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Vu BTD, Kamona N, Kim Y, Ng JJ, Jones BC, Wehrli FW, Song HK, Bartlett SP, Lee H, Rajapakse CS. Three contrasts in 3 min: Rapid, high-resolution, and bone-selective UTE MRI for craniofacial imaging with automated deep-learning skull segmentation. Magn Reson Med 2024. [PMID: 39219299 DOI: 10.1002/mrm.30275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 07/17/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
PURPOSE Ultrashort echo time (UTE) MRI can be a radiation-free alternative to CT for craniofacial imaging of pediatric patients. However, unlike CT, bone-specific MR imaging is limited by long scan times, relatively low spatial resolution, and a time-consuming bone segmentation workflow. METHODS A rapid, high-resolution UTE technique for brain and skull imaging in conjunction with an automatic segmentation pipeline was developed. A dual-RF, dual-echo UTE sequence was optimized for rapid scan time (3 min) and smaller voxel size (0.65 mm3). A weighted least-squares conjugate gradient method for computing the bone-selective image improves bone specificity while retaining bone sensitivity. Additionally, a deep-learning U-Net model was trained to automatically segment the skull from the bone-selective images. Ten healthy adult volunteers (six male, age 31.5 ± 10 years) and three pediatric patients (two male, ages 12 to 15 years) were scanned at 3 T. Clinical CT for the three patients were obtained for validation. Similarities in 3D skull reconstructions relative to clinical standard CT were evaluated based on the Dice similarity coefficient and Hausdorff distance. Craniometric measurements were used to assess geometric accuracy of the 3D skull renderings. RESULTS The weighted least-squares method produces images with enhanced bone specificity, suppression of soft tissue, and separation from air at the sinuses when validated against CT in pediatric patients. Dice similarity coefficient overlap was 0.86 ± 0.05, and the 95th percentile Hausdorff distance was 1.77 ± 0.49 mm between the full-skull binary masks of the optimized UTE and CT in the testing dataset. CONCLUSION An optimized MRI acquisition, reconstruction, and segmentation workflow for craniofacial imaging was developed.
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Affiliation(s)
- Brian-Tinh Duc Vu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nada Kamona
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yohan Kim
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jinggang J Ng
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Brandon C Jones
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hee Kwon Song
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Scott P Bartlett
- Division of Plastic, Reconstructive and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Hyunyeol Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- School of Electronics Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Chamith S Rajapakse
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Jerban S, Ma Y, Wei Z, Shen M, Ibrahim Z, Jang H, Lu P, Chang DG, Woods G, Chung CB, Chang EY, Du J. Ultrashort echo time MRI detects significantly lower collagen but higher pore water in the tibial cortex of female patients with osteopenia and osteoporosis. J Bone Miner Res 2024; 39:707-716. [PMID: 38591788 DOI: 10.1093/jbmr/zjae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 03/10/2024] [Accepted: 04/04/2024] [Indexed: 04/10/2024]
Abstract
Ultrashort echo time (UTE) MRI can quantify the major proton pool densities in cortical bone, including total (TWPD), bound (BWPD), and pore water (PWPD) proton densities, as well as the macromolecular proton density (MMPD), associated with the collagen content, which is calculated using macromolecular fraction (MMF) from UTE magnetization transfer (UTE-MT) modeling. This study aimed to investigate the differences in water and collagen contents in tibial cortical bone, between female osteopenia (OPe) patients, osteoporosis (OPo) patients, and young participants (Young). Being postmenopausal and above 55 yr old were the inclusion criteria for OPe and OPo groups. The tibial shaft of 14 OPe (72.5 ± 6.8 yr old), 31 OPo (72.0 ± 6.4 yr old), and 31 young subjects (28.0 ± 6.1 yr old) were scanned using a knee coil on a clinical 3T scanner. Basic UTE, inversion recovery UTE, and UTE-MT sequences were performed. Investigated biomarkers were compared between groups using Kruskal-Wallis test. Spearman's correlation coefficients were calculated between the TH DXA T-score and UTE-MRI results. MMF, BWPD, and MMPD were significantly lower in OPo patients than in the young group, whereas T1, TWPD, and PWPD were significantly higher in OPo patients. The largest OPo/Young average percentage differences were found in MMF (41.9%), PWPD (103.5%), and MMPD (64.0%). PWPD was significantly higher (50.7%), while BWPD was significantly lower (16.4%) in OPe than the Young group on average. MMF was found to be significantly lower (27%) in OPo patients compared with OPe group. T1, MMF, TWPD, PWPD, and MMPD values significantly correlated with the TH DXA T-scores (provided by the patients and only available for OPe and OPo patients). DXA T-score showed the highest correlations with PWPD (R = 0.55) and MMF (R = 0.56) values. TWPD, PWPD, and MMF estimated using the UTE-MRI sequences were recommended to evaluate individuals with OPe and OPo.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Zhao Wei
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Meghan Shen
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Zubaid Ibrahim
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA 92093, United States
| | - Pengzhe Lu
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, United States
- Department of Neurosciences, University of California, San Diego, CA 92093, United States
| | - Douglas G Chang
- Department of Orthopaedic Surgery, University of California, San Diego, CA 92093, United States
| | - Gina Woods
- Department of Medicine, University of California, San Diego, CA 92093, United States
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, CA 92093, United States
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, United States
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA 92093, United States
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA 92093, United States
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, United States
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Sango-Solanas P, Tse Ve Koon K, Van Reeth E, Nicolle S, Palierne JF, Caussy C, Beuf O. Ultrashort echo time magnetic resonance elastography for quantification of the mechanical properties of short T2 tissues via optimal control-based radiofrequency pulses. NMR IN BIOMEDICINE 2024:e5210. [PMID: 38993021 DOI: 10.1002/nbm.5210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 05/22/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
The aim of the current study is to demonstrate the feasibility of radiofrequency (RF) pulses generated via an optimal control (OC) algorithm to perform magnetic resonance elastography (MRE) and quantify the mechanical properties of materials with very short transverse relaxation times (T2 < 5 ms) for the first time. OC theory applied to MRE provides RF pulses that bring isochromats from the equilibrium state to a fixed target state, which corresponds to the phase pattern of a conventional MRE acquisition. Such RF pulses applied with a constant gradient allow to simultaneously perform slice selection and motion encoding in the slice direction. Unlike conventional MRE, no additional motion-encoding gradients (MEGs) are needed, enabling shorter echo times. OC pulses were implemented both in turbo spin echo (OC rapid acquisition with refocused echoes [RARE]) and ultrashort echo time (OC UTE) sequences to compare their motion-encoding efficiency with the conventional MEG encoding (classical MEG MRE). MRE experiments were carried out on agar phantoms with very short T2 values and on an ex vivo bovine tendon. Magnitude images, wave field images, phase-to-noise ratio (PNR), and shear storage modulus maps were compared between OC RARE, OC UTE, and classical MEG MRE in samples with different T2 values. Shear storage modulus values of the agar phantoms were in agreement with values found in the literature, and that of the bovine tendon was corroborated with rheometry measurements. Only the OC sequences could encode motion in very short T2 samples, and only OC UTE sequences yielded magnitude images enabling proper visualization of short T2 samples and tissues. The OC UTE sequence produced the best PNRs, demonstrating its ability to perform anatomical and mechanical characterization. Its success warrants in vivo confirmation in further studies.
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Affiliation(s)
- Pilar Sango-Solanas
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
| | - Kevin Tse Ve Koon
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
| | - Eric Van Reeth
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
- CPE Lyon, Département Sciences du Numérique, Lyon, France
| | - Stéphane Nicolle
- Univ Lyon, Univ Gustave Eiffel, Univ Claude Bernard Lyon 1, LBMC UMR_T 9406, Lyon, France
| | | | - Cyrielle Caussy
- Univ Lyon, CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
- Hospices Civils de Lyon, Département Endocrinologie, Diabète et Nutrition, Hôpital Lyon Sud, Pierre-Bénite, France
| | - Olivier Beuf
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
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Kassey VB, Walle M, Egan J, Yeritsyan D, Beeram I, Wu Y, Snyder BD, Rodriguez EK, Ackerman JL, Nazarian A. Quantitative 31P magnetic resonance imaging on pathologic rat bones by ZTE at 7T. Bone 2024; 180:116996. [PMID: 38154764 PMCID: PMC10843610 DOI: 10.1016/j.bone.2023.116996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023]
Abstract
BACKGROUND Osteoporosis is characterized by low bone mineral density (BMD), which predisposes individuals to frequent fragility fractures. Quantitative BMD measurements can potentially help distinguish bone pathologies and allow clinicians to provide disease-relieving therapies. Our group has developed non-invasive and non-ionizing magnetic resonance imaging (MRI) techniques to measure bone mineral density quantitatively. Dual-energy X-ray Absorptiometry (DXA) is a clinically approved non-invasive modality to diagnose osteoporosis but has associated disadvantages and limitations. PURPOSE Evaluate the clinical feasibility of phosphorus (31P) MRI as a non-invasive and non-ionizing medical diagnostic tool to compute bone mineral density to help differentiate between different metabolic bone diseases. MATERIALS AND METHODS Fifteen ex-vivo rat bones in three groups [control, ovariectomized (osteoporosis), and vitamin-D deficient (osteomalacia - hypo-mineralized) were scanned to compute BMD. A double-tuned (1H/31P) transmit-receive single RF coil was custom-designed and in-house-built with a better filling factor and strong radiofrequency (B1) field to acquire solid-state 31P MR images from rat femurs with an optimum signal-to-noise ratio (SNR). Micro-computed tomography (μCT) and gold-standard gravimetric analyses were performed to compare and validate MRI-derived bone mineral densities. RESULTS Three-dimensional 31P MR images of rat bones were obtained with a zero-echo-time (ZTE) sequence with 468 μm spatial resolution and 12-17 SNR on a Bruker 7 T Biospec having multinuclear capability. BMD was measured quantitatively on cortical and trabecular bones with a known standard reference. A strong positive correlation (R = 0.99) and a slope close to 1 in phantom measurements indicate that the densities measured by 31P ZTE MRI are close to the physical densities in computing quantitative BMD. The 31P NMR properties (resonance linewidth of 4 kHz and T1 of 67 s) of ex-vivo rat bones were measured, and 31P ZTE imaging parameters were optimized. The BMD results obtained from MRI are in good agreement with μCT and gravimetry results. CONCLUSION Quantitative measurements of BMD on ex-vivo rat femurs were successfully conducted on a 7 T preclinical scanner. This study suggests that quantitative measurements of BMD are feasible on humans in clinical MRI with suitable hardware, RF coils, and pulse sequences with optimized parameters within an acceptable scan time since human femurs are approximately ten times larger than rat femurs. As MRI provides quantitative in-vivo data, various systemic musculoskeletal conditions can be diagnosed potentially in humans.
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Affiliation(s)
- Victor B Kassey
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Department of Orthopaedic Surgery, Children's Hospital, Boston, MA 02115, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Matthias Walle
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Jonathan Egan
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Diana Yeritsyan
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Indeevar Beeram
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Yaotang Wu
- Department of Orthopaedic Surgery, Children's Hospital, Boston, MA 02115, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Brian D Snyder
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Department of Orthopaedic Surgery, Children's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Edward K Rodriguez
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Jerome L Ackerman
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Ara Nazarian
- Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Department of Orthopaedic Surgery, Yerevan State Medical University, Yerevan, Armenia; Harvard Medical School, Boston, MA 02115, USA.
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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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Kamona N, Jones BC, Lee H, Song HK, Rajapakse CS, Wagner CS, Bartlett SP, Wehrli FW. Cranial bone imaging using ultrashort echo-time bone-selective MRI as an alternative to gradient-echo based "black-bone" techniques. MAGMA (NEW YORK, N.Y.) 2024; 37:83-92. [PMID: 37934295 PMCID: PMC10923077 DOI: 10.1007/s10334-023-01125-8] [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: 06/23/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023]
Abstract
OBJECTIVES CT is the clinical standard for surgical planning of craniofacial abnormalities in pediatric patients. This study evaluated three MRI cranial bone imaging techniques for their strengths and limitations as a radiation-free alternative to CT. METHODS Ten healthy adults were scanned at 3 T with three MRI sequences: dual-radiofrequency and dual-echo ultrashort echo time sequence (DURANDE), zero echo time (ZTE), and gradient-echo (GRE). DURANDE bright-bone images were generated by exploiting bone signal intensity dependence on RF pulse duration and echo time, while ZTE bright-bone images were obtained via logarithmic inversion. Three skull segmentations were derived, and the overlap of the binary masks was quantified using dice similarity coefficient. Craniometric distances were measured, and their agreement was quantified. RESULTS There was good overlap of the three masks and excellent agreement among craniometric distances. DURANDE and ZTE showed superior air-bone contrast (i.e., sinuses) and soft-tissue suppression compared to GRE. DISCUSSIONS ZTE has low levels of acoustic noise, however, ZTE images had lower contrast near facial bones (e.g., zygomatic) and require effective bias-field correction to separate bone from air and soft-tissue. DURANDE utilizes a dual-echo subtraction post-processing approach to yield bone-specific images, but the sequence is not currently manufacturer-supported and requires scanner-specific gradient-delay corrections.
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Affiliation(s)
- Nada Kamona
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Brandon C Jones
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Hyunyeol Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- School of Electronics Engineering, Kyungpook National University, Daegu, South Korea
| | - Hee Kwon Song
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Chamith S Rajapakse
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Connor S Wagner
- Division of Plastic, Reconstructive, and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Scott P Bartlett
- Division of Plastic, Reconstructive, and Oral Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Griffith JF, Yip SWY, van der Heijden RA, Valenzuela RF, Yeung DKW. Perfusion Imaging of the Musculoskeletal System. Magn Reson Imaging Clin N Am 2024; 32:181-206. [PMID: 38007280 DOI: 10.1016/j.mric.2023.07.004] [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] [Indexed: 11/27/2023]
Abstract
Perfusion imaging is the aspect of functional imaging, which is most applicable to the musculoskeletal system. In this review, the anatomy and physiology of bone perfusion is briefly outlined as are the methods of acquiring perfusion data on MR imaging. The current clinical indications of perfusion related to the assessment of soft tissue and bone tumors, synovitis, osteoarthritis, avascular necrosis, Keinbock's disease, diabetic foot, osteochondritis dissecans, and Paget's disease of bone are reviewed. Challenges and opportunities related to perfusion imaging of the musculoskeletal system are also briefly addressed.
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Affiliation(s)
- James F Griffith
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong.
| | - Stefanie W Y Yip
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong
| | - Rianne A van der Heijden
- Department of Radiology and Nuclear Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Raul F Valenzuela
- Department of Musculoskeletal Imaging, The University of Texas, MD Anderson Cancer Center, USA
| | - David K W Yeung
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong
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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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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: 1] [Impact Index Per Article: 1.0] [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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10
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Ketsiri T, Uppuganti S, Harkins KD, Gochberg DF, Nyman JS, Does MD. T 1 relaxation of bound and pore water in cortical bone. NMR IN BIOMEDICINE 2023; 36:e4878. [PMID: 36418236 DOI: 10.1002/nbm.4878] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/01/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
MRI measures of bound and/or pore water concentration in cortical bone offer potential diagnostics of bone fracture risk. The transverse relaxation characteristics of both bound and pore water are relatively well understood and have been used to design clinical MRI pulse sequences to image each water pool quantitatively. However, these methods are also sensitive to longitudinal relaxation characteristics, which have been less well studied. Here, spectroscopic relaxometry measurements of 31 human cortical bone specimens provided a more detailed picture of T 1 of both bound and pore water. The results included mean, standard deviation, and range of T 1 spectra from both bound and pore water, as well as novel presentations of the 2D T 1 - T 2 distribution of pore water. Importantly, for each sample the pore water T 1 spectrum was found to span more than one order of magnitude and varied substantially across the 31 sample studies. Because many existing methods assume pore water T 1 to be mono-exponential and constant across individuals, the results were used to compute the potential effect neglecting this intra- and intersample T 1 variation on accurate MRI measurement of both bound and pore water concentrations. The greatest effect was found for adiabatic inversion recovery (AIR) based measurements of bound water concentration, which showed an average of 8.8% and as much as 37% error when using a common mono-exponential assumption of pore water T 1 . Despite these errors, the simulated AIR measurements were still moderately well correlated with the bound water concentrations derived from the spectroscopic data.
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Affiliation(s)
- Thammathida Ketsiri
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sasidhar Uppuganti
- Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Kevin D Harkins
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
| | - Jeffry S Nyman
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark D Does
- Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Electrical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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11
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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: 7] [Impact Index Per Article: 7.0] [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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12
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Lombardi AF, Ma YJ, Jang H, Jerban S, Du J, Chang EY, Chung CB. Synthetic CT in Musculoskeletal Disorders: A Systematic Review. Invest Radiol 2023; 58:43-59. [PMID: 36070535 PMCID: PMC9742139 DOI: 10.1097/rli.0000000000000916] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT Repeated computed tomography (CT) examinations increase patients' ionizing radiation exposure and health costs, making an alternative method desirable. Cortical and trabecular bone, however, have short T2 relaxation times, causing low signal intensity on conventional magnetic resonance (MR) sequences. Different techniques are available to create a "CT-like" contrast of bone, such as ultrashort echo time, zero echo time, gradient-echo, and susceptibility-weighted image MR sequences, and artificial intelligence. This systematic review summarizes the essential technical background and developments of ultrashort echo time, zero echo time, gradient-echo, susceptibility-weighted image MR imaging sequences and artificial intelligence; presents studies on research and clinical applications of "CT-like" MR imaging; and describes their main advantages and limitations. We also discuss future opportunities in research, which patients would benefit the most, the most appropriate situations for using the technique, and the potential to replace CT in the clinical workflow.
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Affiliation(s)
- Alecio F Lombardi
- From the Department of Radiology, University of California San Diego, La Jolla, and the Research Service, Veterans Affairs San Diego Healthcare System, California
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13
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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: 14] [Impact Index Per Article: 7.0] [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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14
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Bharadwaj UU, Coy A, Motamedi D, Sun D, Joseph GB, Krug R, Link TM. CT-like MRI: a qualitative assessment of ZTE sequences for knee osseous abnormalities. Skeletal Radiol 2022; 51:1585-1594. [PMID: 35088162 PMCID: PMC9198000 DOI: 10.1007/s00256-021-03987-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 12/15/2021] [Accepted: 12/29/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To qualitatively evaluate the utility of zero echo-time (ZTE) MRI sequences in identifying osseous findings and to compare ZTE with optimized spoiled gradient echo (SPGR) sequences in detecting knee osseous abnormalities. MATERIALS AND METHODS ZTE and standard knee MRI sequences were acquired at 3T in 100 consecutive patients. Three radiologists rated confidence in evaluating osseous abnormalities and image quality on a 5-grade Likert scale in ZTE compared to standard sequences. In a subset of knees (n = 57) SPGR sequences were also obtained, and diagnostic confidence in identifying osseous structures was assessed, comparing ZTE and SPGR sequences. Statistical significance of using ZTE over SPGR was characterized with a paired t-test. RESULTS Image quality of the ZTE sequences was rated high by all reviewers with 278 out of 299 (100 studies, 3 radiologists) scores ≥ 4 on the Likert scale. Diagnostic confidence in using ZTE sequences was rated "very high confidence" in 97%, 85%, 71%, and 73% of the cases for osteophytosis, subchondral cysts, fractures, and soft tissue calcifications/ossifications, respectively. In 74% of cases with osseous findings, reviewer scores indicated confidence levels (score ≥ 3) that ZTE sequences improved diagnostic certainty over standard sequences. The diagnostic confidence in using ZTE over SPGR sequences for osseous structures as well as abnormalities was favorable and statistically significant (p < 0.01). CONCLUSION Incorporating ZTE sequences in the standard knee MRI protocol was technically feasible and improved diagnostic confidence for osseous findings in relation to standard MR sequences. In comparison to SPGR sequences, ZTE improved assessment of osseous abnormalities.
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Affiliation(s)
- Upasana Upadhyay Bharadwaj
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA.
| | - Adam Coy
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
- Musculoskeletal Radiology, Vision Radiology, Dallas, TX, USA
| | - Daria Motamedi
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
| | - Dong Sun
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gabby B Joseph
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
| | - Roland Krug
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
| | - Thomas M Link
- Musculoskeletal Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA, 94107, USA
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15
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Heckelman LN, Soher BJ, Spritzer CE, Lewis BD, DeFrate LE. Design and validation of a semi-automatic bone segmentation algorithm from MRI to improve research efficiency. Sci Rep 2022; 12:7825. [PMID: 35551485 PMCID: PMC9098419 DOI: 10.1038/s41598-022-11785-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Segmentation of medical images into different tissue types is essential for many advancements in orthopaedic research; however, manual segmentation techniques can be time- and cost-prohibitive. The purpose of this work was to develop a semi-automatic segmentation algorithm that leverages gradients in spatial intensity to isolate the patella bone from magnetic resonance (MR) images of the knee that does not require a training set. The developed algorithm was validated in a sample of four human participants (in vivo) and three porcine stifle joints (ex vivo) using both magnetic resonance imaging (MRI) and computed tomography (CT). We assessed the repeatability (expressed as mean ± standard deviation) of the semi-automatic segmentation technique on: (1) the same MRI scan twice (Dice similarity coefficient = 0.988 ± 0.002; surface distance = - 0.01 ± 0.001 mm), (2) the scan/re-scan repeatability of the segmentation technique (surface distance = - 0.02 ± 0.03 mm), (3) how the semi-automatic segmentation technique compared to manual MRI segmentation (surface distance = - 0.02 ± 0.08 mm), and (4) how the semi-automatic segmentation technique compared when applied to both MRI and CT images of the same specimens (surface distance = - 0.02 ± 0.06 mm). Mean surface distances perpendicular to the cartilage surface were computed between pairs of patellar bone models. Critically, the semi-automatic segmentation algorithm developed in this work reduced segmentation time by approximately 75%. This method is promising for improving research throughput and potentially for use in generating training data for deep learning algorithms.
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Affiliation(s)
- Lauren N Heckelman
- Department of Orthopaedic Surgery, Duke University School of Medicine, DUMC Box 3093, Durham, NC, 27710, USA
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Brian J Soher
- Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Charles E Spritzer
- Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Brian D Lewis
- Department of Orthopaedic Surgery, Duke University School of Medicine, DUMC Box 3093, Durham, NC, 27710, USA
| | - Louis E DeFrate
- Department of Orthopaedic Surgery, Duke University School of Medicine, DUMC Box 3093, Durham, NC, 27710, USA.
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA.
- Department of Mechanical Engineering & Materials Science, Pratt School of Engineering, Duke University, Durham, NC, USA.
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16
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Jerban S, Alenezi S, Afsahi AM, Ma Y, Du J, Chung CB, Chang EY. MRI-based mechanical competence assessment of bone using micro finite element analysis (micro-FEA): Review. Magn Reson Imaging 2022; 88:9-19. [PMID: 35091024 PMCID: PMC8988995 DOI: 10.1016/j.mri.2022.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 12/09/2021] [Accepted: 01/20/2022] [Indexed: 12/18/2022]
Abstract
Areal bone mineral density (aBMD) from dual-energy x-ray absorptiometry (DEXA) and volumetric bone mineral density (vBMD) have demonstrated limited capabilities in the evaluation of bone mechanical competence and prediction of bone fracture. Predicting the macroscopic mechanical behavior of the bone structure has been challenging because of the heterogeneous and anisotropic nature of bone, such as the dependencies on loading direction, anatomical location, and sample dimensions. Magnetic resonance imaging (MRI) has been introduced as a promising modality that can be coupled with finite element analysis (FEA) for the assessment of bone mechanical competence. This review article describes studies investigating MRI-based micro-FEA as a potential non-invasive method to predict bone mechanical competence and facilitate bone fracture risk estimation without exposure to ionizing radiation. Specifically, the steps, applications, and future potential of FEA using indirect and direct bone imaging are discussed.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, CA, USA.
| | - Salem Alenezi
- Research and Laboratories Sector, Saudi Food and Drug Authority, Saudi Arabia
| | | | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, CA, USA; Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
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17
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Abdala-Junior R, No-Cortes J, Arita ES, Ackerman JL, da Silva RLB, Kim JH, Cortes ARG. Influence of receiver bandwidth on MRI artifacts caused by orthodontic brackets composed of different alloys. Imaging Sci Dent 2022; 51:413-419. [PMID: 34988002 PMCID: PMC8695464 DOI: 10.5624/isd.20210099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose The aim of this in vitro study was to assess the role of bandwidth on the area of magnetic resonance imaging (MRI) artifacts caused by orthodontic appliances composed of different alloys, using different pulse sequences in 1.5 T and 3.0 T magnetic fields. Materials and Methods Different phantoms containing orthodontic brackets (ceramic, ceramic bracket with a stainless-steel slot, and stainless steel) were immersed in agar gel and imaged in 1.5 T and 3.0 T MRI scanners. Pairs of gradient-echo (GE), spin-echo (SE), and ultrashort echo time (UTE) pulse sequences were used differing in bandwidth only. The area of artifacts from orthodontic devices was automatically estimated from pixel value thresholds within a region of interest (ROI). Mean values for similar pulse sequences differing in bandwidth were compared at 1.5 T and 3.0 T using analysis of variance. Results The comparison of groups revealed a significant inverse association between bandwidth values and artifact areas of the stainless-steel bracket and the self-ligating ceramic bracket with a stainless-steel slot (P<0.05). The areas of artifacts from the ceramic bracket were the smallest, but were not reduced significantly in pulse sequences with higher bandwidth values (P<0.05). Significant differences were also observed between 1.5 T and 3.0 T MRI using SE and UTE, but not using GE 2-dimensional or 3-dimensional pulse sequences. Conclusion Higher receiver bandwidth might be indicated to prevent artifacts from orthodontic appliances in 1.5 T and 3.0 T MRI using SE and UTE pulse sequences.
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Affiliation(s)
- Reinaldo Abdala-Junior
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Juliana No-Cortes
- Department of Dental Surgery, Faculty of Dental Surgery, University of Malta, Msida, Malta
| | - Emiko Saito Arita
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
| | - Jerome L Ackerman
- Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | | | - Jun Ho Kim
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul, Korea
| | - Arthur Rodriguez Gonzalez Cortes
- Department of Oral Radiology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.,Department of Radiology, Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
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18
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Zhang M, Li Z, Wang H, Chen T, Lu Y, Yan F, Zhang Y, Wei H. Simultaneous Quantitative Susceptibility Mapping of Articular Cartilage and Cortical Bone of Human Knee Joint Using Ultrashort Echo Time Sequences. Front Endocrinol (Lausanne) 2022; 13:844351. [PMID: 35273576 PMCID: PMC8901574 DOI: 10.3389/fendo.2022.844351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 01/31/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND It is of great clinical importance to assess the microstructure of the articular cartilage and cortical bone of the human knee joint. While quantitative susceptibility mapping (QSM) is a promising tool for investigating the knee joint, however, previous QSM studies using conventional gradient recalled echo sequences or ultrashort echo time (UTE) sequences only focused on mapping the magnetic susceptibility of the articular cartilage or cortical bone, respectively. Simultaneously mapping the underlying susceptibilities of the articular cartilage and cortical bone of human in vivo has not been explored and reported. METHOD Three-dimensional multi-echo radial UTE sequences with the shortest TE of 0.07 msec and computed tomography (CT) were performed on the bilateral knee joints of five healthy volunteers for this prospective study. UTE-QSM was reconstructed from the local field map after water-fat separation and background field removal. Spearman's correlation analysis was used to explore the relationship between the magnetic susceptibility and CT values in 158 representative regions of interest of cortical bone. RESULT The susceptibility properties of the articular cartilage and cortical bone were successfully quantified by UTE-QSM. The laminar structure of articular cartilage was characterized by the difference of susceptibility value in each layer. Susceptibility was mostly diamagnetic in cortical bone. A significant negative correlation (r=-0.43, p<0.001) between the susceptibility value and CT value in cortical bone was observed. CONCLUSION UTE-QSM enables simultaneous susceptibility mapping of the articular cartilage and cortical bone of human in vivo. Good association between susceptibility and CT values in cortical bone suggests the potential of UTE-QSM for bone mapping for further clinical application.
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Affiliation(s)
- Ming Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zhihui Li
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hanqi Wang
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Tongtong Chen
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yong Lu
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yuyao Zhang
- School of Information and Science and Technology, ShanghaiTech University, Shanghai, China
| | - Hongjiang Wei
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Hongjiang Wei,
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19
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Afsahi AM, Ma Y, Jang H, Jerban S, Chung CB, Chang EY, Du J. Ultrashort Echo Time Magnetic Resonance Imaging Techniques: Met and Unmet Needs in Musculoskeletal Imaging. J Magn Reson Imaging 2021; 55:1597-1612. [PMID: 34962335 DOI: 10.1002/jmri.28032] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/14/2022] Open
Abstract
This review article summarizes recent technical developments in ultrashort echo time (UTE) magnetic resonance imaging of musculoskeletal (MSK) tissues with short-T2 relaxation times. A series of contrast mechanisms are discussed for high-contrast morphological imaging of short-T2 MSK tissues including the osteochondral junction, menisci, ligaments, tendons, and bone. Quantitative UTE mapping of T1, T2*, T1ρ, adiabatic T1ρ, magnetization transfer ratio, MT modeling of macromolecular proton fraction, quantitative susceptibility mapping, and water content is also introduced. Met and unmet needs in MSK imaging are discussed. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Amir Masoud Afsahi
- Department of Radiology, University of California, San Diego, California, USA
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, California, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California, USA
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California, USA
| | - Christine B Chung
- Department of Radiology, University of California, San Diego, California, USA.,Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, California, USA.,Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California, USA.,Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California, USA
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20
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Sandberg JK, Young VA, Yuan J, Hargreaves BA, Wishah F, Vasanawala SS. Zero echo time pediatric musculoskeletal magnetic resonance imaging: initial experience. Pediatr Radiol 2021; 51:2549-2560. [PMID: 34156504 DOI: 10.1007/s00247-021-05125-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/24/2021] [Accepted: 06/10/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Projection radiography (XR) is often supplemented by both CT (to evaluate osseous structures with ionizing radiation) and MRI (for marrow and soft-tissue assessment). Zero echo time (ZTE) MR imaging produces a "CT-like" osseous contrast that might obviate CT. OBJECTIVE This study investigated our institution's initial experience in implementing an isotropic ZTE MR imaging sequence for pediatric musculoskeletal examinations. MATERIALS AND METHODS Pediatric patients referred for extremity MRI at 3 tesla (T) underwent ZTE MR imaging to yield images with contrast similar to that of CT. A radiograph-like image was also created with ray-sum image processing. We assessed ZTE-CT/XR anatomical image quality (Sanat) from 0 (nondiagnostic) to 5 (outstanding). Further, we made image comparisons on a 5-point scale (Scomp) (range of -2 = conventional CT/XR greater anatomical delineation to +2 = ZTE-CT/XR greater anatomical delineation; 0=same) for three cohorts: (1) ZTE-XR to conventional radiography, (2) ZTE-CT to conventional CT and (3) pathological lesion assessment on ZTE-XR to conventional radiography. We measured cortical thickness of ZTE-XR and ZTE-CT and compared these with conventional imaging. We calculated confidence interval of proportions, Wilcoxon rank sum test and intraclass correlation coefficients for inter-reader agreement. RESULTS Cohorts 1, 2 and 3 consisted of 40, 20 and 35 cases, respectively (age range 0.6-23.0 years). ZTE-CT versus CT and ZTE-XR versus radiography of cortical thicknesses were not significantly different (P=0.55 and P=0.31, respectively). Cortical delineation was rated diagnostic or better (score of 3, 4 or 5) in all cases (confidence interval of proportions = 100%) for ZTE-CT/XR. Similarly, intramedullary cavity delineation was rated diagnostic or better in all cases for ZTE-CT, and ZTE-XR was at least diagnostic in 58-63% of cases. For cohort 2, cortex and intramedullary cavity Scomp for ZTE-CT was comparable to those of conventional CT, with confidence interval of proportion (sum of score of -1 to +2) of 93-100% and 95%, respectively. Pathology visualized on ZTE-CT/XR was comparable; Scomp confidence interval of proportions was 95%/97-100%, with improved delineation of non-displaced fractures on ZTE-XR. Readers had moderate to near-perfect intraclass correlation coefficient (range=0.60-0.93). CONCLUSION Implementation of a diagnostic-quality ZTE MRI sequence in the pediatric population is feasible and can be performed as a complementary pulse sequence to enhance musculoskeletal MRI studies. Compared to conventional CT, ZTE has comparable cortical delineation, intramedullary cavity and pathology visualization. While not intended as a replacement for conventional radiography, ZTE-XR provides similar visualization of pathology.
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Affiliation(s)
- Jesse K Sandberg
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA.
| | - Victoria A Young
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Jianmin Yuan
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Brian A Hargreaves
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Fidaa Wishah
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
| | - Shreyas S Vasanawala
- Department of Radiology, Stanford University School of Medicine, 725 Welch Road, Room 1844, Stanford, CA, 94305, USA
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21
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Xiong X, Ye Z, Tang H, Wei Y, Nie L, Wei X, Liu Y, Song B. MRI of Temporomandibular Joint Disorders: Recent Advances and Future Directions. J Magn Reson Imaging 2021; 54:1039-1052. [PMID: 32869470 DOI: 10.1002/jmri.27338] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 02/05/2023] Open
Abstract
Temporomandibular joint disorders (TMDs) are a prevalent disease covering pain and dysfunction of temporomandibular joints and masticatory muscles, which can be detrimental to quality of life. Magnetic resonance imaging (MRI) is a powerful and noninvasive tool for the imaging and understanding of TMD. With the recent technical development of dynamic and quantitative MRI techniques, including diffusion-weighted imaging, T2 mapping, and ultrashort/zero echo time, it is now feasible in TMD imaging and has been preliminarily investigated with promising results. In this review we will discuss the recent advances of MRI techniques in TMD and its future directions, and hope to highlight the scientific potential and clinical value of novel MRI techniques in diagnosing and treating TMD. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.
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Affiliation(s)
- Xin Xiong
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zheng Ye
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Hehan Tang
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Wei
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | | | | | - Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Bin Song
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
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22
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Talebi M, Abbasi-Rad S, Malekzadeh M, Shahgholi M, Ardakani AA, Foudeh K, Rad HS. Cortical Bone Mechanical Assessment via Free Water Relaxometry at 3 T. J Magn Reson Imaging 2021; 54:1744-1751. [PMID: 34142413 DOI: 10.1002/jmri.27765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Investigation of cortical bone using magnetic resonance imaging is a developing field, which uses short/ultrashort echo time (TE) pulse sequences to quantify bone water content and to obtain indirect information about bone microstructure. PURPOSE To improve the accuracy of the previously proposed technique of free water T1 quantification and to seek the relationship between cortical bone free water T1 and its mechanical competence. STUDY TYPE Prospective. SUBJECTS Twenty samples of bovine tibia bone. FIELD STRENGTH/SEQUENCES 3.0 T; ultra-fast two-dimensional gradient echo, Radio frequency-spoiled three-dimensional gradient echo. ASSESSMENT Cortical bone free water T1 was quantified via three different methods: inversion recovery (IR), variable flip angle (VFA), and variable repetition time (VTR). Signal-to-noise ratio was measured by dividing the signal of each segmented sample to background noise. Segmentation was done manually. The effect of noise on T1 quantification was evaluated. Then, the samples were subjected to mechanical compression test to measure the toughness, yield stress, ultimate stress, and Young modulus. STATISTICAL TESTS All the statistical analysis (Shapiro-Wilk, way analysis of variance, paired t test, Pearson correlation, and Bland-Altman plot) were done using SPSS. RESULTS Significant difference was found between T1 quantification groups (P < 0.05). Average T1 of each quantification method differed significantly after adding noise (P < 0.05). VFA-T1 values significantly correlated with toughness (r = -0.68, P < 0.05), ultimate stress (r = -0.71, P < 0.05), and yield stress (r = -0.62, P < 0.05). No significant correlation was found between VTR-T1 values and toughness (P = 0.07), ultimate stress (P = 0.47), yield stress (P = 0.30), and Young modulus (P = 0.39). DATA CONCLUSION Pore water T1 value is associated with bone mechanical competence, and VFA method employing short-TE pulse sequence seems a superior technique to VTR method for this quantification. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: 1.
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Affiliation(s)
- Mahsa Talebi
- Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.,The Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahrokh Abbasi-Rad
- The Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Malakeh Malekzadeh
- The Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran.,Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohamad Shahgholi
- The Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran.,Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
| | - Ali A Ardakani
- Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kimia Foudeh
- Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
| | - Hamidreza S Rad
- Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.,The Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran.,Osteoporosis Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.,Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
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23
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Wei Z, Jang H, Bydder GM, Yang W, Ma YJ. Fast T 1 measurement of cortical bone using 3D UTE actual flip angle imaging and single-TR acquisition (3D UTE-AFI-STR). Magn Reson Med 2021; 85:3290-3298. [PMID: 33404142 DOI: 10.1002/mrm.28655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To describe a new method for accurate T1 measurement of cortical bone that fits the data sets of both 3D UTE actual flip angle imaging (UTE-AFI) and UTE with a single TR (UTE-STR) simultaneously (UTE-AFI-STR). THEORY AND METHODS To make both the constant values and longitudinal mapping functions in the signal equations for UTE-AFI and UTE-STR identical, the same RF pulses and flip angles were used. Therefore, there were three unknowns in the three equations. This was sufficient to fit the data. Numerical simulation as well as ex vivo and in vivo cortical bone studies were performed to validate the T1 measurement accuracy with the UTE-AFI-STR method. The original UTE-AFI variable TR (VTR) (ie, combined UTE-AFI and UTE with VTR) and simultaneous fitting (sf) of UTE-AFI and UTE-VTR (sf-UTE-AFI-VTR) methods were performed for comparison. RESULTS The numerical simulation study showed that the UTE-AFI-STR method provided accurate value of T1 when the SNR of the UTE-STR image was higher than 40. The ex vivo study showed that the UTE-AFI-STR method measured the T1 of cortical bone accurately, with difference ratios ranging from -5.0% to 0.4%. The in vivo study showed a mean T1 of 246 ms with the UTE-AFI-STR method, and mean difference ratios of 2.4% and 5.0%, respectively, compared with the other two methods. CONCLUSION The 3D UTE-AFI-STR method provides accurate mapping of the T1 of cortical bone with improved time efficiency compared with the UTE-AFI-VTR/sf-UTE-AFI-VTR methods.
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Affiliation(s)
- Zhao Wei
- Department of Radiology, University of California San Diego, San Diego, California, USA
- Institute of Electrical Engineering Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, California, USA
| | - Graeme M Bydder
- Department of Radiology, University of California San Diego, San Diego, California, USA
| | - Wenhui Yang
- Institute of Electrical Engineering Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ya-Jun Ma
- Department of Radiology, University of California San Diego, San Diego, California, USA
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24
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Abstract
Attenuation correction has been one of the main methodological challenges in the integrated positron emission tomography and magnetic resonance imaging (PET/MRI) field. As standard transmission or computed tomography approaches are not available in integrated PET/MRI scanners, MR-based attenuation correction approaches had to be developed. Aspects that have to be considered for implementing accurate methods include the need to account for attenuation in bone tissue, normal and pathological lung and the MR hardware present in the PET field-of-view, to reduce the impact of subject motion, to minimize truncation and susceptibility artifacts, and to address issues related to the data acquisition and processing both on the PET and MRI sides. The standard MR-based attenuation correction techniques implemented by the PET/MRI equipment manufacturers and their impact on clinical and research PET data interpretation and quantification are first discussed. Next, the more advanced methods, including the latest generation deep learning-based approaches that have been proposed for further minimizing the attenuation correction related bias are described. Finally, a future perspective focused on the needed developments in the field is given.
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Affiliation(s)
- Ciprian Catana
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States of America
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25
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Ma YJ, Jerban S, Jang H, Chang D, Chang EY, Du J. Quantitative Ultrashort Echo Time (UTE) Magnetic Resonance Imaging of Bone: An Update. Front Endocrinol (Lausanne) 2020; 11:567417. [PMID: 33071975 PMCID: PMC7531487 DOI: 10.3389/fendo.2020.567417] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/17/2020] [Indexed: 12/24/2022] Open
Abstract
Bone possesses a highly complex hierarchical structure comprised of mineral (~45% by volume), organic matrix (~35%) and water (~20%). Water exists in bone in two forms: as bound water (BW), which is bound to bone mineral and organic matrix, or as pore water (PW), which resides in Haversian canals as well as in lacunae and canaliculi. Magnetic resonance (MR) imaging has been increasingly used for assessment of cortical and trabecular bone. However, bone appears as a signal void on conventional MR sequences because of its short T2*. Ultrashort echo time (UTE) sequences with echo times (TEs) 100-1,000 times shorter than those of conventional sequences allow direct imaging of BW and PW in bone. A series of quantitative UTE MRI techniques has been developed for bone evaluation. UTE and adiabatic inversion recovery prepared UTE (IR-UTE) sequences have been developed to quantify BW and PW. UTE magnetization transfer (UTE-MT) sequences have been developed to quantify collagen backbone protons, and UTE quantitative susceptibility mapping (UTE-QSM) sequences have been developed to assess bone mineral.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Douglas Chang
- Department of Orthopedic Surgery, University of California, San Diego, San Diego, CA, United States
| | - Eric Y. Chang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
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26
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Harries J, Jochimsen TH, Scholz T, Schlender T, Barthel H, Sabri O, Sattler B. A realistic phantom of the human head for PET-MRI. EJNMMI Phys 2020; 7:52. [PMID: 32757099 PMCID: PMC7406590 DOI: 10.1186/s40658-020-00320-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 07/16/2020] [Indexed: 12/27/2022] Open
Abstract
Background The combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) (PET-MRI) is a unique hybrid imaging modality mainly used in oncology and neurology. The MRI-based attenuation correction (MRAC) is crucial for correct quantification of PET data. A suitable phantom to validate quantitative results in PET-MRI is currently missing. In particular, the correction of attenuation due to bone is usually not verified by commonly available phantoms. The aim of this work was, thus, the development of such a phantom and to explore whether such a phantom might be used to validate MRACs. Method Various materials were investigated for their attenuation and MR properties. For the substitution of bone, water-saturated gypsum plaster was used. The attenuation of 511 keV annihilation photons was regulated by addition of iodine. Adipose tissue was imitated by silicone and brain tissue by agarose gel, respectively. The practicability with respect to the comparison of MRACs was checked as follows: A small flask inserted into the phantom and a large spherical phantom (serving as a reference with negligible error in MRAC) were filled with the very same activity concentration. The activity concentration was measured and compared using clinical protocols on PET-MRI and different built-in and offline MRACs. The same measurements were carried out using PET-CT for comparison. Results The phantom imitates the human head in sufficient detail. All tissue types including bone were detected as such so that the phantom-based comparison of the quantification accuracy of PET-MRI was possible. Quantitatively, the activity concentration in the brain, which was determined using different MRACs, showed a deviation of about 5% on average and a maximum deviation of 11% compared to the spherical phantom. For PET-CT, the deviation was 5%. Conclusions The comparatively small error in quantification indicates that it is possible to construct a brain PET-MRI phantom that leads to MR-based attenuation-corrected images with reasonable accuracy.
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Affiliation(s)
- Johanna Harries
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany.,Department of Radiation Safety and Medical Physics, Medizinische Hochschule Hannover, Carl-Neuberg Straße 1, Hannover, Germany
| | - Thies H Jochimsen
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany.
| | - Thomas Scholz
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany
| | - Tina Schlender
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany
| | - Henryk Barthel
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany
| | - Bernhard Sattler
- Department of Nuclear Medicine, Leipzig University Hospital, Liebigstr. 18, Leipzig, Germany
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27
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Jerban S, Ma Y, Wei Z, Jang H, Chang EY, Du J. Quantitative Magnetic Resonance Imaging of Cortical and Trabecular Bone. Semin Musculoskelet Radiol 2020; 24:386-401. [PMID: 32992367 DOI: 10.1055/s-0040-1710355] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bone is a composite material consisting of mineral, organic matrix, and water. Water in bone can be categorized as bound water (BW), which is bound to bone mineral and organic matrix, or as pore water (PW), which resides in Haversian canals as well as in lacunae and canaliculi. Bone is generally classified into two types: cortical bone and trabecular bone. Cortical bone is much denser than trabecular bone that is surrounded by marrow and fat. Magnetic resonance (MR) imaging has been increasingly used for noninvasive assessment of both cortical bone and trabecular bone. Bone typically appears as a signal void with conventional MR sequences because of its short T2*. Ultrashort echo time (UTE) sequences with echo times 100 to 1,000 times shorter than those of conventional sequences allow direct imaging of BW and PW in bone. This article summarizes several quantitative MR techniques recently developed for bone evaluation. Specifically, we discuss the use of UTE and adiabatic inversion recovery prepared UTE sequences to quantify BW and PW, UTE magnetization transfer sequences to quantify collagen backbone protons, UTE quantitative susceptibility mapping sequences to assess bone mineral, and conventional sequences for high-resolution imaging of PW as well as the evaluation of trabecular bone architecture.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, California
| | - Zhao Wei
- Department of Radiology, University of California, San Diego, California
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, California.,Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California
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28
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Sollmann N, Löffler MT, Kronthaler S, Böhm C, Dieckmeyer M, Ruschke S, Kirschke JS, Carballido-Gamio J, Karampinos DC, Krug R, Baum T. MRI-Based Quantitative Osteoporosis Imaging at the Spine and Femur. J Magn Reson Imaging 2020; 54:12-35. [PMID: 32584496 DOI: 10.1002/jmri.27260] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/31/2020] [Accepted: 06/01/2020] [Indexed: 12/27/2022] Open
Abstract
Osteoporosis is a systemic skeletal disease with a high prevalence worldwide, characterized by low bone mass and microarchitectural deterioration, predisposing an individual to fragility fractures. Dual-energy X-ray absorptiometry (DXA) has been the clinical reference standard for diagnosing osteoporosis and for assessing fracture risk for decades. However, other imaging modalities are of increasing importance to investigate the etiology, treatment, and fracture risk. The purpose of this work is to review the available literature on quantitative magnetic resonance imaging (MRI) methods and related findings in osteoporosis at the spine and proximal femur as the clinically most important fracture sites. Trabecular bone microstructure analysis at the proximal femur based on high-resolution MRI allows for a better prediction of osteoporotic fracture risk than DXA-based bone mineral density (BMD) alone. In the 1990s, T2 * mapping was shown to correlate with the density and orientation of the trabecular bone. Recently, quantitative susceptibility mapping (QSM), which overcomes some of the limitations of T2 * mapping, has been applied for trabecular bone quantifications at the spine, whereas ultrashort echo time (UTE) imaging provides valuable surrogate markers of cortical bone quantity and quality. Magnetic resonance spectroscopy (MRS) and chemical shift encoding-based water-fat MRI (CSE-MRI) enable the quantitative assessment of the nonmineralized bone compartment through extraction of the bone marrow fat fraction (BMFF). Furthermore, CSE-MRI allows for the differentiation of osteoporotic vs. pathologic fractures, which is of high clinical relevance. Lastly, advanced postprocessing and image analysis tools, particularly considering statistical parametric mapping and region-specific BMFF distributions, have high potential to further improve MRI-based fracture risk assessments at the spine and hip. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Nico Sollmann
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Maximilian T Löffler
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sophia Kronthaler
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Christof Böhm
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Michael Dieckmeyer
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Stefan Ruschke
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jan S Kirschke
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,TUM-Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Julio Carballido-Gamio
- Department of Radiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Roland Krug
- Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Thomas Baum
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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29
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Mastrogiacomo S, Dou W, Jansen JA, Walboomers XF. Magnetic Resonance Imaging of Hard Tissues and Hard Tissue Engineered Bio-substitutes. Mol Imaging Biol 2020; 21:1003-1019. [PMID: 30989438 DOI: 10.1007/s11307-019-01345-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnetic resonance imaging (MRI) is a non-invasive diagnostic imaging tool based on the detection of protons into the tissues. This imaging technique is remarkable because of high spatial resolution, strong soft tissue contrast and specificity, and good depth penetration. However, MR imaging of hard tissues, such as bone and teeth, remains challenging due to low proton content in such tissues as well as to very short transverse relaxation times (T2). To overcome these issues, new MRI techniques, such as sweep imaging with Fourier transformation (SWIFT), ultrashort echo time (UTE) imaging, and zero echo time (ZTE) imaging, have been developed for hard tissues imaging with promising results reported. Within this article, MRI techniques developed for the detection of hard tissues, such as bone and dental tissues, have been reviewed. The main goal was thus to give a comprehensive overview on the corresponding (pre-) clinical applications and on the potential future directions with such techniques applied. In addition, a section dedicated to MR imaging of novel biomaterials developed for hard tissue applications was given as well.
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Affiliation(s)
- Simone Mastrogiacomo
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands.
- Laboratory of Functional and Molecular Imaging, NINDS, National Institutes of Health, Building 10, 5S261, Bethesda, MD, 20892, USA.
| | - Weiqiang Dou
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
- GE Healthcare, MR Research, Beijing, People's Republic of China
| | - John A Jansen
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands
| | - X Frank Walboomers
- Department of Biomaterials, Radboud University Medical Center, Philips van Leijdenlaan 25, 6525 EX, Nijmegen, The Netherlands
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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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Young IR, Szeverenyi NM, Du J, Bydder GM. Pulse sequences as tissue property filters (TP-filters): a way of understanding the signal, contrast and weighting of magnetic resonance images. Quant Imaging Med Surg 2020; 10:1080-1120. [PMID: 32489930 PMCID: PMC7242304 DOI: 10.21037/qims.2020.04.07] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 03/23/2020] [Indexed: 02/04/2023]
Abstract
This paper describes a quantitative approach to understanding the signal, contrast and weighting of magnetic resonance (MR) images. It uses the concept of pulse sequences as tissue property (TP) filters and models the signal, contrast and weighting of sequences using either a single TP-filter (univariate model) or several TP-filters (the multivariate model). For the spin echo (SE) sequence using the Bloch equations, voxel signal intensity is plotted against the logarithm of the value of the TPs contributing to the sequence signal to produce three TP-filters, an exponential ρm-filter, a low pass T1-filter and a high pass T2-filter. Using the univariate model which considers signal changes in only one of ρm, T1, or T2 at a time, the first partial derivative of signal with respect to the natural logarithm of ρm, T1 or T2 is the sequence weighting for each filter (for small changes in each TP). Absolute contrast is then the sequence weighting multiplied by the fractional change in TP for each filter. For large changes in TPs, the same approach is followed, but using the mean slope of the filter as the sequence weighting. These approaches can also be used for fractional contrast. The univariate TP-filter model provides a mathematical framework for converting conventional qualitative univariate weighting as used in everyday clinical practice into quantitative univariate weighting. Using the multivariate model which considers several TP-filters together, the relative contributions of each TP to overall sequence and image weighting are expressed as sequence and imaging weighting ratios respectively. This is not possible with conventional qualitative weighting which is univariate. The same approaches are used for inversion recovery (IR), pulsed gradient SE, spoiled gradient echo (SGE), balanced steady state free precession, ultrashort echo time and other pulse sequences. Other TPs such as susceptibility, chemical shift and flow can be included with phase along the Y axis of the TP-filter. Contrast agent effects are also included. In the text TP-filters are distinguished from k-space filters, signal filters (S-filters) which are used in imaging processing as well as to describe windowing the signal width and level of images, and spatial filters. The TP-filters approach resolves many of the ambiguities and inconsistencies associated with conventional qualitative weighting and provides a variety of new insights into the signal, contrast and weighting of MR images which are not apparent using qualitative weighting. The TP-filter approach relates the preparation component of pulse sequences to voxel signal, and contrast between two voxels. This is complementary to k-space which relates the acquisition component of pulse sequences to the spatial properties of MR images and their global contrast.
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Affiliation(s)
- Ian R. Young
- Formerly Department of Electrical Engineering, Imperial College of Science, Technology, and Medicine, London, UK
| | | | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, USA
| | - Graeme M. Bydder
- Department of Radiology, University of California San Diego, San Diego, USA
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Chandramohan D, Cao P, Han M, An H, Sunderland JJ, Kinahan PE, Laforest R, Hope TA, Larson PEZ. Bone material analogues for PET/MRI phantoms. Med Phys 2020; 47:2161-2170. [PMID: 32034945 DOI: 10.1002/mp.14079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/18/2019] [Accepted: 01/21/2020] [Indexed: 01/05/2023] Open
Abstract
PURPOSE To develop bone material analogues that can be used in construction of phantoms for simultaneous PET/MRI systems. METHODS Plaster was used as the basis for the bone material analogues tested in this study. It was mixed with varying concentrations of an iodinated CT contrast, a gadolinium-based MR contrast agent, and copper sulfate to modulate the attenuation properties and MRI properties (T1 and T2*). Attenuation was measured with CT and 68 Ge transmission scans, and MRI properties were measured with quantitative ultrashort echo time pulse sequences. A proof-of-concept skull was created by plaster casting. RESULTS Undoped plaster has a 511 keV attenuation coefficient (~0.14 cm-1 ) similar to cortical bone (0.10-0.15 cm-1 ), but slightly longer T1 (~500 ms) and T2* (~1.2 ms) MR parameters compared to bone (T1 ~ 300 ms, T2* ~ 0.4 ms). Doping with the iodinated agent resulted in increased attenuation with minimal perturbation to the MR parameters. Doping with a gadolinium chelate greatly reduced T1 and T2*, resulting in extremely short T1 values when the target T2* values were reached, while the attenuation coefficient was unchanged. Doping with copper sulfate was more selective for T2* shortening and achieved comparable T1 and T2* values to bone (after 1 week of drying), while the attenuation coefficient was unchanged. CONCLUSIONS Plaster doped with copper sulfate is a promising bone material analogue for a PET/MRI phantom, mimicking the MR properties (T1 and T2*) and 511 keV attenuation coefficient of human cortical bone.
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Affiliation(s)
- Dharshan Chandramohan
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, 94143, USA
| | - Peng Cao
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, 94143, USA
| | - Misung Han
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, 94143, USA
| | - Hongyu An
- Department of Radiology, Washington University, St. Louis, MO, 63110, USA
| | - John J Sunderland
- Departments of Radiology, Radiation Oncology, and Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
| | - Paul E Kinahan
- Department of Radiology, University of Washington, Seattle, WA, 98195, USA
| | - Richard Laforest
- Department of Radiology, Washington University, St. Louis, MO, 63110, USA
| | - Thomas A Hope
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, 94143, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, 94143, USA
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Jerban S, Chang DG, Ma Y, Jang H, Chang EY, Du J. An Update in Qualitative Imaging of Bone Using Ultrashort Echo Time Magnetic Resonance. Front Endocrinol (Lausanne) 2020; 11:555756. [PMID: 33117275 PMCID: PMC7551122 DOI: 10.3389/fendo.2020.555756] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022] Open
Abstract
Bone is comprised of mineral, collagenous organic matrix, and water. X-ray-based techniques are the standard approach for bone evaluation in clinics, but they are unable to detect the organic matrix and water components in bone. Magnetic resonance imaging (MRI) is being used increasingly for bone evaluation. While MRI can non-invasively assess the proton pools in soft tissues, cortical bone typically appears as a signal void with clinical MR techniques because of its short T2*. New MRI techniques have been recently developed to image bone while avoiding the ionizing radiation present in x-ray-based methods. Qualitative bone imaging can be achieved using ultrashort echo time (UTE), single inversion recovery UTE (IR-UTE), dual-inversion recovery UTE (Dual-IR-UTE), double-inversion recovery UTE (Double-IR-UTE), and zero echo time (ZTE) sequences. The contrast mechanisms as well as the advantages and disadvantages of each technique are discussed.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Douglas G. Chang
- Departments of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, United States
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
| | - Eric Y. Chang
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, United States
- *Correspondence: Jiang Du,
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Guo T, Ma Y, Jerban S, Jang H, Zhao W, Chang EY, Chen M, Bydder GM, Du J. T 1 measurement of bound water in cortical bone using 3D adiabatic inversion recovery ultrashort echo time (3D IR-UTE) Cones imaging. Magn Reson Med 2019; 84:634-645. [PMID: 31863519 DOI: 10.1002/mrm.28140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/04/2019] [Accepted: 11/30/2019] [Indexed: 11/11/2022]
Abstract
PURPOSE We describe the measurement of bound water T1 ( T 1 BW ) of cortical bone in vitro and in vivo with a 3D adiabatic inversion recovery ultrashort echo time (IR-UTE) Cones sequence using a clinical 3T scanner. METHODS A series IR-UTE data from 6 repetition times (TRs) with 5 inversion times (TIs) at each TR were acquired from 12 human tibial bone specimens, and data from 4 TRs with 5 TIs at each TR were acquired from the tibial midshafts of 8 healthy volunteers. The pore water nulling point was calculated from exponential fitting of the inversion recovery curve at each TR. Bone specimens and volunteers were then scanned again with the calculated nulling point at each TR. T 1 BW was derived through exponential fitting of data from IR-UTE images acquired at different TRs using the calculated pore water nulling point for each TR. RESULTS In vitro pore water nulling TIs were 141.3 ± 11.6, 123.4 ± 8.9, 101.3 ± 6.2, 88.9 ± 5.3, 74.8 ± 4.2, and 59.2 ± 3.9 ms for the 6 TRs of 500, 400, 300, 250, 200, and 150 ms, respectively. In vivo pore water nulling TIs were 132.8 ± 12.8, 110.3 ± 10.0, 80.0 ± 7.2, and 63.9 ± 5.4 ms for the 4 TRs of 400, 300, 200, and 150 ms, respectively. Excellent exponential fitting was achieved for IR-UTE imaging of bound water with pore water nulled at each TR. The mean T 1 BW was 106.9 ± 6.3 ms in vitro and 112.3 ± 16.4 ms in vivo. CONCLUSION Using the 3D IR-UTE Cones with a variable TR/TI approach, T 1 BW of cortical bone was calculated after complete nulling of pore water signals.
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Affiliation(s)
- Tan Guo
- Department of Radiology, Beijing Hospital, Beijing, China.,Department of Radiology, University of California, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, California
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, California
| | - Wei Zhao
- Department of Radiology, University of California, San Diego, California
| | - Eric Y Chang
- Research Service, VA San Diego Healthcare System, San Diego, California
| | - Min Chen
- Department of Radiology, Beijing Hospital, Beijing, China
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, California
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California
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Jerban S, Ma Y, Li L, Jang H, Wan L, Guo T, Searleman A, Chang EY, Du J. Volumetric mapping of bound and pore water as well as collagen protons in cortical bone using 3D ultrashort echo time cones MR imaging techniques. Bone 2019; 127:120-128. [PMID: 31176044 PMCID: PMC6708764 DOI: 10.1016/j.bone.2019.05.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/28/2019] [Accepted: 05/31/2019] [Indexed: 12/13/2022]
Abstract
Cortical bone assessment using magnetic resonance imaging (MRI) has recently received great attention in an effort to avoid the potential harm associated with ionizing radiation-based techniques. Ultrashort echo time MRI (UTE-MRI) techniques can acquire signal from major hydrogen proton pools in cortical bone, including bound and pore water, as well as from the collagen matrix. This study aimed to develop and evaluate the feasibility of a technique for mapping bound water, pore water, and collagen proton densities in human cortical bone ex vivo and in vivo using three-dimensional UTE Cones (3D-UTE-Cones) MRI. Eight human tibial cortical bone specimens (63 ± 19 years old) were scanned using 3D-UTE-Cones sequences on a clinical 3 T MRI scanner and a micro-computed tomography (μCT) scanner. Total, bound, and pore water proton densities (TWPD, BWPD, and PWPD, respectively) were measured using UTE and inversion recovery UTE (IR-UTE) imaging techniques. Macromolecular proton density (MMPD), a collagen representation, was measured using TWPD and macromolecular fraction (MMF) obtained from two-pool UTE magnetization transfer (UTE-MT) modeling. The correlations between proton densities and μCT-based measures were investigated. The 3D-UTE-Cones techniques were further applied on ten young healthy (34 ± 3 years old) and five old (78 ± 6 years old) female volunteers to evaluate the techniques' feasibility for translational clinical applications. In the ex vivo study, PWPD showed the highest correlations with bone porosity and bone mineral density (BMD) (R = 0.79 and - 0.70, p < 0.01). MMPD demonstrated moderate to strong correlations with bone porosity and BMD (R = -0.67 and 0.65, p < 0.01). MMPD showed strong correlation with age in specimens from female donors (R = -0.91, p = 0.03, n = 5). The presented comprehensive 3D-UTE-Cones imaging protocol allows quantitative mapping of protons in major pools of cortical bone ex vivo and in vivo. PWPD and MMPD can serve as potential novel biomarkers to assess bone matrix and microstructure, as well as bone age- or injury-related variations.
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Affiliation(s)
- Saeed Jerban
- Department of Radiology, University of California, San Diego, CA, USA
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, CA, USA
| | - Liang Li
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA, USA
| | - Lidi Wan
- Department of Radiology, University of California, San Diego, CA, USA
| | - Tan Guo
- Department of Radiology, University of California, San Diego, CA, USA
| | - Adam Searleman
- Department of Radiology, University of California, San Diego, CA, USA
| | - Eric Y Chang
- Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA; Department of Radiology, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, USA.
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Park CR, Lee Y. Comparison of PET image quality using simultaneous PET/MR by attenuation correction with various MR pulse sequences. NUCLEAR ENGINEERING AND TECHNOLOGY 2019. [DOI: 10.1016/j.net.2019.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wu PH, Gibbons M, Foreman SC, Carballido-Gamio J, Han M, Krug R, Liu J, Link TM, Kazakia GJ. Cortical bone vessel identification and quantification on contrast-enhanced MR images. Quant Imaging Med Surg 2019; 9:928-941. [PMID: 31367547 DOI: 10.21037/qims.2019.05.23] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Cortical bone porosity is a major determinant of bone strength. Despite the biomechanical importance of cortical bone porosity, the biological drivers of cortical porosity are unknown. The content of cortical pore space can indicate pore expansion mechanisms; both of the primary components of pore space, vessels and adipocytes, have been implicated in pore expansion. Dynamic contrast-enhanced MRI (DCE-MRI) is widely used in vessel detection in cardiovascular studies, but has not been applied to visualize vessels within cortical bone. In this study, we have developed a multimodal DCE-MRI and high resolution peripheral QCT (HR-pQCT) acquisition and image processing pipeline to detect vessel-filled cortical bone pores. Methods For this in vivo human study, 19 volunteers (10 males and 9 females; mean age =63±5) were recruited. Both distal and ultra-distal regions of the non-dominant tibia were imaged by HR-pQCT (82 µm nominal resolution) for bone structure segmentation and by 3T DCE-MRI (Gadavist; 9 min scan time; temporal resolution =30 sec; voxel size 230×230×500 µm3) for vessel visualization. The DCE-MRI was registered to the HR-pQCT volume and the voxels within the MRI cortical bone region were extracted. Features of the DCE data were calculated and voxels were categorized by a 2-stage hierarchical kmeans clustering algorithm to determine which voxels represent vessels. Vessel volume fraction (volume ratio of vessels to cortical bone), vessel density (average vessel count per cortical bone volume), and average vessel volume (mean volume of vessels) were calculated to quantify the status of vessel-filled pores in cortical bone. To examine spatial resolution and perform validation, a virtual phantom with 5 channel sizes and an applied pseudo enhancement curve was processed through the proposed image processing pipeline. Overlap volume ratio and Dice coefficient was calculated to measure the similarity between the detected vessel map and ground truth. Results In the human study, mean vessel volume fraction was 2.2%±1.0%, mean vessel density was 0.68±0.27 vessel/mm3, and mean average vessel volume was 0.032±0.012 mm3/vessel. Signal intensity for detected vessel voxels increased during the scan, while signal for non-vessel voxels within pores did not enhance. In the validation phantom, channels with diameter 250 µm or greater were detected successfully, with volume ratio equal to 1 and Dice coefficient above 0.6. Both statistics decreased dramatically for channel sizes less than 250 µm. Conclusions We have a developed a multi-modal image acquisition and processing pipeline that successfully detects vessels within cortical bone pores. The performance of this technique degrades for vessel diameters below the in-plane spatial resolution of the DCE-MRI acquisition. This approach can be applied to investigate the biological systems associated with cortical pore expansion.
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Affiliation(s)
- Po-Hung Wu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Matthew Gibbons
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Sarah C Foreman
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | | | - Misung Han
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Roland Krug
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Jing Liu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Thomas M Link
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Galateia J Kazakia
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
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Wan L, Wu M, Sheth V, Shao H, Jang H, Bydder G, Du J. Evaluation of cortical bone perfusion using dynamic contrast enhanced ultrashort echo time imaging: a feasibility study. Quant Imaging Med Surg 2019; 9:1383-1393. [PMID: 31559167 DOI: 10.21037/qims.2019.08.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been used to study perfusion in a wide variety of soft tissues including the bone marrow. Study of perfusion in hard tissues such as cortical bone has been much more limited because of the lack of detectable MR signal from them using conventional pulse sequences. However, two-dimensional (2D) ultrashort echo time (UTE) sequences detect signal from cortical bone and allow fast imaging of this tissue. In addition, adiabatic 2D inversion recovery UTE (IR-UTE) sequences can provide excellent signal suppression of soft tissues, such as muscle and marrow, and allow cortical bone to be seen with high contrast and reduced artefacts. We aimed to assess the feasibility of using 2D UTE and 2D IR-UTE sequences to perform DCE-MRI in the cortical bone of rabbits and human volunteers. Methods Cortical bone perfusion was studied in rabbits (n=12) and human volunteers (n=3) using 2D UTE and 2D IR-UTE sequences on a clinical 3T scanner. Dynamic data with an in-plane resolution of ~0.5×0.5 mm2, single slice thickness of 3 mm for rabbits and 10 mm for human volunteers, and temporal resolution of 23 s for 2D UTE imaging of rabbits, 28 s for 2D UTE imaging of human volunteers, and 60 s for 2D IR-UTE imaging of both the rabbits and human volunteers were acquired before and after the injection of a Gd contrast agent (Gd-BOPTA: Multihance; Bracco Imaging SpA, Milan, Italy). The dose was 0.06 mmol/kg for rabbits and 0.2 mmol/kg for human subjects. Kinetic analyses based on the Brix model, as well as simple calculations of maximum enhancement (ME) and enhancement slope (ES), were performed. Results The 12 rabbits showed a mean Ktrans of 0.36±0.07 min-1, Kep of 8.42±3.17 min-1, ME of 28.30±6.83, ES of 0.35±0.18 for the femur with the 2D UTE sequence, and a mean Ktrans of 0.45±0.10 min-1, Kep of 9.80±0.50 min-1, ME of 48.84±12.12, and ES of 0.69±0.27 for the femur with the 2D IR-UTE sequence. Lower ME and ES values were observed in the tibial midshaft of healthy human volunteers compared to rabbits. Conclusions These results show that 2D UTE and 2D IR-UTE sequences are capable of detecting dynamic contrast enhancement in cortical bone in both rabbits and healthy human volunteers. Clinical studies with these techniques are likely to be feasible.
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Affiliation(s)
- Lidi Wan
- Department of Radiology, University of California, San Diego, CA, USA
| | - Mei Wu
- Department of Radiology, University of California, San Diego, CA, USA
| | - Vipul Sheth
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hongda Shao
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hyungseok Jang
- Department of Radiology, University of California, San Diego, CA, USA
| | - Graeme Bydder
- Department of Radiology, University of California, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, CA, USA
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Wan L, Zhao W, Ma Y, Jerban S, Searleman AC, Carl M, Chang EY, Tang G, Du J. Fast quantitative 3D ultrashort echo time MRI of cortical bone using extended cones sampling. Magn Reson Med 2019; 82:225-236. [PMID: 30821032 DOI: 10.1002/mrm.27715] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 01/09/2019] [Accepted: 02/05/2019] [Indexed: 12/20/2022]
Abstract
PURPOSE To investigate the effect of stretching sampling window on quantitative 3D ultrashort TE (UTE) imaging of cortical bone at 3 T. METHODS Ten bovine cortical bone and 17 human tibial midshaft samples were imaged with a 3T clinical MRI scanner using an 8-channel knee coil. Quantitative 3D UTE imaging biomarkers, including T1 , T 2 ∗ , magnetization transfer ratio and magnetization transfer modeling, were performed using radial or spiral Cones sampling trajectories with various durations. Errors in UTE-MRI biomarkers as a function of sampling time were evaluated using radial sampling as a reference standard. RESULTS For both bovine and human cortical bone samples, no significant differences were observed for all UTE biomarkers (single-component T 2 ∗ , bicomponent T 2 ∗ and relative fractions, T1 , magnetization transfer ratio, and magnetization transfer modeling of macromolecular fraction) for spiral sampling windows of 992 µs to 1600 µs compared with a radial sampling window of 688 µs. CONCLUSION The total scan time can be reduced by 76% with quantification errors less than 5%. Quantitative UTE-MRI techniques can be greatly accelerated using longer sampling windows without significant quantification errors.
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Affiliation(s)
- Lidi Wan
- Department of Radiology, University of California, San Diego, California.,Department of Radiology, Shanghai Tenth People's Hospital of Tongji University, School of Medicine, Shanghai, China
| | - Wei Zhao
- Department of Radiology, University of California, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California, San Diego, California
| | - Saeed Jerban
- Department of Radiology, University of California, San Diego, California
| | - Adam C Searleman
- Department of Radiology, University of California, San Diego, California
| | | | - Eric Y Chang
- Department of Radiology, University of California, San Diego, California.,Radiology Service, VA San Diego Healthcare System, San Diego, California
| | - Guangyu Tang
- Department of Radiology, Shanghai Tenth People's Hospital of Tongji University, School of Medicine, Shanghai, China
| | - Jiang Du
- Department of Radiology, University of California, San Diego, California
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41
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Sagl B, Schmid-Schwap M, Piehslinger E, Kronnerwetter C, Kundi M, Trattnig S, Stavness I. In vivo prediction of temporomandibular joint disc thickness and position changes for different jaw positions. J Anat 2019; 234:718-727. [PMID: 30786005 DOI: 10.1111/joa.12951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2019] [Indexed: 12/31/2022] Open
Abstract
Temporomandibular joint disorders (TMD) are common dysfunctions of the masticatory region and are often linked to dislocation or changes of the temporomandibular joint (TMJ) disc. Magnetic resonance imaging (MRI) is the gold standard for TMJ imaging but standard clinical sequences do not deliver a sufficient resolution and contrast for the creation of detailed meshes of the TMJ disc. Additionally, bony structures cannot be captured appropriately using standard MRI sequences due to their low signal intensity. The objective of this study was to enable researchers to create high resolution representations of all structures of the TMJ and consequently investigate morphological as well as positional changes of the masticatory system. To create meshes of the bony structures, a single computed tomography (CT) scan was acquired. In addition, a high-resolution MRI sequence was produced, which is used to collect the thickness and position change of the disc for various static postures using bite blocks. Changes in thickness of the TMJ disc as well as disc translation were measured. The newly developed workflow successfully allows researchers to create high resolution models of all structures of the TMJ for various static positions, enabling the investigation of TMJ disc translation and deformation. Discs were thinnest in the lateral part and moved mainly anteriorly and slightly medially. The procedure offers the most comprehensive picture of disc positioning and thickness changes reported to date. The presented data can be used for the development of a biomechanical computer model of TMJ anatomy and to investigate dynamic and static loads on the components of the system, which could be useful for the prediction of TMD onset.
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Affiliation(s)
- Benedikt Sagl
- Department of Prosthodontics, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Martina Schmid-Schwap
- Department of Prosthodontics, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Eva Piehslinger
- Department of Prosthodontics, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Claudia Kronnerwetter
- Department of Biomedical Imaging and Image-guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria
| | - Michael Kundi
- Institute of Environmental Health, Medical University of Vienna, Vienna, Austria
| | - Siegfried Trattnig
- Department of Biomedical Imaging and Image-guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria.,CD Laboratory for Clinical Molecular MR Imaging, Medical University of Vienna, Vienna, Austria
| | - Ian Stavness
- Department of Computer Science, University of Saskatchewan, Saskatoon, SK, Canada
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42
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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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43
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Aiello M, Cavaliere C, Marchitelli R, d'Albore A, De Vita E, Salvatore M. Hybrid PET/MRI Methodology. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 141:97-128. [PMID: 30314608 DOI: 10.1016/bs.irn.2018.07.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The hybrid PET/MR scanner represents the first implementation of the effective integration of two modalities allowing truly synchronous/simultaneous acquisition of their imaging signals. This integration, resulting from the innovation and development of specific hardware components has paved the way for new approaches in the study of neurodegenerative diseases. This chapter will describe the hardware development that has led to the availability of different clinical solutions for PET/MR imaging as well as the still-open technological challenges and opportunities related to the processing and exploitation of the simultaneous acquisition in neurological studies.
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Affiliation(s)
| | | | | | | | - Enrico De Vita
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
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44
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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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45
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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: 53] [Impact Index Per Article: 8.8] [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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46
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Mannheim JG, Schmid AM, Schwenck J, Katiyar P, Herfert K, Pichler BJ, Disselhorst JA. PET/MRI Hybrid Systems. Semin Nucl Med 2018; 48:332-347. [PMID: 29852943 DOI: 10.1053/j.semnuclmed.2018.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the last decade, the combination of PET and MRI in one system has proven to be highly successful in basic preclinical research, as well as in clinical research. Nowadays, PET/MRI systems are well established in preclinical imaging and are progressing into clinical applications to provide further insights into specific diseases, therapeutic assessments, and biological pathways. Certain challenges in terms of hardware had to be resolved concurrently with the development of new techniques to be able to reach the full potential of both combined techniques. This review provides an overview of these challenges and describes the opportunities that simultaneous PET/MRI systems can exploit in comparison with stand-alone or other combined hybrid systems. New approaches were developed for simultaneous PET/MRI systems to correct for attenuation of 511 keV photons because MRI does not provide direct information on gamma photon attenuation properties. Furthermore, new algorithms to correct for motion were developed, because MRI can accurately detect motion with high temporal resolution. The additional information gained by the MRI can be employed to correct for partial volume effects as well. The development of new detector designs in combination with fast-decaying scintillator crystal materials enabled time-of-flight detection and incorporation in the reconstruction algorithms. Furthermore, this review lists the currently commercially available systems both for preclinical and clinical imaging and provides an overview of applications in both fields. In this regard, special emphasis has been placed on data analysis and the potential for both modalities to evolve with advanced image analysis tools, such as cluster analysis and machine learning.
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Affiliation(s)
- Julia G Mannheim
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Andreas M Schmid
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Johannes Schwenck
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany; Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Prateek Katiyar
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Kristina Herfert
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany.
| | - Jonathan A Disselhorst
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
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47
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Rai R, Manton D, Jameson MG, Josan S, Barton MB, Holloway LC, Liney GP. 3D printed phantoms mimicking cortical bone for the assessment of ultrashort echo time magnetic resonance imaging. Med Phys 2017; 45:758-766. [DOI: 10.1002/mp.12727] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 11/13/2017] [Accepted: 12/03/2017] [Indexed: 11/08/2022] Open
Affiliation(s)
- Robba Rai
- South Western Sydney Clinical School; University of New South Wales; Liverpool NSW 2170 Australia
- Liverpool and Macarthur Cancer Therapy Centre; Liverpool Hospital; Liverpool NSW 2170 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
| | - David Manton
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
| | - Michael G. Jameson
- South Western Sydney Clinical School; University of New South Wales; Liverpool NSW 2170 Australia
- Liverpool and Macarthur Cancer Therapy Centre; Liverpool Hospital; Liverpool NSW 2170 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Centre of Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
| | - Sonal Josan
- Siemens Healthcare; Melbourne Vic. 3207 Australia
| | - Michael B. Barton
- South Western Sydney Clinical School; University of New South Wales; Liverpool NSW 2170 Australia
- Liverpool and Macarthur Cancer Therapy Centre; Liverpool Hospital; Liverpool NSW 2170 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
| | - Lois C. Holloway
- South Western Sydney Clinical School; University of New South Wales; Liverpool NSW 2170 Australia
- Liverpool and Macarthur Cancer Therapy Centre; Liverpool Hospital; Liverpool NSW 2170 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Centre of Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
- Institute of Medical Physics; School of Physics; University of Sydney; Sydney NSW Australia
| | - Gary P. Liney
- South Western Sydney Clinical School; University of New South Wales; Liverpool NSW 2170 Australia
- Liverpool and Macarthur Cancer Therapy Centre; Liverpool Hospital; Liverpool NSW 2170 Australia
- Ingham Institute for Applied Medical Research; Liverpool NSW 2170 Australia
- Centre of Radiation Physics; University of Wollongong; Wollongong NSW 2522 Australia
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48
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Hudson TJ, Looi T, Pichardo S, Amaral J, Temple M, Drake JM, Waspe AC. Simulating thermal effects of MR-guided focused ultrasound in cortical bone and its surrounding tissue. Med Phys 2017; 45:506-519. [DOI: 10.1002/mp.12704] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Affiliation(s)
- Thomas J. Hudson
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Thomas Looi
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Samuel Pichardo
- Thunder Bay Regional Health Research Institute; Thunder Bay Ontario P7B 6V4 Canada
- Electrical Engineering and Physics; Lakehead University; Thunder Bay Ontario P7B 5E1 Canada
| | - Joao Amaral
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
| | - Michael Temple
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
| | - James M. Drake
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Adam C. Waspe
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
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49
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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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50
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Ma YJ, Tadros A, Du J, Chang EY. Quantitative two-dimensional ultrashort echo time magnetization transfer (2D UTE-MT) imaging of cortical bone. Magn Reson Med 2017; 79:1941-1949. [PMID: 28776754 DOI: 10.1002/mrm.26846] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 06/28/2017] [Accepted: 06/30/2017] [Indexed: 01/19/2023]
Abstract
PURPOSE To investigate quantitative 2D ultrashort echo time magnetization transfer (UTE-MT) imaging in ex vivo bovine cortical bone and in vivo human tibial cortical bone. METHODS Data were acquired from five fresh bovine cortical bone samples and five healthy volunteer tibial cortical bones using a 2D UTE-MT sequence on a clinical 3T scanner. The 2D UTE-MT sequence used four or five MT powers with five frequency offsets. Results were analyzed with a two-pool quantitative MT model, providing measurements of macromolecular fraction (f), macromolecular proton transverse relaxation times (T2m ), proton exchange rates from water/macromolecular to the macromolecular/water pool (RM0m /RM0w ), and spin-lattice relaxation rate of water pool (R1w ). A sequential air-drying study for a small bovine cortical bone chip was used to investigate whether above MT modeling parameters were sensitive to the water loss. RESULTS Mean fresh bovine cortical bone values for f, T2m , R1w , RM0m , and RM0w were 59.9 ± 7.3%, 14.6 ± 0.3 μs, 9.9 ± 2.4 s-1 , 17.9 ± 3.6 s-1 , and 11.8 ± 2.0 s-1 , respectively. Mean in vivo human cortical bone values for f, T2m , R1w , RM0m and RM0w were 54.5 ± 4.9%, 15.4 ± 0.6 μs, 8.9 ± 1.1 s-1 , 11.5 ± 3.5 s-1 , and 9.5 ± 1.9 s-1 , respectively. The sequential air-drying study shows that f, RM0m , and R1w were increased with longer drying time. CONCLUSION UTE-MT two-pool modeling provides novel and useful quantitative information for cortical bone. Magn Reson Med 79:1941-1949, 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, San Diego, California, USA
| | - Anthony Tadros
- Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, California, USA
| | - Eric Y Chang
- Department of Radiology, University of California, San Diego, San Diego, California, USA.,Radiology Service, VA San Diego Healthcare System, San Diego, California, USA
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