Usefulness of Cone Beam Intra-Arterial CTA for Evaluation of Flow Diverters: A Practical Approach for Daily Use

Cone beam computed tomography (CBCT), initially used for evaluation of intraprocedural complications such as hemorrhage, has evolved to provide details of implanted devices such as flow diverters. The study aim is to present our experience in using CBCT with intra-arterial injection and provide a step-by-step approach for postprocessing in a practical protocol for daily use. IRB approval was obtained, and the neurointerventional database was retrospectively reviewed from July 2012 to June 2017. Patients who underwent cone beam intra-arterial CT angiography for evaluation of implanted flow diverter devices were reviewed. Patient demographics, aneurysm location (internal carotid artery [ICA]-cavernous, ICA-paraclinoid, and ICA-distal; middle cerebral artery [MCA], anterior cerebral artery [ACA]-acom, ACA-pericallosal, vertebral artery [VA]), type (saccular, dissecting fusiform, or blister) and size, device, injection technique (contrast dilution, rate, and volume), and reconstruction protocol were recorded. Acquired images were postprocessed using a Philips Xtravision workstation. Eighty patients (63 women and 17 men) met the inclusion criteria of our study. Age range was 25-80 years old. Treated aneurysms were located in the ICA-paraclinoid in 48 cases (60%), ICA-distal in 12 cases, ICA-cavernous in 8 cases, MCA in 4 cases, VA in 4 cases, ACA-acom in 2 cases, ACA-pericallosal in 2 cases; 69 were saccular, 8 fusiform, and 3 ruptured blister aneurysms. There were 52 small, 20 large, and 8 giant aneurysms. Pipeline (Medtronic, MN, USA) was the predominant device used in 77 procedures. Two injection techniques were used: 2.5 mL/s for a total volume of 55 mL with a 2-s imaging delay or 3 mL/s for a total volume of 70 mL with a 3-s imaging delay; contrast (Ioxilan 300 mgI/mL) dilution was 10-20% in all cases. The device's landing zones, conformability, presence of deformities, and wall apposition were successfully visualized in all cases. Metal artifact reduction program was applied in 9 coiled aneurysms, and this was satisfactory as well.