Correlation of FDG PET/CT Findings with Long-Term Growth and Clinical Course of Abdominal Aortic Aneurysm.

Purpose: Herein, we report characteristics of 18 F-fluorodeoxyglucose (FDG) uptake in abdominal aortic aneurysms (AAAs) during a long-term follow-up. In addition, we investigated the association between FDG uptake and the physician decision to perform an intervention.

Methods: We performed a retrospective review of 42 patients with AAAs who underwent FDG positron emission tomography (PET)/computed tomography (CT). The size of the AAA was measured in serial CT or PET/CT images. The long-term growth rate of AAAs was calculated by linear regression of the size change. Maximal SUV of the AAA (SUVAAA ) and mean SUV of the blood pool (SUVBlood ) were measured in PET/CT fusion images. To assess the FDG uptake of AAAs, the target-to-background ratio (TBR) was defined as the ratio of SUVAAA to SUVBlood . We compared FDG uptake of AAAs with the long-term growth rate of AAAs and clinical data.

Results: TBR was not significantly different between patients with and without significant growth (1.55 ± 0.20 vs. 1.57 ± 0.14; P  = 0.5599). However, in patients with significant growth, TBR exhibited a significant positive correlation with the growth rate ( r 2  = 0.2601, P  = 0.0306). TBR also exhibited a significant difference between patients with and without intervention ( P  = 0.0228).

Conclusion: FDG uptake of AAA is associated with long-term growth of AAAs in a specified group that exhibits growth. FDG PET/CT may only be effective in predicting the long-term growth of AAAs in specific subgroups of patients. It is also suggested that FDG PET is potentially related to the clinical conditions of AAA patients who need surgical or interventional treatment.