What is the relationship between super(18)F-FDG aortic aneurysm uptake on PET/CT and future growth rate?

• Published in: European journal of nuclear medicine and molecular imaging 2011-08, Vol.38 (8), p.1493-1499
• Main Authors: Kotze, Carl W, Groves, Ashley M, Menezes, Leon J, Harvey, Richard, Endozo, Raymondo, Kayani, Irfan A, Ell, Peter J, Yusuf, Syed W
• Format: Article
• Language: English
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-011-1799-8

Purpose: In this study we investigate the relationship between super(18)F-fluorodeoxyglucose (FDG) metabolism and future aneurysm expansion measured by serial duplex ultrasound. Current screening programmes are increasing the identification of patients with abdominal aortic aneurysm (AAA). The management of these patients remains challenging and methods of risk stratification are sought. Methods: Thirty-four consecutive patients [31 men, 3 women, median age 75 years, interquartile range (IQR) 71-78] with aortic aneurysms under routine surveillance with serial ultrasound were prospectively recruited for super(18)F-FDG positron emission tomography (PET)/CT. A whole vessel type analysis was performed measuring the highest aortic wall super(18)F-FDG uptake (standardized uptake value or SUV sub(max)), and target to background ratio (TBR) for each axial image and median SUV sub(max) and TBR value were calculated. Institutional Review Board permission and informed patient consent were obtained. Results: Nine patients failed to undergo 12-month follow-up study (deceased n=2, withdrew n=1, failed to attend ultrasound scan n=5, emergency aneurysm repair n=1) leaving 25 patients for analysis. The median whole vessel SUV sub(max) was 1.70 (IQR 1.45-2.08). The median whole vessel TBR was 1.15 (IQR 1.00-1.40). The median aneurysm expansion at 12 months was 2.0 mm (IQR 0.5-5.0). The correlation (r) between super(18)F-FDG SUV sub(max) and ultrasound expansion at 1 year was -0.501 (p=0.011). Conclusion: The preliminary findings from this observational longitudinal pilot study suggest that there is an inverse trend between super(18)F-FDG uptake on PET and future AAA expansion. Aortic aneurysms with lower metabolic activity may therefore be more likely to expand.