Automated neck-plane positioning on rotational angiography for intracranial aneurysm quantification

BACKGROUND AND PURPOSE: The precise three-dimensional (3D) mapping of cerebral aneurysms is crucial for treatment planning. However, traditional methods utilizing 2D digital subtraction angiography with manual cutting planes (MCP) are operator-dependent and often fail to capture the 3D geometry of complex aneurysms. MATERIALS AND METHODS: We evaluated an automated cutting plane (ACP) that isolates aneurysm necks from 3D rotational-angiography meshes, using all 112 aneurysms (99 meshes) of the public AneuRisk dataset. ACP was compared with a single-rater 2D MCP and a reference set of four independent 3D MCPs, using the average inter-curve distance (AICD) of the neck contour and the volumetric error. RESULTS: At the aneurysm level, ACP neck contours agreed with the reference within 1 mm in 90.2% of aneurysms (median AICD 0.36 mm), similar to inter-rater agreement (0.32 mm, 93.8%; paired Wilcoxon p = 0.39); the single-rater 2D MCP agreed within 1 mm in 83.9% (median AICD 0.35 mm). Using a relative difference (difference from the mean of four 3D MCP volumes), the median ACP volumetric error was -1.03% (IQR -4.62% to 0.48%; Wilcoxon p < 0.001), with 74% within 5% error and a heavier negative tail (5th percentile -28.1%). CONCLUSIONS: The ACP achieves neck-contour agreement comparable to inter-rater agreement and a small median aneurysm-volume error, though a minority of complex aneurysms are underestimated. It could serve as a human-in-the-loop first-pass proposal that the operator verifies.