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Sussman MS, Jhaveri KS. A short-TR single-echo spin-echo breath-hold method for assessing liver T2. MAGMA 2024; 37:101-113. [PMID: 38071698 DOI: 10.1007/s10334-023-01132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/27/2023] [Accepted: 10/28/2023] [Indexed: 02/21/2024]
Abstract
OBJECTIVE Conventional single-echo spin-echo T2 mapping used for liver iron quantification is too long for breath-holding. This study investigated a short TR (~100 ms) single-echo spin-echo T2 mapping technique wherein each image (corresponding to a single TE) could be acquired in ~17 s-short enough for a breath-hold. TE images were combined for T2 fitting. To avoid T1 bias, each TE acquisition incremented TR to maintain a constant TR-TE. MATERIALS AND METHODS Experiments at 1.5T validated the technique's accuracy in phantoms, 9 healthy volunteers, and 5 iron overload patients. In phantoms and healthy volunteers, the technique was compared to the conventional approach of constant TR for all TEs. Iron overload results were compared to FerriScan. RESULTS In phantoms, the constant TR-TE technique provided unbiased estimates of T2, while the conventional constant TR approach underestimated it. In healthy volunteers, there was no significant discrepancy at the 95% confidence level between constant TR-TE and reference T2 values, whereas there was for constant TR scans. In iron overload patients, there was a high correlation between constant TR-TE and FerriScan T2 values (r2 = 0.95), with a discrepancy of 0.6+/- 1.4 ms. DISCUSSION The short-TR single-echo breath-hold spin-echo technique provided unbiased estimates of T2 in phantoms and livers.
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Affiliation(s)
- Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital, and Women's College Hospital, University of Toronto, 585 University Avenue, Room NUW-1-141D, Toronto, ON, M5G 2N2, Canada.
| | - Kartik S Jhaveri
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital, and Women's College Hospital, University of Toronto, 585 University Avenue, Room NUW-1-141D, Toronto, ON, M5G 2N2, Canada
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Brakel BA, Sussman MS, Majeed H, Teitel J, Man C, Rayner T, Weiss R, Moineddin R, Blanchette V, Doria AS. T2 mapping magnetic resonance imaging of cartilage in hemophilia. Res Pract Thromb Haemost 2023; 7:102182. [PMID: 37767061 PMCID: PMC10520564 DOI: 10.1016/j.rpth.2023.102182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 06/16/2023] [Accepted: 06/17/2023] [Indexed: 09/29/2023] Open
Abstract
Background In hemophilia, recurrent hemarthrosis may lead to irreversible arthropathy. T2 mapping MRI may reflect cartilage changes at an earlier reversible stage of arthropathy as opposed to structural MRI. Objectives To evaluate interval changes of T2 mapping compared with the International Prophylaxis Study Group (IPSG) structural MRI scores of ankle cartilage in boys with hemophilia receiving prophylaxis. Methods Eight boys with hemophilia A (median age, 13; range, 9-17 years), 7 age- and sex-matched healthy boys (controls, median age, 15; range, 7-16 years). A multiecho spin-echo T2-weighted MRI sequence at 3.0T was used to obtain T2 maps of cartilage of boys with hemophilia and controls. Structural joint status was evaluated using the IPSG MRI score. Results T2 relaxation times of ankle cartilage increased significantly over time in both persons with hemophilia and controls (P = .002 and P = .00009, respectively). Changes in T2 relaxation time strongly correlated with changes in IPSG cartilage scores (rs = 0.93 to rs = 0.78 [P = .0007 to P = .023]), but not with changes in age (P = .304 to P = .840). Responsiveness of T2 relaxation times were higher than that of IPSG cartilage scores, with standardized response means >1.4 for T2 mapping in all regions-of-interest compared with 0.84 for IPSG cartilage scores. Baseline T2 relaxation time strongly correlated with timepoint 2 IPSG cartilage score (rs = 0.93 to rs = 0.82 [P = .001 to P = .012]) and T2 relaxation time (rs = 0.98 to rs = 0.88 [P = .00003 to P = .004]) changes in most regions-of-interest. Conclusion T2 mapping shows sensitivity to biochemical changes in cartilage prior to detectable damage using conventional MRI, offering potential for early detection of bleed-related cartilage damage in boys with hemophilia.
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Affiliation(s)
- Benjamin A. Brakel
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S. Sussman
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Haris Majeed
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Jerry Teitel
- Division of Hematology/Oncology, St Michael’s Hospital, Toronto, ON, Canada
| | - Carina Man
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Tammy Rayner
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Ruth Weiss
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Rahim Moineddin
- Division of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Victor Blanchette
- Department of Pediatrics, University of Toronto, Toronto, ON, Canada
- Division of Hematology/Oncology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Andrea S. Doria
- Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
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Thavendiranathan P, Shalmon T, Fan CPS, Houbois C, Amir E, Thevakumaran Y, Somerset E, Malowany JM, Urzua-Fresno C, Yip P, McIntosh C, Sussman MS, Brezden-Masley C, Yan AT, Koch CA, Spiller N, Abdel-Qadir H, Power C, Hanneman K, Wintersperger BJ. Comprehensive Cardiovascular Magnetic Resonance Tissue Characterization and Cardiotoxicity in Women With Breast Cancer. JAMA Cardiol 2023; 8:524-534. [PMID: 37043251 PMCID: PMC10099158 DOI: 10.1001/jamacardio.2023.0494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/12/2023] [Indexed: 04/13/2023]
Abstract
Importance There is a growing interest in understanding whether cardiovascular magnetic resonance (CMR) myocardial tissue characterization helps identify risk of cancer therapy-related cardiac dysfunction (CTRCD). Objective To describe changes in CMR tissue biomarkers during breast cancer therapy and their association with CTRCD. Design, Setting, and Participants This was a prospective, multicenter, cohort study of women with ERBB2 (formerly HER2)-positive breast cancer (stages I-III) who were scheduled to receive anthracycline and trastuzumab therapy with/without adjuvant radiotherapy and surgery. From November 7, 2013, to January 16, 2019, participants were recruited from 3 University of Toronto-affiliated hospitals. Data were analyzed from July 2021 to June 2022. Exposures Sequential therapy with anthracyclines, trastuzumab, and radiation. Main Outcomes and Measures CMR, high-sensitivity cardiac troponin I (hs-cTnI), and B-type natriuretic peptide (BNP) measurements were performed before anthracycline treatment, after anthracycline and before trastuzumab treatment, and at 3-month intervals during trastuzumab therapy. CMR included left ventricular (LV) volumes, LV ejection fraction (EF), myocardial strain, early gadolinium enhancement imaging to assess hyperemia (inflammation marker), native/postcontrast T1 mapping (with extracellular volume fraction [ECV]) to assess edema and/or fibrosis, T2 mapping to assess edema, and late gadolinium enhancement (LGE) to assess replacement fibrosis. CTRCD was defined using the Cardiac Review and Evaluation Committee criteria. Fixed-effects models or generalized estimating equations were used in analyses. Results Of 136 women (mean [SD] age, 51.1 [9.2] years) recruited from 2013 to 2019, 37 (27%) developed CTRCD. Compared with baseline, tissue biomarkers of myocardial hyperemia and edema peaked after anthracycline therapy or 3 months after trastuzumab initiation as demonstrated by an increase in mean (SD) relative myocardial enhancement (baseline, 46.3% [16.8%] to peak, 56.2% [18.6%]), native T1 (1012 [26] milliseconds to 1035 [28] milliseconds), T2 (51.4 [2.2] milliseconds to 52.6 [2.2] milliseconds), and ECV (25.2% [2.4%] to 26.8% [2.7%]), with P <.001 for the entire follow-up. The observed values were mostly within the normal range, and the changes were small and recovered during follow-up. No new replacement fibrosis developed. Increase in T1, T2, and/or ECV was associated with increased ventricular volumes and BNP but not hs-cTnI level. None of the CMR tissue biomarkers were associated with changes in LVEF or myocardial strain. Change in ECV was associated with concurrent and subsequent CTRCD, but there was significant overlap between patients with and without CTRCD. Conclusions and Relevance In women with ERBB2-positive breast cancer receiving sequential anthracycline and trastuzumab therapy, CMR tissue biomarkers suggest inflammation and edema peaking early during therapy and were associated with ventricular remodeling and BNP elevation. However, the increases in CMR biomarkers were transient, were not associated with LVEF or myocardial strain, and were not useful in identifying traditional CTRCD risk.
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Affiliation(s)
- Paaladinesh Thavendiranathan
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Tamar Shalmon
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Chun-Po Steve Fan
- Ted Rogers Computational Program, Ted Rogers Centre for Heart Research, Peter Munk Cardiac Centre, UHN, Toronto, Ontario, Canada
| | - Christian Houbois
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Eitan Amir
- Department of Medicine, Division of Medical Oncology and Hematology, Princess Margaret Cancer Center, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Yobiga Thevakumaran
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Emily Somerset
- Ted Rogers Computational Program, Ted Rogers Centre for Heart Research, Peter Munk Cardiac Centre, UHN, Toronto, Ontario, Canada
| | - Julia M. Malowany
- Peter Munk Cardiac Center, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Camila Urzua-Fresno
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Paul Yip
- Division of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Ontario, Canada
| | - Chris McIntosh
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
- Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada
- Techna Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Vector Institute, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S. Sussman
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Christine Brezden-Masley
- Department of Medicine, Division of Medical Oncology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Andrew T. Yan
- Keenan Research Centre, Li Ka Shing Knowledge Institute, Division of Cardiology, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
| | - C. Anne Koch
- Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Neil Spiller
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Husam Abdel-Qadir
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Women’s College Hospital, Toronto, Ontario, Canada
| | - Coleen Power
- Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Kate Hanneman
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Bernd J. Wintersperger
- Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
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Sussman MS. Editorial on "Visualization of Human Aortic Valve Dynamics Using MRI With Sub-Millisecond Temporal Resolution". J Magn Reson Imaging 2021; 54:1255-1256. [PMID: 33987948 DOI: 10.1002/jmri.27695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 11/10/2022] Open
Affiliation(s)
- Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada.,Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
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Majeed H, Ahmed H, Sussman MS, Macgowan C, Rayner T, Weiss R, Feldman BM, Doria AS. Understanding Early Hemophilic Arthropathy in Children and Adolescents Through MRI T 2 Mapping. J Magn Reson Imaging 2020; 53:827-837. [PMID: 33135834 DOI: 10.1002/jmri.27406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Persons with hemophilia experience hemarthrosis, which can lead to cartilage degeneration, causing physical impairment. MRI T2 mapping has the potential to be used as a tool to evaluate early arthropathic changes and cartilage degeneration in patients with hemophilia. PURPOSE To assess the value of MRI-T2 mapping as a tool for investigating the cartilage status of children and adolescents with hemophilic arthropathy. STUDY TYPE Prospective, cross-sectional. SUBJECTS Twenty-eight boys with hemophilia (aged 5-17 years) and 23 healthy boys (aged 7-17 years). FIELD STRENGTH/SEQUENCES A multiecho spin-echo T2 -weighted gradient echo sequence was used on a 3.0T magnet. ASSESSMENT MRI-T2 maps of ankle (tibia-talus) (n = 19) or knee (femur-tibia) (n = 9) cartilage were assessed in hemophilia and healthy groups. An anatomically-based MRI score was also assigned to each ankle/knee. STATISTICAL TESTS Pearson's correlation coefficient (r), linear regression, intraclass correlation coefficient (ICC), and analysis of variance (ANOVA) test. RESULTS Negative associations between age and ankle/knee cartilage T2 relaxation times were found in hemophilia (r = -0.72 [P = 0.03] to -0.55 [P = 0.01]) and healthy (r = -0.84 [P < 0.001] to -0.55 [P = 0.20]) groups. There were nonsignificant associations between ankle cartilage T2 relaxation times and MRI scores (r = -0.15 [P = 0.54] to 0.31 [P = 0.19]). DATA CONCLUSION Results of this clinical investigation emphasize the potential importance of MRI-T2 maps as a tool to understand the functional status of cartilage in children and adolescents with hemophilic arthropathy, while holding promise for the detection of early cartilage degeneration prior to macroscopic characterization by conventional MRI. MRI-T2 mapping may provide novel information that is not reflected in the anatomically-based MRI scoring system. LEVEL OF EVIDENCE 3 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Haris Majeed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Humayun Ahmed
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S Sussman
- Department of Medical Imaging, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Christopher Macgowan
- Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Tammy Rayner
- Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ruth Weiss
- Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Brian M Feldman
- Division of Rheumatology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, Faculty of Medicine, Institute of Health Policy, Management & Evaluation, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Andrea S Doria
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Imaging, University Health Network and University of Toronto, Toronto, Ontario, Canada.,Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
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D'Errico L, Sussman MS, Hanneman K, Wintersperger BJ. Precision-optimized single protocol pre-/post-contrast modified-look locker inversion T1 mapping using composite inversion group fitting. Magn Reson Imaging 2020; 74:195-202. [PMID: 33010378 DOI: 10.1016/j.mri.2020.09.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 09/10/2020] [Accepted: 09/27/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Investigation of a simple, precision optimized, identical pre-/post-contrast modified look locker inversion recovery (MOLLI) protocol employing Composite inversion group (IG) fitting in a clinical cardiomyopathy population. METHODS Cardiac magnetic resonance imaging (MRI) was performed at 3 Tesla in 36 patients (48.0 years [IQR: 35.7, 58.2 years]) with known/suspicion of hypertrophic cardiomyopathy. T1 mapping was performed pre-/post-contrast (0.15 mmol/kg Gadobutrol) using a standard 3-parameter fit (STANDARD) and an optimized (OPTIMAL) single-protocol Composite-IG fitting MOLLI approach. The OPTIMAL protocol was based on a simulation study (for 11hb acquisitions) with cost metric analysis across the range of expected T1 values (300-1400 ms) and heart rates (50-80 bpm). All maps were generated offline based on motion corrected source images. Based on region of interest analysis, the precision of both approaches was assessed using a previously validated propagation of errors technique for pre-/post-contrast T1 mapping as well as calculated ECV (based on point-of care hematocrit measurements. Furthermore, respective T1 and ECV values were calculated. Statistical methods included Wilcoxon Signed-Rank tests and Student's paired t-test. RESULTS A total of ~9000 11hb inversion groupings were simulated with a 4(0)2(0)2(0)2(0)1 grouping providing the optimal precision across the specified T1/heart rate range. In comparison to standard pre-contrast 5(3)3 MOLLI, this OPTIMAL protocol demonstrated a significantly improved pre-contrast precision (9.1 [6.2, 9.9]ms vs. 9.4 [7.3, 10.8]ms; P < 0.001) while no significant differences were found for post-contrast T1 mapping (4.5 [2.6, 5.3]ms vs. 4.2 [2.8, 5.1]ms; P = 0.25) and EVC mapping (0.38 [0.28, 0.45]ms vs. 0.35 [0.25, 0.44]ms; P = 0.07) or reproducibility (0.16 [0.14, 0.19] vs. 0.19 [0.13, 0.23]P = 0.53). Direct comparison of resulting T1/ECV values demonstrated no significant differences between STANDARD and OPTIMAL techniques for pre-contrast T1 (1178 [1158, 1199]ms vs. 1173 [1143, 1195]ms; P = 0.46) and significant differences for post-contrast T1 (466 [446, 506]ms vs. 456 [433, 503]ms; P = 0.04) and ECV (23.1 [20.8, 25.1]% vs. 23.9 [22.3, 26.4]%; P = 0.001). CONCLUSIONS A single optimized Composite-IG fitting protocol for pre-/post-contrast T1 mapping demonstrated improved precision over standard MOLLI techniques. It enables a simplified workflow with reduction of potential sources of error especially with respect to image data co-registration easing advanced post-processing for generation of patient specific ECV maps.
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Affiliation(s)
- Luigia D'Errico
- Department of Medical Imaging, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S Sussman
- Department of Medical Imaging, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Kate Hanneman
- Department of Medical Imaging, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Bernd J Wintersperger
- Department of Medical Imaging, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
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Wong AKO, Szabo E, Erlandson M, Sussman MS, Duggina S, Song A, Reitsma S, Gillick H, Adachi JD, Cheung AM. A Valid and Precise Semiautomated Method for Quantifying Intermuscular Fat Intramuscular Fat in Lower Leg Magnetic Resonance Images. J Clin Densitom 2020; 23:611-622. [PMID: 30352783 DOI: 10.1016/j.jocd.2018.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 11/28/2022]
Abstract
The accumulation of INTERmuscular fat and INTRAmuscular fat (IMF) has been a hallmark of individuals with diabetes, those with mobility impairments such as spinal cord injuries and is known to increase with aging. An elevated amount of IMF has been associated with fractures and frailty, but the imprecision of IMF measurement has so far limited the ability to observe more consistent clinical associations. Magnetic resonance imaging has been recognized as the gold standard for portraying these features, yet reliable methods for quantifying IMF on magnetic resonance imaging is far from standardized. Previous investigators used manual segmentation guided by histogram-based region-growing, but these techniques are subjective and have not demonstrated reliability. Others applied fuzzy classification, machine learning, and atlas-based segmentation methods, but each is limited by the complexity of implementation or by the need for a learning set, which must be established each time a new disease cohort is examined. In this paper, a simple convergent iterative threshold-optimizing algorithm was explored. The goal of the algorithm is to enable IMF quantification from plain fast spin echo (FSE) T1-weighted MR images or from water-saturated images. The algorithm can be programmed into Matlab easily, and is semiautomated, thus minimizing the subjectivity of threshold-selection. In 110 participants from 3 cohort studies, IMF area measurement demonstrated a high degree of reproducibility with errors well within the 5% benchmark for intraobserver, interobserver, and test-retest analyses; in contrast to manual segmentation which already yielded over 20% error for intraobserver analysis. This algorithm showed validity against manual segmentations (r > 0.85). The simplicity of this technique lends itself to be applied to fast spin echo images commonly ordered as part of standard of care and does not require more advanced fat-water separated images.
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Affiliation(s)
- Andy K O Wong
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada; University Health Network, Osteoporosis Program, Toronto General Research Institute, Toronto, Ontario, Canada; McMaster University, Department of Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada.
| | - Eva Szabo
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Marta Erlandson
- University of Saskatchewan, College of Kinesiology, Saskatoon, Saskatchewan, Canada
| | - Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Sravani Duggina
- McMaster University, Department of Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Anny Song
- University Health Network, Osteoporosis Program, Toronto General Research Institute, Toronto, Ontario, Canada
| | - Shannon Reitsma
- McMaster University, Department of Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Hana Gillick
- McMaster University, Department of Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Jonathan D Adachi
- McMaster University, Department of Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada
| | - Angela M Cheung
- University Health Network, Osteoporosis Program, Toronto General Research Institute, Toronto, Ontario, Canada
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Altaha MA, Nolan M, Marwick TH, Somerset E, Houbois C, Amir E, Yip P, Connelly KA, Michalowska M, Sussman MS, Wintersperger BJ, Thavendiranathan P. Can Quantitative CMR Tissue Characterization Adequately Identify Cardiotoxicity During Chemotherapy? JACC Cardiovasc Imaging 2020; 13:951-962. [DOI: 10.1016/j.jcmg.2019.10.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/08/2019] [Accepted: 10/24/2019] [Indexed: 10/25/2022]
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Sussman MS. Linear signal combination T 2 spectroscopy. Magn Reson Imaging 2019; 66:257-266. [PMID: 31734273 DOI: 10.1016/j.mri.2019.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/31/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
A technique is presented for performing T2 spectroscopy in magnetic resonance imaging (MRI). It is based on a weighted linear combination of T2 decay data. The data is combined in a manner that acts like a filter on the T2 spectrum. The choice of weighting coefficients determines the filter specifications (e.g. passband/stopband locations, stopband suppression factors). To perform spectroscopy, a series of filters are designed with narrow passbands centered about consecutive regions of the T2 spectrum. This provides an estimate of every region of the spectrum. Taken together, an initial estimate of the full T2 spectrum is thus obtained. However, the filtering process causes a distortion of the estimate relative to the true spectrum. To reduce this distortion, deconvolution is performed. The characteristics of the technique are first evaluated through simulation. The technique is then applied to experimental MRI data to demonstrate practical feasibility. T2 spectroscopy falls into a class of problems requiring inverse transformation with a set of exponential basis functions (i.e. the Laplace Transform). It is demonstrated how the present technique may be applied to problems involving non-exponential basis functions as well.
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Affiliation(s)
- Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, University, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
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Sussman MS, Wintersperger BJ. Modified look-locker inversion recovery (MOLLI) T 1 mapping with inversion group (IG) fitting - A method for improved precision. Magn Reson Imaging 2019; 62:38-45. [PMID: 31170429 DOI: 10.1016/j.mri.2019.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/31/2019] [Accepted: 06/02/2019] [Indexed: 11/17/2022]
Abstract
MOLLI-based T1 mapping has been applied to a variety of cardiac pathologies. However, conventional MOLLI's requirement for rest periods between inversion groups increases scan time, and limits the choice of inversion groups. The recently developed inversion group (IG) fitting technique eliminates the rest period requirement, and permits complete flexibility of inversion groups. However, a limitation is that its T1 maps have low precision - up to 30% poorer than conventional 3-parameter methods. In the original IG method, T1 maps were derived from the first inversion group only. In the present study, a technique is presented which utilize data from all inversion groups to generate T1 maps. It is hypothesized this "composite-IG" fitting method will provided improved prevision over conventional-IG T1 mapping methods. Simulations, phantom, and in vivo experiments on nine clinical cardiac patients (congenital heart disease, ischemic- and non-ischemic cardiomyopathy) were performed. Imaging was performed on a 1.5 T Siemens scanner. Myocardial T1 mapping precision and reproducibility were calculated for conventional-IG, composite-IG, and 3-parameter techniques. Precision and reproducibility between the techniques was compared using the Wilcoxon Signed Rank test. Statistical significance was set at the 95% confidence level, with the Bonferroni correction for multiple comparisons employed. Composite-IG improves precision by 16-38% over conventional-IG (p < 0.01). Composite-IG T1 maps provided up to 5% better precision than 3-parameter fits (p < 0.01). Composite-IG had better reproducibility than conventional-IG (p < 0.01). However, there was no significant difference between composite-IG and conventional 5(3)3 3-parameter reproducibility.
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Affiliation(s)
- Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, University, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
| | - Bernd J Wintersperger
- Joint Department of Medical Imaging, University Health Network, University, Toronto, Ontario, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
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Chahal J, Gómez-Aristizábal A, Shestopaloff K, Bhatt S, Chaboureau A, Fazio A, Chisholm J, Weston A, Chiovitti J, Keating A, Kapoor M, Ogilvie-Harris DJ, Syed KA, Gandhi R, Mahomed NN, Marshall KW, Sussman MS, Naraghi AM, Viswanathan S. Bone Marrow Mesenchymal Stromal Cell Treatment in Patients with Osteoarthritis Results in Overall Improvement in Pain and Symptoms and Reduces Synovial Inflammation. Stem Cells Transl Med 2019; 8:746-757. [PMID: 30964245 PMCID: PMC6646697 DOI: 10.1002/sctm.18-0183] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/13/2019] [Indexed: 12/14/2022] Open
Abstract
Patients with late‐stage Kellgren‐Lawrence knee osteoarthritis received a single intra‐articular injection of 1, 10, or 50 million bone marrow mesenchymal stromal cells (BM‐MSCs) in a phase I/IIa trial to assess safety and efficacy using a broad toolset of analytical methods. Besides safety, outcomes included patient‐reported outcome measures (PROMs): Knee Injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); contrast‐enhanced magnetic resonance imaging (MRI) for cartilage morphology (Whole Organ MRI Scores [WORMS]), collagen content (T2 scores), and synovitis; and inflammation and cartilage turnover biomarkers, all over 12 months. BM‐MSCs were characterized by a panel of anti‐inflammatory markers to predict clinical efficacy. There were no serious adverse events, although four patients had minor, transient adverse events. There were significant overall improvements in KOOS pain, symptoms, quality of life, and WOMAC stiffness relative to baseline; the 50 million dose achieved clinically relevant improvements across most PROMs. WORMS and T2 scores did not change relative to baseline. However, cartilage catabolic biomarkers and MRI synovitis were significantly lower at higher doses. Pro‐inflammatory monocytes/macrophages and interleukin 12 levels decreased in the synovial fluid after MSC injection. The panel of BM‐MSC anti‐inflammatory markers was strongly predictive of PROMs over 12 months. Autologous BM‐MSCs are safe and result in significant improvements in PROMs at 12 months. Our analytical tools provide important insights into BM‐MSC dosing and BM‐MSC reduction of synovial inflammation and cartilage degradation and provide a highly predictive donor selection criterion that will be critical in translating MSC therapy for osteoarthritis. stem cells translational medicine2019;8:746&757
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Affiliation(s)
- Jaskarndip Chahal
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Alejandro Gómez-Aristizábal
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada
| | - Konstantin Shestopaloff
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Shashank Bhatt
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada
| | - Amélie Chaboureau
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada
| | - Antonietta Fazio
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jolene Chisholm
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada
| | - Amanda Weston
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Julia Chiovitti
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Armand Keating
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Mohit Kapoor
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Darrell J Ogilvie-Harris
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Khalid A Syed
- Arthritis Program, University Health Network, Toronto, Ontario, Canada
| | - Rajiv Gandhi
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Nizar N Mahomed
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kenneth W Marshall
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Ali M Naraghi
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Sowmya Viswanathan
- Arthritis Program, University Health Network, Toronto, Ontario, Canada.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Cell Therapy Program, University Health Network, Toronto, Ontario, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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Jhaveri KS, Kannengiesser SA, Ward R, Kuo K, Sussman MS. Prospective Evaluation of an R2* Method for Assessing Liver Iron Concentration (LIC) Against FerriScan: Derivation of the Calibration Curve and Characterization of the Nature and Source of Uncertainty in the Relationship. J Magn Reson Imaging 2018; 49:1467-1474. [DOI: 10.1002/jmri.26313] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Kartik S. Jhaveri
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital, and Women's College Hospital; University of Toronto; Toronto ON Canada
| | | | - Richard Ward
- Division of Medical Oncology & Hematology, University Health Network; University of Toronto; Toronto ON Canada
| | - Kevin Kuo
- Division of Medical Oncology & Hematology, University Health Network; University of Toronto; Toronto ON Canada
| | - Marshall S. Sussman
- Joint Department of Medical Imaging, University Health Network, Mount Sinai Hospital, and Women's College Hospital; University of Toronto; Toronto ON Canada
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13
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McKinney JR, Sussman MS, Moineddin R, Amirabadi A, Rayner T, Doria AS. Accuracy of magnetic resonance imaging for measuring maturing cartilage: A phantom study. Clinics (Sao Paulo) 2016; 71:404-11. [PMID: 27464298 PMCID: PMC4946528 DOI: 10.6061/clinics/2016(07)09] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 04/15/2016] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES To evaluate the accuracy of magnetic resonance imaging measurements of cartilage tissue-mimicking phantoms and to determine a combination of magnetic resonance imaging parameters to optimize accuracy while minimizing scan time. METHOD Edge dimensions from 4 rectangular agar phantoms ranging from 10.5 to 14.5 mm in length and 1.25 to 5.5 mm in width were independently measured by two readers using a steel ruler. Coronal T1 spin echo (T1 SE), fast spoiled gradient-recalled echo (FSPGR) and multiplanar gradient-recalled echo (GRE MPGR) sequences were used to obtain phantom images on a 1.5-T scanner. RESULTS Inter- and intra-reader reliability were high for both direct measurements and for magnetic resonance imaging measurements of phantoms. Statistically significant differences were noted between the mean direct measurements and the mean magnetic resonance imaging measurements for phantom 1 when using a GRE MPGR sequence (512x512 pixels, 1.5-mm slice thickness, 5:49 min scan time), while borderline differences were noted for T1 SE sequences with the following parameters: 320x320 pixels, 1.5-mm slice thickness, 6:11 min scan time; 320x320 pixels, 4-mm slice thickness, 6:11 min scan time; and 512x512 pixels, 1.5-mm slice thickness, 9:48 min scan time. Borderline differences were also noted when using a FSPGR sequence with 512x512 pixels, a 1.5-mm slice thickness and a 3:36 min scan time. CONCLUSIONS FSPGR sequences, regardless of the magnetic resonance imaging parameter combination used, provided accurate measurements. The GRE MPGR sequence using 512x512 pixels, a 1.5-mm slice thickness and a 5:49 min scan time and, to a lesser degree, all tested T1 SE sequences produced suboptimal accuracy when measuring the widest phantom.
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Affiliation(s)
- Jennifer R McKinney
- University of Toronto, The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto/ON, Canada
| | - Marshall S Sussman
- The University Health Network, Toronto General Hospital, Department of Medical Imaging, Toronto/ON, Canada
| | - Rahim Moineddin
- University of Toronto, Department of Family and Community Medicine, Toronto/ON, Canada
| | - Afsaneh Amirabadi
- University of Toronto, The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto/ON, Canada
| | - Tammy Rayner
- University of Toronto, The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto/ON, Canada
| | - Andrea S Doria
- University of Toronto, The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto/ON, Canada
- The University Health Network, Toronto General Hospital, Department of Medical Imaging, Toronto/ON, Canada
- E-mail:
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14
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Robles PG, Sussman MS, Naraghi A, Brooks D, Goldstein RS, White LM, Mathur S. Intramuscular Fat Infiltration Contributes to Impaired Muscle Function in COPD. Med Sci Sports Exerc 2016; 47:1334-41. [PMID: 25373483 DOI: 10.1249/mss.0000000000000556] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
UNLABELLED Muscle weakness is a prevalent complication in chronic obstructive pulmonary disease (COPD). Atrophy does not fully explain muscle weakness in this population. The recent focus on fat infiltration and its clinical implications in age and diseased muscles are important because it may further explain the extent of declining muscle strength and mobility seen in COPD. PURPOSE The objectives of this study are to quantify fat infiltration (muscle quality) of lower-limb muscles in people with COPD and healthy older adults using magnetic resonance imaging and proton magnetic resonance spectroscopy, and to explore its relationship with muscle strength and walking capacity in COPD. METHODS T1-weighted magnetic resonance imaging and proton magnetic resonance spectroscopy were performed in people with COPD (n = 10) and control subjects (n = 10) matched for age, gender, and body mass index. Maximal cross-sectional area (muscle size), isokinetic and isometric muscle peak torques, and 6-min walk distance were also assessed. RESULTS In addition to muscle atrophy (mean between-group differences of 20% to 25%, P < 0.05), COPD group presented with fatty infiltration in thigh and calf muscles that were significantly greater than what was observed in their healthy counterparts (mean between-group differences of 74% to 89%, P = 0.001). There was a strong inverse correlation between intramuscular fat infiltration, muscle peak torque, and walking distance (r = -0.6 to -0.8, P < 0.001) in this group as opposed to fair-to-moderate correlations between muscle size and the same outcomes (r = 0.4-0.6, P < 0.01). CONCLUSION Poor muscle quality accompanies atrophy in people with COPD. Intramuscular fat infiltration not only appears to have a strong correlation with impaired function but also is more profound than muscle atrophy in this group. Monitoring both muscle size and quality may enable a more comprehensive assessment of exercise programs in COPD.
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Affiliation(s)
- Priscila Games Robles
- 1Graduate Department of Rehabilitation Sciences, University of Toronto, Toronto, Ontario, CANADA; 2Joint Department of Medical Imaging, University Health Network and Mount Sinai Hospital, University of Toronto, Toronto, Ontario, CANADA; 3Department of Physical Therapy, University of Toronto, Toronto, Ontario, CANADA; and 4Respiratory Medicine, West Park Healthcare Centre, Toronto, Ontario, CANADA
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15
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Hanneman K, Nguyen ET, Thavendiranathan P, Ward R, Greiser A, Jolly MP, Butany J, Yang IY, Sussman MS, Wintersperger BJ. Quantification of Myocardial Extracellular Volume Fraction with Cardiac MR Imaging in Thalassemia Major. Radiology 2015; 279:720-30. [PMID: 26653680 DOI: 10.1148/radiol.2015150341] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To quantify myocardial extracellular volume (ECV) by using cardiac magnetic resonance (MR) imaging in thalassemia major and to investigate the relationship between ECV and myocardial iron overload. Materials and Methods With institutional review board approval and informed consent, 30 patients with thalassemia major (mean age ± standard deviation, 34.6 years ± 9.5) and 10 healthy control subjects (mean age, 31.5 years ± 4.4) were prospectively recruited (clinicaltrials.gov identification number NCT02090699). Nineteen patients (63.3%) had prior myocardial iron overload (defined as midseptal T2* < 20 msec on any prior cardiac MR images). Cardiac MR imaging at 1.5 T included cine steady-state free precession for ventricular function, T2* for myocardial iron quantification, and unenhanced and contrast material-enhanced T1 mapping. ECV was calculated with input of the patient's hematocrit level. Peak systolic global longitudinal strain by means of speckle tracking was assessed with same-day transthoracic echocardiography. Statistical analysis included use of the two-sample t test, Fisher exact test, and Spearman correlation. Results Unenhanced T1 values were significantly lower in patients with prior myocardial iron overload than in control subjects (850.3 ± 115.1 vs 1006.3 ± 35.4, P < .001) and correlated strongly with T2* values (r = 0.874, P < .001). Patients with prior myocardial iron overload had higher ECV than did patients without iron overload (31.3% ± 2.8 vs 28.2% ± 3.4, P = .030) and healthy control subjects (27.0% ± 3.1, P = .003). There was no difference in ECV between patients without iron overload and control subjects (P = .647). ECV correlated with lowest historical T2* (r = -0.469, P = .010) but did not correlate significantly with left ventricular ejection fraction (r = -0.216, P = .252) or global longitudinal strain (r = -0.164, P = .423). Conclusion ECV is significantly increased in thalassemia major and is associated with myocardial iron overload. These abnormalities may potentially reflect diffuse interstitial myocardial fibrosis. (©) RSNA, 2015 Online supplemental material is available for this article.
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Affiliation(s)
- Kate Hanneman
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Elsie T Nguyen
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Paaladinesh Thavendiranathan
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Richard Ward
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Andreas Greiser
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Marie-Pierre Jolly
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Jagdish Butany
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Issac Y Yang
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Marshall S Sussman
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
| | - Bernd J Wintersperger
- Department of Medical Imaging (K.H., E.T.N., P.T., I.Y.Y., M.S.S., B.J.W.) and Division of Cardiology (P.T.), Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Ave, NCSB-1C557, Toronto, ON, Canada M5G 2N2; Division of Hematology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada (R.W.); Siemens AG Healthcare, Erlangen, Germany (A.G.); Department of Corporate Research, Siemens Corporation, Princeton, NJ (M.P.J.); and Division of Pathology, Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada (J.B.)
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Sussman MS, Yang IY, Fok KH, Wintersperger BJ. Inversion group (IG) fitting: A new T1
mapping method for modified look-locker inversion recovery (MOLLI) that allows arbitrary inversion groupings and rest periods (including no rest period). Magn Reson Med 2015; 75:2332-40. [DOI: 10.1002/mrm.25829] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 05/14/2015] [Accepted: 06/09/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Marshall S. Sussman
- Joint Department of Medical Imaging; University Health Network, University of Toronto; Toronto, Ontario Canada
- Department of Medical Imaging; University of Toronto; Toronto, Ontario
| | - Issac Y. Yang
- Joint Department of Medical Imaging; University Health Network, University of Toronto; Toronto, Ontario Canada
| | - Kai-Ho Fok
- Joint Department of Medical Imaging; University Health Network, University of Toronto; Toronto, Ontario Canada
| | - Bernd J. Wintersperger
- Joint Department of Medical Imaging; University Health Network, University of Toronto; Toronto, Ontario Canada
- Department of Medical Imaging; University of Toronto; Toronto, Ontario
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17
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Tseng CL, Sussman MS, Atenafu EG, Letourneau D, Ma L, Soliman H, Thibault I, Cho BCJ, Simeonov A, Yu E, Fehlings MG, Sahgal A. Magnetic resonance imaging assessment of spinal cord and cauda equina motion in supine patients with spinal metastases planned for spine stereotactic body radiation therapy. Int J Radiat Oncol Biol Phys 2015; 91:995-1002. [PMID: 25832691 DOI: 10.1016/j.ijrobp.2014.12.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 12/14/2014] [Accepted: 12/17/2014] [Indexed: 10/23/2022]
Abstract
PURPOSE To assess motion of the spinal cord and cauda equina, which are critical neural tissues (CNT), which is important when evaluating the planning organ-at-risk margin required for stereotactic body radiation therapy. METHODS AND MATERIALS We analyzed CNT motion in 65 patients with spinal metastases (11 cervical, 39 thoracic, and 24 lumbar spinal segments) in the supine position using dynamic axial and sagittal magnetic resonance imaging (dMRI, 3T Verio, Siemens) over a 137-second interval. Motion was segregated according to physiologic cardiorespiratory oscillatory motion (characterized by the average root mean square deviation) and random bulk shifts associated with gross patient motion (characterized by the range). Displacement was evaluated in the anteroposterior (AP), lateral (LR), and superior-inferior (SI) directions by use of a correlation coefficient template matching algorithm, with quantification of random motion measure error over 3 separate trials. Statistical significance was defined according to P<.05. RESULTS In the AP, LR, and SI directions, significant oscillatory motion was observed in 39.2%, 35.1%, and 10.8% of spinal segments, respectively, and significant bulk motions in all cases. The median oscillatory CNT motions in the AP, LR, and SI directions were 0.16 mm, 0.17 mm, and 0.44 mm, respectively, and the maximal statistically significant oscillatory motions were 0.39 mm, 0.41 mm, and 0.77 mm, respectively. The median bulk displacements in the AP, LR, and SI directions were 0.51 mm, 0.59 mm, and 0.66 mm, and the maximal statistically significant displacements were 2.21 mm, 2.87 mm, and 3.90 mm, respectively. In the AP, LR, and SI directions, bulk displacements were greater than 1.5 mm in 5.4%, 9.0%, and 14.9% of spinal segments, respectively. No significant differences in axial motion were observed according to cord level or cauda equina. CONCLUSIONS Oscillatory CNT motion was observed to be relatively minor. Our results support the importance of controlling bulk patient motion and the practice of applying a planning organ-at-risk margin.
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Affiliation(s)
- Chia-Lin Tseng
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S Sussman
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Eshetu G Atenafu
- Department of Biostatistics, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Letourneau
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lijun Ma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California
| | - Hany Soliman
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Isabelle Thibault
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - B C John Cho
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Anna Simeonov
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Eugene Yu
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Department of Neurosurgery and Spine Program, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
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Cepek J, Lindner U, Ghai S, Louis AS, Davidson SRH, Gertner M, Hlasny E, Sussman MS, Fenster A, Trachtenberg J. Mechatronic system for in-bore MRI-guided insertion of needles to the prostate: An in vivo needle guidance accuracy study. J Magn Reson Imaging 2014; 42:48-55. [PMID: 25195664 DOI: 10.1002/jmri.24742] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 08/11/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND To present our experiences in initial clinical evaluation of a novel mechatronic system for in-bore guidance of needles to the prostate for MRI-guided prostate interventions in 10 patients. We report accuracy of this device in the context of focal laser ablation therapy for localized prostate cancer. METHODS An MRI-compatible needle guidance device was developed for transperineal prostate interventions. Ten patients underwent MRI-guided focal laser ablation therapy with device-mediated laser fiber delivery. We recorded needle guidance error and needle delivery time. RESULTS A total of 37 needle insertions were evaluated. Median needle guidance error was 3.5 mm (interquartile range, 2.1-5.4 mm), and median needle delivery time was 9 min (interquartile range, 6.5-12 min). CONCLUSION This system provides a reliable method of accurately aligning needle guides for in-bore transperineal needle delivery to the prostate.
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Affiliation(s)
- Jeremy Cepek
- Department of Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada.,Robarts Research Institute, The University of Western Ontario, London, Canada
| | - Uri Lindner
- Department of Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada
| | - Sangeet Ghai
- Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Alyssa S Louis
- Department of Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada
| | - Sean R H Davidson
- Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Mark Gertner
- Division of Biophysics and Bioimaging, Ontario Cancer Institute, University Health Network, Toronto, Canada
| | - Eugen Hlasny
- Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Aaron Fenster
- Robarts Research Institute, The University of Western Ontario, London, Canada.,Biomedical Engineering, The University of Western Ontario, London, Canada
| | - John Trachtenberg
- Department of Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada
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Doria AS, Zhang N, Lundin B, Hilliard P, Man C, Weiss R, Detzler G, Blanchette V, Moineddin R, Eckstein F, Sussman MS. Quantitative versus semiquantitative MR imaging of cartilage in blood-induced arthritic ankles: preliminary findings. Pediatr Radiol 2014; 44:576-86. [PMID: 24522564 DOI: 10.1007/s00247-013-2872-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 11/25/2013] [Accepted: 12/26/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND Recent advances in hemophilia prophylaxis have raised the need for accurate noninvasive methods for assessment of early cartilage damage in maturing joints to guide initiation of prophylaxis. Such methods can either be semiquantitative or quantitative. Whereas semiquantitative scores are less time-consuming to be performed than quantitative methods, they are prone to subjective interpretation. OBJECTIVE To test the feasibility of a manual segmentation and a quantitative methodology for cross-sectional evaluation of articular cartilage status in growing ankles of children with blood-induced arthritis, as compared with a semiquantitative scoring system and clinical-radiographic constructs. MATERIALS AND METHODS Twelve boys, 11 with hemophilia (A, n = 9; B, n = 2) and 1 with von Willebrand disease (median age: 13; range: 6-17), underwent physical examination and MRI at 1.5 T. Two radiologists semiquantitatively scored the MRIs for cartilage pathology (surface erosions, cartilage loss) with blinding to clinical information. An experienced operator applied a validated quantitative 3-D MRI method to determine the percentage area of denuded bone (dAB) and the cartilage thickness (ThCtAB) in the joints' MRIs. Quantitative and semiquantitative MRI methods and clinical-radiographic constructs (Hemophilia Joint Health Score [HJHS], Pettersson radiograph scores) were compared. RESULTS Moderate correlations were noted between erosions and dAB (r = 0.62, P = 0.03) in the talus but not in the distal tibia (P > 0.05). Whereas substantial to high correlations (r range: 0.70-0.94, P < 0.05) were observed between erosions, cartilage loss, HJHS and Pettersson scores both at the distal tibia and talus levels, moderate/borderline substantial (r range: 0.55-0.61, P < 0.05) correlations were noted between dAB/ThCtAB and clinical-radiographic constructs. CONCLUSION Whereas the semiquantitative method of assessing cartilage status is closely associated with clinical-radiographic scores in cross-sectional studies of blood-induced arthropathy, quantitative measures provide independent information and are therefore less applicable for that research design.
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Affiliation(s)
- Andrea S Doria
- Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Ave., Toronto, ON, Canada, M5G1X8,
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Sussman MS, Lindner U, Haider M, Kucharczyk W, Hlasny E, Trachtenberg J. Optimizing contrast agent concentration and spoiled gradient echo pulse sequence parameters for catheter visualization in MR-guided interventional procedures: an analytic solution. Magn Reson Med 2013; 70:333-40. [PMID: 23801423 DOI: 10.1002/mrm.24830] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 05/01/2013] [Accepted: 05/08/2013] [Indexed: 11/09/2022]
Abstract
PURPOSE A critical requirement of MR-guided interventions is the visualization of an instrument (e.g., catheter, needle) during the procedure. One approach is to fill the instrument with a contrast agent. Previously, the optimization of contrast agent visualization was performed only empirically. In the present study, an analytic optimization of contrast agent SNR efficiency was performed for a spoiled gradient echo pulse sequence. METHODS Optimal flip angle, repetition time, echo time, and contrast agent concentration were derived analytically. The solution is valid for any contrast agent, provided the relationship between T1 , T2 , and doping concentration is known. RESULTS Phantom experiments validated the analytic optimization for Gd- and MnCl2 -based contrast agents. Results showed excellent agreement between experimentally predicted and theoretically observed magnetization behavior. In vivo experiments demonstrated optimized contrast agent visualization in brain, heart, and prostate applications. The results demonstrated the large SNR that can be achieved with analytic optimization. As a practical guideline, an 11% dilution of 500 mMol/L Gd-DTPA solution, repetition time ≈ 4 ms, echo time ≈ 1 ms, and θ ≈ 65° was found to provide a large SNR. CONCLUSION This study derived and validated a method for analytically optimizing contrast agent SNR efficiency. This information may be useful for visualizing instruments during MR-guided interventions.
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Affiliation(s)
- Marshall S Sussman
- Joint Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Canada.
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Studler U, White LM, Deslandes M, Geddes C, Sussman MS, Theodoropoulos J. Feasibility study of simultaneous physical examination and dynamic MR imaging of medial collateral ligament knee injuries in a 1.5-T large-bore magnet. Skeletal Radiol 2011; 40:335-43. [PMID: 20155417 DOI: 10.1007/s00256-010-0884-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 12/26/2009] [Accepted: 01/11/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the feasibility of evaluating medial knee joint laxity with dynamic magnetic resonance (MR) imaging and simultaneous physical joint examination in a large-bore 1.5-T system. MATERIALS AND METHODS The study included 10 patients (5 women, 5 men; mean age 35 years) with clinically diagnosed and categorized acute injuries of the medial collateral ligament (MCL). Intermittent valgus stress was applied separately to both the affected and the contralateral knee joint during dynamic MR imaging with a two-dimensional fast low-angle shot sequence. The width of the medial joint space and the opening angle between the femoral condyles and the tibial plateau were measured. Results obtained from dynamic MR imaging of the affected knee were compared with morphological MCL changes on static MRI, to kinematics of the contralateral side and to the clinical grading of MCL injuries. RESULTS On clinical examination, all patients had grade 2 MCL injuries except one, who had a grade 1 lesion. Using morphological MRI criteria, 9 grade II and 1 grade III injuries were seen. Mean medial joint space width and opening angles of all affected knees were 2.8 mm and 2.7° respectively, compared with 1.7 mm and 2.1° on the contralateral side. The Wilcoxon signed rank test indicated that the differences in width (P = 0.005) and opening angle (P = 0.037) between the affected and contralateral knees were significant. CONCLUSION Dynamic MR imaging and simultaneous physical joint examination is feasible. Our results suggest that this technique might enable the imaging documentation of medial ligamentous knee instability.
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Affiliation(s)
- Ueli Studler
- Department of Medical Imaging, Mount Sinai Hospital and University Health Network, University of Toronto, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.
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Abstract
A rapid technique for mapping of T(2) relaxation times is presented. The method is based on the conventional single-echo spin echo approach but uses a much shorter pulse repetition time to accelerate data acquisition. The premise of the new method is the use of a constant difference between the echo time and pulse repetition time, which removes the conventional and restrictive requirement of pulse repetition time >> T(1). Theoretical and simulation investigations were performed to evaluate the criteria for accurate T(2) measurements. Measured T(2)s were shown to be within 1% error as long as the key criterion of pulse repetition time/T(2) > or =3 is met. Strictly, a second condition of echo time/T(1) << 1 is also required. However, violations of this condition were found to have minimal impact in most clinical scenarios. Validation was conducted in phantoms and in vivo T(2) mapping of healthy cartilage and brain. The proposed method offers all the advantages of single-echo spin echo imaging (e.g., immunity to stimulated echo effects, robustness to static field inhomogeneity, flexibility in the number and choice of echo times) in a considerably reduced amount of time and is readily implemented on any clinical scanner.
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Studler U, White LM, Andreisek G, Luu S, Cheng HLM, Sussman MS. Impact of motion on T1 mapping acquired with inversion recovery fast spin echo and rapid spoiled gradient recalled-echo pulse sequences for delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in volunteers. J Magn Reson Imaging 2010; 32:394-8. [DOI: 10.1002/jmri.22249] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Lindner U, Lawrentschuk N, Weersink RA, Raz O, Hlasny E, Sussman MS, Davidson SR, Gertner MR, Trachtenberg J. Construction and evaluation of an anatomically correct multi-image modality compatible phantom for prostate cancer focal ablation. J Urol 2010; 184:352-7. [PMID: 20488477 DOI: 10.1016/j.juro.2010.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Indexed: 12/01/2022]
Abstract
PURPOSE Focal therapy using lasers is emerging as an alternative strategy for prostate cancer treatment. However, to our knowledge no anatomically correct models are available to test imaging and ablation techniques. Animal models present ethical, anatomical and cost challenges. We designed and validated an inexpensive but anatomically correct prostate phantom incorporating tumor, rectum and urethra that can be used for simulated and experimental magnetic resonance guided focal intervention. Our secondary aim was to asses the phantom using other imaging modalities. MATERIALS AND METHODS The phantom, which was constructed of ballistic gel, includes an 80 gm prostate with urethra, tumor, perineum and rectum. Gadolinium was added to make the gel visible to magnetic resonance imaging. To recreate a tumor an irregularly shaped 5 cc volume of coagulable gel was inserted into the prostate phantom. The phantom was evaluated using magnetic resonance, computerized tomography and transrectal ultrasound. Thermal ablation was delivered via interstitial placement of laser fibers. Magnetic resonance thermometry was done to record real-time tissue temperatures during thermal ablation. RESULTS With all modalities tested the phantom emulated human prostate anatomy. The coagulable gel tumor allowed us to generate focal thermal lesions. The phantom had magnetic resonance imaging properties comparable to in vivo properties, allowing ablative zones to be accurately assessed and magnetic resonance thermometry to be done. CONCLUSIONS The phantom is a useful tool to test different aspects of thermal focal ablation for prostate cancer using multiple imaging modalities, particularly magnetic resonance. It is inexpensive and easily constructed, and may be considered a valuable model to train on and teach focal therapy.
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Affiliation(s)
- Uri Lindner
- Surgical Oncology, Urology Division, University Health Network, University of Toronto, Toronto, Ontario, Canada
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25
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Doria AS, Chaudry GA, Nasui C, Rayner T, Wang C, Moineddin R, Babyn PS, White LM, Sussman MS. The use of parallel imaging for MRI assessment of knees in children and adolescents. Pediatr Radiol 2010; 40:284-93. [PMID: 19949946 DOI: 10.1007/s00247-009-1426-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 09/02/2009] [Indexed: 11/29/2022]
Abstract
BACKGROUND Parallel imaging provides faster scanning at the cost of reduced signal-to-noise ratio (SNR) and increased artifacts. OBJECTIVE To compare the diagnostic performance of two parallel MRI protocols (PPs) for assessment of pathologic knees using an 8-channel knee coil (reference standard, conventional protocol [CP]) and to characterize the SNR losses associated with parallel imaging. MATERIALS AND METHODS Two radiologists blindly interpreted 1.5 Tesla knee MRI images in 21 children (mean 13 years, range 9-18 years) with clinical indications for an MRI scan. Sagittal proton density, T2-W fat-saturated FSE, axial T2-W fat-saturated FSE, and coronal T1-W (NEX of 1,1,1) images were obtained with both CP and PP. Images were read for soft tissue and osteochondral findings. RESULTS There was a 75% decrease in acquisition time using PP in comparison to CP. The CP and PP protocols fell within excellent or upper limits of substantial agreement: CP, kappa coefficient, 0.81 (95% CIs, 0.73-0.89); PP, 0.80-0.81 (0.73-0.89). The sensitivity of the two PPs was similar for assessment of soft (0.98-1.00) and osteochondral (0.89-0.94) tissues. Phantom data indicated an SNR of 1.67, 1.6, and 1.51 (axial, sagittal and coronal planes) between CP and PP scans. CONCLUSION Parallel MRI provides a reliable assessment for pediatric knees in a significantly reduced scan time without affecting the diagnostic performance of MRI.
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Andreisek G, White LM, Theodoropoulos JS, Naraghi A, Young N, Zhao CY, Mamisch TC, Sussman MS. Synthetic–Echo Time Postprocessing Technique for Generating Images with Variable T2-weighted Contrast: Diagnosis of Meniscal and Cartilage Abnormalities of the Knee. Radiology 2010; 254:188-99. [DOI: 10.1148/radiol.2541090314] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Sparrow P, Amirabadi A, Sussman MS, Paul N, Merchant N. Quantitative assessment of myocardial T2 relaxation times in cardiac amyloidosis. J Magn Reson Imaging 2009; 30:942-6. [DOI: 10.1002/jmri.21918] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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28
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Andreisek G, White LM, Yang Y, Robinson E, Cheng HLM, Sussman MS. Delayed Gadolinium-enhanced MR Imaging of Articular Cartilage: Three-dimensional T1 Mapping with Variable Flip Angles and B1Correction. Radiology 2009; 252:865-73. [DOI: 10.1148/radiol.2531081115] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Andreisek G, White LM, Sussman MS, Kunz M, Hurtig M, Weller I, Essue J, Marks P, Eckstein F. Quantitative MR imaging evaluation of the cartilage thickness and subchondral bone area in patients with ACL-reconstructions 7 years after surgery. Osteoarthritis Cartilage 2009; 17:871-8. [PMID: 19230721 DOI: 10.1016/j.joca.2008.05.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 05/19/2008] [Accepted: 05/31/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To evaluate the cartilage thickness (ThC) and subchondral bone area (tAB) of the operated and contra-lateral non-operated (healthy) knees in patients with anterior cruciate ligament (ACL)-reconstruction 7 years after surgery using a quantitative and regional cartilage MR imaging (qMRI) technique. METHODS Charts of 410 patients with ACL-reconstructions were retrospectively reviewed. Fifty-two patients (male/female, 28/24; mean age, 33.3 years) were included. Patients underwent KT-1000 testing and qMRI of both knees using coronal fat-saturated 3D spoiled gradient-recalled echo (SPGR) sequences (TR/TE, 44/4 ms) at 1.5 T. Quantitative analyses of ThC and tAB in the femoro-tibial cartilage plates were performed using a subregional approach. In addition, qualitative and quantitative assessment of femoral condyle shapes was performed. t tests with Bonferroni corrections were used for statistical analysis of side-to-side differences between the operated and non-operated knees. RESULTS KT-1000 testing was abnormal in 3/52 patients (6%). Lateral femoral tAB was significantly lower (-9.2%), and medial tibial tAB was significantly larger (+2%) in the operated vs non-operated knee (P<0.001). Regional and subregional ThC side-to-side differences were less than 0.1mm and, except for the external lateral femoral subregion, they were not statistically significant. Flattened and broader shapes of medial femoral condyles (P<0.001) were found in operated knees. No significant association of presence of cartilage or meniscus lesions at surgery with ThC 7 years post-operatively was found (P=0.06-0.98). CONCLUSION There is evidence for changes in the tAB and femoral shape 7 years post-ACL-reconstruction, but no side-to-side differences in subregional ThC were found between the operated and contra-lateral non-operated knees.
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Affiliation(s)
- G Andreisek
- Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, Toronto, ON, Canada.
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Macgowan CK, Liu GKC, van Amerom JFP, Sussman MS, Wright GA. Self-gated Fourier velocity encoding. Magn Reson Imaging 2009; 28:95-102. [PMID: 19553052 DOI: 10.1016/j.mri.2009.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 04/01/2009] [Accepted: 05/11/2009] [Indexed: 11/26/2022]
Abstract
Self-gating is investigated to improve the velocity resolution of real-time Fourier velocity encoding measurements in the absence of a reliable electrocardiogram waveform (e.g., fetal magnetic resonance or severe arrhythmia). Real-time flow data are acquired using interleaved k-space trajectories which share a common path near the origin of k-space. These common data provide a rapid self-gating signal that can be used to combine the interleaved data. The combined interleaves cover a greater area of k-space than a single real-time acquisition, thereby providing higher velocity resolution for a given aliasing velocity and temporal resolution. For example, this approach provided velocity spectra with a temporal resolution of 19 ms and velocity resolution of 22 cm/s over an 818 cm/s field-of-view. The method was validated experimentally using a computer-controlled pulsatile flow apparatus and applied in vivo to measure aortic-valve flow in a healthy volunteer.
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Affiliation(s)
- Christopher K Macgowan
- Department of Medical Biophysics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
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Andreisek G, White LM, Kassner A, Tomlinson G, Sussman MS. Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value. Skeletal Radiol 2009; 38:51-9. [PMID: 18773203 DOI: 10.1007/s00256-008-0577-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/28/2008] [Accepted: 08/03/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective of this study was to systematically assess the optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T. MATERIALS AND METHODS This is a prospective study which was carried out with institutional review board approval and written informed consent from the study subjects. Fifteen healthy volunteers (seven men, eight women; mean age, 31.2 years) underwent diffusion tensor imaging of the wrist. A single-shot spin-echo-based echo-planar imaging sequence (TR/TE, 7000/103 ms) was performed in each subject at eight different b values ranging from 325 to 1,550 s/mm(2). Number and length of reconstructed fiber tracts, fiber density index (FDi), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were calculated for the median nerve. Signal-to-noise ratio (SNR) was also calculated for each acquisition. The overall image quality was assessed by two readers in consensus by ranking representative fiber tract images for each subject using a scale range from 1 to 8 (1 = best to 8 = worst image quality). RESULTS Longest fibers were observed for b values between 675 and 1,025 s/mm(2). Maximum FDi was found at b values of 1,025 s/mm(2). FA was between 0.5 and 0.6 for all b values. ADC gradually decreased from 1.44 x 10(-3) to 0.92 x 10(-3) mm(2)/s with increasing b values. Maximum SNR +/- standard deviation (175.4 +/- 72.6) was observed at the lowest b value and decreased with increasing b values. SNR at b values of 1,025 s/mm(2) was 48.5% of the maximum SNR. Optimal fiber tract image quality was found for b values of 1,025 s/mm(2). CONCLUSIONS The optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T was 1,025 s/mm(2).
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Affiliation(s)
- Gustav Andreisek
- Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, 600 University Ave, Toronto, Ontario, Canada, M5G 1X5.
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Prakash V, Stainsby JA, Satkunasingham J, Craig T, Catton C, Chan P, Dawson L, Hensel J, Jaffray D, Milosevic M, Nichol A, Sussman MS, Lockwood G, Ménard C. Validation of Supervised Automated Algorithm for Fast Quantitative Evaluation of Organ Motion on Magnetic Resonance Imaging. Int J Radiat Oncol Biol Phys 2008; 71:1253-60. [DOI: 10.1016/j.ijrobp.2007.11.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2007] [Revised: 11/12/2007] [Accepted: 11/12/2007] [Indexed: 10/22/2022]
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Settecase F, Sussman MS, Wilson MW, Hetts S, Arenson RL, Malba V, Bernhardt AF, Kucharczyk W, Roberts TPL. Magnetically-assisted remote control (MARC) steering of endovascular catheters for interventional MRI: a model for deflection and design implications. Med Phys 2007; 34:3135-42. [PMID: 17879774 PMCID: PMC3980585 DOI: 10.1118/1.2750963] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Current applied to wire coils wound at the tip of an endovascular catheter can be used to remotely steer a catheter under magnetic resonance imaging guidance. In this study, we derive and validate an equation that characterizes the relationship between deflection and a number of physical factors: theta/sin(gamma-theta) = nIABL/EI(A) where theta is the deflection angle, n is the number of solenoidal turns, I is the current, A is the cross-sectional area of the catheter tip, B is the magnetic resonance (MR) scanner main magnetic field, L is the unconstrained catheter length, E is Young's Modulus for the catheter material, and I(A) is the area moment of inertia, and y is the initial angle between the catheter tip and B. Solenoids of 50, 100, or 150 turns were wound on 1.8 F and 5 F catheters. Varying currents were applied remotely using a DC power supply in the MRI control room. The distal catheter tip was suspended within a phantom at varying lengths. Images were obtained with a 1.5 T or a 3 T MR scanner using "real-time" MR pulse sequences. Deflection angles were measured on acquired images. Catheter bending stiffess was determined using a tensile testing apparatus and a stereomicroscope. Predicted relationships between deflection and various physical factors were observed (R2 = 0.98-0.99). The derived equation provides a framework for modeling of the behavior of the specialized catheter tip. Each physical factor studied has implications for catheter design and device implementation.
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Affiliation(s)
- Fabio Settecase
- Department of Medical Imaging and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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Settecase F, Sussman MS, Roberts TPL. A new temperature-sensitive contrast mechanism for MRI: Curie temperature transition-based imaging. Contrast Media Mol Imaging 2007; 2:50-4. [PMID: 17304641 DOI: 10.1002/cmmi.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A temperature-sensitive MRI contrast mechanism is proposed based on the physical property, the Curie temperature (T(c)), at which a ferromagnetic material transitions to paramagnetic state and vice versa. To evaluate the feasibility of this new contrast mechanism, experiments were performed with solid gadolinium metal, which has a T(c) of 20 degrees C. In phantom and ex vivo experiments, the magnetic susceptibility artifact area decreased with increasing temperature transitioning across T(c) (p < 0.05). Similar results would be expected for a variety of ferromagnetic substances with substance-specific T(c) values. Temperature-sensitive MRI contrast agents harnessing this mechanism may be used to (1) indicate regional attainment of specific temperatures in thermotherapy, (2) render an accumulated contrast agent more or less visible by the external application of appropriate heating or cooling, or (3) quantify tissue temperature based on MR image characteristics and magnetic susceptibility artifact caused by a ferromagnetic-paramagnetic transitioning substance.
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Affiliation(s)
- F Settecase
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
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Abstract
Modeling tracer kinetics from dynamic magnetic resonance imaging (dMRI) to understand microvascular characteristics typically requires acquisitions longer than 1 breath-hold. This has limited the application of dMRI in assessment of the upper abdomen. Here we present a template-based motion correction strategy for dMRI of liver metastases based on the correlation coefficient (CC), originally developed for tracking coronary arteries. This postprocessing method allows patient free breathing during sagittal dMRI acquisition and allows a more precise parametric mapping using tracer kinetic models. In a study of 6 subjects, a 64 x 64 template was accurately tracked retrospectively with mean CC = 0.72 +/- 0.07. Mean superior-inferior displacement tracked was 1.82 +/- 1.20 pixels, whereas mean anterior-posterior displacement was 7.72 +/- 4.58 pixels. Application of the CC method significantly improved the global fit (chi2) of a tracer kinetic model throughout tumor regions. Therefore, use of the CC postprocessing method for dMRI scans can improve the precision of dMRI tracer kinetic models.
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White LM, Sussman MS, Hurtig M, Probyn L, Tomlinson G, Kandel R. Cartilage T2 assessment: differentiation of normal hyaline cartilage and reparative tissue after arthroscopic cartilage repair in equine subjects. Radiology 2006; 241:407-14. [PMID: 17057068 DOI: 10.1148/radiol.2412051750] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE To prospectively assess T2 mapping characteristics of normal articular cartilage and of cartilage at sites of arthroscopic repair, including comparison with histologic results and collagen organization assessed at polarized light microscopy (PLM). MATERIALS AND METHODS Study protocol was compliant with the Canadian Council on Animal Care Guidelines and approved by the institutional animal care committee. Arthroscopic osteochondral autograft transplantation (OAT) and microfracture arthroplasty (MFx) were performed in knees of 10 equine subjects (seven female, three male; age range, 3-5 years). A site of arthroscopically normal cartilage was documented in each joint as a control site. Joints were harvested at 12 (n = 5) and 24 (n = 5) weeks postoperatively and were imaged at 1.5-T magnetic resonance (MR) with a 10-echo sagittal fast spin-echo acquisition. T2 maps of each site (21 OAT harvest, 10 MFx, 12 OAT plug, and 10 control sites) were calculated with linear least-squares curve fitting. Cartilage T2 maps were qualitatively graded as "organized" (normal transition of low-to-high T2 signal from deep to superficial cartilage zones) or "disorganized." Quantitative mean T2 values were calculated for deep, middle, and superficial cartilage at each location. Results were compared with histologic and PLM assessments by using kappa analysis. RESULTS T2 maps were qualitatively graded as organized at 20 of 53 sites and as disorganized at 33 sites. Perfect agreement was seen between organized T2 and histologic findings of hyaline cartilage and between disorganized T2 and histologic findings of fibrous reparative tissue (kappa = 1.0). Strong agreement was seen between organized T2 and normal PLM findings and between disorganized T2 and abnormal PLM findings (kappa = .92). Quantitative assessment of the deep, middle, and superficial cartilage, respectively, showed mean T2 values of 53.3, 58.6, and 54.9 msec at reparative fibrous tissue sites and 40.7, 53.6, and 61.6 msec at hyaline cartilage sites. A significant trend of increasing T2 values (from deep to superficial) was found in hyaline cartilage (P < .01). Fibrous tissue sites had no significant change with depth (P > .59). CONCLUSION Qualitative and quantitative T2 mapping helped differentiate hyaline cartilage from reparative fibrocartilage after cartilage repair at 1.5-T MR imaging.
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Affiliation(s)
- Lawrence M White
- Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, 600 University Ave, Toronto, ON, Canada M5G 1X5.
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Al-Kwifi O, Stainsby J, Foltz WD, Sussman MS, Huang Y, Wright GA. Characterizing coronary motion and its effect on MR coronary angiography—Initial experience. J Magn Reson Imaging 2006; 24:842-50. [PMID: 16929527 DOI: 10.1002/jmri.20697] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To characterize coronary artery motion as a prescan procedure to select the optimum scan setting that will produce high-resolution images. MATERIALS AND METHODS A 2D real-time scan was used to image the major coronary arteries during breath-holding and free-breathing conditions. With the use of the 2D images, motion displacement of each artery was measured along three axes. Motion data obtained from a computer simulation were used to estimate point-spread functions (PSFs) associated with different high-resolution spiral acquisition strategies, including real-time, cardiac-gated, and respiratory-gated acquisitions. The simulation output determined the optimum acquisition and scan parameters that would produce the highest-spatial-resolution images of the coronary arteries. The effects of heart rate (HR), extended breath-holding, and number of slices per heart cycle were also investigated. RESULTS Substantial variations in coronary motion occur among individuals, which directly influences the optimum parameters for a high-resolution scan. Lower HRs and longer breath-holds yield substantially increased spatial resolution. The maximum number of slices per heart cycle can also be determined to minimize slice-to-slice distortion. CONCLUSION The results suggest that to obtain high-resolution coronary images, one should perform a prescan coronary-motion characterization for each individual so that the scan parameters can be optimized before data acquisition.
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Affiliation(s)
- Osama Al-Kwifi
- Imaging Research Program, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada.
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Alghamdi AM, Sela G, Haider MA, Kucharczyk W, Sussman MS, Dinniwell R, Milosevic M, Evans A, Jewett MA. 1557: An Image-Guided Surgical Navigation System for Urology. J Urol 2006. [DOI: 10.1016/s0022-5347(18)33761-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Settecase F, Sussman MS, Roberts TPL. SU-CC-J-6C-03: Factors Affecting Remote Control Endovascular Catheter Steering for IMRI. Med Phys 2005. [DOI: 10.1118/1.1997409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Abstract
A method to make a coronary artery segment of interest appear stationary when viewing a sequence of angiographic images is proposed. The purpose of this method is to facilitate the assessment of lesions caused by coronary artery disease by improving detectability. A description of the stabilization algorithm based on template matching is given. Stabilization was performed on 41 clinical coronary angiograms exhibiting various stenoses and was successful in 39/41 cases. A quantitative analysis of stabilization errors was performed by introducing simulated moving vessels of decreasing contrast into sequences of clinical images.
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Affiliation(s)
- Normand Robert
- Sunnybrook and Women's Health Science Centre, University of Toronto, Room S632, 2075 Bayview Avenue, Toronto M4N 3M5, Canada.
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41
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Abstract
Imaging of the coronary arteries at diagnostic resolutions is made difficult due to cardiac and respiratory motion during data acquisition. Cardiac gating and respiratory gating or breath holding are effective ways to reduce the effects of motion. The optimal cardiac and respiratory timings vary widely across individuals. This work presents a real-time magnetic resonance imaging approach with physiologic monitoring that can be used to predict the optimal timings on a subject-by-subject basis during a brief real-time prescan. The feasibility of this approach at determining the optimal cardiac trigger delay and respiratory phase is demonstrated.
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Affiliation(s)
- Jeffrey A Stainsby
- Sunnybrook & Women's College Health Sciences Centre, Toronto, Ontario, Canada.
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42
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Abstract
A technique has been developed for combining a series of low signal-to-noise ratio (SNR) real-time magnetic resonance (MR) images to produce composite images with high SNR and minimal artifact in the presence of motion. The main challenge is identifying a set of real-time images with sufficiently small systematic differences to avoid introducing significant artifact into the composite image. To accomplish this task, one must: 1) identify images identical within the limits of noise; 2) detect systematic errors within such images with sufficient sensitivity. These steps are achieved by evaluating the correlation coefficient (CC) between regions in prospective images and a template containing the anatomy of interest. Images identical within noise are selected by comparing the measured CC values to the theoretical distribution expected due to noise. Sensitivity for systematic error depends on the SNR of the CC (=SNR(CCmax)), which in turn depends on the noise, and the template size and structure. By varying the template size, SNR(CCmax) may be altered. Experiments on phantoms and coronary artery images demonstrate that the SNR(CCmax) necessary to avoid introducing significant artifact varies with the target composite SNR. The future potential of this technique is demonstrated on high-resolution (approximately 0.9 mm), reduced field-of-view real-time coronary images.
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Affiliation(s)
- Marshall S Sussman
- Department of Medical Biophysics, Sunnybrook Health Science Centre, University of Toronto, Toronto, ON M5G 2N2, Canada.
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Al-Kwifi O, Kim JK, Stainsby J, Huang Y, Sussman MS, Farb RI, Wright GA. Pulsatile motion effects on 3D magnetic resonance angiography: Implications for evaluating carotid artery stenoses. Magn Reson Med 2004; 52:605-11. [PMID: 15334581 DOI: 10.1002/mrm.20185] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In-plane carotid artery motion during a 3D MR angiography (MRA) scan can significantly degrade the resulting image resolution. This study characterizes the effect of cardiac pulsatility on 3D contrast-enhanced (CE) MRA with elliptical centric acquisitions using a point-spread function (PSF) analysis. Internal carotid artery (ICA) motion was collected from volunteers and patients using both MR and ultrasound (US) scans. After measuring the carotid artery motion displacement, a simulation was performed which calculated the blurring effects for three different protocols: nongated and two different cardiac gating schemes. The motion sensitivity of each protocol was evaluated for different spatial resolutions. The selection of optimal imaging parameters for a given scan time was investigated. The final results showed that cardiac-gated acquisitions only over a limited region of k-space high spatial frequencies are more time-efficient than cardiac gating for the entire k-space, as it allows for higher resolutions to be achieved and for capturing the arterial phase with low spatial frequencies. Selecting the optimal gating parameters depends directly on the motion characteristics of each individual. Our initial clinical experience is presented, and the need for a real-time tool that characterizes motion behavior for each individual as a prescan protocol is discussed.
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Affiliation(s)
- Osama Al-Kwifi
- Medical Imaging Research, Sunnybrook and Women's College Health Science Centre, Toronto, Ontario, Canada.
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Abstract
Microcirculation oxygen levels and blood volumes should be reflected in measurements of myocardial T(2) relaxation. This work describes the optimization of a spiral imaging strategy for robust myocardial T(2) measurement to minimize the standard deviation of T(2) measurement (sigmaT(2)). Theoretical and experimental studies of blurring at muscle/blood interfaces enabled the derivation of parameter sets which reduce sigma T(2) to the level of 5%. T(2) relaxation mapping within healthy volunteers provided estimation of residual sigmaT(2) within the optimized technique. The standard deviation in T(2) measurement across regions of interest (ROIs) in different locations is about 9%. The standard deviation in T(2) measurement in an ROI across different time points is about 5%.
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Affiliation(s)
- Warren D Foltz
- Department of Medical Biophysics, University of Toronto, Canada.
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Sussman MS, Wright GA. Factors affecting the correlation coefficient template matching algorithm with application to real-time 2-D coronary artery MR imaging. IEEE Trans Med Imaging 2003; 22:206-216. [PMID: 12715997 DOI: 10.1109/tmi.2002.808363] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper characterizes factors affecting the accuracy of the correlation coefficient (CC) template matching algorithm, as applied to motion tracking from two-dimensional real-time coronary artery magnetic resonance images. The performance of this algorithm is analyzed in the presence of both random and systematic error. In the presence of random error, it is shown that a necessary and sufficient condition for accurate motion tracking is a large CC difference-to-noise ratio (CCDNR). The CCDNR itself is in turn affected by five factors: image and template size, image and template structure, and the magnitude of the noise. Techniques are introduced for manipulating some of these factors in order to increase the CCDNR for greater motion tracking accuracy. In the presence of superimposed systematic error it is shown that, while large CCDNR is necessary, it alone is not sufficient to ensure accurate motion tracking. Techniques are developed for improving motion tracking accuracy that minimize the effects of systematic error, while maintaining an adequate CCDNR level. The ability of these techniques to improve motion tracking accuracy is demonstrated both in phantoms and in coronary artery images.
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Affiliation(s)
- Marshall S Sussman
- Department of Medical Biophysics, Room. S612, Imaging Research Program, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, North York, ON M4N 3M5, Canada.
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Abstract
Variable-density (VD) spiral k-space acquisitions are used to acquire high-resolution (0.78 mm), motion-compensated images of the coronary arteries. Unlike conventional methods, information for motion compensation is obtained directly from the coronary anatomy itself. Specifically, periods of minimal coronary distortion are identified by applying the correlation coefficient template matching algorithm to real-time images generated from the inner, high-density portions of the VD spirals. Combining the data associated with these images together, high-resolution, motion-compensated coronary images are generated. Because coronary motion is visualized directly, the need for cardiac-triggering, breath-holding, and navigator echoes is eliminated. The motion compensation capability of the technique is determined by the inner-spiral spatial and temporal resolution. Results indicate that the best performance is achieved using inner-spiral images with high spatial resolution (1.6-2.9 mm), even though temporal resolution (four to six independent frames per second) suffers as a result. Image quality within the template region in healthy volunteers was found to be comparable to that achieved with cardiac-triggered breath-hold scans, although extended acquisition times of around 5 min were needed to overcome reduced SNR efficiency.
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Affiliation(s)
- Marshall S Sussman
- Imaging Research Program, Department of Medical Biophysics, Sunnybrook and Women's College Health Sciences Center, University of Toronto, Toronto, Canada.
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Post WS, Goldschmidt-Clermont PJ, Wilhide CC, Heldman AW, Sussman MS, Ouyang P, Milliken EE, Issa JP. Methylation of the estrogen receptor gene is associated with aging and atherosclerosis in the cardiovascular system. Cardiovasc Res 1999; 43:985-91. [PMID: 10615426 DOI: 10.1016/s0008-6363(99)00153-4] [Citation(s) in RCA: 381] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Methylation of the promoter region of the estrogen receptor gene alpha (ER alpha) occurs as a function of age in human colon, and results in inactivation of gene transcription. In this study, we sought to determine whether such age-related methylation occurs in the cardiovascular system, and whether it is associated with atherosclerotic disease. METHODS We used Southern blot analysis to determine the methylation state of the ER alpha gene in human right atrium, aorta, internal mammary artery, saphenous vein, coronary atherectomy samples, as well as cultured aortic endothelial cells and smooth muscle cells. RESULTS An age related increase in ER alpha gene methylation occurs in the right atrium (range 6 to 19%, R = 0.36, P < 0.05). Significant levels of ER alpha methylation were detected in both veins and arteries. In addition, ER alpha gene methylation appears to be increased in coronary atherosclerotic plaques when compared to normal proximal aorta (10 +/- 2% versus 4 +/- 1%, P < 0.01). In endothelial cells explanted from human aorta and grown in vitro, ER alpha gene methylation remains low. In contrast, cultured aortic smooth muscle cells contain a high level of ER alpha gene methylation (19-99%). CONCLUSIONS Methylation associated inactivation of the ER alpha gene in vascular tissue may play a role in atherogenesis and aging of the vascular system. This potentially reversible defect may provide a new target for intervention in heart disease.
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Affiliation(s)
- W S Post
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Abstract
Traditional T2-based imaging techniques are geared toward imaging long-T2 species. Traditional techniques are, therefore, not optimal in clinical situations where the information of interest lies in the short-T2 species. T2-selective RF excitation (TELEX) is a technique for obtaining a T2-based contrast that highlights short-T2 values while suppressing long-T2 values-opposite to traditional T2 contrast. Previously, TELEX has been demonstrated qualitatively to highlight only very short-T2 values (T2 approximately 0.001 s). When applied to longer T2 values (T2 > or = 0.01 s), TELEX becomes sensitive to deltaB0 non-uniformities. This restricts its application to problems in which the T2 of interest is very short. In this study, TELEX is characterized quantitatively. Furthermore, a bandwidth broadening scheme is developed that reduces the deltaB0 sensitivity of TELEX. This permits the technique to be applied to longer T2 values. The capabilities and limitations of a practical implementation of TELEX are discussed.
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Affiliation(s)
- M S Sussman
- Department of Medical Biophysics, Sunnybrook Health Science Centre, University of Toronto, North York, Ontario, Canada
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49
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Abstract
OBJECTIVE Minimally invasive direct coronary artery bypass (MIDCAB) is performed under direct vision without sternotomy or cardiopulmonary bypass. The technique is used in reoperative patients through various incisions to revascularize one or two areas of the heart. The internal mammary artery, gastroepiploic artery, radial artery, or saphenous vein are used as graft conduits. METHODS Anterior coronary targets are grafted with the internal mammary artery via a small anterior thoracotomy. Inferior coronary targets are grafted with the gastroepiploic artery via a small midline epigastric incision. Lateral coronary targets are grafted with radial artery or saphenous vein via a posterior thoracotomy. After partial heparinization, the anastomosis is facilitated by local coronary occlusion and stabilization. Graft follow-up consists of outpatient Doppler examination and selective recatheterization. RESULTS Between January 1994 and August 1997, 81 patients underwent reoperative MIDCAB grafting. Twenty-one patients (25.9%) had internal mammary grafting, 39 (48.2%) had gastroepiploic grafting, and 21 (25.9%) had lateral grafting with radial artery or saphenous vein. There were nine early deaths (four cardiac, five non-cardiac), five late deaths (three cardiac, two non-cardiac), and nine myocardial infarctions in remaining patients. Sixteen patients underwent recatheterization; there were one graft occlusion, two graft stenoses, and eight anastomotic stenoses. Mean postoperative length of stay was 3.8 days. Ninety percent (55/61) of patients are free of symptoms at a mean follow-up of 7.8 months (range 0-39). CONCLUSIONS Reoperative MIDCAB grafting avoids the risks of resternotomy, aortic manipulation, and cardiopulmonary bypass. The techniques yield an early patency rate of 94%, which includes eight patients who had postoperative catheter-based interventions. Reoperative MIDCAB grafting had lower rates of supraventricular arrhythmia and transfusion when compared with conventional coronary artery bypass grafting, but did not offer an advantage for mortality, stroke or myocardial infarction. This 3-year experience suggests that while reoperative MIDCAB grafting can effectively revascularize focal areas of the heart, patients should be carefully selected to minimize operative risk.
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Affiliation(s)
- J R Doty
- Division of Cardiac Surgery, Johns Hopkins and Sinai Hospital of Baltimore, MD 21287, USA
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Doty JR, Fonger JD, Nicholson CF, Sussman MS, Salomon NW. Cost analysis of current therapies for limited coronary artery revascularization. Circulation 1997; 96:II-16-20. [PMID: 9386069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Single or double (limited) coronary artery revascularization using percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass (CAB) surgery has recently been enhanced with further innovation in intracoronary stenting and the emergence of minimally invasive direct coronary artery bypass (MIDCAB) grafting. Resource allocation for all modalities is directly dependent on hospitalization costs, length of stay, and clinical results. METHODS AND RESULTS Four groups of 25 consecutive patients over 9 months at a single center received either PTCA, stenting, MIDCAB, or conventional CAB for single-vessel coronary disease, primarily of the left anterior descending circulation. Day, supply, and procedural charges were evaluated, along with the total hospital charge. Postprocedural length of stay was calculated and compared with a national database. MIDCAB surgery day charges were less than stenting but greater than PTCA, MIDCAB supply charges were the least of all groups, and MIDCAB procedural charges were less than for conventional CAB. Total charges for MIDCAB grafting were less than for stenting but greater than for PTCA. Postprocedural length of stay for MIDCAB patients was equivalent to PTCA patients and significantly less than for stenting or for conventional CAB. CONCLUSIONS MIDCAB grafting provides a new surgical approach that is comparable in charges to catheter-based interventions. The technique markedly reduces length of stay and perioperative morbidity. The selection of medical or surgical limited coronary revascularization can now be based primarily on clinical outcomes without consideration for associated resource allocation.
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Affiliation(s)
- J R Doty
- Division of Cardiac Surgery, Johns Hopkins Hospital/Sinai Hospital of Baltimore, Md, USA
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