Visualization of flow diverter stent wall apposition during intracranial aneurysm treatment using a virtually diluted...

Flow diverters (FD) have poor radiopacity, challenging visualization of deployment and vessel wall apposition with conventional neuroimaging modalities. We evaluated a novel cone beam computed tomography (CT) imaging technique that allows virtual dilution (VD) of contrast media to facilitate workflow and ensure accurate assessment of FD wall apposition.

We retrospectively evaluated all patients treated for intracranial aneurysms with FD at our institution between November 2018 and November 2019. Undiluted injected dual cone beam CT acquisitions performed post-stenting were displayed with VD software (GE Healthcare). The resulting images were compared with conventional two-dimensional (2D) digital subtraction angiography (DSA) images. Two neurointerventionalists (Reader 1 and Reader 2, (R1, R2)) independently assessed FD deployment and wall apposition. Confidence in the diagnosis, inter-reader agreement, and X-ray exposure were assessed.

A total of 27 cases were reviewed. FD deployment and wall apposition scores were 4.2 ± 1.0 (R1) and 4.0 ± 1.1 (R2) for DSA and 3.7 ± 1.2 (R1) and 4.1 ± 1.0 (R2) for VD. Confidence in the diagnosis was improved with VD, with scores of 3.7 ± 0.7 (R1) and 4.0 ± 0.7 (R2) using DSA and 4.9 ± 0.2 (R1) and 4.9 ± 0.2 (R2) using VD (P < 0.001). Inter-reader agreement using 2D DSA was improved from moderate (0.49324) to good (0.7272) (P < 0.0001). There were no significant differences in inter-reader agreement in the deployment assessment (P = 0.68) or dose-area product (P = 0.54) between techniques.

VD imaging with dual cone beam CT enables accurate assessment of FD wall apposition after deployment with greater confidence and improved inter-reader agreement versus conventional 2D DSA alone, with comparable X-ray exposure.