ABSTRACT Background Coronary microvascular dysfunction (CMD) is a major contributor to cardiovascular complications in diabetes. Although noninvasive techniques such as arterial spin labeling cardiac MRI (ASL‐MRI) and transthoracic echocardiography (TTE) are available, their comparative performance for CMD remains unclear. Purpose To compare ASL‐MRI and TTE for CMD assessment in type 1 and type 2 (T1DM, T2DM) mouse models and relate functional indices to histological microvascular and myocardial remodeling, including early‐stage T2DM (8w‐T2DM). Study Type Prospective. Animal Model Forty 8‐week‐old male C57BL/6J mice allocated to five groups: control, T1DM, and T2DM ( n = 10 per group, imaged 16 weeks postinduction), and early‐stage T2DM (8w‐T2DM) and age‐matched controls ( n = 5 per group, imaged 8 weeks post‐induction). Field Strength/Sequence Segmented FLASH cine, steady‐pulsed labeling ASL, and inversion‐recovery segmented FLASH (T1 mapping) sequences at 9.4 T. Assessment Rest/stress myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) were derived from ASL data using a model‐based approach incorporating native T1 (from segmented FLASH data). Coronary flow velocity (CFV) and reserve (CFVR) were measured by TTE at rest (1.5% isoflurane) and stress (2.5% isoflurane). Histology included assessment of hematoxylin–eosin (myocyte area), Masson (collagen), and IB4 (capillary density). Statistical Tests Group comparisons used t ‐tests, Mann–Whitney U tests, and one‐/two‐way ANOVA with Bonferroni correction; correlations were assessed with Pearson or Spearman coefficients ( r ). p < 0.05 was considered significant. Results 38 animals completed MR and TTE imaging. At 16 weeks, stress diastolic MBF was significantly lower in T1DM (14.67 ± 1.62 mL/g/min) and T2DM (13.42 ± 2.44 mL/g/min) vs. controls (22.19 ± 0.25 mL/g/min), with significantly reduced MPR in T2DM (1.53 ± 0.17 vs. 2.27 ± 0.15). TTE showed significantly reduced CFVR only in T2DM (2.16 ± 0.24 vs. 2.75 ± 0.24). In 8w‐T2DM, ASL‐MRI detected significantly reduced MPR (1.87 ± 0.16 vs. 2.26 ± 0.13), whereas TTE showed no significant CFVR change ( p = 0.900). Capillary density significantly decreased in 16‐week and 8‐week T2DM. IB4‐positive area correlated with CFVR ( r = 0.673) and more strongly with MPR ( r = 0.810). Conclusion ASL‐MRI detected CMD in diabetic mice, outperforming TTE in early‐stage disease and showing a strong association with microvascular injury. Evidence Level 1. Technical Efficacy Stage 2.
Miao et al. (2026) studied this question.