Evaluation of Abdominal Aortic Aneurysm (AAA) endoleak after Endovascular Abdominal Aortic Repair (EVAR) by FDG PET/CT

Objectives There has been a significant increase in the endovascular aortic repair (EVAR) procedures in the recent years. One of the known complications of this procedure is endoleak which represents 15-25% of EVARs. Endoleak is considered the main cause of rupture after the procedure. The aim of this study is to evaluate the vulnerability of the patients with AAA who underwent EVAR procedure to vascular rupture and develop endoleak using FDG PET/CT.

Methods Total of 54 patients in four groups were included in this study (15 controls, 15 with AAA, 14 with EVAR, and 10 with endoleak after EVAR). PET/CT images were acquired in all patients. In the AAA, EVAR and endoleak patients the volume covered the aneurysm sac. In control it covered the infra-renal aorta to aortic bifurcation. Regions of interest were drawn on the Cross-sectional images encirculating the entire circumference of aorta, in all groups. The SUVmean and SUVmax were measured and compared between the groups.

Results In the control group, the mean SUVmax was 1.07±0.40 (range 0.82 - 1.76 ±0.40) and the mean SUVmean was 0.70±0.20 (range 0.49 - 1.2 ±0.20). In the AAA group, the mean SUVmax was 1.71±0.55 (range 1.04 - 2.66 ±0.55) and the mean SUVmean was 0.89±0.27 (range 0.49 - 1.44 ±0.27). In the post EVAR group, the mean SUVmax was 1.59±0.38 (range 0.78 - 1.91 ±0.38) and the mean SUVmean was 0.71±0.24 (range 0.29 - 1.18 ±0.24). For the endoleak group, the mean SUVmax was 1.43±0.42 (range 0.98 - 2.25 ±0.42) and the mean SUVmean was 0.69±0.21 (range 0.44 - 1.23 ±0.21). By comparing the groups, there was a significant difference between controls and AAA in SUVmax (p<0.0015) and SUVmean (p<0.0468). In addition, there was a significant difference between controls and EVAR group in SUVmax (p<0.0021) but not in the SUVmean. There is no significant difference between the other groups in both SUVmax and SUVmean. Interestingly, there is no significant difference in SUVmax and SUVmean between the controls and endoleak group in our study population.

Conclusions Our results show no strong correlation between the FDG activity in the abdominal aortic aneurysm and endoleak development. Larger sample size and measuring other parameters (e.g. heterogeneity) along with SUVmax and SUVmean is recommended for better evaluation.