Evaluation of myocardial microcirculation using intravoxel incoherent motion imaging

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.