Maximilian De Bucourt MD, Presenter: Nothing to Disclose

Anja Weiss MSC, Abstract Co-Author: Nothing to Disclose

Ulf Karl Martin Teichgraeber MD, Abstract Co-Author: Nothing to Disclose

Marion Hanel, Abstract Co-Author: Nothing to Disclose

Patrick Alexander Hein MD, Abstract Co-Author: Nothing to Disclose

To investigate a monophasic computed tomography angiography (CTA) protocol using a pre-bolus injection technique in order to visualize stent graft lumen and endoleak after aortic endovascular aneurysm repair (EAR).

Out of 162 patients referred for CTA after aortic endovascular aneurysm repair over a 2 year time period including 62 patients with presence of an endoleak, 18 patients (mean age 66.4; min 47, max 81; 15 men, 3 women) met the following study inclusion criteria: Constant endoleak size and all of the CT protocols were used at least once during follow-up imaging: A monophasic (C1) and a biphasic (C2.1 and C2.2; second acquisition after 30 seconds) CTA, each with single bolus injection of 120 mL contrast medium, as well as a single acquisition CTA using a pre-bolus (PB; 60 mL) followed by injection of further 60 mL contrast medium after 60 seconds delay. In all CTA examinations the same contrast material (350 mmol/L iodine) was injected at a flow rate of 3.5 mL/s. All CTA scans were started manually using a bolus tracking technique. Attenuation was measured using a region of interest within the aortic lumen proximal to the stent prosthesis (Ao) and within the endoleak itself (EL).

Mean attenuation within Ao ranged between 200 HU (C2.2) and 313 HU (C2.1) and within EL between 172 HU (C2.2) and 235 HU (C2.1). Attenuation difference between Ao (C1) and Ao (PB) as well as between Ao (C2.1) and Ao(PB) was not statistically significant. Attenuation between Ao(C2.2) and Ao(PB) differed significantly (t-test; p = .0004) with greater HU values for PB. Attenuation between EL (C1), EL (C2.1) and EL (C2.2) each compared to EL (PB) was not statistically significant. The attenuation difference between Ao and EL was largest in PB (mean 90 HU), followed by C1, C2.1 and C2.2 (mean HU 81, 78 and 28, respectively), reaching statistical significance solely for the comparison of protocol PB vs. C2.2. (p = .0027).

The investigated pre-bolus CTA protocol after aortic EAR combines late phase attenuation of a biphasic image acquisition protocol for endoleak visualization and concomitant high opacification of the stent lumen without exposing the patient to radiation twice, due to single phase scanning.

CT units using a biphasic CTA protocol for follow-up of constant size endoleaks after aortic EAR may consider using a pre-bolus protocol instead.

De Bucourt, M, Weiss, A, Teichgraeber, U, Hanel, M, Hein, P, Endoleak after Aortic Endovascular Aneurysm Repair: Evaluation of a Monophasic Computed Tomography Angiography (CTA) Protocol Using a Prebolus.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9006632.html