One scan, two answers: RAPID vs Brainomix agreement in thrombectomy patients

Background Automated CT perfusion (CTP) software is widely used to select patients with large-vessel occlusion stroke for endovascular thrombectomy (EVT), yet treatment thresholds are often applied as if outputs from different platforms are interchangeable. This study compared RAPID and Brainomix CTP outputs in the same thrombectomy cohort.

Methods We performed a retrospective observational study of patients with large vessel occlusion who underwent CTP imaging. Paired volumetric data were analyzed using both RAPID and Brainomix algorithms. Inter-platform agreement was assessed using intraclass correlation coefficients (ICC), Pearson correlation (r), and Bland-Altman analysis.

Results 328 EVT patients had complete paired outputs. Median core volumes were 4 mL (RAPID) vs 10 mL (Brainomix); median penumbra volumes 65 mL vs 80 mL. Core agreement was good (r=0.82; ICC=0.81) but showed systematic bias with wide limits of agreement. Mismatch classification agreed in 91.5%. Clinically significant core discrepancies occurred in 20.1%.

Conclusion RAPID and Brainomix correlate overall but are not interchangeable; systematic biases and wide limits of agreement can alter mismatch-based eligibility. Rigid CTP thresholds for EVT selection should be applied cautiously and integrated with broader clinical assessment.