Acute Pulmonary Embolism Detected by Perfusion SPECT/CT Masquerading as an Intermediate Probability Planar V/Q Scan

A 51-year-old man with renal cell carcinoma, renal insufficiency, and a remote pulmonary embolism (PE) was referred for a ventilation-perfusion (V/Q) scan because of dyspnea and chest pain one day after left partial nephrectomy. Planar V/Q scan revealed an intermediate probability for PE. As the pretest probability for PE was high, a perfusion SPECT/CT was obtained, which clearly demonstrated a large segmental perfusion defect on a background of clear lung parenchyma, consistent with the presence of PE. Follow-up planar V/Q scan after 1 month of anticoagulation therapy was normal.