Established binary cutoffs for cine-CMR basal slice selection - an unrecognized source of CMR discordance with echocardiography and necropsy derived LV mass

Background Left ventricular mass (LVM) is widely used to guide clinical decision-making. CMR is well suited to measure LVM as it provides high-resolution delineation of myocardial contours. CMR quantification of LVM is typically performed via planimetry of contiguous short axis images, an approach fundamentally dependent on reader selection of short axis images to be contoured. Established methods have applied different binary cutoffs using circumferential extent of LV myocardium to define the basal LV, while omitting short axis images containing lesser fractions of LV myocardium. This study compared LVM, quantified using different established methods for basal slice selection, to independent references of LVM measured by echocardiography and necropsy.