Are Echocardiogram and Magnetic Resonance Imaging (MRI) Comparable in Measuring Maximal Septal Thickness in Children with Hypertrophic Cardiomyopathy (HCM)?

Background: Maximal interventricular septal wall thickness is a key measurement in patients with HCM, influencing decision making for ICD placement. Frequent MRIs are often obtained due to perceived inaccuracy of wall thickness with echocardiographic measurements. As children generally have good acoustic windows, we hypothesize that that in children there will be strong correlation between echocardiogram and MRI assessment of myocardial thickness and left ventricular dimensions. Methods: Using a cohort from the Pediatric Cardiomyopathy Biomarkers Study, protocolized echocardiograms and MRIs from 55 children (median age 13.8 yr, range 1-20 yr) were analyzed in a core lab for left ventricular end-diastolic (LVEDV) and end-systolic dimensions (LVESV), LV mass, and maximal interventricular septal wall thickness. Studies were obtained on average within 4 days of each other. Results: 51/55 pairs of echocardiograms and MRIs were analyzed for LVEDV and LVESV. No strong correlation was seen between LVEDV (r = 0.18...