Delayed Hyper-Enhancement of myocardium in hypertrophic cardiomyopathy with asymmetrical septal hypertrophy: Comparison with global and regional cardiac MR imaging appearances

Purpose: To evaluate the relationship between delayed hyper-enhancement of the myocardium and global and regional cardiac abnormalities in hypertrophic cardiomyopathy (HCM) with asymmetrical septal hypertrophy using magnetic resonance (MR) imaging. Materials and Methods: Twenty-three patients with HCM with asymmetrical septal hypertrophy were examined using a 1.5-T MR unit. Contrast-enhanced inversion-recovery gradient-echo imaging was performed to observe the myocardial damages associated with HCM. Balanced steady-state free precession imaging was performed to assess regional wall abnormalities and ejection fraction, and black-blood fast spin-echo imaging was performed to assess left atrial diameter. Results: Delayed hyper-enhancement of the myocardium was primarily observed in the interventricular septal wall. Septal walls with the higher transmural extent of delayed hyper-enhancement were significantly thicker at end-diastole and end-systole (P < 0.05), and tended to show a decreased percentage systolic wall thickening (P = 0.079). There were no differences in theses values between nonenhancing septal walls and septal walls with the transmural extent < 50%. Conclusion: The high transmural extent of delayed hyperenhancement of the myocardium may reflect the severe myocardial damage associated with the regional hypertrophy and hypokinesia in HCM.