Predictive Value of CT Perfusion in Spatially and Volumetrically Identifying Ischemic Penumbra Against Final Infarct Size in Anterior Circulation Stroke With and Without Successful Reperfusion.

Abstract

Background and purpose: CT perfusion is important for acute ischemic stroke imaging and treatment, but defining the ischemic penumbra and infarct core remains debated. This study examined the relationship between initial hypoperfused tissue and final infarct in acute anterior circulation occlusion patients, stratified by reperfusion status, to assess CT perfusion's predictive spatial and volumetric accuracy and re-evaluate its role in prognostication, nuanced clinical decision making, and novel pathophysiology research in the new large core era.

Materials and methods: This retrospective single-center study included patients diagnosed with anterior circulation acute ischemic stroke who underwent CT perfusion between 05/2021-02/2024. Initial imaging and follow-up non-contrast head CT scans were automatically co-registered. CT perfusion-derived ischemic core and penumbra segmentations were compared to manually segmented final infarcts on follow-up imaging. Groups with (endovascular thrombectomy [EVT] with modified Treatment in Cerebral Infarction score ≥ 2b) and without successful reperfusion (no or unsuccessful EVT) were compared using the Dice similarity coefficient for spatial alignment and Spearman correlation for volumetric agreement.

Results: One hundred twenty-one patients were included (51% males, median age: 70 years, median NIHSS score: 14). Successful reperfusion was achieved in 37 patients, while 84 received no or unsuccessful EVT. Significant differences in regions of hypoperfusion were observed between the non-reperfusion and reperfusion groups concerning spatial alignment (median Dice similarity coefficient:0.52 vs. 0.29, P < 0.001) and volumetric agreement (Spearman correlation between predicted and actual infarct volumes: 0.72 vs. 0.07, P < 0.001).

Conclusions: CT perfusion offers valuable insights into salvageable tissue in acute ischemic stroke, guiding treatments, predicting infarct volumes, aiding in future stroke pathophysiology research in the large core era, and potentially improving prognostication.

Abbreviations: EVT = Endovascular Thrombectomy; IQR = Interquartile Range; mTICI = modified Thrombolysis In Cerebral Infarction; rCBF = relative Cerebral Blood Flow.