99mTc MAA Pulmonary Perfusion Scintigraphy in 2 Cases of Anomalous Systemic Arterial Supply to Normal Basal Segments of the Left Lower Lobe of the Lung

Reports of 99mTc macroaggregated albumin pulmonary perfusion scintigraphy for anomalous systemic arterial supply to normal basal segments of the left lower lobe of the lung are extremely rare. We performed scintigraphy in 2 patients with the disease to verify their diagnoses and guide the operation as both were initially misdiagnosed. Segmental radiotracer defects in the basal segments of the left lower lobe, which are also characteristic features of pulmonary embolism, were evident in both cases, as expected. Our report provides a complementary noninvasive diagnostic modality of the disease and helps prevent potential misinterpretation of 99mTc macroaggregated albumin scintigraphy.