Abstract Body: Introduction: Pretreatment CT Perfusion (CTP) marker relative cerebral blood volume (rCBV) <42% lesion volume has recently been shown to predict poor collateral status (CS), infarct volume, and unfavorable 90-day functional outcomes. However, there are no studies assessing its association with hemorrhagic transformation (HT). This study aims to evaluate the relationship between rCBV <42% volume and HT.

Patients and Methods: This retrospective study included patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO) in the anterior circulation who achieved successful recanalization at two comprehensive stroke centers between September 1, 2017, and October 1, 2023. Successful recanalization was defined as modified treatment in cerebral infarction (mTICI) ≥ 2b. Logistic regression and ROC analysis were used to assess the relationship between rCBV <42% and HT.

Results: A total of 150 patients (median age: 69 years) met the inclusion criteria. Multivariable logistic regression analysis, accounting for age, sex, hypertension, hyperlipidemia, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, and intravenous thrombolysis, revealed that rCBV <34% (aOR: 1.01, p<0.05), rCBV <38% (aOR: 1.01, p<0.05), and rCBV <42% (aOR: 1.01, p<0.05) volumes were independently associated with HT. ROC analysis showed that rCBV <42% (AUC = 0.61, p<0.05) performed slightly better than rCBV <38% (AUC = 0.59, p<0.05) and rCBV <34% (AUC = 0.59, p<0.05) in predicting HT. In contrast, commonly used CT perfusion markers, such as rCBF <30% and Tmax >6s volumes, did not show significant associations with HT.

Discussion: Our results further validate the role of rCBV <42% as a poor prognostic biomarker for HT in anterior circulation LVO cases that achieved successful reperfusion following mechanical thrombectomy (MT). The risk of HT is higher in large core cases post-MT. Given the increasing interest in performing MT in AIS-LVO cases regardless of core size and collateral status, following recent successes in large-core trials, CTP markers like rCBV <42% could serve as valuable prognostic indicators for predicting HT.

Conclusion: The rCBV <42% lesion volume is independently and negatively associated with HT in successfully reperfused AIS-LVO patients.