Delayed enhancement in hypertrophic cardiomyopathy: Comparison with myocardial tagging MRI

Purpose: To evaluate the relationship between delayed enhancement (DE) and regional left ventricular function in hypertrophic cardiomyopathy (HCM) using gadolinium enhancement MRI and myocardial tagging MRI. Materials and Methods: Cine imaging, delayed enhancement imaging, and tagging MRI were performed in 25 patients with HCM. The location, pattern, and extent of DE were evaluated. Circumferential shortening (Ecc) was obtained by analyzing MR tagging images with HARP software. Results: DE occurred in 21 (84%) patients with a high frequency of localization in the septum and the right ventricular attachment sites. Circumferential shortening was significantly decreased in the enhanced segments compared with nonenhanced segments (P < 0.0001). The myocardial wall was thicker in the enhanced segments than in the nonenhanced segments (P < 0.0001). However, circumferential shortening was significantly decreased in the enhanced segments of the same thickness (P < 0.0001). Circumferential shortening was more substantially impaired in the segments with focal nodular enhancement than those in the segments with ill-defined patchy enhancement (P = 0.0002). Conclusion: In HCM, DE is commonly found and circumferential shortening is significantly impaired in the regions with DE, regardless of the degree of myocardial hypertrophy. Focal nodular enhancement is particularly related with regional dysfunction in patients with HCM.