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Jerban S, Jang H, Chang EY, Bukata S, Du J, Chung CB. Bone Biomarkers Based on Magnetic Resonance Imaging. Semin Musculoskelet Radiol 2024; 28:62-77. [PMID: 38330971 DOI: 10.1055/s-0043-1776431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Magnetic resonance imaging (MRI) is increasingly used to evaluate the microstructural and compositional properties of bone. MRI-based biomarkers can characterize all major compartments of bone: organic, water, fat, and mineral components. However, with a short apparent spin-spin relaxation time (T2*), bone is invisible to conventional MRI sequences that use long echo times. To address this shortcoming, ultrashort echo time MRI sequences have been developed to provide direct imaging of bone and establish a set of MRI-based biomarkers sensitive to the structural and compositional changes of bone. This review article describes the MRI-based bone biomarkers representing total water, pore water, bound water, fat fraction, macromolecular fraction in the organic matrix, and surrogates for mineral density. MRI-based morphological bone imaging techniques are also briefly described.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, La Jolla, California
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Susan Bukata
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, California
| | - Jiang Du
- Department of Radiology, University of California, San Diego, La Jolla, California
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California
- Department of Bioengineering, University of California, San Diego, La Jolla, California
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, La Jolla, California
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California
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Cui L, McWalter EJ, Moran G, Venugopal N. Design and development of a novel flexible ultra-short echo time (FUSE) sequence. Magn Reson Med 2023; 90:1905-1918. [PMID: 37392415 DOI: 10.1002/mrm.29784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/28/2023] [Accepted: 06/13/2023] [Indexed: 07/03/2023]
Abstract
PURPOSE To present the validation of a new Flexible Ultra-Short Echo time (FUSE) pulse sequence using a short-T2 phantom. METHODS FUSE was developed to include a range of RF excitation pulses, trajectories, dimensionalities, and long-T2 suppression techniques, enabling real-time interchangeability of acquisition parameters. Additionally, we developed an improved 3D deblurring algorithm to correct for off-resonance artifacts. Several experiments were conducted to validate the efficacy of FUSE, by comparing different approaches for off-resonance artifact correction, variations in RF pulse and trajectory combinations, and long-T2 suppression techniques. All scans were performed on a 3 T system using an in-house short-T2 phantom. The evaluation of results included qualitative comparisons and quantitative assessments of the SNR and contrast-to-noise ratio. RESULTS Using the capabilities of FUSE, we demonstrated that we could combine a shorter readout duration with our improved deblurring algorithm to effectively reduce off-resonance artifacts. Among the different RF and trajectory combinations, the spiral trajectory with the regular half-inc pulse achieves the highest SNRs. The dual-echo subtraction technique delivers better short-T2 contrast and superior suppression of water and agar signals, whereas the off-resonance saturation method successfully suppresses water and lipid signals simultaneously. CONCLUSION In this work, we have validated the use of our new FUSE sequence using a short T2 phantom, demonstrating that multiple UTE acquisitions can be achieved within a single sequence. This new sequence may be useful for acquiring improved UTE images and the development of UTE imaging protocols.
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Affiliation(s)
- Lumeng Cui
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Emily J McWalter
- Department of Mechanical Engineering and Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Gerald Moran
- Siemens Healthcare Limited, Oakville, Ontario, Canada
| | - Niranjan Venugopal
- Department of Radiology, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada
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Nyman JS, Ketsiri T, Louie EA, Harkins KD, Manhard MK, Gochberg DF, Lee DH, Desai MJ, Maslow J, Tanner SB, Does MD. Toward the use of MRI measurements of bound and pore water in fracture risk assessment. Bone 2023; 176:116863. [PMID: 37527697 PMCID: PMC10528882 DOI: 10.1016/j.bone.2023.116863] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023]
Abstract
The current clinical assessment of fracture risk lacks information about the inherent quality of a person's bone tissue. Working toward an imaging-based approach to quantify both a bone tissue quality marker (tissue hydration as water bound to the matrix) and a bone microstructure marker (porosity as water in pores), we hypothesized that the concentrations of bound water (Cbw) are lower and concentrations of pore water (Cpw) are higher in patients with osteoporosis (OP) than in age- and sex-matched adults without the disease. Using recent developments in ultrashort echo time (UTE) magnetic resonance imaging (MRI), maps of Cbw and Cpw were acquired from the uninjured distal third radius (Study 1) of 20 patients who experienced a fragility fracture of the distal radius (Fx) and 20 healthy controls (Non-Fx) and from the tibia mid-diaphysis (Study 2) of 30 women with clinical OP (low T-scores) and 15 women without OP (normal T-scores). In Study 1, Cbw was significantly lower (p = 0.0018) and Cpw was higher (p = 0.0022) in the Fx than in the Non-Fx group. In forward stepwise, logistic regression models using Bayesian Information Criterion for selecting the best set of predictors (from imaging parameters, age, BMI, and DXA scanner type), the area-under-the-receiver operator characteristics-curve (AUC with 95 % confidence intervals) was 0.73 (0.56, 0.86) for hip aBMD (best predictors without MRI) and 0.86 (0.70, 0.95) for the combination of Cbw and Cpw (best predictors overall). In Study 2, Cbw was significantly lower (p = 0.0005) in women with OP (23.8 ± 4.3 1H mol/L) than in women without OP (29.9 ± 6.4 1H mol/L); Cpw was significantly higher by estimate of 2.9 1H mol/L (p = 0.0298) with clinical OP, but only when accounting for the type of UTE-MRI scan with 3D providing higher values than 2D (p < 0.0001). Lastly, Cbw, but not Cpw, was sensitive to bone forming osteoporosis medications over 12-months. UTE-MRI-derived measurements of bound and pore water concentrations are potential, aBMD-independent predictors of fracture risk.
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Affiliation(s)
- Jeffry S Nyman
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, 1215 21st Ave. S., Suite 4200, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN 37232, USA; Department of Veterans Affairs, Tennessee Valley Healthcare System, 1310 24th Ave. S., Nashville, TN 37212, USA; Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center,1211 Medical Center Dr., Nashville, TN 37212, USA.
| | - Thammathida Ketsiri
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN 37232, USA; Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Elizabeth A Louie
- Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Kevin D Harkins
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN 37232, USA; Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Mary Kate Manhard
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229, USA
| | - Daniel F Gochberg
- Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Donald H Lee
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, 1215 21st Ave. S., Suite 4200, Nashville, TN 37232, USA
| | - Mihir J Desai
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, 1215 21st Ave. S., Suite 4200, Nashville, TN 37232, USA
| | - Jed Maslow
- Department of Orthopaedic Surgery, Vanderbilt University Medical Center, 1215 21st Ave. S., Suite 4200, Nashville, TN 37232, USA
| | - S Bobo Tanner
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center,1211 Medical Center Dr., Nashville, TN 37212, USA; Department of Medicine, Division of Rheumatology, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Mark D Does
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, TN 37232, USA; Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Ave. S., Nashville, TN 37232, USA; Department of Electrical Engineering and Computer Science, Vanderbilt University, 400 24th Ave. S., Nashville, TN 37212, USA.
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Achar S, Hwang D, Finkenstaedt T, Malis V, Bae WC. Deep-Learning-Aided Evaluation of Spondylolysis Imaged with Ultrashort Echo Time Magnetic Resonance Imaging. SENSORS (BASEL, SWITZERLAND) 2023; 23:8001. [PMID: 37766055 PMCID: PMC10538057 DOI: 10.3390/s23188001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/31/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
Isthmic spondylolysis results in fracture of pars interarticularis of the lumbar spine, found in as many as half of adolescent athletes with persistent low back pain. While computed tomography (CT) is the gold standard for the diagnosis of spondylolysis, the use of ionizing radiation near reproductive organs in young subjects is undesirable. While magnetic resonance imaging (MRI) is preferable, it has lowered sensitivity for detecting the condition. Recently, it has been shown that ultrashort echo time (UTE) MRI can provide markedly improved bone contrast compared to conventional MRI. To take UTE MRI further, we developed supervised deep learning tools to generate (1) CT-like images and (2) saliency maps of fracture probability from UTE MRI, using ex vivo preparation of cadaveric spines. We further compared quantitative metrics of the contrast-to-noise ratio (CNR), mean squared error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM) between UTE MRI (inverted to make the appearance similar to CT) and CT and between CT-like images and CT. Qualitative results demonstrated the feasibility of successfully generating CT-like images from UTE MRI to provide easier interpretability for bone fractures thanks to improved image contrast and CNR. Quantitatively, the mean CNR of bone against defect-filled tissue was 35, 97, and 146 for UTE MRI, CT-like, and CT images, respectively, being significantly higher for CT-like than UTE MRI images. For the image similarity metrics using the CT image as the reference, CT-like images provided a significantly lower mean MSE (0.038 vs. 0.0528), higher mean PSNR (28.6 vs. 16.5), and higher SSIM (0.73 vs. 0.68) compared to UTE MRI images. Additionally, the saliency maps enabled quick detection of the location with probable pars fracture by providing visual cues to the reader. This proof-of-concept study is limited to the data from ex vivo samples, and additional work in human subjects with spondylolysis would be necessary to refine the models for clinical use. Nonetheless, this study shows that the utilization of UTE MRI and deep learning tools could be highly useful for the evaluation of isthmic spondylolysis.
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Affiliation(s)
- Suraj Achar
- Department of Family Medicine, University of California-San Diego, La Jolla, CA 92093, USA
| | - Dosik Hwang
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Healthcare Robotics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Department of Radiology, Research Institute of Radiological Science and Center for Clinical Imaging Data Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
- Department of Oral and Maxillofacial Radiology, Yonsei University College of Dentistry, Seoul 03722, Republic of Korea
| | - Tim Finkenstaedt
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich, 8091 Zurich, Switzerland
| | - Vadim Malis
- Department of Radiology, University of California-San Diego, La Jolla, CA 92093, USA
| | - Won C. Bae
- Department of Radiology, University of California-San Diego, La Jolla, CA 92093, USA
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA 92161, USA
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He T, Pang Z, Yin Y, Xue H, Pang Y, Song H, Li J, Bai R, Qin A, Kong X. Micron-resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300959. [PMID: 37339792 PMCID: PMC10460861 DOI: 10.1002/advs.202300959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/11/2023] [Indexed: 06/22/2023]
Abstract
Compact, mineralized cortical bone tissues are often concealed on magnetic resonance (MR) images. Recent development of MR instruments and pulse techniques has yielded significant advances in acquiring anatomical and physiological information from cortical bone despite its poor 1 H signals. This work demonstrates the first MR research on cortical bones under an ultrahigh magnetic field of 14 T. The 1 H signals of different mammalian species exhibit multi-exponential decays of three characteristic T2 or T2 * values: 0.1-0.5 ms, 1-4 ms, and 4-8 ms. Systematic sample comparisons attribute these T2 /T2 * value ranges to collagen-bound water, pore water, and lipids, respectively. Ultrashort echo time (UTE) imaging under 14 T yielded spatial resolutions of 20-80 microns, which resolves the 3D anatomy of the Haversian canals. The T2 * relaxation characteristics further allow spatial classifications of collagen, pore water and lipids in human specimens. The study achieves a record of the spatial resolution for MR imaging in bone and shows that ultrahigh-field MR has the unique ability to differentiate the soft and organic compartments in bone tissues.
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Affiliation(s)
- Tian He
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Zhenfeng Pang
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Yu Yin
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Huadong Xue
- Department of ChemistryZhejiang UniversityHangzhou310027China
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Yichuan Pang
- Shanghai Key Laboratory of Orthopedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai200011China
| | - Haixin Song
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Jianhua Li
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Ruiliang Bai
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT)College of Biomedical Engineering and Instrument ScienceZhejiang UniversityHangzhou310027China
- School of MedicineZhejiang UniversityHangzhou310058China
| | - An Qin
- Shanghai Key Laboratory of Orthopedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai200011China
| | - Xueqian Kong
- Department of ChemistryZhejiang UniversityHangzhou310027China
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
- Institute of Translational MedicineShanghai Jiaotong UniversityShanghai200240China
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Jerban S, Ma Y, Alenezi S, Moazamian D, Athertya J, Jang H, Dorthe E, Dlima D, Woods G, Chung CB, Chang EY, Du J. Ultrashort Echo Time (UTE) MRI porosity index (PI) and suppression ratio (SR) correlate with the cortical bone microstructural and mechanical properties: Ex vivo study. Bone 2023; 169:116676. [PMID: 36657630 PMCID: PMC9987215 DOI: 10.1016/j.bone.2023.116676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/19/2022] [Accepted: 01/08/2023] [Indexed: 01/18/2023]
Abstract
Ultrashort echo time (UTE) MRI can image and consequently enable quantitative assessment of cortical bone. UTE-MRI-based evaluation of bone is largely underutilized due to the high cost and time demands of MRI in general. The signal ratio in dual-echo UTE imaging, known as porosity index (PI), as well as the signal ratio between UTE and inversion recovery UTE (IR-UTE) imaging, known as the suppression ratio (SR), are two rapid UTE-based bone evaluation techniques (∼ 5 mins scan time each), which can potentially reduce the time demand and cost in future clinical studies. This study aimed to investigate the correlations of PI and SR measures with cortical bone microstructural and mechanical properties. Cortical bone strips (n = 135) from tibial and femoral midshafts of 37 donors (61 ± 24 years old) were scanned using a dual-echo 3D Cones UTE sequence and a 3D Cones IR-UTE sequence for PI and SR calculations, respectively. Average bone mineral density, porosity, and pore size were measured using microcomputed tomography (μCT). Bone mechanical properties were measured using 4-point bending tests. The μCT measures showed significant correlations with PI (moderate to strong, R = 0.68-0.71) and SR (moderate, R = 0.58-0.68). Young's modulus, yield stress, and ultimate stress demonstrated significant moderate correlations with PI and SR (R = 0.52-0.62) while significant strong correlations with μCT measures (R > 0.7). PI and SR can potentially serve as fast and noninvasive (non-ionizing radiation) biomarkers for evaluating cortical bone in various bone diseases.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA; Department of Orthopedic Surgery, University of California, San Diego, La Jolla, CA, USA.
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA
| | - Salem Alenezi
- Research and Laboratories Sector, Saudi Food and Drug Authority, Riyadh, Kingdom of Saudi Arabia
| | - Dina Moazamian
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Jiyo Athertya
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA
| | - Erik Dorthe
- Shiley Center for Orthopedic Research and Education at Scripps Clinic, La Jolla, CA, USA
| | - Darryl Dlima
- Shiley Center for Orthopedic Research and Education at Scripps Clinic, La Jolla, CA, USA
| | - Gina Woods
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, USA.
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Ma Y, Jang H, Jerban S, Chang EY, Chung CB, Bydder GM, Du J. Making the invisible visible-ultrashort echo time magnetic resonance imaging: Technical developments and applications. APPLIED PHYSICS REVIEWS 2022; 9:041303. [PMID: 36467869 PMCID: PMC9677812 DOI: 10.1063/5.0086459] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 09/12/2022] [Indexed: 05/25/2023]
Abstract
Magnetic resonance imaging (MRI) uses a large magnetic field and radio waves to generate images of tissues in the body. Conventional MRI techniques have been developed to image and quantify tissues and fluids with long transverse relaxation times (T2s), such as muscle, cartilage, liver, white matter, gray matter, spinal cord, and cerebrospinal fluid. However, the body also contains many tissues and tissue components such as the osteochondral junction, menisci, ligaments, tendons, bone, lung parenchyma, and myelin, which have short or ultrashort T2s. After radio frequency excitation, their transverse magnetizations typically decay to zero or near zero before the receiving mode is enabled for spatial encoding with conventional MR imaging. As a result, these tissues appear dark, and their MR properties are inaccessible. However, when ultrashort echo times (UTEs) are used, signals can be detected from these tissues before they decay to zero. This review summarizes recent technical developments in UTE MRI of tissues with short and ultrashort T2 relaxation times. A series of UTE MRI techniques for high-resolution morphological and quantitative imaging of these short-T2 tissues are discussed. Applications of UTE imaging in the musculoskeletal, nervous, respiratory, gastrointestinal, and cardiovascular systems of the body are included.
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Affiliation(s)
- Yajun Ma
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California 92037, USA
| | | | | | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, California 92037, USA
| | - Jiang Du
- Author to whom correspondence should be addressed:. Tel.: (858) 246-2248, Fax: (858) 246-2221
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Zhang R, Lee H, Zhao X, Song HK, Vossough A, Wehrli FW, Bartlett SP. Bone-Selective MRI as a Nonradiative Alternative to CT for Craniofacial Imaging. Acad Radiol 2020; 27:1515-1522. [PMID: 32299762 DOI: 10.1016/j.acra.2020.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/17/2020] [Accepted: 03/05/2020] [Indexed: 12/12/2022]
Abstract
RATIONAL AND OBJECTIVES Computed tomography (CT) is the clinical gold-standard for high-resolution 3D visualization of cortical bone structures. However, ionizing radiation is of concern, particularly for pediatric patients. This study evaluates the feasibility of producing 3D human skull renderings using a novel bone-selective magnetic resonance imaging technique. MATERIALS AND METHODS A dual-radiofrequency pulse, dual-echo, 3D ultrashort echo time sequence was applied for scanning of a cadaver skull and five healthy adult subjects. Scans were each completed within 6 minutes. Semiautomatic segmentation of bone voxels was performed using ITK-SNAP software, leading to 3D renderings of the skulls. For comparison, thin-slice head CT scans were performed. Mimics software was used to measure eight anatomic distances from 3D renderings. Lin's Concordance Correlation test was applied to assess agreement between measurements from MR-based and CT-based 3D skull renderings. RESULTS The 3D rendered MR images depict most craniofacial features (e.g., zygomatic arch), although some voxels were erroneously included or excluded in the renderings. MR-based measurements differed from CT-based measurements by mean percent difference ranging from 2.3%-5.0%. Lin's Concordance Correlation Coefficients for MR-based vs CT-based measurements ranged from 0.998-1.000. CONCLUSION The proposed dual-radiofrequency dual-echo 3D ultrashort echo time imaging technique produces high-resolution bone-specific images within a clinically feasible imaging time, leading to clear visualization of craniofacial skeletal structures. Concordance coefficients suggest good reliability of the method compared to CT. The method is currently limited by time and manual input necessary for segmentation correction. Further investigation is needed for more accurate 3D renderings and for scanning of pediatric patients.
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Affiliation(s)
- Rosaline Zhang
- Division of Plastic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania, Buerger Center, 3500 Civic Center Boulevard, Philadelphia, PA 19104
| | - Hyunyeol Lee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - Xia Zhao
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - Hee Kwon Song
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - Arastoo Vossough
- Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, PA
| | - Scott P Bartlett
- Division of Plastic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania, Buerger Center, 3500 Civic Center Boulevard, Philadelphia, PA 19104.
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Hancin EC, Borja AJ, Nikpanah M, Raynor WY, Haldar D, Werner TJ, Morris MA, Saboury B, Alavi A, Gholamrezanezhad A. PET/MR Imaging in Musculoskeletal Precision Imaging - Third wave after X-Ray and MR. PET Clin 2020; 15:521-534. [DOI: 10.1016/j.cpet.2020.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Li S, Huang X, Li G, Zhang Y, Li Z, Liu L, Gao S. Exponential subtraction in 3D ultrashort echo time imaging to visualize short T2 tissues in tibia. Acta Radiol 2020; 61:760-767. [PMID: 31569946 DOI: 10.1177/0284185119877797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Short T2 tissues can be directly visualized by dual-echo ultrashort echo time imaging with weighted subtraction. As a type of post-processing method, exponential subtraction of ultrashort echo time images with an optimal exponential factor is expected to provide improved positive short T2 contrast. PURPOSE To test the feasibility and effectiveness of exponential subtraction in three-dimensional ultrashort echo time imaging and to determine the optimal exponential factor. MATERIAL AND METHODS A dual-echo three-dimensional ultrashort echo time sequence was implemented on a 3-T MRI system. Exponential subtraction was performed on dual three-dimensional ultrashort echo time images of the tibia of seven healthy volunteers with exponential factors in the range of 1.00-3.00 in increments of 0.01. The regions of interest, including cortical bone, marrow, and muscle, were depicted on subtracted images of different exponential factors. Contrast-to-noise ratio values were calculated from these regions of interest and then used to assess the optimal exponential factor. To determine intra-observer agreement regarding region of interest selection, paired intra-observer measurements of regions of interest in all direct subtraction images were conducted with a one-week interval and the paired measurements were assessed using Bland-Altman analysis and paired-samples t-test. RESULTS Cortical bone can be better visualized by using exponential subtraction in three-dimensional ultrashort echo time imaging; the suggested optimal exponential factor is 1.99-2.03 in the tibia. Paired measurements showed excellent intra-observer agreement. CONCLUSION It is feasible to visualize cortical bone of the tibia using exponential subtraction in three-dimensional ultrashort echo time imaging. Compared with weighted subtraction images, exponential subtraction images with an optimal exponential factor provide enhanced visualization of short T2 tissues.
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Affiliation(s)
- Sha Li
- Department of Medical Physics, Institute of Medical Humanities, Peking University, Beijing, PR China
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing Cancer Hospital & Institute, Beijing, PR China
| | - Xinrui Huang
- Department of Biophysics, School of basic medical sciences, Peking University, Beijing, PR China
| | - Guozhen Li
- Department of Precision Instrument, Tsinghua University, Beijing, PR China
| | - Yibao Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing Cancer Hospital & Institute, Beijing, PR China
| | - Zhaotong Li
- Department of Medical Physics, Institute of Medical Humanities, Peking University, Beijing, PR China
| | - Liangyou Liu
- Department of Medical Physics, Institute of Medical Humanities, Peking University, Beijing, PR China
| | - Song Gao
- Department of Medical Physics, Institute of Medical Humanities, Peking University, Beijing, PR China
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11
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Ling Z, Li L, Chen Y, Hu H, Zhao X, Wilson J, Qi Q, Liu D, Wei F, Chen X, Lu J, Zhou Z, Zou X. Changes of the end plate cartilage are associated with intervertebral disc degeneration: A quantitative magnetic resonance imaging study in rhesus monkeys and humans. J Orthop Translat 2020; 24:23-31. [PMID: 32542179 PMCID: PMC7281301 DOI: 10.1016/j.jot.2020.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/10/2020] [Accepted: 04/09/2020] [Indexed: 02/04/2023] Open
Abstract
Background The end plate plays an important role in intervertebral disc degeneration progression. The aim of the study was to examine the compositional and structural changes of the end plate with age and to investigate the correlation between end plate and disc degeneration by T1ρ and T2 map magnetic resonance imaging. Methods There were 12 young monkeys (6-7 years old), 20 aged monkeys (14-17 years old) and 12 human participants (30-50 years old) in this study. T1ρ or T2 map values of the nucleus pulposus and end plate cartilage were analyzed according to Pfirrmann grades and age. Afterwards, micro computed tomography and histological analysis were used to confirm the end plate changes in monkeys. Pearson’s correlation was performed to investigate the relationship between end plate and disc degeneration. Results In monkeys, T1ρ (r=-0.794, P<0.001) and T2 map values (r=-0.8, P<0.001) of the nucleus pulposus were negatively associated with Pfirrmann grades. Moreover, the T2 map was more suitable than T1ρ for the evaluation of end plate degeneration. Age was an important influence factor of end plate and disc degeneration, which was confirmed by microcomputed tomography, Safranin O/fast green staining, and collagen II staining. The T2 map value of lower end plate degeneration positively correlated with that of the intervertebral discs in monkeys (R2=0.3133, P<0.001) and humans (R2=0.2092, P<0.001). Conclusion This study suggests that the compositional and structural changes of the end plate can be quantitatively evaluated by T2 map. Furthermore, cartilage end plate degeneration is associated with disc degeneration during ageing. The translational potential of this article A better understanding of how the cartilage end plate affects disc degeneration is needed, which may propose a new clinical application using T2 map to evaluate end plate degeneration.
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Affiliation(s)
- Zemin Ling
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Liangping Li
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China.,Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yan Chen
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Hao Hu
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Xiaoxiao Zhao
- Department of Radiology, The Eastern Hospital of the First Affiliated Hospital, Sun Yat-sen University, China
| | - Jordan Wilson
- Department of Orthopaedics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Qihua Qi
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Delong Liu
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
| | - Fuxin Wei
- Department of Orthopaedic Surgery, The Seventh Affiliated Hospital and Orthopedic Research, Institute of Sun Yat-sen University, Shenzhen, China
| | - Xiaoying Chen
- Department of Emergency, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jianhua Lu
- Department of Radiology, Johns Hopkins Hospital, Baltimore, USA
| | - Zhiyu Zhou
- Department of Orthopaedic Surgery, The Seventh Affiliated Hospital and Orthopedic Research, Institute of Sun Yat-sen University, Shenzhen, China
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, Department of Spinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
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12
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Quantifying cortical bone free water using short echo time (STE-MRI) at 1.5 T. Magn Reson Imaging 2020; 71:17-24. [PMID: 32387394 DOI: 10.1016/j.mri.2020.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/12/2020] [Accepted: 04/19/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE The purpose of our study was to use Dual-TR STE-MR protocol as a clinical tool for cortical bone free water quantification at 1.5 T and validate it by comparing the obtained results (MR-derived results) with dehydration results. METHODS Human studies were compliant with HIPPA and were approved by the institutional review board. Short Echo Time (STE) MR imaging with different Repetition Times (TRs) was used for quantification of cortical bone free water T1 (T1free) and concentration (ρfree). The proposed strategy was compared with the dehydration technique in seven bovine cortical bone samples. The agreement between the two methods was quantified by using Bland and Altman analysis. Then we applied the technique on a cross-sectional population of thirty healthy volunteers (18F/12M) and examined the association of the biomarkers with age. RESULTS The mean values of ρfree for bovine cortical bone specimens were quantified as 4.37% and 5.34% by using STE-MR and dehydration techniques, respectively. The Bland and Altman analysis showed good agreement between the two methods along with the suggestion of 0.99% bias between them. Strong correlations were also reported between ρfree (r2 = 0.62) and T1free and age (r2 = 0.8). The reproducibility of the method, evaluated in eight subjects, yielded an intra-class correlation of 0.95. CONCLUSION STE-MR imaging with dual-TR strategy is a clinical solution for quantifying cortical bone ρfree and T1free.
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Fathi Kazerooni A, Pozo JM, McCloskey EV, Saligheh Rad H, Frangi AF. Diffusion MRI for Assessment of Bone Quality; A Review of Findings in Healthy Aging and Osteoporosis. J Magn Reson Imaging 2020; 51:975-992. [PMID: 31709670 PMCID: PMC7078977 DOI: 10.1002/jmri.26973] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 01/13/2023] Open
Abstract
Diffusion MRI (dMRI) is a growing imaging technique with the potential to provide biomarkers of tissue variation, such as cellular density, tissue anisotropy, and microvascular perfusion. However, the role of dMRI in characterizing different aspects of bone quality, especially in aging and osteoporosis, has not yet been fully established, particularly in clinical applications. The reason lies in the complications accompanied with implementation of dMRI in assessment of human bone structure, in terms of acquisition and quantification. Bone is a composite tissue comprising different elements, each contributing to the overall quality and functional competence of bone. As diffusion is a critical biophysical process in biological tissues, early changes of tissue microstructure and function can affect diffusive properties of the tissue. While there are multiple MRI methods to detect variations of individual properties of bone quality due to aging and osteoporosis, dMRI has potential to serve as a superior method for characterizing different aspects of bone quality within the same framework but with higher sensitivity to early alterations. This is mainly because several properties of the tissue including directionality and anisotropy of trabecular bone and cell density can be collected using only dMRI. In this review article, we first describe components of human bone that can be potentially detected by their diffusivity properties and contribute to variations in bone quality during aging and osteoporosis. Then we discuss considerations and challenges of dMRI in bone imaging, current status, and suggestions for development of dMRI in research studies and clinics to segregate different contributing components of bone quality in an integrated acquisition. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:975-992.
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Affiliation(s)
- Anahita Fathi Kazerooni
- Department of Radiology, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Jose M. Pozo
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, School of Computing and School of MedicineUniversity of LeedsLeedsUK
| | - Eugene Vincent McCloskey
- Department of Oncology & Metabolism, Mellanby Centre for Bone Research, Centre for Integrated research in Musculoskeletal AgeingUniversity of SheffieldSheffieldUK
| | - Hamidreza Saligheh Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular ImagingTehran University of Medical SciencesTehranIran
- Department of Medical Physics and Biomedical EngineeringTehran University of Medical SciencesTehranIran
| | - Alejandro F. Frangi
- CISTIB Centre for Computational Imaging & Simulation Technologies in Biomedicine, School of Computing and School of MedicineUniversity of LeedsLeedsUK
- LICAMM Leeds Institute of Cardiovascular and Metabolic Medicine, School of MedicineUniversity of LeedsLeedsUK
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14
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Latta P, Starčuk Z, Kojan M, Gruwel MLH, Tomanek B, Trattnig S, Juras V. Simple compensation method for improved half-pulse excitation profile with rephasing gradient. Magn Reson Med 2020; 84:1796-1805. [PMID: 32129544 DOI: 10.1002/mrm.28233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/14/2020] [Accepted: 02/07/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE To improve the slice profile quality obtained by RF half-pulse excitation for 2D-UTE applications. METHODS The overall first-order and zero-order phase errors along the slice-selection direction were obtained with the help of an optimization task to minimize the out-of-slice signal contamination from the calibration 1-dimenisonal (1D) profile data. The time-phase-error evolution was approximated from the k-space readout data, which were acquired primarily for correction of the readout trajectories during data regridding to the rectilinear grids. The correction of the slice profile was achieved by rephasing gradient pulses applied immediately after the end of excitation. The total prescan calibration typically took less than 2 minutes. RESULTS The improved image quality using the proposed calibration method was demonstrated both on phantoms and on ankle images obtained from healthy volunteers. It was demonstrated that calibration can be performed either as a separate water phantom measurement or directly as a prescan procedure. CONCLUSION The slice-profile distortion from the half-pulse excitation could substantially affect the overall fidelity of 2D-UTE images. The presented experiments proved that the image quality could be substantially increased by application of the proposed slice-correction method.
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Affiliation(s)
- Peter Latta
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Zenon Starčuk
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Martin Kojan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Marco L H Gruwel
- Biological Resources Imaging Laboratory, Mark Wainwright Analytical Centre, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Boguslaw Tomanek
- Department of Oncology, Division of Medical Physics, University of Alberta, Edmonton, AB, Canada
| | - Siegfried Trattnig
- High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Vladimir Juras
- High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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15
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Bouazizi K, Guillot G. Cross-relaxation parameters in cortical bone assessed with different MR sequences. NMR IN BIOMEDICINE 2019; 32:e4098. [PMID: 30986332 DOI: 10.1002/nbm.4098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 02/21/2019] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
This study aimed to show evidence of MR cross-relaxation effects in cortical bone and to compare different MR sequences for the quantification of cross-relaxation parameters. Measurements were performed on bovine diaphysis samples with spectroscopic methods (inversion-recovery, off-resonance saturation) and with a variable flip angle (VFA) UTE imaging method on a 4.7 T laboratory-assembled scanner. Cross-relaxation parameter assessment was carried out via a two-pool model simulation with a matrix algebra approach. A proton signal amplitude of 28 Mol/L was observed (equivalent water fraction of 25%). It was attributed to collagen-bound water, with T2* values of ~ 0.3 ms, a "long-T2 " proton pool, in exchange with protons from the collagen macromolecules ( T2* of 10-20 μs). Magnetization transfer (MT) effects were detected with all sequences. The best precision of model parameters was obtained with off-resonance saturation; the fraction of collagen methylene protons was found in the range of 22-28% and the transverse relaxation time for collagen methylene protons was 11 μs (1% precision). The model parameters obtained were compatible with VFA-UTE results but could not be assessed with acceptable accuracy and precision using this method. In vivo MT quantification using off-resonance saturation with a single B1 amplitude and offset frequency may provide information about the relative amount of collagen per unit volume in cortical bone.
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Affiliation(s)
- Khaoula Bouazizi
- Imagerie par Résonance Magnétique Médicale et Multi-Modalités (UMR8081), CNRS, Université Paris-Saclay, Orsay, France
| | - Geneviève Guillot
- Imagerie par Résonance Magnétique Médicale et Multi-Modalités (UMR8081), CNRS, Université Paris-Saclay, Orsay, France
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16
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Alizai H, Chang G, Regatte RR. MR Imaging of the Musculoskeletal System Using Ultrahigh Field (7T) MR Imaging. PET Clin 2019; 13:551-565. [PMID: 30219187 DOI: 10.1016/j.cpet.2018.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
MR imaging is an indispensable instrument for the diagnosis of musculoskeletal diseases. In vivo MR imaging at 7T offers many advantages, including increased signal-to-noise ratio, higher spatial resolution, improved spectral resolution for spectroscopy, improved sensitivity for X-nucleus imaging, and decreased image acquisition times. There are also however technical challenges of imaging at a higher field strength compared with 1.5 and 3T MR imaging systems. We discuss the many potential opportunities as well as the challenges presented by 7T MR imaging systems and highlight recent developments in in vivo research imaging of musculoskeletal applications in general and cartilage, skeletal muscle, and bone in particular.
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Affiliation(s)
- Hamza Alizai
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA.
| | - Gregory Chang
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
| | - Ravinder R Regatte
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
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17
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Lee H, Zhao X, Song HK, Zhang R, Bartlett SP, Wehrli FW. Rapid dual-RF, dual-echo, 3D ultrashort echo time craniofacial imaging: A feasibility study. Magn Reson Med 2018; 81:3007-3016. [PMID: 30565286 DOI: 10.1002/mrm.27625] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/12/2018] [Accepted: 11/14/2018] [Indexed: 01/23/2023]
Abstract
PURPOSE To develop a dual-radiofrequency (RF), dual-echo, 3D ultrashort echo-time (UTE) pulse sequence and bone-selective image reconstruction for rapid high-resolution craniofacial MRI. METHODS The proposed pulse sequence builds on recently introduced dual-RF UTE imaging. While yielding enhanced bone specificity by exploiting high sensitivity of short T2 signals to variable RF pulse widths, the parent technique exacts a 2-fold scan time penalty relative to standard dual-echo UTE. In the proposed method, the parent sequence's dual-RF scheme was incorporated into dual-echo acquisitions while radial view angles are varied every pulse-to-pulse repetition period. The resulting 4 echoes (2 for each RF) were combined by view-sharing to construct 2 sets of k-space data sets, corresponding to short and long TEs, respectively, leading to a 2-fold increase in imaging efficiency. Furthermore, by exploiting the sparsity of bone signals in echo-difference images, acceleration was achieved by solving a bone-sparsity constrained image reconstruction problem. In vivo studies were performed to evaluate the effectiveness of the proposed acceleration approaches in comparison to the parent method. RESULTS The proposed technique achieves 1.1-mm isotropic skull imaging in 3 minutes without visual loss of image quality, compared to the parent technique (scan time = 12 minutes). Bone-specific images and corresponding 3D renderings of the skull were found to depict the expected craniofacial anatomy over the entire head. CONCLUSION The proposed method is able to achieve high-resolution volumetric craniofacial images in a clinically practical imaging time, and thus may prove useful as a potential alternative to computed tomography.
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Affiliation(s)
- Hyunyeol Lee
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xia Zhao
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hee Kwon Song
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rosaline Zhang
- Department of Plastic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott P Bartlett
- Department of Plastic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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18
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Mahar R, Batool S, Badar F, Xia Y. Quantitative measurement of T2, T1ρ and T1 relaxation times in articular cartilage and cartilage-bone interface by SE and UTE imaging at microscopic resolution. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 297:76-85. [PMID: 30366222 PMCID: PMC6289866 DOI: 10.1016/j.jmr.2018.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 05/25/2023]
Abstract
Both spin-echo (SE) and ultra-short echo (UTE) based MRI sequences were used on a 7 T µMRI system to quantify T2, T1ρ and T1 relaxation times from articular cartilage to the cartilage-bone interface on canine humeral specimens at 19.5 µm pixel resolution. A series of five relaxation-weighted images were acquired to calculate one relaxation map (T2, T1ρ or T1), from which the depth-dependent profiles were examined between the SE method and the UTE method, over the entire non-calcified cartilage and within the cartilage-bone interface. SE-based methods enabled the quantification of relaxation profiles over the noncalcified cartilage, from 0 µm (articular surface) to approximately 460 µm in depth (near the end of radial zone). Most of the cartilage-bone interface was imaged by the UTE-based methods, to a tissue depth of about 810 µm. Pixel-by-pixel calculation of the relaxation times between the independent SE and UTE methods correlated well with each other. A better understanding of the tissue properties reliably over the cartilage-bone interface region by a non-invasive MRI approach could contribute to the clinical diagnostics of trauma-induced osteoarthritis.
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Affiliation(s)
- Rohit Mahar
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA
| | - Syeda Batool
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA
| | - Farid Badar
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA
| | - Yang Xia
- Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA.
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Yi J, Lee YH, Song HT, Suh JS. Comparison of T2* mapping between regular echo time and ultrashort echo time with 3D cones at 3 tesla for knee meniscus. Medicine (Baltimore) 2018; 97:e13443. [PMID: 30508961 PMCID: PMC6283210 DOI: 10.1097/md.0000000000013443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The objectives of this study were to compare the ultrashort T2* relaxation time with the T2* relaxation time using the 3 dimensional (3D) cones sequence in 3 groups of patients with normal, degenerated, and torn knee menisci, and to demonstrate the additional effect of the ultrashort echo time (UTE) signal intensity.Following institutional review board approval, 42 knee magnetic resonance imaging (MRI) scans of 42 patients who presented with knee pain and underwent knee MRIs, with the 3D Cones of UTE sequence (minimum TEs: 32 μs) and a 3T MRI scanner (Discovery 750, GE Healthcare, Waukesha, WI), were analyzed. The enrolled patients were classified into 3 subgroups:normal meniscus on conventional MRI, with no positive meniscus-related physical examination in medical records;meniscal degeneration with signal changes on conventional MRI; andmeniscal tear.For the quantitative assessment, the mean values inside user-drawn regions of interest (ROIs) of the medial menisci were drawn on UTE T2* map and T2* map. For statistical analyses, 1-way analysis of variance (ANOVA) with post-hoc analysis using the Tukey HSD test was conducted to compare groups, and effect size was used to compare the discrimination power.The ultrashort T2* relaxation times were higher in patients with meniscal tear than in those with normal and degeneration groups (P <.05, respectively) whereas T2* relaxation times were not statistically significantly different. The ultrashort T2* relaxation times showed higher effect sizes than the T2* times between tear and normal/degeneration.The ultrashort T2* relaxation times showed better delineation of meniscal degeneration or tears than T2* relaxation times. The ultrashort T2* relaxation times could be more sensitive at differentiating between normal and pathologic meniscal conditions in patients.
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Affiliation(s)
- Jisook Yi
- Department of Radiology, Research Institute of Radiological Science, YUHS-KRIBB, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul
- Department of Radiology, Inje University College of Medicine, Haeundae Paik Hospital, Republic of Korea
| | - Young Han Lee
- Department of Radiology, Research Institute of Radiological Science, YUHS-KRIBB, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul
| | - Ho-Taek Song
- Department of Radiology, Research Institute of Radiological Science, YUHS-KRIBB, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul
| | - Jin-Suck Suh
- Department of Radiology, Research Institute of Radiological Science, YUHS-KRIBB, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul
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20
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Chen X, Qiu B. A pilot study of short T2* measurements with ultrashort echo time imaging at 0.35 T. Biomed Eng Online 2018; 17:70. [PMID: 29866123 PMCID: PMC5987637 DOI: 10.1186/s12938-018-0505-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/23/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Ultrashort echo time (UTE) sequences play a key role in imaging and quantifying short T2 species. However, almost all of the relevant studies was conducted at relatively high fields. The purpose of this work was to further explore the feasibility of UTE imaging and T2* measurement for short T2 species at low fields. METHODS A 2D UTE sequence with an echo time (TE) of 0.37 ms was developed on a 0.35 T permanent magnet scanner. This sequence acquires multiecho images to fit the monoexponential signal decay model for quantitative T2* calculations. In the phantom experiments, MnCl2 solutions with different T2* values were used to assess the curve fitting model in low fields. In the in vivo experiments, T2* measurements were performed on the Achilles tendon of five normal volunteers. RESULTS The phantom studies showed a significant linear relationship between the MnCl2 solution concentration and R2* (1/T2*) values, which indicated the stability and accuracy of the T2* quantification model. The in vivo studies demonstrated that mean T2* value of Achilles tendon is 1.83 ± 0.21 ms, and the mean coefficient of determination (R-squared) was 0.996. CONCLUSIONS Both phantom and in vivo experiments showed that UTE imaging and quantification for short T2 components were feasible at low field 0.35 T scanner. This pilot study presents preliminary conclusions for future work.
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Affiliation(s)
- Xiuyuan Chen
- Center for Biomedical Engineering, University of Science and Technology of China, Jinzhai Road, NO.96, Hefei, 230026, China
| | - Bensheng Qiu
- Center for Biomedical Engineering, University of Science and Technology of China, Jinzhai Road, NO.96, Hefei, 230026, China.
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21
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Latta P, Starčuk Z, Gruwel MLH, Lattova B, Lattova P, Štourač P, Tomanek B. Influence of k-space trajectory corrections on proton density mapping with ultrashort echo time imaging: Application for imaging of short T2 components in white matter. Magn Reson Imaging 2018; 51:87-95. [PMID: 29729437 DOI: 10.1016/j.mri.2018.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/30/2018] [Accepted: 04/30/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate the impact of MR gradient system imperfections and limitations for the quantitative mapping of short T2* signals performed by ultrashort echo time (UTE) acquisition approach. MATERIALS AND METHODS The measurement of short T2* signals from a phantom and a healthy volunteer study (8 subjects of average age 28 ± 4 years) were performed on a 3T scanner. The characteristics of the gradient system were obtained using calibration method performed directly on the measured subject or phantom. This information was used to calculate the actual sampling trajectory with the help of a parametric eddy current model. The actual sample positions were used to reconstruct corrected images and compared with uncorrected data. RESULTS Comparison of both approaches, i.e., without and with correction of k-space sampling trajectories revealed substantial improvement when correction was applied. The phantom experiments demonstrate substantial in-plane signal intensity variations for uncorrected sampling trajectories. In the case of the volunteer study, this led to significant differences in relative proton density (RPD) estimation between the uncorrected and corrected data (P = 0.0117 by Wilcoxon matched-pairs test) and provides for about ~15% higher values for short T2* components of white matter (WM) in the case of uncorrected images. CONCLUSION The imperfection of the applied gradients could induce errors in k-space data sampling which further propagates into the fidelity of the UTE images and jeopardizes precision of quantification. However, the study proved that measurement of gradient errors together with correction of sample positions can contribute to increased accuracy and unbiased characterization of short T2* signals.
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Affiliation(s)
- Peter Latta
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
| | - Zenon Starčuk
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Marco L H Gruwel
- Biological Resources Imaging Laboratory, Mark Wainwright Analytical Centre, Level 4, Lowy Cancer Research Centre, UNSW Australia, Sydney, NSW 2052, Australia
| | - Barbora Lattova
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Petra Lattova
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Pavel Štourač
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Department of Neurology, University Hospital Brno, Jihlavska 20, 62500 Brno, Czech Republic
| | - Boguslaw Tomanek
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic; University of Alberta, Department of Oncology, Division of Medical Physics, 8303 - 112 Street NW, Edmonton, AB T6G 2T4, Canada
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Ma YJ, Zhu Y, Lu X, Carl M, Chang EY, Du J. Short T 2 imaging using a 3D double adiabatic inversion recovery prepared ultrashort echo time cones (3D DIR-UTE-Cones) sequence. Magn Reson Med 2018; 79:2555-2563. [PMID: 28913879 PMCID: PMC5821562 DOI: 10.1002/mrm.26908] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/22/2017] [Accepted: 08/16/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate high contrast imaging of short T2 tissues with a three-dimensional double adiabatic inversion recovery prepared ultrashort echo time Cones (3D DIR-UTE-Cones) sequence. METHODS The sequence used two sequential adiabatic inversion pulses to suppress signals from long T2 tissues, followed by multispoke UTE acquisition to detect signals from short T2 tissues. The two adiabatic inversion pulses are identical with a center frequency located at the water peak, but the spectral width is broad enough to cover both water and fat frequencies. The feasibility of this technique was demonstrated through numerical simulation and phantom studies. Finally, DIR-UTE-Cones was applied to three healthy volunteers to image cortical bone, patellar tendon, and Achilles tendon. T2* was also measured via single-component exponential fitting. RESULTS Numerical simulation suggests that the DIR technique provides perfect nulling of muscle and fat as well as efficient suppression of other long T2 tissues with T1 values between fat and water or those above water. Excellent image contrast can be achieved with DIR-UTE-Cones for the short T2 tissues, with fitted T2* values of 0.28-0.38 ms for cortical bone, 0.56 ± 0.07 ms for the patella tendon, and 0.45 ± 0.06 ms for the Achilles tendon, respectively. CONCLUSION The 3D DIR-UTE-Cones sequence provides robust suppression of long T2 tissues and allows selective imaging as well as T2* measurement of short T2 tissues such as cortical bone, patellar tendon, and the Achilles tendon. Magn Reson Med 79:2555-2563, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
| | - Yanchun Zhu
- Department of Radiology, University of California, San Diego, CA
| | - Xing Lu
- Department of Radiology, University of California, San Diego, CA
| | | | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA
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Yon M, Sarou-Kanian V, Scheler U, Bouler JM, Bujoli B, Massiot D, Fayon F. Solid-state 31P and 1H chemical MR micro-imaging of hard tissues and biomaterials with magic angle spinning at very high magnetic field. Sci Rep 2017; 7:8224. [PMID: 28811630 PMCID: PMC5557955 DOI: 10.1038/s41598-017-08458-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/10/2017] [Indexed: 11/09/2022] Open
Abstract
In this work, we show that it is possible to overcome the limitations of solid-state MRI for rigid tissues due to large line broadening and short dephasing times by combining Magic Angle Spinning (MAS) with rotating pulsed field gradients. This allows recording ex vivo 31P 3D and 2D slice-selected images of rigid tissues and related biomaterials at very high magnetic field, with greatly improved signal to noise ratio and spatial resolution when compared to static conditions. Cross-polarization is employed to enhance contrast and to further depict spatially localized chemical variations in reduced experimental time. In these materials, very high magnetic field and moderate MAS spinning rate directly provide high spectral resolution and enable the use of frequency selective excitation schemes for chemically selective imaging. These new possibilities are exemplified with experiments probing selectively the 3D spatial distribution of apatitic hydroxyl protons inside a mouse tooth with attached jaw bone with a nominal isotropic resolution nearing 100 µm.
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Affiliation(s)
- Maxime Yon
- CNRS, CEMHTI UPR3079, Université d'Orléans, F-45071, Orléans, France.
| | | | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, Dresden, Germany
| | - Jean-Michel Bouler
- CEISAM, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 92208, 44322, Nantes, Cedex 3, France
| | - Bruno Bujoli
- CEISAM, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 92208, 44322, Nantes, Cedex 3, France
| | - Dominique Massiot
- CNRS, CEMHTI UPR3079, Université d'Orléans, F-45071, Orléans, France
| | - Franck Fayon
- CNRS, CEMHTI UPR3079, Université d'Orléans, F-45071, Orléans, France.
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Abbasi-Rad S, Saligheh Rad H. Quantification of Human Cortical Bone Bound and Free Water in Vivo with Ultrashort Echo Time MR Imaging: A Model-based Approach. Radiology 2017; 283:862-872. [DOI: 10.1148/radiol.2016160780] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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25
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Manhard MK, Nyman JS, Does MD. Advances in imaging approaches to fracture risk evaluation. Transl Res 2017; 181:1-14. [PMID: 27816505 PMCID: PMC5357194 DOI: 10.1016/j.trsl.2016.09.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/19/2016] [Accepted: 09/27/2016] [Indexed: 01/23/2023]
Abstract
Fragility fractures are a growing problem worldwide, and current methods for diagnosing osteoporosis do not always identify individuals who require treatment to prevent a fracture and may misidentify those not a risk. Traditionally, fracture risk is assessed using dual-energy X-ray absorptiometry, which provides measurements of areal bone mineral density at sites prone to fracture. Recent advances in imaging show promise in adding new information that could improve the prediction of fracture risk in the clinic. As reviewed herein, advances in quantitative computed tomography (QCT) predict hip and vertebral body strength; high-resolution HR-peripheral QCT (HR-pQCT) and micromagnetic resonance imaging assess the microarchitecture of trabecular bone; quantitative ultrasound measures the modulus or tissue stiffness of cortical bone; and quantitative ultrashort echo-time MRI methods quantify the concentrations of bound water and pore water in cortical bone, which reflect a variety of mechanical properties of bone. Each of these technologies provides unique characteristics of bone and may improve fracture risk diagnoses and reduce prevalence of fractures by helping to guide treatment decisions.
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Affiliation(s)
- Mary Kate Manhard
- Biomedical Engineering, Vanderbilt University, Nashville, TN; Vanderbilt University Institute of Imaging Science, Nashville, TN
| | - Jeffry S Nyman
- Biomedical Engineering, Vanderbilt University, Nashville, TN; Vanderbilt University Institute of Imaging Science, Nashville, TN; Orthopaedic Surgery and Rehabilitation, Vanderbilt University, Nashville, TN; Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN; Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN
| | - Mark D Does
- Biomedical Engineering, Vanderbilt University, Nashville, TN; Vanderbilt University Institute of Imaging Science, Nashville, TN; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN; Electrical Engineering, Vanderbilt University, Nashville, TN.
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26
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Manhard MK, Harkins KD, Gochberg DF, Nyman JS, Does MD. 30-Second bound and pore water concentration mapping of cortical bone using 2D UTE with optimized half-pulses. Magn Reson Med 2017; 77:945-950. [PMID: 28090655 DOI: 10.1002/mrm.26605] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 11/18/2016] [Accepted: 12/21/2016] [Indexed: 11/09/2022]
Abstract
PURPOSE MRI of cortical bone has the potential to offer new information about fracture risk. Current methods are typically performed with 3D acquisitions, which suffer from long scan times and are generally limited to extremities. This work proposes using 2D UTE with half pulses for quantitatively mapping bound and pore water in cortical bone. METHODS Half-pulse 2D UTE methods were implemented on a 3T Philips Achieva scanner using an optimized slice-select gradient waveform, with preparation pulses to selectively image bound or pore water. The 2D methods were quantitatively compared with previously implemented 3D methods in the tibia in five volunteers. RESULTS The mean difference between bound and pore water concentration acquired from 3D and 2D sequences was 0.6 and 0.9 mol 1 H/Lbone (3 and 12%, respectively). While 2D pore water methods tended to slightly overestimate concentrations relative to 3D methods, differences were less than scan-rescan uncertainty and expected differences between healthy and fracture-prone bones. CONCLUSION Quantitative bound and pore water concentration mapping in cortical bone can be accelerated by 2 orders of magnitude using 2D protocols with optimized half-pulse excitation. Magn Reson Med 77:945-950, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Mary Kate Manhard
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA
| | - Kevin D Harkins
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
| | - Jeffry S Nyman
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA.,Orthopaedic Surgery and Rehabilitation, Vanderbilt University, Nashville, Tennessee, USA.,Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark D Does
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Electrical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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Hwang D, Kim S, Abeydeera NA, Statum S, Masuda K, Chung CB, Siriwanarangsun P, Bae WC. Quantitative magnetic resonance imaging of the lumbar intervertebral discs. Quant Imaging Med Surg 2016; 6:744-755. [PMID: 28090450 DOI: 10.21037/qims.2016.12.09] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human lumbar spine is composed of multiple tissue components that serve to provide structural stability and proper nutrition. Conventional magnetic resonance (MR) imaging techniques have been useful for evaluation of IVD, but inadequate at imaging the discovertebral junction and ligamentous tissues due primarily to their short T2 nature. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal from these short T2 tissues, thereby allowing direct and quantitative evaluation. This article discusses the anatomy of the lumbar spine, MR techniques available for morphologic and quantitative MR evaluation of long and short T2 tissues of the lumbar spine, considerations for T2 relaxation modeling and fitting, and existing and new techniques for spine image post-processing, focusing on segmentation. This article will be of interest to radiologic and orthopaedic researchers performing lumbar spine imaging.
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Affiliation(s)
- Dosik Hwang
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA; ; School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Sewon Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Nirusha A Abeydeera
- Department of Radiology, University of California-San Diego, La Jolla, CA, USA
| | - Sheronda Statum
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA; ; Department of Radiology, University of California-San Diego, La Jolla, CA, USA
| | - Koichi Masuda
- Department of Orthopaedic Surgery, University of California-San Diego, La Jolla, CA, USA
| | - Christine B Chung
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA; ; Department of Radiology, University of California-San Diego, La Jolla, CA, USA
| | - Palanan Siriwanarangsun
- Department of Radiology, University of California-San Diego, La Jolla, CA, USA;; Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Won C Bae
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA; ; Department of Radiology, University of California-San Diego, La Jolla, CA, USA
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Yang W, Lee JS, Kharkov B, Ilott AJ, Jerschow A. Low-power slice selective imaging of broad signals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 272:61-67. [PMID: 27639897 PMCID: PMC5071165 DOI: 10.1016/j.jmr.2016.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
One of the major challenges in using magnetic resonance imaging (MRI) to study immobile samples, such as solid materials or rigid tissues like bone or ligaments, is that the images appear dark due to these samples' short-lived signals. Although it is well known that narrowband signals can be excited in inhomogeneously-broadened lines, it is less well known that similar effects can be observed in dipolar-broadened systems. These long-lived signals have not been used much, mainly because their description frequently does not match intuition. While 3D imaging with these signals has previously been reported, here we focus on the demonstration of faster, 2D slice-selective imaging. The faster imaging provides more flexibility for visualizing these rigid objects. We also focus on the frequently-encountered regime wherein the maximum power achievable for rf pulses is significantly weaker than the linewidth. This regime is typically encountered in clinical MRI scans or large volume setups. When compared to UTE and conventional slice-selective spin echo methods, this technique provides better representations of the sample considered here (an eraser sample), and higher signal-to-noise ratios than spin-echo techniques in both the high and low power regimes.
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Affiliation(s)
- Weiqi Yang
- Department of Chemistry, New York University, New York, NY, United States
| | - Jae-Seung Lee
- Department of Chemistry, New York University, New York, NY, United States; Department of Radiology, New York University Langone Medical Center, New York, NY, United States
| | - Boris Kharkov
- Department of Chemistry, New York University, New York, NY, United States
| | - Andrew J Ilott
- Department of Chemistry, New York University, New York, NY, United States
| | - Alexej Jerschow
- Department of Chemistry, New York University, New York, NY, United States.
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29
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Mandl P, Kainberger F, Friberg Hitz M. Imaging in osteoporosis in rheumatic diseases. Best Pract Res Clin Rheumatol 2016; 30:751-765. [PMID: 27931966 DOI: 10.1016/j.berh.2016.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/06/2016] [Accepted: 08/04/2016] [Indexed: 12/25/2022]
Abstract
Osteoporosis is a common comorbidity of all major rheumatic diseases, and manifests itself both systemically and locally. Systemic bone loss manifests because of several factors, primarily inflammation, immobility, and commonly used medical treatment for rheumatic diseases. Local bone loss manifests as periarticular demineralization and bone erosion due to local release of inflammatory agents and cytokines, which promote bone resorption. All these factors contribute to the phenomenon of arthritis-associated osteoporosis. This review summarized the currently available and used methods that play a role in the diagnosis and monitoring of osteoporosis and in the detection of osteoporotic fractures.
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Affiliation(s)
- Peter Mandl
- Division of Rheumatology, 3rd Department of Internal Medicine, Medical University of Vienna, 18-20 Währinger Gürtel, 1090 Vienna, Austria.
| | - Franz Kainberger
- Division of Neuro- and Musculoskeletal Radiology, Department of Radiology and Nuclear Medicine, Medical University of Vienna, 18-20 Währinger Gürtel, 1090 Vienna, Austria.
| | - Mette Friberg Hitz
- Department of Medicine, Endocrinology, Zealand University Hospital, Lykkebaekvej 1, 4600 Koege, Denmark.
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30
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Magnetization transfer imaging of cortical bone in vivo using a zero echo time sequence in mice at 4.7 T: a feasibility study. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:853-862. [PMID: 27384463 DOI: 10.1007/s10334-016-0577-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/09/2016] [Accepted: 06/18/2016] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the feasibility of magnetization transfer (MT) imaging in mice in vivo for the assessment of cortical bone. MATERIALS AND METHODS MT-zero echo time data were acquired at 4.7 T in six mice using MT preparation pulses with two different flip angles (FAs) and a series of ten different off-resonance frequencies (500-15000 Hz). Regions of interest were drawn at multiple levels of the femoral cortical bone. The MT ratio (MTR) was computed for each combination of FAs and off-resonance frequencies. T1 measurements were used to estimate the direct saturation (DS) using a Bloch equation simulation. Estimation of the absorption line width of cortical bone from T2* measurements was also performed. RESULTS MTR values were higher using 3000° FA than 1000° FA. MTR values decreased toward higher off-resonance frequencies. Maximum mean MTR ± standard deviation (SD) of 58.57 ± 5.22 (range 50.44-70.61) was measured with a preparation pulse of 3000° and off-resonance frequency of 500 Hz. Maximum "true" MT effect was estimated at around 2-3 and 5 kHz, respectively, for 1000° and 3000° FA. Mean full width at half maximum ± SD of 577 ± 91 Hz was calculated for the absorption spectral line of the cortical bone. CONCLUSION MT imaging can be used for the assessment of cortical bone in mice in vivo. DS effects are negligible using preparation pulses with off-resonance frequencies greater than 3 kHz.
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Ma YJ, Chang EY, Bydder GM, Du J. Can ultrashort-TE (UTE) MRI sequences on a 3-T clinical scanner detect signal directly from collagen protons: freeze-dry and D2 O exchange studies of cortical bone and Achilles tendon specimens. NMR IN BIOMEDICINE 2016; 29:912-7. [PMID: 27148693 PMCID: PMC4909542 DOI: 10.1002/nbm.3547] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/17/2016] [Accepted: 04/03/2016] [Indexed: 05/24/2023]
Abstract
Ultrashort-TE (UTE) sequences can obtain signal directly from short-T2 , collagen-rich tissues. It is generally accepted that bound and free water can be detected with UTE techniques, but the ability to detect protons directly on the collagen molecule remains controversial. In this study, we investigated the potential of UTE sequences on a 3-T clinical scanner to detect collagen protons via freeze-drying and D2 O-H2 O exchange studies. Experiments were performed on bovine cortical bone and human Achilles tendon specimens, which were either subject to freeze-drying for over 66 h or D2 O-H2 O exchange for 6 days. Specimens were imaged using two- and three-dimensional UTE with Cones trajectory techniques with a minimum TE of 8 μs at 3 T. UTE images before treatment showed high signal from all specimens with bi-component T2 * behavior. Bovine cortical bone showed a shorter T2 * component of 0.36 ms and a longer T2 * component of 2.30 ms with fractions of 78.2% and 21.8% by volume, respectively. Achilles tendon showed a shorter T2 * component of 1.22 ms and a longer T2 * component of 15.1 ms with fractions of 81.1% and 18.9% by volume, respectively. Imaging after freeze-drying or D2 O-H2 O exchange resulted in either the absence or near-absence of signal. These results indicate that bound and free water are the sole sources of UTE signal in bovine cortical bone and human Achilles tendon samples on a clinical 3-T scanner. Protons on the native collagen molecule are not directly visible when imaged using UTE sequences. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, CA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA
- Radiology Service, VA San Diego Healthcare System, San Diego, CA
| | - Graeme M. Bydder
- Department of Radiology, University of California, San Diego, CA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA
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Abstract
Magnetic resonance imaging (MRI) plays a pivotal role for assessment of the musculoskeletal system. It is currently the clinical modality of choice for evaluation of soft tissues including cartilage, ligaments, tendons, muscle, and bone marrow. By comparison, the study of calcified tissue by MRI is still in its infancy. In this article, we review the potential of the modality for assessment of cortical bone properties known to be affected in degenerative bone disease, with focus on parameters related to matrix and mineral densities, and porosity, by means of emerging solid-state (1)H and (31)P MRI techniques. In contrast to soft tissues, the MRI signal in calcified tissues has very short lifetime, on the order of 100 μs to a few milliseconds, demanding customized imaging approaches that allow capture of the signal almost immediately after excitation. The technologies described are suited for quantitatively imaging human cortical bone in specimens as well as in vivo in patients on standard clinical imagers, yielding either concentrations in absolute units when measured against a reference standard, or more simply, in the form of surrogate biomarkers. The two major water fractions in cortical bone are those of collagen-bound and pore water occurring at an approximately 3:1 ratio. Collagen-bound water density provides a direct quantitative measure of osteoid density. While at an earlier stage of development, quantification of mineral phosphorus by (31)P MRI yields mineral density and, together with knowledge of matrix density, should allow quantification of the degree of bone mineralization.
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Affiliation(s)
- Alan C Seifert
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania Medical Center, MRI Education Center, 1st Floor Founders, 3400 Spruce St., Philadelphia, PA, 19104, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania Medical Center, MRI Education Center, 1st Floor Founders, 3400 Spruce St., Philadelphia, PA, 19104, USA.
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Akbari A, Abbasi-Rad S, Rad HS. T1 correlates age: A short-TE MR relaxometry study in vivo on human cortical bone free water at 1.5T. Bone 2016; 83:17-22. [PMID: 26475122 DOI: 10.1016/j.bone.2015.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 10/03/2015] [Accepted: 10/12/2015] [Indexed: 11/30/2022]
Abstract
Large pores of human cortical bone (>30μm) are filled with fluids, essentially consisting of water, suggesting that cortical bone free water can be considered as a reliable surrogate measure of cortical bone porosity and hence quality. Signal from such pores can be reliably captured using Short Echo Time (STE) pulse sequence with echo-time in the range of 1-1.5msec (which should be judiciously selected correspond to T2(⁎) value of free water molecules). Furthermore, it is well-known that cortical bone T1-relaxivity is a function of its geometry, suggesting that cortical bone free water increases with age. In this work, we quantified cortical bone free water longitudinal relaxation time (T1) by a Dual-TR technique using STE pulse sequence. In the sequel, we investigated relationship between STE-derived cortical bone free water T1-values and age in a group of healthy volunteers (thirty subjects covering the age range of 20-70years) at 1.5T. Preliminary results showed that cortical bone free water T1 highly correlates with age (r(2)=0.73, p<0.0001), representing cortical bone free water T1 as a reliable indicator of cortical bone porosity and age-related deterioration. It can be concluded that STE-MRI can be utilized as proper alternative in quantifying cortical bone porosity parameters in-vivo, with the advantages of widespread clinical availability and being cost-effective.
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Affiliation(s)
- Atena Akbari
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahrokh Abbasi-Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamidreza Saligheh Rad
- Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
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Seifert AC, Li C, Wehrli SL, Wehrli FW. A Surrogate Measure of Cortical Bone Matrix Density by Long T2 -Suppressed MRI. J Bone Miner Res 2015; 30:2229-38. [PMID: 26085307 PMCID: PMC4683123 DOI: 10.1002/jbmr.2580] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/05/2015] [Accepted: 06/14/2015] [Indexed: 11/06/2022]
Abstract
Magnetic resonance has the potential to image and quantify two pools of water within bone: free water within the Haversian pore system (transverse relaxation time, T2 > 1 ms), and water hydrogen-bonded to matrix collagen (T2 ∼ 300 to 400 μs). Although total bone water concentration quantified by MRI has been shown to scale with porosity, greater insight into bone matrix density and porosity may be gained by relaxation-based separation of bound and pore water fractions. The objective of this study was to evaluate a recently developed surrogate measurement for matrix density, single adiabatic inversion recovery (SIR) zero echo-time (ZTE) MRI, in human bone. Specimens of tibial cortical bone from 15 donors (aged 27 to 97 years; 8 female and 7 male) were examined at 9.4T field strength using two methods: (1) (1)H ZTE MRI, to capture total (1)H signal, and (2) (1)H SIR-ZTE MRI, to selectively image matrix-associated (1)H signal. Total water, bone matrix, and bone mineral densities were also quantified gravimetrically, and porosity was measured by micro-CT. ZTE apparent total water (1)H concentration was 32.7 ± 3.2 M (range 28.5 to 40.3 M), and was correlated positively with porosity (R(2) = 0.80) and negatively with matrix and mineral densities (R(2) = 0.90 and 0.82, respectively). SIR-ZTE apparent bound water (1)H concentration was 32.9 ± 3.9 M (range 24.4 to 39.8 M), and its correlations were opposite to those of apparent total water: negative with porosity (R(2) = 0.73) and positive with matrix density (R(2) = 0.74) and mineral density (R(2) = 0.72). Porosity was strongly correlated with gravimetric matrix density (R(2) = 0.91, negative) and total water density (R(2) = 0.92, positive). The strong correlations of SIR-ZTE-derived apparent bound water (1)H concentration with ground-truth measurements suggest that this quantitative solid-state MRI method provides a nondestructive surrogate measure of bone matrix density.
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Affiliation(s)
- Alan C Seifert
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Cheng Li
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Suzanne L Wehrli
- NMR Core Facility, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Rajapakse CS, Bashoor-Zadeh M, Li C, Sun W, Wright AC, Wehrli FW. Volumetric Cortical Bone Porosity Assessment with MR Imaging: Validation and Clinical Feasibility. Radiology 2015. [PMID: 26203710 DOI: 10.1148/radiol.15141850] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop a method to assess volumetric cortical bone porosity in clinically practical acquisition times by measuring the signal decay at only two echo times (TEs) as part of a single three-dimensional ultrashort TE (UTE) magnetic resonance (MR) examination. MATERIALS AND METHODS The study was approved by the institutional review board and complied with HIPAA guidelines. Written informed consent was obtained from all subjects. A marker of cortical bone porosity called porosity index was defined as the ratio of UTE image intensities at a long and short TE, and the results were compared with biexponential analysis. Porosity index of midtibia cortical bone samples obtained from 16 donors was compared with ground-truth porosity by using micro-computed tomographic (CT) imaging and bone mineral density by peripheral quantitative CT scanner. Reproducibility of porosity index were tested in volunteers, and clinical feasibility was evaluated in postmenopausal women. Interparameter associations were assessed by using Pearson or Spearman correlation coefficient. RESULTS Bone specimen porosity index was correlated with micro-CT imaging porosity (R(2) = 0.79) and pore size (R(2) = 0.81); age (R(2) = 0.64); peripheral quantitative CT scanner density (R(2) = 0.49, negatively); and pore water fraction (R(2) = 0.62) and T2* (R(2) = 0.64) by biexponential analysis. The reproducibility study yielded a coefficient of variation of 2.2% and intraclass correlation coefficient of 0.97. The study that involved postmenopausal women showed a wide range of porosity index (15%-38%). CONCLUSION A two-point MR imaging method to assess cortical bone porosity in humans was conceived and validated. This approach has the potential for clinical use to assess changes in cortical bone porosity that result from disease or in response to therapy. (©) RSNA, 2015 Online supplemental material is available for this article.
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Affiliation(s)
- Chamith S Rajapakse
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
| | - Mahdieh Bashoor-Zadeh
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
| | - Cheng Li
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
| | - Wenli Sun
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
| | - Alexander C Wright
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
| | - Felix W Wehrli
- From the Department of Radiology, University of Pennsylvania, 1 Founders, 3400 Spruce St, Philadelphia, PA 19104
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Li S, Chang EY, Bae WC, Chung CB, Gao S, Bao S, Bydder GM, Hua Y, Du J. Ultrashort echo time bi-component analysis of cortical bone--a field dependence study. Magn Reson Med 2015; 71:1075-81. [PMID: 23630048 DOI: 10.1002/mrm.24769] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
PURPOSE The purpose of this study is to investigate the effect of differing field strength on the T2* of cortical bone at 1.5 T and 3 T. METHODS Ultrashort echo time pulse sequences were used to study six bovine and nine human bone samples at 1.5 T and 3 T using single- and bi-component T2* analysis. RESULTS On average, the bound water T2* of bovine bone decreased by 16% (from 0.32 ms at 1.5 T to 0.27 ms at 3 T, P < 0.01) and the bound water T2* of human bone decreased by 21% (from 0.42 ms at 1.5 T to 0.33 ms at 3 T, P < 0.01) at the higher field strength. The free water T2* of bovine bone decreased by 50% (from 4.23 ms at 1.5 T to 2.12 ms at 3 T, P < 0.001) and the free water T2* of human bone decreased by 68% (from 7.65 ms at 1.5 T to 2.46 ms at 3 T, P < 0.001) at the higher field strength. Bound and free water fractions showed only minor change with field strength in bovine (< 2%, P > 0.05) and human bone (< 4%, P > 0.05). CONCLUSION Ultrashort echo time bi-component analysis provides consistent bound and free water fractions at 1.5 T and 3 T, thereby allowing field-independent comparisons.
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Affiliation(s)
- Shihong Li
- Department of Radiology, University of California, San Diego, California, USA; Department of Radiology, Hua Dong Hospital, Fudan University, Shanghai, People's Republic of China; Yancheng Medical College, Jiangsu, People's Republic of China
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Manhard MK, Horch RA, Gochberg DF, Nyman JS, Does MD. In Vivo Quantitative MR Imaging of Bound and Pore Water in Cortical Bone. Radiology 2015; 277:221-9. [PMID: 26020434 DOI: 10.1148/radiol.2015140336] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To translate and evaluate an in vivo magnetic resonance (MR) imaging protocol for quantitative mapping of collagen-bound and pore water concentrations in cortical bone that involves relaxation-selective ultrashort echo time (UTE) methods. MATERIALS AND METHODS All HIPAA-compliant studies were performed with institutional review board approval and written informed consent. UTE imaging sequences were implemented on a clinical 3.0-T MR imaging unit and were used for in vivo imaging of bound and pore water in cortical bone. Images of the lower leg and wrist were acquired in five volunteers each (lower leg: two men and three women aged 24, 24, 49, 30, and 26 years; wrist: two men and three women aged 31, 23, 25, 24, and 26 years) to generate bound and pore water concentration maps of the tibia and radius. Each volunteer was imaged three times, and the standard error of the measurements at the region-of-interest (ROI) level was computed as the standard deviation across studies, pooled across volunteers and ROIs. RESULTS Quantitative bound and pore water maps in the tibia and radius, acquired in 8-14 minutes, had per-voxel signal-to-noise ratios of 18 (bound water) and 14 (pore water) and inter-study standard errors of approximately 2 mol (1)H per liter of bone at the ROI level. CONCLUSION The results of this study demonstrate the feasibility of quantitatively mapping bound and pore water in vivo in human cortical bone with practical human MR imaging constraints.
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Affiliation(s)
- Mary Kate Manhard
- From the Departments of Biomedical Engineering (M.K.H., M.D.D.), Radiology (R.A.H., D.F.G.), and Orthopedic Surgery and Rehabilitation (J.S.N.), Vanderbilt University, 1161 21st Ave S, AA-1105 MCN, Nashville, TN 37232-2310
| | - R Adam Horch
- From the Departments of Biomedical Engineering (M.K.H., M.D.D.), Radiology (R.A.H., D.F.G.), and Orthopedic Surgery and Rehabilitation (J.S.N.), Vanderbilt University, 1161 21st Ave S, AA-1105 MCN, Nashville, TN 37232-2310
| | - Daniel F Gochberg
- From the Departments of Biomedical Engineering (M.K.H., M.D.D.), Radiology (R.A.H., D.F.G.), and Orthopedic Surgery and Rehabilitation (J.S.N.), Vanderbilt University, 1161 21st Ave S, AA-1105 MCN, Nashville, TN 37232-2310
| | - Jeffry S Nyman
- From the Departments of Biomedical Engineering (M.K.H., M.D.D.), Radiology (R.A.H., D.F.G.), and Orthopedic Surgery and Rehabilitation (J.S.N.), Vanderbilt University, 1161 21st Ave S, AA-1105 MCN, Nashville, TN 37232-2310
| | - Mark D Does
- From the Departments of Biomedical Engineering (M.K.H., M.D.D.), Radiology (R.A.H., D.F.G.), and Orthopedic Surgery and Rehabilitation (J.S.N.), Vanderbilt University, 1161 21st Ave S, AA-1105 MCN, Nashville, TN 37232-2310
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Wurnig MC, Calcagni M, Kenkel D, Vich M, Weiger M, Andreisek G, Wehrli FW, Boss A. Characterization of trabecular bone density with ultra-short echo-time MRI at 1.5, 3.0 and 7.0 T--comparison with micro-computed tomography. NMR IN BIOMEDICINE 2014; 27:1159-66. [PMID: 25088271 PMCID: PMC5730971 DOI: 10.1002/nbm.3169] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 05/30/2014] [Accepted: 06/23/2014] [Indexed: 05/16/2023]
Abstract
The goal of this study was to test the potential of ultra-short echo-time (UTE) MRI at 1.5, 3.0 and 7.0 T for depiction of trabecular bone structure (of the wrist bones), to evaluate whether T2* relaxation times of bone water and parametric maps of T2* of trabecular bone could be obtained at all three field strengths, and to compare the T2* relaxation times with structural parameters obtained from micro-computed tomography (micro-CT) as a reference standard. Ex vivo carpal bones of six wrists were excised en bloc and underwent MRI at 1.5, 3.0 and 7.0 T in a whole-body MR imager using the head coil. A three-dimensional radial fat-suppressed UTE sequence was applied with subsequent acquisitions, with six different echo times TE of 150, 300, 600, 1200, 3500 and 7000 µs. The T2* relaxation time and pixel-wise computed T2* parametric maps were compared with a micro-computed-tomography reference standard providing trabecular bone structural parameters including porosity (defined as the bone-free fraction within a region of interest), trabecular thickness, trabecular separation, trabecular number and fractal dimension (Dk). T2* relaxation curves and parametric maps could be computed from datasets acquired at all field strengths. Mean T2* relaxation times of trabecular bone were 4580 ± 1040 µs at 1.5 T, 2420 ± 560 µs at 3.0 T and 1220 ± 300 µs at 7.0 T, when averaged over all carpal bones. A positive correlation of T2* with trabecular bone porosity and trabecular separation, and a negative correlation of T2* relaxation time with trabecular thickness, trabecular number and fractal dimension, was detected (p < 0.01 for all field strengths and micro-CT parameters). We conclude that UTE MRI may be useful to characterize the structure of trabecular bone, comparable to micro-CT.
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Affiliation(s)
- Moritz C. Wurnig
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
- Correspondence to: M. C. Wurnig, Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland.
| | - Maurizio Calcagni
- Division of Plastic and Reconstructive Surgery, University Hospital Zurich, Switzerland
| | - David Kenkel
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
| | | | - Markus Weiger
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Gustav Andreisek
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
| | - Felix W. Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, USA
| | - Andreas Boss
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
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Seifert AC, Li C, Rajapakse CS, Bashoor-Zadeh M, Bhagat YA, Wright AC, Zemel BS, Zavaliangos A, Wehrli FW. Bone mineral (31)P and matrix-bound water densities measured by solid-state (31)P and (1)H MRI. NMR IN BIOMEDICINE 2014; 27:739-748. [PMID: 24846186 PMCID: PMC4077547 DOI: 10.1002/nbm.3107] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/20/2014] [Accepted: 03/08/2014] [Indexed: 06/02/2023]
Abstract
Bone is a composite material consisting of mineral and hydrated collagen fractions. MRI of bone is challenging because of extremely short transverse relaxation times, but solid-state imaging sequences exist that can acquire the short-lived signal from bone tissue. Previous work to quantify bone density via MRI used powerful experimental scanners. This work seeks to establish the feasibility of MRI-based measurement on clinical scanners of bone mineral and collagen-bound water densities, the latter as a surrogate of matrix density, and to examine the associations of these parameters with porosity and donors' age. Mineral and matrix-bound water images of reference phantoms and cortical bone from 16 human donors, aged 27-97 years, were acquired by zero-echo-time 31-phosphorus ((31)P) and 1-hydrogen ((1)H) MRI on whole body 7T and 3T scanners, respectively. Images were corrected for relaxation and RF inhomogeneity to obtain density maps. Cortical porosity was measured by micro-computed tomography (μCT), and apparent mineral density by peripheral quantitative CT (pQCT). MRI-derived densities were compared to X-ray-based measurements by least-squares regression. Mean bone mineral (31)P density was 6.74 ± 1.22 mol/l (corresponding to 1129 ± 204 mg/cc mineral), and mean bound water (1)H density was 31.3 ± 4.2 mol/l (corresponding to 28.3 ± 3.7 %v/v). Both (31)P and bound water (BW) densities were correlated negatively with porosity ((31)P: R(2) = 0.32, p < 0.005; BW: R(2) = 0.63, p < 0.0005) and age ((31)P: R(2) = 0.39, p < 0.05; BW: R(2) = 0.70, p < 0.0001), and positively with pQCT density ((31)P: R(2) = 0.46, p < 0.05; BW: R(2) = 0.50, p < 0.005). In contrast, the bone mineralization ratio (expressed here as the ratio of (31)P density to bound water density), which is proportional to true bone mineralization, was found to be uncorrelated with porosity, age or pQCT density. This work establishes the feasibility of image-based quantification of bone mineral and bound water densities using clinical hardware.
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Affiliation(s)
- Alan C Seifert
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Li C, Seifert AC, Rad HS, Bhagat YA, Rajapakse CS, Sun W, Lam SCB, Wehrli FW. Cortical bone water concentration: dependence of MR imaging measures on age and pore volume fraction. Radiology 2014; 272:796-806. [PMID: 24814179 DOI: 10.1148/radiol.14132585] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
PURPOSE To quantify bulk bone water to test the hypothesis that bone water concentration (BWC) is negatively correlated with bone mineral density (BMD) and is positively correlated with age, and to propose the suppression ratio (SR) (the ratio of signal amplitude without to that with long-T2 suppression) as a potentially stronger surrogate measure of porosity, which is evaluated ex vivo and in vivo. MATERIALS AND METHODS Human subject studies were conducted in compliance with institutional review board and HIPAA regulations. Healthy men and women (n = 72; age range, 20-80 years) were examined with a hybrid radial ultrashort echo time magnetic resonance (MR) imaging sequence at 3.0 T, and BWC was determined in the tibial midshaft. In a subset of 40 female subjects, the SR was measured with a similar sequence. Cortical volumetric BMD (vBMD) was measured by means of peripheral quantitative computed tomography (CT). The method was validated against micro-CT-derived porosity in 13 donor human cortical bone specimens. Associations among parameters were evaluated by using standard statistical tools. RESULTS BWC was positively correlated with age (r = 0.52; 95% confidence interval [CI]: 0.22, 0.73; P = .002) and negatively correlated with vBMD at the same location (r = -0.57; 95% CI: -0.76, -0.29; P < .001). Data were suggestive of stronger associations with SR (r = 0.64, 95% CI: 0.39, 0.81, P < .001 for age; r = -0.67, 95% CI: -0.82, -0.43, P < .001 for vBMD; P < .001 for both), indicating that SR may be a more direct measure of porosity. This interpretation was supported by ex vivo measurements showing SR to be strongly positively correlated with micro-CT porosity (r = 0.88; 95% CI: 0.64, 0.96; P < .001) and with age (r = 0.87; 95% CI: 0.62, 0.96; P < .001). CONCLUSION The MR imaging-derived SR may serve as a biomarker for cortical bone porosity that is potentially superior to BWC, but corroboration in larger cohorts is indicated.
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Affiliation(s)
- Cheng Li
- From the Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, 1 Founders Building, MRI Education Center, 3400 Spruce St, Philadelphia, PA 19104
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Lee YH, Kim S, Song HT, Kim I, Suh JS. Weighted subtraction in 3D ultrashort echo time (UTE) imaging for visualization of short T2 tissues of the knee. Acta Radiol 2014; 55:454-61. [PMID: 23934936 DOI: 10.1177/0284185113496994] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ultrashort echo time (UTE) image to directly visualize short T2 tissues requires postprocessing for the suppression of the surrounding long T2 tissues in a clinical magnetic resonance imaging (MRI) scanner. Weighted subtraction of UTE images with an optimal weighting factor could provide high positive contrast with adequate suppression. PURPOSE To demonstrate in-vivo UTE MRI with weighted subtractions of dual echo UTE imaging using a 3 T clinical MRI and to determine the optimal weighting factors through the analyses of signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs). MATERIAL AND METHODS Forty-seven consecutive knee MR including dual echo 3D UTE sequence (TE of 70 µs and 3.82 ms) were reviewed. Seven patients with normal findings in the knee MR were included in the current study. For variably weighted subtraction images, the initial UTE image was rescaled relative to that of the second echo image with weighting factors from 0.1 to 4.0. Thirty-five pairs of the ROI measurements of the UTE image and second long echo images were repeated after 2 weeks. For quantitative assessment, SNR and CNR were measured from the ROIs on the patellar tendon, cartilage, cortical bone, meniscus, and infrapatellar fat pad. Intra-observer agreement was assessed by using both Cohen's Kappa and Bland-Altman approach. RESULTS The short T2 tissue could be visualized with adequate suppression on the subtraction images. Considering the CNRs and SNRs, the optimal ranges of the weighting factors could be suggested: 0.3 for the tendon, 0.4 for the cortical bone, and 1.0 for the meniscus. The 35 paired measurements showed excellent agreement with statistical significance (P < 0.05). CONCLUSION The 3D UTE MRI provides imaging of short T2 tissues which cannot be visualized by conventional MRI. Using weighted subtractions with optimal weighting values, each tissue can be optimally depicted by overcoming the reduced T2 contrast.
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Affiliation(s)
- Young Han Lee
- Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sungjun Kim
- Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ho-Taek Song
- Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - InSeong Kim
- Siemens Healthcare, Seoul, Republic of Korea
| | - Jin-Suck Suh
- Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute, and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
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Abstract
The osteochondral junction is composed of numerous tissue components and serves important functions relating to structural stability and proper nutrition in joints such as the knee and spine. Conventional MR techniques have been inadequate at imaging the tissues of the osteochondral junction primarily because of the intrinsically short T2 nature of these tissues, rendering them "invisible" with the standard acquisitions. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal of osteochondral tissues, thereby allowing direct evaluation. This article reviews the anatomy of the osteochondral junction of the knee and the spine, technical aspects of UTE MRI, and the application of UTE MRI for evaluation of the osteochondral junction.
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Affiliation(s)
- Won C Bae
- Department of Radiology, University of California, San Diego, 408 Dickinson St., San Diego, CA 92103-8226, USA
| | - Reni Biswas
- Department of Radiology, University of California, San Diego, 408 Dickinson St., San Diego, CA 92103-8226, USA
| | - Karen Chen
- Department of Radiology, University of California, San Diego, 408 Dickinson St., San Diego, CA 92103-8226, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, 408 Dickinson St., San Diego, CA 92103-8226, USA
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, 408 Dickinson St., San Diego, CA 92103-8226, USA
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Deligianni X, Bär P, Scheffler K, Trattnig S, Bieri O. Water-selective excitation of short T2
species with binomial pulses. Magn Reson Med 2013; 72:800-5. [DOI: 10.1002/mrm.24978] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 09/05/2013] [Accepted: 09/11/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Xeni Deligianni
- Department of Radiology; Division of Radiological Physics, University of Basel Hospital; Basel Switzerland
| | - Peter Bär
- MR Center of Excellence, Department of Radiology; Medical University Vienna; Vienna Austria
| | - Klaus Scheffler
- High-Field Magnetic Resonance Center; Max-Planck Institute for Biological Cybernetics; Tübingen Germany
- Department of Biomedical Magnetic Resonance; University Hospital Tübingen; Tübingen Germany
| | - Siegfried Trattnig
- MR Center of Excellence, Department of Radiology; Medical University Vienna; Vienna Austria
| | - Oliver Bieri
- Department of Radiology; Division of Radiological Physics, University of Basel Hospital; Basel Switzerland
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Seifert AC, Wright AC, Wehrli SL, Ong HH, Li C, Wehrli FW. 31P NMR relaxation of cortical bone mineral at multiple magnetic field strengths and levels of demineralization. NMR IN BIOMEDICINE 2013; 26:1158-66. [PMID: 23505120 PMCID: PMC3715596 DOI: 10.1002/nbm.2930] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 01/07/2013] [Accepted: 01/08/2013] [Indexed: 05/10/2023]
Abstract
Recent work has shown that solid-state (1) H and (31) P MRI can provide detailed insight into bone matrix and mineral properties, thereby potentially enabling differentiation of osteoporosis from osteomalacia. However, (31) P MRI of bone mineral is hampered by unfavorable relaxation properties. Hence, accurate knowledge of these properties is critical to optimizing MRI of bone phosphorus. In this work, (31) P MRI signal-to-noise ratio (SNR) was predicted on the basis of T1 and T2 * (effective transverse relaxation time) measured in lamb bone at six field strengths (1.5-11.7 T) and subsequently verified by 3D ultra-short echo-time and zero echo-time imaging. Further, T1 was measured in deuterium-exchanged bone and partially demineralized bone. (31) P T2 * was found to decrease from 220.3 ± 4.3 µs to 98.0 ± 1.4 µs from 1.5 to 11.7 T, and T1 to increase from 12.8 ± 0.5 s to 97.3 ± 6.4 s. Deuteron substitution of exchangeable water showed that 76% of the (31) P longitudinal relaxation rate is due to (1) H-(31) P dipolar interactions. Lastly, hypomineralization was found to decrease T1, which may have implications for (31) P MRI based mineralization density quantification. Despite the steep decrease in the T2 */T1 ratio, SNR should increase with field strength as B0 (0.4) for sample-dominated noise and as B0 (1.1) for coil-dominated noise. This was confirmed by imaging experiments.
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Affiliation(s)
- Alan C Seifert
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Zhang B, Lee JS, Khitrin A, Jerschow A. Long lived NMR signal in bone. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:1-4. [PMID: 23562664 PMCID: PMC3660456 DOI: 10.1016/j.jmr.2013.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 06/02/2023]
Abstract
Solids and rigid tissues, such as bone, ligaments, and tendons, typically appear dark in MRI, which is due to the extremely short-lived proton nuclear magnetic resonance signals. This short lifetime is due to strong dipolar interactions between immobilized proton spins, which render it challenging to detect these signals with sufficient resolution and sensitivity. Here we show the possibility of exciting long-lived signals in cortical bone tissue with a signature consistent with that of bound water signals. It is further shown that dipolar coupling networks are an integral requirement for the excitation of these long-lived signals. The use of these signals could enhance the ability to visualize rigid tissues and solid samples with high resolution and sensitivity via MRI.
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Affiliation(s)
- Boyang Zhang
- Chemistry Department, New York University, New York, NY 10003
| | - Jae-Seung Lee
- Chemistry Department, New York University, New York, NY 10003
- Center for Biomedical Imaging, Radiology Department, New York University, New York, NY 10003
| | - Anatoly Khitrin
- Department of Chemistry, Kent State University, Kent, OH 44242
| | - Alexej Jerschow
- Chemistry Department, New York University, New York, NY 10003
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Du J, Bydder GM. Qualitative and quantitative ultrashort-TE MRI of cortical bone. NMR IN BIOMEDICINE 2013; 26:489-506. [PMID: 23280581 PMCID: PMC4206448 DOI: 10.1002/nbm.2906] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 10/19/2012] [Accepted: 11/18/2012] [Indexed: 05/08/2023]
Abstract
Osteoporosis causes over 1.5 million fractures per year, costing about $15 billion annually in the USA. Current guidelines utilize bone mineral density (BMD) to assess fracture risk; however, BMD alone only accounts for 30-50% of fractures. The other two major components of bone, organic matrix and water, contribute significantly to bone mechanical properties, but cannot be assessed with conventional imaging techniques in spite of the fact that they make up about 57% of cortical bone by volume. Conventional clinical MRI usually detects signals from water in tissues without difficulty, but cannot detect the water bound to the organic matrix, or the free water in the microscopic pores of the Haversian and the lacunar-canalicular system of cortical bone, because of their very short apparent transverse relaxation times (T2 *). In recent years, a new class of sequences, ultrashort-TE (UTE) sequences, with nominal TEs of less than 100 µs, which are much shorter than the TEs available with conventional sequences, have received increasing interest. These sequences can detect water signals from within cortical bone and provide an opportunity to study disease of this tissue in a new way. This review summarizes the recent developments in qualitative UTE imaging (techniques and contrast mechanisms to produce bone images with high contrast) and quantitative UTE imaging (techniques to quantify the MR properties, including T1 , T2 * and the magnetization transfer ratio, and tissue properties, including bone perfusion, as well as total, bound and free water content) of cortical bone in vitro and in vivo. The limitations of the current techniques for clinical applications and future directions are also discussed.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, CA 92103-8226, USA.
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Wehrli FW. Magnetic resonance of calcified tissues. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 229:35-48. [PMID: 23414678 PMCID: PMC4746726 DOI: 10.1016/j.jmr.2012.12.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 05/06/2023]
Abstract
MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues--key among them bone--are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author's laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI.
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Affiliation(s)
- Felix W Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, USA.
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Browaeys P, Larson TL, Wong ML, Patel U. Can MRI replace CT in evaluating semicircular canal dehiscence? AJNR Am J Neuroradiol 2013; 34:1421-7. [PMID: 23518357 DOI: 10.3174/ajnr.a3459] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND PURPOSE Patients with symptoms of semicircular canal dehiscence often undergo both CT and MR imaging. We assessed whether FIESTA can replace temporal bone CT in evaluating patients for SC dehiscence. MATERIALS AND METHODS We retrospectively reviewed 112 consecutive patients (224 ears) with vestibulocochlear symptoms who underwent concurrent MR imaging and CT of the temporal bones between 2007 and 2009. MR imaging protocol included a FIESTA sequence covering the temporal bone (axial 0.8-mm section thickness, 0.4-mm spacing, coronal/oblique reformations; 41 patients at 1.5T, 71 patients at 3T). CT was performed on a 64-row multidetector row scanner (0.625-mm axial acquisition, with coronal/oblique reformations). Both ears of each patient were evaluated for dehiscence of the superior and posterior semicircular canals in consensual fashion by 2 neuroradiologists. Analysis of the FIESTA sequence and reformations was performed first for the MR imaging evaluation. CT evaluation was performed at least 2 weeks after the MR imaging review, resulting in a blinded comparison of CT with MR imaging. CT was used as the reference standard to evaluate the MR imaging results. RESULTS For SSC dehiscence, MR imaging sensitivity was 100%, specificity was 96.5%, positive predictive value was 61.1%, and negative predictive value was 100% in comparison with CT. For PSC dehiscence, MR imaging sensitivity was 100%, specificity was 99.1%, positive predictive value was 33.3%, and negative predictive value was 100% in comparison with CT. CONCLUSIONS MR imaging, with a sensitivity and negative predictive value of 100%, conclusively excludes SSC or PSC dehiscence. Negative findings on MR imaging preclude the need for CT to detect SC dehiscence. Only patients with positive findings on MR imaging should undergo CT evaluation.
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Affiliation(s)
- P Browaeys
- Department of Radiology, University Hospital, Lausanne, Switzerland.
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Deligianni X, Bär P, Scheffler K, Trattnig S, Bieri O. High-resolution Fourier-encoded sub-millisecond echo time musculoskeletal imaging at 3 Tesla and 7 Tesla. Magn Reson Med 2012; 70:1434-9. [DOI: 10.1002/mrm.24578] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/06/2012] [Accepted: 11/12/2012] [Indexed: 11/11/2022]
Affiliation(s)
- X. Deligianni
- Division of Radiological Physics; Department of Radiology; University of Basel Hospital; Basel Switzerland
| | - P. Bär
- Siemens Healthcare; Erlangen Germany
| | - K. Scheffler
- High-Field Magnetic Resonance Center; Max-Planck Institute for Biological Cybernetics; Tübingen Germany
- Department of Biomedical Magnetic Resonance; University Hospital Tübingen; Tübingen Germany
| | - S. Trattnig
- Department of Radiology; MR Center of Excellence; Medical University Vienna; Vienna Austria
| | - O. Bieri
- Division of Radiological Physics; Department of Radiology; University of Basel Hospital; Basel Switzerland
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Ong HH, Wright AC, Wehrli FW. Deuterium nuclear magnetic resonance unambiguously quantifies pore and collagen-bound water in cortical bone. J Bone Miner Res 2012; 27:2573-81. [PMID: 22807107 PMCID: PMC3488140 DOI: 10.1002/jbmr.1709] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/26/2012] [Accepted: 07/05/2012] [Indexed: 12/22/2022]
Abstract
Bone water (BW) plays a pivotal role in nutrient transport and conferring bone with its viscoelastic mechanical properties. BW is partitioned between the pore spaces of the Haversian and lacuno-canalicular system, and water predominantly bound to the matrix proteins (essentially collagen). The general model of BW is that the former predominantly experiences fast isotropic molecular reorientation, whereas water in the bone matrix undergoes slower anisotropic rotational diffusion. Here, we provide direct evidence for the correctness of this model and show that unambiguous quantification in situ of these two functionally and dynamically different BW fractions is possible. The approach chosen relies on nuclear magnetic resonance (NMR) of deuterium ((2) H) that unambiguously separates and quantifies the two fractions on the basis of their distinguishing microdynamic properties. Twenty-four specimens of the human tibial cortex from 6 donors (3 male, 3 female, ages 27-83 years) were cored and (2) H spectra recorded at 62 MHz (9.4 Tesla) on a Bruker Instruments DMX 400 spectrometer after exchange of native BW with (2) H(2) O. Spectra consisted of a doublet signal resulting from quadrupole interaction of water bound to collagen. Doublet splittings were found to depend on the orientation of the osteonal axis with respect to the magnetic field direction (8.2 and 4.3 kHz for parallel and perpendicular orientation, respectively). In contrast, the isotropically reorienting pore-resident water yielded a single resonance line superimposed on the doublet. Nulling of the singlet resonance allowed separation of the two fractions. The results indicate that in human cortical bone 60% to 80% of detectable BW is collagen-bound. Porosity determined as the difference between total BW and collagen bound water fraction was found to strongly parallel micro-computed tomography (µCT)-based measurements (R(2) = 0.91). Our method provides means for direct validation of emerging relaxation-based measurements of cortical bone porosity by proton MRI.
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Affiliation(s)
- Henry H Ong
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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