Intracoronary 99m Tc-Sestamibi Single Photon Emission Computed Tomography/Computed Tomography for Preoperative Evaluation of At-Risk Myocardium

Abstract

A 73-year-old man with a history of previous coronary artery bypass surgery (left internal mammary artery [LIMA]–to–first obtuse marginal artery graft, right internal mammary artery–to–left anterior descending artery graft, and venous graft to second obtuse marginal branch) and previously treated melanoma and gastric carcinoma was referred for evaluation of an enlarging lung mass adjacent to a vascular graft on computed tomography (CT). CT coronary angiography confirmed that the suspicious left upper lobe lung mass was encasing the LIMA graft (Figure 1). 18F-fluorodeoxyglucose positron emission tomography/CT study confirmed isolated, intense metabolic activity within the lesion consistent with malignancy (Figure 2). Echocardiography confirmed normal left ventricular systolic function. A decision for surgical resection was made, with the need for further evaluation of the coronary circulation to assess the implications of potential sacrifice of the LIMA graft. At the time of coronary angiography (Figure 3), 76 MBq 99mTc-sestamibi was injected directly into the LIMA graft to establish the area of viable myocardium perfused by this vessel. Single photon emission CT/CT imaging performed 1 hour later (Figure 4) demonstrated that, at most, sacrifice of the LIMA graft would result in only a small infarct of the lateral wall. Subtraction of these images from …