Clinical significance of endoleak detected on follow-up CT after endovascular repair of abdominal aortic aneurysm

OBJECTIVE. The purpose of this study was to evaluate the clinical significance of endoleaks detected on combined arterial and delayed contrast-enhanced follow-up CT examinations of patients who have undergone endovascular aneurysm repair of abdominal aortic aneurysm. MATERIALS AND METHODS. One hundred forty-four patients underwent periodic follow-up CT examinations 12-72 months after abdominal aortic aneurysm repair. The CT protocol consisted of an unenhanced scan and contrast-enhanced scans in the arterial and 90-second delayed phases. The endoleaks detected on dual-phase CT scans were evaluated in association with the outcome (therapeutic intervention or endoleak resolution). RESULTS. The 144 patients underwent 728 CT examinations with a mean follow-up period of 35.5 ± 14.5 months. Fifty endoleaks were detected in 50 (34.7%) of the patients. Eight endoleaks were detected in the arterial phase only, eight in the delayed phase only, and 34 in both phases. Intervention was performed to manage 16 endoleaks detected in both phases. CT showed that three endoleaks were stable (two in the arterial phase only and one in both phases) and that 31 had resolved completely (six in the arterial phase only, eight in the delayed phase only, and 17 in both phases). This finding represents a higher frequency of resolution of endoleaks detected in one phase only than in both phases (Fisher's exact test, p = 0.006). CONCLUSION. Endoleaks detected only in the delayed phase of CT had resolved spontaneously without intervention. Therefore, we can consider eliminating the delayed phase of acquisition to minimize radiation exposure.