Abstract P557: Hypoperfusion Intensity Ratio and Cerebral Blood Volume Index as Predictors of Outcome for Recanalized Middle Cerebral Artery Occlusions
Introduction: Preliminary data suggest the Hypoperfusion Intensity Ratio (HIR) and the Cerebral Blood Volume Index (CBVI) derived from Computerized Tomography Perfusion (CTP) imaging predict the rate of collateral flow, speed of infarct growth, and clinical outcome. We hypothesized that functional outcomes at hospital discharge would be significantly better for middle cerebral artery (MCA) occlusion patients achieving Thrombolysis in Cerebral Infarction (TICI) 2b or greater recanalization with presenting hospital CTPs consistent with “good” (HIR <0.5 and CBVI >0.7) versus “poor” (HIR ≥0.5 and CBVI ≤0.7) indices. Methods: We conducted a retrospective cohort study. A neuroradiologist confirmed the MCA occlusion based on the initial Computerized Tomography Angiogram (CTA). All TICI scores were confirmed by neurointerventionalists blinded to patient outcomes. We defined independent outcome as mRS ≤2, and favorable outcome as an mRS ≤3. We additionally stratified patients as initially presenting to thrombectomy versus non-thrombectomy centers. Results: We identified a total of 162 patients over a 3 ½ year period with an MCA occlusion achieving TICI 2b recanalization or greater, of whom 67 had good indices and 48 had poor indices. For patients with good compared to poor indices, there was a trend for achieving independent outcome (55% vs 37%, p=0.061) that reached significance for favorable outcome (69% vs 50%, p=0.043). Limiting the analysis to only patients presenting to non-thrombectomy centers (n=67), these findings were consistent, with a trend for achieving independent outcome for good versus poor collaterals (48% vs 30% p=0.173), which was again significant for a favorable outcome (66% vs 39%, p=0.036). Across all patients, HIR <0.5 (n=86) or CBVI >0.7 (n=95) were not independently associated with independent outcomes, but for patients presenting to non-thrombectomy centers, an HIR <0.5 alone (n=51) was significantly associated with favorable outcome. Conclusion: For MCA occlusion patients achieving TICI 2b recanalization, the combination of good HIR and CBVI is significantly associated with a favorable functional outcome. For patients presenting to non-thrombectomy centers, HIR alone may be sufficient to predict favorable outcome.