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Updated: Aug 13, 2026

Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation
Published on: May 31, 2016
Macrophage-mediated inflammation and microcalcification are associated with abdominal aortic aneurysm progression and
Rachael O Forsythe1,2, Olivia M B McBride3, Jennifer M J Robson4
1Edinburgh Vascular Unit, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, United Kingdom.
Introduction:
Molecular and cellular imaging biomarkers of abdominal aortic aneurysms (AAA) show promise as potential predictors of clinical events. This study assessed long-term clinical outcomes using ultrasmall superparamagnetic particles of iron oxide (USPIO) enhanced magnetic resonance imaging (MRI; ISRCTN76413758) and fluorine-18 sodium fluoride ([18F]NaF) positron emission tomography computed tomography (PET/CT; NCT02229006).
Methods:
A prospective multi-centre co-enrolled observational cohort studies of patients with asymptomatic AAA. Evaluation of aortic wall inflammation using USPIO-enhanced MRI in 338 patients was followed by [18F]NaF PET/CT in a sub-group of 72 patients, to evaluate microcalcification. Aneurysms were classified according to aortic wall USPIO enhancement and into tertiles of [18F]NaF uptake. Aneurysm expansion, composite of rupture or repair, and overall survival were compared.
Results:
In 338 predominantly elderly (74±7.2 years) men (85%) with mean aneurysm diameter 49.5±7.3 mm, aneurysm expansion was increased in patients with USPIO enhancement (median [inter-quartile interval], 3.3 [2.0-4.6] versus 2.5 [1.4-3.6] mm/y; p=.002) or high [18F]NaF uptake (4.0 [2.6-5.4] versus 1.9 [0.9-3.0] mm/y; p<.001), even when adjusted for hypertension, smoking and baseline AAA diameter (p=.04 and p=.003). After a median follow up of 102 [58-119] months, 63% patients met the composite endpoint of rupture or repair with high [18F]NaF uptake associated with more than two-fold higher risk (72% versus 36%; log rank p=.002). There was no association between USPIO enhancement and future rupture or repair.
Conclusions:
Aortic wall USPIO enhancement and [18F]NaF uptake are independently associated with AAA expansion. These non-invasive imaging biomarkers provide an opportunity to identify those are at greatest risk of AAA progression and may help inform further research to determine optimal surveillance intervals.
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