Intravenous C-Arm Conebeam CT Angiography following Long-Term Flow-Diverter Implantation: Technologic Evaluation and Preliminary Results

BACKGROUND AND PURPOSE: A noninvasive investigation with high spatial resolution and without metal artifacts is necessary for long-term imaging follow-up after flow-diverter implantation. We aimed to evaluate the diagnostic value of conebeam CT angiography with intravenous contrast enhancement in the assessment of vascular status following implantation of the Pipeline Embolization Device and to analyze the preliminary results of vascular status following long-term Pipeline Embolization Device implantation. MATERIALS AND METHODS: This was an ongoing prospective study of consecutive patients with intracranial aneurysms treated with the Pipeline Embolization Device. Patients with a modified Rankin Scale score of 4-5 were excluded. The median and interquartile range of the time interval of Pipeline Embolization Device implantation to conebeam CT angiography with intravenous contrast enhancement were 56.6 and 42.9-62.4 months, respectively. Conebeam CT angiography with intravenous contrast enhancement was performed with the patient fully conscious, by using a C-arm CT with a flat panel detector. RESULTS: There were 34 patients and 34 vascular segments. In all 34 cases, contrast effect and image quality were good and not substantially different from those of intra-arterial conebeam CTA. Metal artifacts occurred in all 14 cases with coil masses; the Pipeline Embolization Device was obscured in 3 cases. In all 34 cases, there was no residual aneurysm, no vascular occlusion, 1 vascular stenosis (50%), good Pipeline Embolization Device apposition to the vessel, and no Pipeline Embolization Device-induced calcification. All 28 Pipeline Embolization Device-covered side branches were patent. CONCLUSIONS: Conebeam CT angiography with intravenous contrast enhancement is potentially promising and useful for effective evaluation of the vascular status following intracranial flow diverters. The Pipeline Embolization Device for intracranial aneurysms is probably safe and promising for long-term placement, with favorable morphologic outcome and without delayed complications.