title: Compression of the right pulmonary artery by a massive descending aortic aneurysm causing bilateral perfusion defects on pulmonary scintigraphy.
abstract: A 67-year-old woman, who presented with a 2 month history of dyspnea, had a ventilation and perfusion lung scan that showed absent perfusion of the entire right lung with normal ventilation, as well as a rounded matched defect in the left lower lung adjacent to midline, suspicious for an aortic aneurysm or dissection. CT pulmonary angiography revealed a massive descending aortic aneurysm compressing the right pulmonary artery as well as the left lung parenchyma, accounting for the bilateral perfusion scan defects. We present the Xe-133 ventilation, Tc-99m MAA perfusion and CT pulmonary angiography imaging findings of this rare case.
authors.affiliation: Department of Nuclear Medicine, Brandon Regional Health Centre, 150 McTavish Ave E, Brandon, MB R7A 2B3 Canada.
authors.forename: William
authors.initials: W
authors.lastname: Makis
authors.affiliation: Department of Nuclear Medicine, Royal Victoria Hospital, McGill University Health Centre, 687 Pine Ave West, Floor M2, Montreal, Quebec H3A 1A1 Canada.
authors.forename: Vilma
authors.initials: V
authors.lastname: Derbekyan
keywords: CT pulmonary angiography; Descending aortic aneurysm; Unilateral absent perfusion; VQ scan; Ventilation and perfusion scan