Utility of four-dimensional computed tomography scan following endovascular aneurysm repair

The aim of this study was to investigate whether post-EVAR endoleak that cannot be diagnosed accurately by conventional computed tomography (CT) and color Doppler ultrasonography can be diagnosed using four-dimensional (4D)-CT.

A total of 461 patients that received endovascular aortic repair (EVAR) between 2011 and 2022 were included. From 2017, 4D-CT was done to post-EVAR patients with enlarged aneurysms that could not be explained by conventional CT or ultrasound results. The results of 4D-CT, whether or not additional treatment was performed, and clinical course over 6 months and 12 months after 4D-CT were retrospectively investigated.

Among post-EVAR cases that were followed up by CT, enlarged aneurysm was observed in 75 cases (16.3%), of which 27 (36%) could not be diagnosed accurately by conventional methods and underwent 4D-CT. 4D-CT enabled classification of endoleaks in 20 cases (74.1%; 1 [5.0%] type I; 1 [5.0%] type Ib; 12 [60.0%] type II; and 10 [50.0%] type IIIb; 1 [5.0%] type Ia and type II overlap, and 4 [20.0%] type II and type IIIb overlap]. Nineteen cases consented to additional treatment; nine (47.4%) underwent re-EVAR, seven (36.8%) underwent transarterial embolization (TAE), and three (15.8%) underwent re-EVAR and TAE. Of the cases that underwent additional treatment based on 4D-CT results, there were no perioperative deaths, and two (10.5%) aorta-related late deaths. Seventeen cases could be followed up, of which interruption of aneurysm enlargement was observed in 14 cases (82.4%).

4D-CT allowed for classification of endoleaks that were previously difficult to determine by conventional diagnostic measures. It was useful especially for the diagnosis of type IIIb endoleaks and cases with multiple simultaneous endoleaks. The cases that underwent additional treatment based on the results of 4D-CT showed positive clinical outcomes, further supporting the accuracy of 4D-CT.