Contrast-Enhanced Myocardial T1-Weighted Scout (Look-Locker) Imaging for the Detection of Myocardial Damages in Hypertrophic Cardiomyopathy

Purpose: To assess the myocardial damage in hypertrophic cardiomyopathy (HCM) using contrast-enhanced myocardial T1-weighted scout (Look-Locker) magnetic resonance imaging (MRI). Materials and Methods: Twenty-three patients with HCM and seven comparative patients without known HCM serving as controls underwent cine, contrast-enhanced myocardial T1-weighted scout and delayed-enhancement MRI using a 1.5T unit. Intervals of null points between myocardium and blood were compared among hyperenhancing and nullified myocardium of HCM and the normal myocardium. The relationship between these myocardial patterns and global cardiac functions was analyzed in HCM. Results: The hyperenhancing myocardium, dense myocardial fibrosis in HCM had null points significantly shorter than blood, normal myocardium, and nullified myocardium of HCM (P < 0.0001). The number of hyperenhancing myocardial segments correlated with the ejection fraction (P = 0.045). The nullified myocardium of HCM showed shorter intervals of the null points between myocardium and blood than did the normal myocardium, indicating the dispersed myocardial fibrosis (P = 0.0032). The interval of null points between the nullified myocardium and blood showed a significant correlation with the increase in myocardial mass in HCM (P = 0,034). Conclusion: Contrast-enhanced myocardial T1-weighted scout imaging has the potential for showing dispersed myocardial damage leading to increased myocardial mass in HCM, while the dense myocardial fibrosis correlated with reduced ejection fraction.