Uptake of ^sup 18^F-FDG in Acute Aortic Dissection: A Determinant of Unfavorable Outcome

Imaging with ^sup 18^F-FDG PET/CT is able to reveal vascular inflammation, and several studies have shown that increased ^sup 18^F-FDG uptake in carotid artery plaques can qualify the degree of atherosclerotic inflammation. However, clinical assessment of acute aortic dissection (AAD) by PET/CT remains largely unexplored. This study aimed to investigate the use of ^sup 18^F-FDG PET/CT to predict short- and midterm outcomes in medically controlled AAD patients. Methods: A total of 28 medically treated AAD patients (2 Stanford type A and 26 type B, aged 69.5 ± 11.6 y) were prospectively studied. All patients were examined by enhanced CT for diagnosis of AAD and underwent serial imaging studies during follow-up. PET/CT images were acquired 50 and 100 min after ^sup 18^F-FDG injection in all patients in the acute phase. Results: Of the 28 patients, 8 who had an unfavorable outcome due to death from rupture (n = 2), surgical repair (n = 4), and progression of dissection (n = 2) were categorized as having unfavorable AAD. The remaining 20 patients were categorized as having favorable AAD. Maximum dissection diameter in the unfavorable group was significantly greater than that in the favorable group (P = 0.0207). On 50-min images, maximal and mean standardized uptake values (SUVs) at maximum aortic dissection sites were significantly greater for the unfavorable group than for the favorable group (all P < 0.01). A stepwise-forward selection procedure demonstrated that the mean SUV at sites of maximum aortic dissection on 50-min images significantly and independently predicted an unfavorable outcome for AAD (P = 0.0171; odds ratio, 7.72; 95% confidence interval, 1.44-41.4; R^sup 2^ = 0.2372). A mean SUV greater than 3.029 had significant predictive power, with sensitivity of 75.0%, specificity of 70.0%, a positive predictive value of 50.0%, a negative predictive value of 87.5%, and accuracy of 71.4%. Conclusion: Greater uptake of ^sup 18^F-FDG in AAD was significantly associated with an increased risk for rupture and progression. ^sup 18^F-FDG PET/CT may be used to improve AAD patient management, although more studies are still needed to clarify its role in this clinical scenario. [PUBLICATION ABSTRACT]