(A) Stress and rest perfusion polar maps of SPECT study with mixed basal anterolateral defect and reversible inferoapical perfusion defect (arrowheads). (B) and (D) Fused SPECT/CT images reveal total occlusion of LAD and subtotal occlusion of first diagonal branch (DA1), which are confirmed by conventional coronary angiography (C). Anterolateral perfusion defect is caused by lesion of partially calcified small intermediary branch (IM). However, this vessel is not well visualized by coronary angiography. Reproduced with permission from Gaemperli O, Schepis T, Valenta I, et al. Cardiac image fusion from stand-alone SPECT and CT: clinical experience. J Nucl Med 2007; 48: 696–703.