Discrepancies in Vessel Diameter Measurements Between CTA and DSA in MCA M1 Occlusions: An Interobserver Study

Area of Science:

• Neurology
• Vascular Imaging
• Interventional Neuroradiology

Background:

• Accurate vessel diameter measurement is critical for endovascular thrombectomy (EVT) in acute ischemic stroke.
• Discrepancies between computed tomography angiography (CTA) and digital subtraction angiography (DSA) can impact procedural planning and device selection.

Purpose of the Study:

• To compare vessel diameter measurements of the middle cerebral artery (MCA) M1 segment between CTA and DSA in patients undergoing EVT.
• To assess the impact of imaging modality on vessel sizing for stroke intervention.

Main Methods:

• Retrospective analysis of 90 patients with MCA M1 occlusions undergoing EVT.
• Independent measurements of M1 vessel diameters by three neuroradiologists using CTA and DSA (pre- and post-intervention).
• Statistical analysis included Wilcoxon signed-rank tests, ICC, and Bland-Altman analysis.

Main Results:

• CTA consistently overestimated M1 diameter compared to DSA (mean difference +0.13 mm).
• CTA values exceeded DSA in 70% of cases, with a median difference of 0.4 mm.
• Good inter-rater agreement (ICC = .785) was observed; no significant change in DSA measurements pre- vs. post-EVT.

Conclusions:

• CTA tends to overestimate MCA M1 diameter relative to DSA.
• This modest discrepancy may influence device selection in borderline cases for EVT.
• Awareness of CTA-DSA variability is crucial for optimizing stroke treatment planning.