LAUSR

A 79-year-old man presented with chest pain radiating to the back. Acute aortic syndrome was suspected and a thoracic computed tomography angiography (CTA) was performed, demonstrating penetrating aortic ulcer (PAU) in the descending thoracic aorta with adjacent inflammatory tissue (arrow, Panel A). Blood cultures revealed methicillin-sensitive Staphylococcus aureus. Fluorine-18-fluorodeoxyglucose (18FFDG) positron emission tomography/computed tomography (PET/CT) showed marked tracer uptake in the descending thoracic aortic wall and the adjacent lung parenchymal consolidation (arrow, Panel B). After intravenous antibiotic treatment and establishing the stability of PAU, the patient was transferred to a medical rehabilitation center. After 5 weeks, the patient re-presented with fever, anemia, and altered mental status. Gadolinium-enhanced magnetic resonance angiography (MRA) sagittal fat-saturated T1 images demonstrated an enlarging pseudoaneurysm at the left posterolateral aspect of the descending thoracic aorta with adjacent inflammatory tissue (arrow, Panel C). Given the comorbidities, the patient underwent endovascular repair with a 34 mm thoracic endoprosthesis, rather than open repair. Follow-up CTA with sagittal images confirmed adequacy of the endovascular repair (Panel D). Mycotic aortic aneurysms (MAA) arise due to infection of the aortic wall and comprise only 0.7–2.6% of all aortic Multimodality imaging of a thoracic aortic mycotic pseudoaneurysm