METASTATIC PLEURAL CANCER IN RADIONUCLIDE ANGIOCARDIOGRAPHY - A PULMONARY TIME-ACTIVITY CURVE MIMICKING LEFT-TO-RIGHT CARDIAC SHUNT

A 55-year-old man, with a history of nephrectomy for renal cell carcin oma, was evaluated using radionuclide angiocardiography to exclude car diac shunts as the cause of vascular bruits heard at auscultation. A p ulmonary time-activity curve derived from the right lung showed a patt ern typical of a large left-to-right shunt, whereas that from the left lung was normal. Increased systemic arterial flow to the lateral righ t chest was noted in early dynamic images. Subsequent studies revealed that this flow and the abnormal time-activity curve of the right lung were due to systemic arterial supply to metastatic pleural cancer, or iginating from the kidney. the authors conclude that special caution s hould be undertaken in the interpretation of the radionuclide angiocar diography for determining left-to-right cardiac shunts, especially in those showing a asymmetric pulmonary time-activity curve.