Application of High-Resolution Flat Detector Computed Tomography in Stent Implantation for Intracranial Atherosclerotic Stenosis

OBJECTIVE: To evaluate the utility of high-resolution flat-detector computed tomography (HR-FDCT) compared with conventional flat-detector computed tomography (FDCT) for stent placement in symptomatic intracranial atherosclerotic stenosis (ICAS). METHODS: We retrospectively reviewed the clinical data of 116 patients with symptomatic ICAS who underwent stent implantation. Images were acquired using conventional FDCT [voxel size = 0.43 mm (isotropic)] and HR-FDCT [voxel size = 0.15 mm (isotropic)]. Immediately after stent deployment, dual-volume three-dimensional (3D) fusion images were obtained from 3D digital subtraction angiography (DSA) and HR-FDCT. The image quality for stent visualization was graded from 0 to 2 (0: not able to assess; 1: limited, but able to assess; 2: clear visualization), and the stent-expansion status (“full,” “under-expanded” or “poor apposition”) was recorded. RESULTS: A total of 116 patients with symptomatic ICAS were treated successfully using 116 stents (58 Neuroform(TM) EZ, 42 Enterprise(TM), and 16 Apollo(TM)). The mean pre-stent stenosis was 80.5 ± 6.4%, which improved to 20.8 ± 6.9% after stenting. Compared with FDCT, HR-FDCT improved visualization of the fine structures of the stent to improve the image quality that significantly (mean score: 1.63 ± 0.60 vs. 0.41 ± 0.59, P < 0.001). In 19 patients, stent under-expansion (n = 11) or poor apposition (n = 8) was identified by HR-FDCT but not by conventional FDCT. After balloon dilatation, stent malapposition was shown to have improved on HR-FDCT. None of the 19 patients with stent malapposition experienced short-term complications during hospitalization or had in-stent stenosis at 6-month follow-up. CONCLUSION: High-resolution flat-detector computed tomography (HR-FDCT) improves visualization of the fine structures of intracranial stents deployed for symptomatic ICAS compared with that visualized using conventional FDCT. High-resolution flat-detector computed tomography improves assessment of stent deployment and could reduce the risk of complications.