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Discrepancies in Vessel Diameter Measurements Between CTA and DSA in MCA M1 Occlusions: An Interobserver Study
Patrick Rogers1, Ellen Parker2, Marco Marangoni1
1Department of Diagnostic Imaging, Dalhousie University, Halifax, NS, Canada.
Insights
Computed tomography angiography (CTA) overestimates middle cerebral artery (MCA) M1 vessel diameter compared to digital subtraction angiography (DSA). This difference, though small, may affect device selection during endovascular thrombectomy (EVT) for stroke.
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.
Purpose:
Accurate vessel measurement is essential in endovascular thrombectomy (EVT) for acute ischemic stroke. Discrepancies between computed tomography angiography (CTA) and digital subtraction angiography (DSA) may impact procedural planning and device selection. This study compares vessel diameter measurements from CTA and DSA in patients with middle cerebral artery (MCA) M1 occlusions.
Methods:
In this single-center retrospective study, 90 consecutive patients who underwent EVT for MCA M1 occlusions between February 2020 and March 2024 were included. Vessel diameters were independently measured by 3 neuroradiologists using CTA and DSA (pre- and post-intervention). Statistical analysis included Wilcoxon signed-rank tests, intraclass correlation coefficient (ICC), and Bland-Altman analysis.
Results:
CTA consistently overestimated vessel diameter compared to DSA. The mean M1 diameter was 2.29 ± 0.27 mm on CTA and 2.16 ± 0.30 mm on pre-EVT DSA (P < .001), with a median difference of 0.4 mm (IQR: 0.2-0.6 mm). In 70% of cases, CTA values exceeded DSA. Bland-Altman analysis confirmed a mean difference of +0.13 mm (limits of agreement: -0.25 to +0.51 mm). No significant change was observed between pre- and post-EVT DSA measurements (P = .103). Clot-side M1 segments were significantly smaller than contralateral measurements on CTA (P = .003). Inter-rater agreement was good (ICC = .785).
Conclusions:
CTA overestimates MCA M1 diameter relative to DSA. While the discrepancy is modest, it may influence device selection in borderline cases. Awareness of this variability is important, and further research is warranted to explore its clinical implications.
