Purpose: To explore whether cardiac magnetic resonance-intravoxel incoherent motion imaging (MR-IVIM) is feasible for the clinical evaluation of myocardial microcirculation.
Materials and methods: The study included 30 patients (with hypertrophic cardiomyopathy, diabetes mellitus, hypertension, or combined diabetes and hypertension) and 34 healthy volunteers. MR-IVIM with a maximum gradient strength of 50 mT/m was performed on the left ventricular short axis (apex, middle, and base), using multiple b values (0-500 s/mm2 ) on a 3.0T MR scanner. MR-IVIM parameters of the left ventricle included apparent diffusion coefficient (ADC)slow , ADCfast , and f (fraction of ADCfast ). With a double-blind design, the image quality and IVIM parameters were assessed by two cardiovascular radiologists at 1-month intervals. Participants were stratified into two groups (failure or success), based on criteria for success of MR-IVIM acquisition. The heart rate of each participant was recorded.
Results: The success rates for image acquisition were 68.23% (131/192) overall, with the healthy group (74.51% [76/102]) significantly higher than the patient group (61.11% [55/90]). The mean heart rate was significantly higher in the failure group than the success group. The two radiologists were comparable in quality evaluations of the images (kappa = 0.82). Both the interobserver and intraobserver reliability for IVIM parameters were excellent for patients and healthy volunteers (intraclass correlation coefficient >0.8). However, the left ventricle myocardial ADCfast of each patient group was significantly lower than that of the healthy volunteers.
Conclusion: MR-IVIM could noninvasively assess human myocardial microcirculation, but challenges remain before this method can be applied in the clinic.
Level of evidence: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1818-1828.
Keywords: intravoxel incoherent motion; magnetic resonance; myocardial microcirculation.
© 2017 International Society for Magnetic Resonance in Medicine.