3D Volume Rendering of Ultrahigh-Resolution Photon-Counting Detector CT Angiography for Preoperative Assessment of Intracranial Aneurysms: Initial Experience.

Abstract

Three-dimensional volume rendering (3DVR) enables the detailed visualization of complex vascular anatomy. However, the utility of combining ultrahigh-resolution (UHR) photon-counting detector CT angiography (PCD-CTA) with 3DVR post-processing for preoperative intracranial aneurysm assessment has not yet been evaluated. This study explored whether combining UHR PCD-CTA with 3DVR post-processing provides reliable morphologic assessment and reproducible size measurements in the preoperative evaluation of intracranial aneurysms. In this retrospective study of 32 aneurysms in 21 patients, two neurosurgeons evaluated 2D UHR and 3DVR datasets. Image quality, aneurysm characterization, and clinical usefulness were subjectively rated via questionnaire, while inter-modality and inter-reader agreement for dome and neck dimensions were assessed using intraclass correlation coefficients (ICC) and Bland-Altman analysis. Image quality and clinical usefulness of 3DVR images were rated as excellent. Agreement between 2D-CTA and 3DVR was good for both dome (ICC = 0.83, 95% CI 0.66-0.92, p<0.01) and neck size (ICC = 0.82, 95% CI 0.59-0.92, p<0.01). Inter-reader reliability on 3DVR reconstructions was moderate for dome (ICC = 0.74, 95% CI 0.52-0.87, p<0.01) and neck size (ICC = 0.55, 95% CI 0.23-0.76, p<0.01). Bland-Altman analysis demonstrated a small systematic underestimation on 3DVR, with measurement variability numerically greater between readers than between imaging approaches. In conclusion, UHR PCD-CTA-based 3DVR provides high-quality visualization of intracranial aneurysms with good agreement compared with 2D UHR CTA measurements. These findings support the technical feasibility and reproducibility of this approach, though reader-related factors may influence measurement differences.