Inter-modality correlation across invasive and noninvasive angiography in the three-dimensional assessment of...

Non-invasive and invasive methods of cerebral angiography, including computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA), are commonly used to characterize and follow cerebral aneurysms. Prior work has validated two-dimensional size measurements across these modalities. Our study aims to compare the reliability of three-dimensional (3D) shape measurements across CTA, MRA, and DSA.

A subset of cerebral aneurysms in which more than one form of angiography was performed was selected. Aneurysms were included if they did not change in size or shape between angiographic studies. Aneurysm domes were segmented, and morphometric features were measured consistent with prior reports. Intraclass correlation coefficients (ICCs) for each morphometric measure were calculated using a two-way mixed effect model.

A total of 65 individual aneurysms from 55 patients were included in the study. The majority of aneurysms were imaged with DSA and CTA (43%) or MRA and CTA (40%), with 14% having DSA, MRA, and CTA available for review. The majority of aneurysms were located in the anterior circulation (77%), with an average size was 5 (4-8) mm. ICC ranged from 0.66 to 0.99 for 3D morphometric features, corresponding to "moderate" to "excellent" correlation. Sphericity and non-sphericity index showed the lowest ICC values. With the exception of these two variables, 3D morphometrics showed "good" or "excellent" reliability. No significant difference in mean absolute difference was noted across imaging modalities for each morphometric feature.

The majority of 3D morphometric measures show "good" to "excellent" reliability across CTA, MRA, and DSA, allowing for comparison across imaging modalities.