The Utility of Standard, Diastolic Phase, Cardiac Computed Tomography (dCCT) in Diagnosing and Identifying High-risk features in Apical Hypertrophic Cardiomyopathy (ApHCM)

Abstract

Apical hypertrophic cardiomyopathy (ApHCM) is increasingly prevalent and not as benign as previously thought. Cardiac magnetic resonance imaging (CMR) has been the gold-standard for diagnosing ApHCM, however certain factors preclude their use prompting the use of other modalities i.e cardiac computed tomography (CCT). The utility of CCTs in ApHCM however is still limited. We aimed to assess the sensitivity of a standard, diastolic phase, cardiac computed tomography (dCCT) compared to CMR in identifying ApHCM by comparing left ventricular (LV) wall thickness, LV wall ratio, & presence of high-risk features, i.e apical aneurysm and cardiac thrombus, in addition to coronary artery disease (CAD) severity. We conducted a retrospective analysis of 38 patients from a multicentre database who had a dCCT, CMR, and a confirmed diagnosis of ApHCM. ApHCM was defined as apex thickness of ≥15 mm & apex:basal posterior wall thickness ratio≥1.3. LV wall measurements, presence of apical aneurysm and cardiac thrombus were obtained for both dCCT and CMR. CAD severity was assessed. Standard dCCTs were highly sensitive (94.7%) at diagnosing ApHCM compared to CMR, with good correlation (R=0.8; p <0.05) between dCCT & CMR measurements. 44.7% patients had mild CAD and 5.3% patients had severe CAD. 3 patients had apical aneurysm on dCCT compared to 4 in the CMR group, conferring a specificity of 97.1% and sensitivity of 80%. Standard dCCT performed for coronary artery assessment has a potential role in diagnosing ApHCM, identifying high-risk features and delineating CAD relative to dedicated ‘gold standard’ CMR.Figure 1Apical aneurysm on Cardiac CT (left) vs Cardiac MR (right).View Large Image Figure ViewerDownload Hi-res image Download (PPT)