Cardiac intravoxel incoherent motion diffusion-weighted imaging to assess myocardial microcirculation dysfunction in hypertension.

Background: Myocardial microcirculation dysfunction is the most potent predictor of adverse cardiovascular events in hypertension. The current study aimed to apply intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) to assess hypertension-related microcirculation dysfunction.

Methods: In this prospective study, 102 participants were recruited from our hospital and underwent cardiac magnetic resonance (CMR) examination on a 3T scanning system. Hypertensive patients were divided into 3 subgroups based on blood pressure (BP) types. Two experienced CMR radiologists independently analyzed all images, and Bland-Altman analysis was applied to assess intra- and inter-observer reproducibility. Cardiac function indexes and IVIM-DWI parameters were compared between the hypertension and healthy control groups, as well as among the three hypertension subgroups.

Results: Totally 62 participants with hypertension and 27 healthy controls were included. 13 participants were excluded for poor quality of IVIM-DWI images. Significantly higher maximal left ventricular wall thickness (10.3±2.0 vs. 8.6±1.4 mm, P<0.001) and left ventricular mass index (49.0±9.1 vs. 42.1±7.5 g/m², P<0.05) were observed inhypertension group compared with healthy control group. There were significant statistical differences in pseudo diffusion (D*) between them (81.3±16.3 vs. 111.8±18.9 mm²/s, P<0.001), as well as among the three hypertension subgroups (99.4±13.9 vs. 79.7±10.6 vs. 67.1±6.6 mm²/s, P<0.001). Participants with poor quality of IVIM-DWI images had higher heart rates (72.2±10.0 vs. 62.0±8.1 bpm, P<0.001).

Conclusions: IVIM-DWI is feasible for quantitatively evaluating myocardial microcirculation dysfunction in hypertension. The D* parameter has a potential value for assessing the severity of microcirculation dysfunction in different BP categories.