title: Unilateral absence of ventilation and perfusion due to thoracic aortic aneurysm.
abstract: An elderly man presented with progressive atelectasis of the left lung, a mediastinal mass, and dilatation of the thoracic aorta. Ventilation and perfusion radionuclide lung scans revealed the complete absence of ventilation in the left lung and near-complete absence of perfusion. Evaluation by MRI and angiography showed an obstructing mediastinal "mass" to be a saccular aortic aneurysm. A thoracic aortic aneurysm should be a consideration in the differential diagnosis for unilateral decrease or absence of ventilation and perfusion with a history or findings of mediastinal mass or aneurysm.
authors.affiliation: Department of Radiology, University of Tennessee, Memphis.
authors.forename: R A
authors.initials: RA
authors.lastname: Duke
authors.forename: M R
authors.initials: MR
authors.lastname: Barrett
authors.forename: S D
authors.initials: SD
authors.lastname: Payne
authors.forename: J D
authors.initials: JD
authors.lastname: Massie
authors.forename: J E
authors.initials: JE
authors.lastname: Salazar
authors.forename: M L
authors.initials: ML
authors.lastname: Gavant
mesh_terms: D000368:Aged; D001013:Aorta, Thoracic; D001014:Aortic Aneurysm / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D011877:Radionuclide Imaging; D012119:Respiration