Assessment of left ventricular (LV) myocardial structural alteration by calibrated integrated backscatter (IBS) in a mutation carrier without HCM phenotype expression (Mut+/Phen−).A fixed region of interest is positioned at the level of the basal anteroseptal wall (ASW, yellow circle), of the basal posterior wall (PW, blue circle) and in the pericardium (red circle, for calibration). The basal ASW calibrated IBS of this Mut+/Phen− patient was −14.4 dB and the basal PW calibrated IBS was −19.8 dB, indicating an altered myocardial structure.