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Tian Y, Nayak KS. New clinical opportunities of low-field MRI: heart, lung, body, and musculoskeletal. MAGMA (NEW YORK, N.Y.) 2024; 37:1-14. [PMID: 37902898 PMCID: PMC10876830 DOI: 10.1007/s10334-023-01123-w] [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: 05/26/2023] [Revised: 09/28/2023] [Accepted: 10/05/2023] [Indexed: 11/01/2023]
Abstract
Contemporary whole-body low-field MRI scanners (< 1 T) present new and exciting opportunities for improved body imaging. The fundamental reason is that the reduced off-resonance and reduced SAR provide substantially increased flexibility in the design of MRI pulse sequences. Promising body applications include lung parenchyma imaging, imaging adjacent to metallic implants, cardiac imaging, and dynamic imaging in general. The lower cost of such systems may make MRI favorable for screening high-risk populations and population health research, and the more open configurations allowed may prove favorable for obese subjects and for pregnant women. This article summarizes promising body applications for contemporary whole-body low-field MRI systems, with a focus on new platforms developed within the past 5 years. This is an active area of research, and one can expect many improvements as MRI physicists fully explore the landscape of pulse sequences that are feasible, and as clinicians apply these to patient populations.
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Affiliation(s)
- Ye Tian
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, CA, 90089-2564, USA.
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, CA, 90089-2564, USA
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Allaire BT, Mousavi SJ, James JN, Bouxsein ML, Anderson DE. Dependence of trunk muscle size and position on age, height, and weight in a multi-ethnic cohort of middle-aged and older men and women. J Biomech 2023; 157:111710. [PMID: 37437459 PMCID: PMC10470847 DOI: 10.1016/j.jbiomech.2023.111710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/25/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023]
Abstract
Trunk muscle size and location relative to the spine are key factors affecting their capacity to assist in trunk movement, strength, and function. There remains limited information on how age, weight and height affect these measurements across multiple spinal levels, and prior studies had limited samples in terms of size and ethnicity. In this study, we measured trunk muscles in coronal plane slices at T4 - L4 of CT scans acquired in 507 participants, aged 40-90 years, from the community-based Framingham Heart Study. Mixed-effects linear regressions, stratified by sex, determined the contributions of age, height and weight, to muscle cross-sectional area (CSA), the distance from the vertebral body centroid (CD), and the in-plane angle of the line between the vertebral body and the muscle centroids (CA). Muscle CSA decreased with higher age by an average of -0.8% per year, but weight (average 0.8% per kg) and height (average -0.05% per cm) had mixed results, with both positive and negative effects depending on muscle group and level. Muscle CD increased with weight by an average of 0.3% per kg, but had mixed effects for age (average 0.8% per year) and height (average 0.1% per cm). Muscle CA had mixed associations with age (average 0.05% per year), weight (average 0.01% per kg) and height (average -0.05% per cm). A prediction program created with these results provides a simple approach for estimating probable values for trunk muscle size and position in the absence of medical imaging.
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Affiliation(s)
- Brett T Allaire
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Seyed Javad Mousavi
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, United States
| | - Joanna N James
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Mary L Bouxsein
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, United States
| | - Dennis E Anderson
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, United States.
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Pai S A, Zhang H, Ashjaee N, Wilson DR, Brown SH, Fels S, Street J, Oxland TR. Estimation and assessment of sagittal spinal curvature and thoracic muscle morphometry in different postures. Proc Inst Mech Eng H 2021; 235:883-896. [PMID: 33977818 DOI: 10.1177/09544119211014668] [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: 11/15/2022]
Abstract
Spine models are typically developed from supine clinical imaging data, and hence clearly do not fully reflect postures that replicate subjects' clinical symptoms. Our objectives were to develop a method to: (i) estimate the subject-specific sagittal curvature of the whole spine in different postures from limited imaging data, (ii) obtain muscle lines-of-action in different postures and analyze the effect of posture on muscle fascicle length, and (iii) correct for cosine between the magnetic resonance imaging (MRI) scan plane and dominant fiber line-of-action for muscle parameters (cross-sectional area (CSA) and position). The thoracic spines of six healthy volunteers were scanned in four postures (supine, standing, flexion, and sitting) in an upright MRI. Geometry of the sagittal spine was approximated with a circular spline. A pipeline was developed to estimate spine geometry in different postures and was validated. The lines-of-action for two muscles, erector spinae (ES) and transversospinalis (TS) were obtained for every posture and hence muscle fascicle lengths were computed. A correction factor based on published literature was then computed and applied to the muscle parameters. The maximum registration error between the estimated spine geometry and MRI data was small (average RMSE∼1.2%). The muscle fascicle length increased (up to 20%) in flexion when compared to erect postures. The correction factor reduced muscle parameters (∼5% for ES and ∼25% for TS) when compared to raw MRI data. The proposed pipeline is a preliminary step in subject-specific modeling. Direction cosines of muscles could be used while improving the inputs of spine models.
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Affiliation(s)
- Anoosha Pai S
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
- ICORD, University of British Columbia, Vancouver, BC, Canada
| | - Honglin Zhang
- Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada
| | - Nima Ashjaee
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada
| | - David R Wilson
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
| | - Stephen Hm Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Sidney Fels
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada
| | - John Street
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
| | - Thomas R Oxland
- ICORD, University of British Columbia, Vancouver, BC, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
- Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada
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