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Intravoxel Incoherent Motion Diffusion Weighted MR Imaging to Evaluate Myocardial Microvascular Dysfunction of Exertional Heat Illness12. Department of Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China, 24. MR Research, GE Healthcare, Beijing, China
Synopsis
Keywords: Heart, Myocardium
Purpose: To investigate the feasibility of assessing myocardial microvascular perfusion of patients with exertional heat illness (EHI) by intravoxel incoherent motion imaging.
Methods: CMR-IVIM image quality was evaluated with a 3-point scale. CMR-IVIM derived parameters were analyzed and compared between EHI and HC. Receiver operating characteristic curve was used.
Results: CMR-IVIM image quality were significantly improved. EHI patients showed decreased D*, decreased f values and higher D values compared to HC. f showed the most robust efficacy for detecting EHI related myocardial injury with the highest area under the curve.
Conclusion: CMR-IVIM can evaluate myocardial injury of EHI patients.
abstract
Purpose: To investigate the feasibility of myocardial strain curve derived trigger delay (TD) method in cardiac magnetic resonance intravoxel incoherent motion imaging (CMR-IVIM) and in assessing myocardial diffusion and microvascular perfusion of patients with exertional heat illness (EHI).
Material and Methods: 42 male EHI patients with high level outdoor training and 22 male healthy controls (HC) undergoing 3.0-T CMR were prospectively recruited. CMR-IVIM was randomly acquired by conventional TD method (Group A) or myocardial strain curve based TD method (Group B). TD time and the difference were compared in two groups. CMR-IVIM image quality was evaluated with a 3-point scale. CMR-IVIM derived parameters (pseudo diffusion in the capillaries [D*], perfusion fraction [f] and slow apparent diffusion coefficient [D]) were analyzed and compared between EHI and HC. Receiver operating characteristic curve was used. The correlation between IVIM parameters and myocardial biomarkers was investigated.
Results: CMR-IVIM image quality (3 [2-3] vs 2 [1-3], P=.014) and technical success rate (score 3) (61.9% [13/21] vs 28.6% [6/21], P = .030) were significantly improved in Group B due to shorter TD difference (133.95 ± 80.11 ms vs 58.38 ± 49.36 ms; P = .001) compared to Group A. EHI patients showed decreased D* (118.13 ± 23.34 x 10-3 mm2/s vs 142.74 ± 42.56 x 10-3 mm2/s, P = .023), decreased f values (0.42 ± 0.12 vs 0.51 ± 0.11; P = .021) and higher D values (2.98 ± 0.87 x 10-3 mm2/s vs 2.54 ± 0.63 x 10-3 mm2/s, P = .009) compared to HC. Relative to D and D*, f showed the most robust efficacy for detecting EHI related myocardial injury with the highest area under the curve (95% confident interval, 0.906: 0.799, 0.967, P<.001) and sensitivity of 88.5% and specificity of 85.6%. f value negatively correlated with creatine kinase-MB isoenzymes (r = -0.532, P = .001) and cardiac troponin I (r = -0.604, P<.001).
Conclusion: Myocardial strain curve based TD method substantially improved image quality and technical success rate of CMR-IVIM, which can evaluate myocardial injury and f value can be an effective biomarker to assess myocardial microcirculation abnormalities of EHI patients.
Acknowledgements
No acknowledgement found.References
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Figures
Panel A. A 23-year-old (first row) healthy male had normal LGE image, D value (2.13 x 10-3mm2/s), D* value (152.74 x 10–3 mm2/s) and f value (0.582). Panel B. A 23-year-old male (middle row) with EHI shows negative LGE, but the D value is increased (3.01 x 10-3 mm2/s), while D* value (102.74 x 10–3 mm2/s) and f (0.318) value are reduced. Panel C. A 21-year-old (bottom row) with EHI and positive LGE in the LV septal segment (arrow) had higher D value (3.72 x 10-3 mm2/s), reduced D* value (98.21 x 10–3 mm2/s) and f value (0.286).
Receiver-operator characteristics curve (ROC) analyses to assess diagnostic performance of CMR-IVIM parameters in the myocardial injury of EHI. AUC = area under the ROC curve.