3.0 T magnetic resonance myocardial perfusion imaging for semi-quantitative evaluation of coronary microvascular dysfunction in hypertrophic cardiomyopathy

This study aimed to assess coronary microvascular dysfunction (CMD) differences in hypertrophic cardiomyopathy (HCM) patients using cardiac magnetic resonance (CMR) first-pass perfusion and late gadolinium enhancement imaging. Forty-seven patients with HCM and twenty-one healthy volunteers underwent CMR at rest. Imaging protocols included short axis cine, first-pass myocardial perfusion, and late gadolinium enhancement (LGE). Left ventricular end-diastolic wall thickness (EDTH), LGE, time to peak (T_peak), maximal up-slope (Slope_max), and peak signal intensity (SI_peak) were assessed for each myocardial segment. The HCM myocardial segments were grouped by the degree of LGE and hypertrophy. T_peak, SI_peak, Slope_max and EDTH in multiple groups were assessed and compared by ANOVA test/Kruskal-Wallis test. The Spearman correlation test was used to determine the relationships between EDTH, LGE and perfusion parameters (T_peak, Slope_max and SI_peak). Compared to control group segments, T_peak increased while Slope_max and SI_peak decreased in non-LGE/non-hypertrophic segments and LGE/hypertrophic segments in the HCM group, while T_peak increased more significantly in LGE/hypertrophic segments (all p < 0.05). T_peak statistically increased with increasing degrees of myocardial LGE (p < 0.01). Differences in T_peak, SI_peak and EDTH were observed between segments with and without hypertrophy (p < 0.05). EDTH and LGE were positively correlated with T_peak (r = 0.279, p = 0.031 and r = 0.237, p < 0.001). 3.0 T magnetic resonance myocardial perfusion imaging identifies abnormal perfusion in non-LGE and non-hypertrophic segments of HCM patients, and it may be helpful in the early diagnosis of coronary microvascular dysfunction in HCM. This abnormal perfusion is associated with the severity of myocardial fibrosis and the degree of hypertrophy.