The clinical course and predictors of adverse aortic events (AAE) in patients with acute Stanford type B intramural hematoma (IMH) remain controversial. This study aimed to investigate whether ¹⁸F-FDG PET/CT can predict risk in patients with acute type B IMH.

This study included 34 patients with acute type B IMH who underwent PET/CT within 14 days from the onset of symptoms. The maximal standardized uptake values (SUVmax) of ¹⁸F-FDG uptake was significantly different between patients with or without AAE (4.3 ± 0.6 vs 3.7 ± 1.0, P = 0.020), but not the target to blood ratio (TBR, SUVmax divided by SUV in the superior vena cava) (1.6 ± 0.2 vs 1.5 ± 0.5, P = 0.064). In patients with initial ulcer-like projection (ULP), a blood-filled pouch protruding into the IMH, which was seen in 25 patients(74%), both the SUVmax and TBR were significantly higher in patients who developed AAE, (4.3 ± 0.6 vs 3.3 ± 0.5, P = 0.001; 1.6 ± 0.2 vs 1.4 ± 0.2, P = 0.01); the TBR >1.5, which is determined from receiver-operating-characteristic curve, had a sensitivity of 73% and a specificity of 80% in predicting AAE.

Patients with ULP and high ¹⁸F-FDG uptake were more likely to develop AAE and may require closer surveillance with serial imaging.