Delayed enhancement in hypertrophic cardiomyopathy: Comparison with myocardial tagging MRI

Abstract

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 Ͻ 0.0001). The myocardial wall was thicker in the enhanced segments than in the nonenhanced segments (P Ͻ 0.0001). However, circumferential shortening was significantly decreased in the enhanced segments of the same thickness (P Ͻ 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 ϭ 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. HYPERTROPHIC CARDIOMYOPATHY (HCM) is a genetic disorder that is histologically characterized by myocyte disarray, interstitial fibrosis, and small vessel disease (1,2). Studies using gadolinium enhancement MRI have reported that delayed myocardial enhancement (DE) may be seen in patients with HCM and is positively correlated with myocardial wall thickness (3-6). A recent report revealed that DE is related to myocardial collagen, which is a major component of fibrosis (7).Regional heterogeneity of left ventricular function in HCM has been reported, and circumferential strain or systolic wall thickening is often decreased in hypertrophied areas (8 -13). However, the relationship between DE and regional performance has not been established. The purpose of our study is to evaluate the prevalence and pattern of DE in HCM and to determine the relationship between DE and regional performance using gadolinium enhancement MRI and tagged MRI. MATERIALS AND METHODS Patient PopulationThe study population consisted of 25 patients (M:F ϭ 19:6; mean age, 48.6 years old; range, 22-68 years) who were diagnosed with HCM by echocardiography and referred for MRI. We included the patients who met the following criteria: (i) the presence of a hypertrophied left ventricle (LV; Ͼ15 mm in thickness on echocardiography), (ii) normal coronary arteries as determined by conventional coronary angiography or coronary MR angiography, and (iii) no secondary causes of hypertrophy such as severe aortic valvular disease or hypertension. The study protocol was approved by the institutional review board.

Echocardiography as a Screening Test for Myocardial Scarring in Children with Hypertrophic Cardiomyopathy

“…These segments include the right ventricular insertion points into the interventricular septum. These findings are similar to that reported in adult HCM patients [26], with these junctions as well as the septum itself previously identified as the areas most commonly involved in myocardial scarring in adult patients with HCM [25]. …”

Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques–pulse sequences, analysis algorithms, and applications

“…Later, two studies confirmed the impaired diastolic function in HCM [64,274]. Recently, Kim et al showed that impaired circumferential shortening occurs in delayed hyperenhancement areas in HCM [273]. …”

Myocardial tissue tagging with cardiovascular magnetic resonance

“…In a prospective trial including 53 patients, Soler et al [67] found good correlation between delayed enhancement areas in hypertrophic cardiomyopathy and perfusion defects (r = 0.5, p < 0.01), whereas a weak but significant correlation was detected between delayed enhancement and hypokinetic segments. Recently, Kim et al [68] demonstrated impaired circumferential shortening in delayed enhancement areas, where E CC was more substantially reduced in the regions displaying focal nodular enhancement patterns rather than in patchy enhanced regions.…”