Inflammation and the absence of edema in the abdominal aortic aneurysm as determined by T2-weighted cardiovascular magnetic resonance imaging

Abstract

Objective: The non-specific abdominal aortic aneurysm (AAA) is a local manifestation of a systemic disease, in which inflammation may play a role. This cardiovascular magnetic resonance (CMR) study utilizes a water-sensitive, T2-
weighted, short tau inversion recovery sequence (T2-STIR) to identify vessel wall edema as a marker for inflammation.

Methods: Twenty-two patients were included: 10 AAA patients, 10 healthy subjects, and two patients with known inflammation. MR T2-STIR images of aorta vessel wall and intraluminal thrombi were analyzed using OSIRIX software.  Signal intensity values were normalized, and values from blinded and independent viewers were then averaged and analyzed using SPSS statistical software. The Kruskal-Wallis H test was used with post hoc analysis for differences of significance.

Results: Average AAA anterior-posterior diameter was 5.9 ± 0.6cm (range, 5.3-7.0cm). The Kruskal-Wallis H test revealed a significant difference between independent samples (H(3) = 20.36, P < .001). There was no significant difference in average intensities between AAA and healthy subjects (P = .766).

Conclusion: This is the first study to examine edema in walls and thrombi of AAAs using T2-STIR imaging. No evidence of edema was identified in the aortic aneurysm wall, suggesting a lack of inflammatory activity.