Kamran Akram MD, Presenter: Nothing to Disclose

Gerald Mordecai Kolodny, Abstract Co-Author: Nothing to Disclose

FDG-PET is able to image active vascular inflammation. FDG uptake is seen frequently in the AAA wall suggesting active areas of inflammation with unknown clinical significance. We hypothesized that increased FDG uptake in the AAA wall predicts accelerated AAA expansion.

15 patients who had a baseline oncologic PET/CT study and a follow-up PET/CT or CT study within one year were included. The AAA size in two dimensions and SUVmax in the AAA wall on the baseline PET/CT and the AAA size on the follow-up study were recorded. A difference greater than 1 mm in size on repeated measurements in any dimension between the first and second study defined AAA size progression. ROC curve analysis and t-test were used for statistical analysis. A p-value<0.05 defined statistical significance.

9/15 (60%) had an increase (G1), 6/15 (40%) had stable (G2) AAA size. Cardiovascular risk factors were similar between the groups (Male 53%, HTN 80%, Hypercholesterolemia 60%, DM 13%, Smoker 53%, CAD or CAD equivalent 100%, Statin use 53%). Mean AAA growth in G1 was 5.1 mm/year. Mean SUVmax in the AAA wall was significantly higher for G1 compared to G2 (2.9 vs. 2.1, p=0.011). ROC analysis showed FDG uptake in the AAA wall to be an excellent test to predict AAA expansion as evidenced by an AUC=0.87. A SUVmax of 2.6 served as the best cutoff to predict AAA expansion (sensitivity 67%, specificity 100%, p<0.001). The correlation between SUVmax and degree of AAA expansion was r=0.63 (p=0.013).

This pilot study demonstrates that it may be possible to use FDG uptake in the AAA wall to predict the subsequent expansion of the aneurysm. A larger study is now underway to confirm these promising findings.

FDG uptake is frequently seen on PET/CT in AAA walls with unknown clinical significance. Our study shows that the intensity of FDG uptake in the AAA wall can significantly predict AAA growth.

Akram, K, Kolodny, G, Use of FDG Uptake in the Wall of Abdominal Aortic Aneurysms (AAA) to Predict AAA Expansion.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6013078.html