LAUSR

Noninvasive imaging is crucial for diagnosing aortitis. However, increased wall thickness detected by CT is not specific because of correlation with age and vascular calcifications. Used as an in vivo biomarker, F-FDG may help reveal aortic inflammation. FFDG PET/CT likewise allows managing infectious aortitis, as shown for abdominal septic aortic localizations. Indeed, thoracic aorta is affected in only 17% of the cases. We report a case of thoracic infectious aortitis managed by F–FDG PET/CT as a complication of a Salmonella typhimurium sepsis. An 82-year old woman, with seropositive rheumatoid arthritis, was referred because of abdominal pain. Clinical examination revealed abdominal tenderness in the left flank. Urine analysis was related with S. typhimurium infection. Diagnosis of acute left nephritis was made. Ofloxacin was introduced but fever appeared and CRP level increased. Blood cultures grew S. typhimurium. Thoracic and abdominal CT showed aortic calcifications with no aneurysm. MRI and echocardiography, respectively, ruled out spondylodiscitis and endocarditis. Ofloxacin was replaced by ceftriaxone and gentamycin. The patient remained febrile and CRP was still elevated. Due to a suspicion of abdominal infectious aortitis, F-FDG PET/CT was performed, showing focal FDG uptake in pulmonary bi-apical nodulations (Figure 1B) and in the sternum (Figure 1C), thus revealing septic emboli. Moreover, metabolic aortic activity was focally increased in descending thoracic aorta wall thickening, then consistent with an infectious aortitis (Figure 1A). After 6-week ceftriaxone treatment, CRP decreased; F-FDG PET/CT performed three months later showed a metabolic regression of infectious lesions (Figure 2A–C); and follow up was uneventful. Associated to septic emboli, the pattern of F-FDG accumulation pointed the infectious origin of the increased thoracic aortic wall thickness. Metabolic evolution after antibiotic treatment achieved to enhance imaging specificity, regarding this patient with seropositive rheumatoid arthritis, thus candidate for a noninfectious aortitis.