Quantification of aortic distensibility in abdominal aortic aneurysm using ECG-gated multi-detector computed tomography

Rationale and objectives To detect distensibility changes that might be an indicator for an increased risk of rupture, cross-sectional area changes of abdominal aortic aneurysms (AAA) have been determined using ECG-gated CT. Materials and methods Distensibility measurements of the aorta were performed in 67 patients with AAA. Time-resolved images were acquired with a four detector-row CT system using a modified CT-angiography protocol. Pulsatility-related cross-sectional area changes were calculated above and at AAA level by semiautomatic segmentation; distensibility values were obtained using additional systemic blood pressure measurements. Values were compared for small Ø< 5 cm (n=44) and large Ø> 5 cm (n = 23) aneurysms. Results The aorta could be segmented successfully in all patients. Upstream AAA distensibility D was significantly higher than at AAA level for both groups: means above AAA (at AAA) D above = (1.3±0.8)·10 −5 Pa −1 ( D AAA = (0.6±0.5)·10 −5 Pa −1 ) t-test p D