G, Wilman AH. Discriminative analysis of regional evolution of iron and myelin/calcium in deep gray matter of multiple sclerosis and healthy subjects. J Magn Reson Imaging 2018; 48:652-668. [PMID: 29537720 DOI: 10.1002/jmri.26004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Combined R2* and quantitative susceptibility (QS) has been previously used in cross-sectional multiple sclerosis (MS) studies to distinguish deep gray matter (DGM) iron accumulation and demyelination. PURPOSE We propose and apply discriminative analysis of regional evolution (DARE) to define specific changes in MS and healthy DGM. STUDY TYPE Longitudinal (baseline and 2-year follow-up) retrospective study. SUBJECTS Twenty-seven relapsing-remitting MS (RRMS), 17 progressive MS (PMS), and corresponding age-matched healthy subjects. FIELD STRENGTH/SEQUENCE 4.7T 10-echo gradient-echo acquisition. ASSESSMENT Automatically segmented caudate nucleus (CN), thalamus (TH), putamen (PU), globus pallidus, red nucleus (RN), substantia nigra, and dentate nucleus were retrospectively analyzed to quantify regional volumes, bulk mean R2*, and bulk mean QS. DARE utilized combined R2* and QS localized changes to compute spatial extent, mean intensity, and total changes of DGM iron and myelin/calcium over 2 years. STATISTICAL TESTS We used mixed factorial analysis for bulk analysis, nonparametric tests for DARE (α = 0.05), and multiple regression analysis using backward elimination of DGM structures (α = 0.05, P = 0.1) to regress bulk and DARE measures with the follow-up Multiple Sclerosis Severity Score (MSSS). False detection rate correction was applied to all tests. RESULTS Bulk analysis only detected significant (Q ≤ 0.05) interaction effects in RRMS CN QS (η = 0.45; Q = 0.004) and PU volume (η = 0.38; Q = 0.034). DARE demonstrated significant group differences in all RRMS structures, and in all PMS structures except the RN. The largest RRMS effect size was CN total R2* iron decrease (r = 0.74; Q = 0.00002), and TH mean QS myelin/calcium decrease for PMS (r = 0.70; Q = 0.002). DARE iron increase using total QS demonstrated the highest correlation with MSSS (r = 0.68; Q = 0.0005). DATA CONCLUSION DARE enabled discriminative assessment of specific DGM changes over 2 years, where iron and myelin/calcium changes were the primary drivers in RRMS and PMS compared to age-matched controls, respectively. Specific DARE measures of MS DGM correlated with follow-up MSSS, and may reflect complex disease pathology. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.
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Affiliation(s)
- Ahmed M Elkady
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Dana Cobzas
- Department of Computing Science, University of Alberta, Edmonton, AB, Canada
| | - Hongfu Sun
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Gregg Blevins
- Division of Neurology, University of Alberta, Edmonton, AB, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
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Zhang L, Cobzas D, Wilman AH, Kong L. Significant Anatomy Detection Through Sparse Classification: A Comparative Study. IEEE Trans Med Imaging 2018; 37:128-137. [PMID: 28783628 DOI: 10.1109/tmi.2017.2735239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a comparative study for discriminative anatomy detection in high dimensional neuroimaging data. While most studies solve this problem using mass univariate approaches, recent works show better accuracy and variable selection using a sparse classification model. Two types of image-based regularization methods have been proposed in the literature based on either a Graph Net (GN) model or a total variation (TV) model. These studies showed increased classification accuracy and interpretability of results when using image-based regularization, but did not look at the accuracy and quality of the recovered significant regions. In this paper, we theoretically prove bounds on the recovered sparse coefficients and the corresponding selected image regions in four models (two based on GN penalty and two based on TV penalty). Practically, we confirm the theoretical findings by measuring the accuracy of selected regions compared with ground truth on simulated data. We also evaluate the stability of recovered regions over cross-validation folds using real MRI data. Our findings show that the TV penalty is superior to the GN model. In addition, we showed that adding an l2 penalty improves the accuracy of estimated coefficients and selected significant regions for the both types of models.
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37
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Uddin MN, McPhee KC, Blevins G, Wilman AH. Recovery of accurate T 2 from historical 1.5 tesla proton density and T 2 -weighted images: Application to 7-year T 2 changes in multiple sclerosis brain. Magn Reson Imaging 2017; 37:21-26. [DOI: 10.1016/j.mri.2016.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/11/2016] [Accepted: 11/12/2016] [Indexed: 01/12/2023]
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38
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Sun H, Seres P, Wilman AH. Structural and functional quantitative susceptibility mapping from standard fMRI studies. NMR Biomed 2017; 30:e3619. [PMID: 27687150 DOI: 10.1002/nbm.3619] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 07/15/2016] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Standard functional MRI (fMRI), which includes resting-state or paradigm-driven designs, is widely used in studies of brain function, aging, and disease. These fMRI studies typically use two-dimensional gradient echo-planar imaging, which inherently contains phase data that enables quantitative susceptibility mapping (QSM). This work focuses on the dual value of QSM within fMRI studies, by providing both a localized analysis of functional changes in activated tissue, and iron-sensitive structural maps in deep grey matter (DGM). Using a visual paradigm fMRI study on healthy volunteers at clinical (1.5 T) and high field strength (4.7 T), we perform functional analysis of magnitude and QSM time series, and at the same time harness structural QSM of iron-rich DGM, including globus pallidus, putamen, caudate head, substantia nigra, and red nucleus. The effects of fMRI spatial resolution and time series variation on structural DGM QSM are investigated. Our results indicate that structural DGM QSM is feasible within existing fMRI studies, provided that the voxel dimensions are equal to or less than 3 mm, with higher resolutions preferred. The mean DGM QSM values were about 40 to 220 ppb, while the interquartile ranges of the DGM QSM time series varied from about 3 to 9 ppb, depending on structure and resolution. In contrast, the peak voxel functional QSM (fQSM) changes in activated visual cortex ranged from about -10 to -30 ppb, and functional clusters were consistently smaller on QSM than magnitude fMRI. Mean-level DGM QSM of the time series was successfully extracted in all cases, while fQSM results were more prone to residual background fields and showed less functional change compared with standard magnitude fMRI. Under the conditions prescribed, standard fMRI studies may be used for robust mean-level DGM QSM, enabling study of DGM iron accumulation, in addition to functional analysis. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- H Sun
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - P Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - A H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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39
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Elkady AM, Cobzas D, Sun H, Blevins G, Wilman AH. Progressive iron accumulation across multiple sclerosis phenotypes revealed by sparse classification of deep gray matter. J Magn Reson Imaging 2017; 46:1464-1473. [DOI: 10.1002/jmri.25682] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/06/2017] [Indexed: 12/14/2022] Open
Affiliation(s)
- Ahmed M. Elkady
- Department of Biomedical Engineering; University of Alberta; Edmonton AB Canada
| | - Dana Cobzas
- Department of Biomedical Engineering; University of Alberta; Edmonton AB Canada
| | - Hongfu Sun
- Department of Biomedical Engineering; University of Alberta; Edmonton AB Canada
| | - Gregg Blevins
- Division of Neurology; University of Alberta; Edmonton AB Canada
| | - Alan H. Wilman
- Department of Biomedical Engineering; University of Alberta; Edmonton AB Canada
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40
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Wang Y, Spincemaille P, Liu Z, Dimov A, Deh K, Li J, Zhang Y, Yao Y, Gillen KM, Wilman AH, Gupta A, Tsiouris AJ, Kovanlikaya I, Chiang GCY, Weinsaft JW, Tanenbaum L, Chen W, Zhu W, Chang S, Lou M, Kopell BH, Kaplitt MG, Devos D, Hirai T, Huang X, Korogi Y, Shtilbans A, Jahng GH, Pelletier D, Gauthier SA, Pitt D, Bush AI, Brittenham GM, Prince MR. Clinical quantitative susceptibility mapping (QSM): Biometal imaging and its emerging roles in patient care. J Magn Reson Imaging 2017; 46:951-971. [PMID: 28295954 DOI: 10.1002/jmri.25693] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/10/2017] [Indexed: 12/13/2022] Open
Abstract
Quantitative susceptibility mapping (QSM) has enabled magnetic resonance imaging (MRI) of tissue magnetic susceptibility to advance from simple qualitative detection of hypointense blooming artifacts to precise quantitative measurement of spatial biodistributions. QSM technology may be regarded to be sufficiently developed and validated to warrant wide dissemination for clinical applications of imaging isotropic susceptibility, which is dominated by metals in tissue, including iron and calcium. These biometals are highly regulated as vital participants in normal cellular biochemistry, and their dysregulations are manifested in a variety of pathologic processes. Therefore, QSM can be used to assess important tissue functions and disease. To facilitate QSM clinical translation, this review aims to organize pertinent information for implementing a robust automated QSM technique in routine MRI practice and to summarize available knowledge on diseases for which QSM can be used to improve patient care. In brief, QSM can be generated with postprocessing whenever gradient echo MRI is performed. QSM can be useful for diseases that involve neurodegeneration, inflammation, hemorrhage, abnormal oxygen consumption, substantial alterations in highly paramagnetic cellular iron, bone mineralization, or pathologic calcification; and for all disorders in which MRI diagnosis or surveillance requires contrast agent injection. Clinicians may consider integrating QSM into their routine imaging practices by including gradient echo sequences in all relevant MRI protocols. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:951-971.
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Affiliation(s)
- Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Biomedical Engineering, Ithaca, New York, USA
| | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Zhe Liu
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Biomedical Engineering, Ithaca, New York, USA
| | - Alexey Dimov
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Biomedical Engineering, Ithaca, New York, USA
| | - Kofi Deh
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Jianqi Li
- Department of Physics, East China Normal University, Shanghai, P.R. China
| | - Yan Zhang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China
| | - Yihao Yao
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA.,Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China
| | - Kelly M Gillen
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Ajay Gupta
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | | | - Ilhami Kovanlikaya
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
| | | | - Jonathan W Weinsaft
- Division of Cardiology, Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | | | - Weiwei Chen
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China
| | - Wenzhen Zhu
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, P.R. China
| | - Shixin Chang
- Department of Radiology, Yueyang Hospital of Integrated Traditional Chinese & Western Medicine, Shanghai, P.R. China
| | - Min Lou
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, P.R. China
| | - Brian H Kopell
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York, USA
| | - Michael G Kaplitt
- Department of Neurological Surgery, Weill Cornell Medical College, New York, New York, USA
| | - David Devos
- Department of Medical Pharmacology, University of Lille, Lille, France.,Department of Neurology and Movement Disorders, University of Lille, Lille, France.,Department of Toxicology, Public Health and Environment, University of Lille, Lille, France.,INSERM U1171, University of Lille, Lille, France
| | - Toshinori Hirai
- Department of Radiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Xuemei Huang
- Department of Neurology, Penn State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.,Department of Pharmacology, Penn State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.,Department of Neurosurgery, Penn State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.,Department of Radiology, Penn State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Yukunori Korogi
- Department of Radiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Alexander Shtilbans
- Department of Neurology, Hospital for Special Surgery, New York, New York, USA.,Parkinson's Disease and Movement Disorder Institute, Weill Cornell Medical College, New York, New York, USA
| | - Geon-Ho Jahng
- Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, South Korea
| | - Daniel Pelletier
- Department of Neurology, Department of Neurology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Susan A Gauthier
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA
| | - David Pitt
- Department of Neurology, School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Ashley I Bush
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Gary M Brittenham
- Department of Pediatrics, Columbia University, Children's Hospital of New York, New York, New York, USA
| | - Martin R Prince
- Department of Radiology, Weill Cornell Medical College, New York, New York, USA
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Fujiwara E, Kmech JA, Cobzas D, Sun H, Seres P, Blevins G, Wilman AH. Cognitive Implications of Deep Gray Matter Iron in Multiple Sclerosis. AJNR Am J Neuroradiol 2017; 38:942-948. [PMID: 28232497 DOI: 10.3174/ajnr.a5109] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/18/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Deep gray matter iron accumulation is increasingly recognized in association with multiple sclerosis and can be measured in vivo with MR imaging. The cognitive implications of this pathology are not well-understood, especially vis-à-vis deep gray matter atrophy. Our aim was to investigate the relationships between cognition and deep gray matter iron in MS by using 2 MR imaging-based iron-susceptibility measures. MATERIALS AND METHODS Forty patients with multiple sclerosis (relapsing-remitting, n = 16; progressive, n = 24) and 27 healthy controls were imaged at 4.7T by using the transverse relaxation rate and quantitative susceptibility mapping. The transverse relaxation rate and quantitative susceptibility mapping values and volumes (atrophy) of the caudate, putamen, globus pallidus, and thalamus were determined by multiatlas segmentation. Cognition was assessed with the Brief Repeatable Battery of Neuropsychological Tests. Relationships between cognition and deep gray matter iron were examined by hierarchic regressions. RESULTS Compared with controls, patients showed reduced memory (P < .001) and processing speed (P = .02) and smaller putamen (P < .001), globus pallidus (P = .002), and thalamic volumes (P < .001). Quantitative susceptibility mapping values were increased in patients compared with controls in the putamen (P = .003) and globus pallidus (P = .003). In patients only, thalamus (P < .001) and putamen (P = .04) volumes were related to cognitive performance. After we controlled for volume effects, quantitative susceptibility mapping values in the globus pallidus (P = .03; trend for transverse relaxation rate, P = .10) were still related to cognition. CONCLUSIONS Quantitative susceptibility mapping was more sensitive compared with the transverse relaxation rate in detecting deep gray matter iron accumulation in the current multiple sclerosis cohort. Atrophy and iron accumulation in deep gray matter both have negative but separable relationships to cognition in multiple sclerosis.
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Affiliation(s)
- E Fujiwara
- From the Departments of Psychiatry (E.F., J.A.K.)
| | - J A Kmech
- From the Departments of Psychiatry (E.F., J.A.K.)
| | | | - H Sun
- Biomedical Engineering (H.S., P.S., A.H.W.)
| | - P Seres
- Biomedical Engineering (H.S., P.S., A.H.W.)
| | - G Blevins
- Medicine (G.B.), Division of Neurology, University of Alberta, Edmonton, Alberta, Canada.,Northern Alberta Multiple Sclerosis Clinic (G.B.), Edmonton, Alberta, Canada
| | - A H Wilman
- Biomedical Engineering (H.S., P.S., A.H.W.)
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42
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Juhás M, Sun H, Brown MRG, MacKay MB, Mann KF, Sommer WH, Wilman AH, Dursun SM, Greenshaw AJ. Deep grey matter iron accumulation in alcohol use disorder. Neuroimage 2017; 148:115-122. [PMID: 28065850 DOI: 10.1016/j.neuroimage.2017.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/01/2016] [Accepted: 01/04/2017] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Evaluate brain iron accumulation in alcohol use disorder (AUD) patients compared to controls using quantitative susceptibility mapping (QSM). METHODS QSM was performed retrospectively by using phase images from resting state functional magnetic resonance imaging (fMRI). 20 male AUD patients and 15 matched healthy controls were examined. Susceptibility values were manually traced in deep grey matter regions including caudate nucleus, combined putamen and globus pallidus, combined substantia nigra and red nucleus, dentate nucleus, and a reference white matter region in the internal capsule. Average susceptibility values from each region were compared between the patients and controls. The relationship between age and susceptibility was also explored. RESULTS The AUD group exhibited increased susceptibility in caudate nucleus (+8.5%, p=0.034), combined putamen and globus pallidus (+10.8%, p=0.006), and dentate nucleus (+14.9%, p=0.022). Susceptibility increased with age in two of the four measured regions - combined putamen and globus pallidus (p=0.013) and combined substantia nigra and red nucleus (p=0.041). AUD did not significantly modulate the rate of susceptibility increase with age in our data. CONCLUSION Retrospective QSM computed from standard fMRI datasets provides new opportunities for brain iron studies in psychiatry. Substantially elevated brain iron was found in AUD subjects in the basal ganglia and dentate nucleus. This was the first human AUD brain iron study and the first retrospective clinical fMRI QSM study.
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Affiliation(s)
- Michal Juhás
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
| | - Hongfu Sun
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew R G Brown
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Marnie B MacKay
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada; Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada
| | - Karl F Mann
- Department of Addictive Behaviour & Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Wolfgang H Sommer
- Department of Addictive Behaviour & Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Psychopharmacology, Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Serdar M Dursun
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew J Greenshaw
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
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43
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Uddin MN, Lebel RM, Seres P, Blevins G, Wilman AH. Spin echo transverse relaxation and atrophy in multiple sclerosis deep gray matter: A two-year longitudinal study. Mult Scler 2016; 22:1133-43. [DOI: 10.1177/1352458515614091] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/03/2015] [Indexed: 02/04/2023]
Abstract
Background: Deep gray matter (DGM) is affected in relapsing–remitting multiple sclerosis (RRMS) and may be studied using short-term longitudinal MRI. Objective: To investigate two-year changes in spin-echo transverse relaxation rate (R2) and atrophy in DGM, and its relationship with disease severity in RRMS patients. Methods: Twenty six RRMS patients and 26 matched controls were imaged at 4.7 T. Multiecho spin-echo R2 maps and atrophy measurements were obtained in DGM at baseline and two-year follow-up. Differences between MRI measures and correlations to disease severity were examined. Results: After two years, mean R2 values in the globus pallidus and pulvinar increased by ~4% ( p<0.001) in patients and <1.7% in controls. Two-year changes in R2 showed significant correlation to disease severity in the globus pallidus, pulvinar, substantia nigra, and thalamus. Multiple regression of the two-year R2 difference using these four DGM structures as variables, yielded high correlation with disease severity ( r=0.83, p<0.001). Two-year changes in volume and R2 showed significant correlation only for the globus pallidus in multiple sclerosis (MS) ( p<0.05). Conclusions: Two-year difference R2 measurements in DGM correlate to disease severity in MS. R2 mapping and atrophy measurements over two years can be used to identify changes in DGM in MS.
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Affiliation(s)
- Md Nasir Uddin
- Department of Biomedical Engineering, University of Alberta, Canada
| | - R Marc Lebel
- Department of Biomedical Engineering, University of Alberta, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Canada
| | - Gregg Blevins
- Division of Neurology, Department of Medicine, University of Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Canada
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McPhee KC, Wilman AH. Transverse relaxation and flip angle mapping: Evaluation of simultaneous and independent methods using multiple spin echoes. Magn Reson Med 2016; 77:2057-2065. [DOI: 10.1002/mrm.26285] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Kelly C. McPhee
- Department of PhysicsUniversity of AlbertaEdmonton Alberta Canada
- Department of Biomedical EngineeringUniversity of AlbertaEdmonton Alberta Canada
| | - Alan H. Wilman
- Department of PhysicsUniversity of AlbertaEdmonton Alberta Canada
- Department of Biomedical EngineeringUniversity of AlbertaEdmonton Alberta Canada
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45
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Elkady AM, Sun H, Wilman AH. Importance of extended spatial coverage for quantitative susceptibility mapping of iron-rich deep gray matter. Magn Reson Imaging 2016; 34:574-8. [DOI: 10.1016/j.mri.2015.12.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/18/2015] [Indexed: 11/16/2022]
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46
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Uddin MN, Lebel RM, Wilman AH. Value of transverse relaxometry difference methods for iron in human brain. Magn Reson Imaging 2016; 34:51-9. [DOI: 10.1016/j.mri.2015.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 05/06/2015] [Accepted: 09/11/2015] [Indexed: 01/14/2023]
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Sun H, Kate M, Gioia LC, Emery DJ, Butcher K, Wilman AH. Quantitative susceptibility mapping using a superposed dipole inversion method: Application to intracranial hemorrhage. Magn Reson Med 2015; 76:781-91. [PMID: 26414757 DOI: 10.1002/mrm.25919] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 08/04/2015] [Accepted: 08/12/2015] [Indexed: 12/25/2022]
Abstract
PURPOSE To investigate gradient-echo phase errors caused by intracranial hemorrhage (ICH) of low signal magnitude, and propose methods to reduce artifacts from phase errors in quantitative susceptibility mapping (QSM) of ICH. METHODS Two QSM methods are proposed: (1) mask-inversion that masks the phase of low signal magnitude regions, and (2) ICH magnetic dipole field isolation followed by susceptibility superposition using multiple boundaries for background field removal. The reconstruction methods were tested in eight subjects with ICH using standard single-echo susceptibility-weighted imaging at 1.5 Tesla with 40 ms echo time. Different phase unwrapping algorithms were also compared. RESULTS Significant phase errors were evident inside ICHs with low signal magnitude. The mask-inversion method recovered susceptibility of ICH in numerical simulation and minimized phase error propagation in patients with ICH. The additional superposed dipole inversion process substantially suppressed and constrained streaking artifacts in all subjects. Using the proposed superposition method, ICH susceptibilities measured from long and short echo times were similar. Laplacian based phase unwrapping substantially underestimated the ICH dipole field as compared to a path-based method. CONCLUSION The proposed methods of mask-inversion as well as ICH isolation and superposition can substantially reduce artifacts in QSM of ICH. Magn Reson Med 76:781-791, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Hongfu Sun
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | - Mahesh Kate
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Laura C Gioia
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Derek J Emery
- Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada
| | - Kenneth Butcher
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
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McPhee KC, Wilman AH. T2 quantification from only proton density and T2-weighted MRI by modelling actual refocusing angles. Neuroimage 2015; 118:642-50. [DOI: 10.1016/j.neuroimage.2015.05.079] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 11/30/2022] Open
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Cobzas D, Sun H, Walsh AJ, Lebel RM, Blevins G, Wilman AH. Subcortical gray matter segmentation and voxel-based analysis using transverse relaxation and quantitative susceptibility mapping with application to multiple sclerosis. J Magn Reson Imaging 2015; 42:1601-10. [DOI: 10.1002/jmri.24951] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/01/2015] [Indexed: 11/10/2022] Open
Affiliation(s)
- Dana Cobzas
- Biomedical Engineering; University of Alberta; Edmonton Canada
- Computing Science; University of Alberta; Edmonton Canada
| | - Hongfu Sun
- Biomedical Engineering; University of Alberta; Edmonton Canada
| | - Andrew J. Walsh
- Biomedical Engineering; University of Alberta; Edmonton Canada
| | - R. Marc Lebel
- Biomedical Engineering; University of Alberta; Edmonton Canada
| | - Gregg Blevins
- Division of Neurology; University of Alberta; Edmonton Canada
| | - Alan H. Wilman
- Biomedical Engineering; University of Alberta; Edmonton Canada
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Sun H, Wilman AH. Quantitative susceptibility mapping using single-shot echo-planar imaging. Magn Reson Med 2015. [DOI: 10.1002/mrm.25735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hongfu Sun
- Department of Biomedical Engineering; University of Alberta; Edmonton Canada
| | - Alan H. Wilman
- Department of Biomedical Engineering; University of Alberta; Edmonton Canada
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