Purpose: To investigate a single-acquisition computed tomographic angiography (CTA) protocol using a prebolus injection technique to visualize the stent-graft lumen and endoleak after endovascular aneurysm repair (EVAR).
Methods: Of 162 EVAR patients referred for CTA over a 2-year period, 18 (15 men; mean age 66.4 years) with an endoleak met the study inclusion criteria, which included constant endoleak size and scans using 3 different CT protocols at least once during follow-up: monophasic CTA (C1), biphasic CTA (C2.1 and C2.2), and single-acquisition CTA using a prebolus (PB). All CTA examinations were performed with the same overall volume of contrast medium (120 mL) and were started manually using a bolus-tracking technique. Attenuation was measured within the aortic lumen proximal to the stent prosthesis (Ao) and within the endoleak itself (EL).
Results: Mean attenuation ranged between 200 (C2.2) and 313 HU (C2.1) within Ao and between 172 (C2.2) and 235 HU (C2.1) within the endoleak. The attenuation differences between Ao (C1) and Ao (PB), as well as between Ao (C2.1) and Ao (PB), were not statistically significant, while the attenuations of Ao (C2.2) and Ao (PB) differed significantly (p<0.001), with higher attenuation in PB. Compared to EL (PB), none of the mean EL attenuation values (C1, C2.1, and C2.2) differed significantly.
Conclusion: This prebolus CTA protocol combines late-phase attenuation of a biphasic image acquisition protocol for endoleak visualization with high opacification of the stent lumen without exposing the patient to radiation twice.