A significant decrease of cerebral blood flow (CBF) is a risk factor for hemorrhagic transformation (HT) in acute ischemic stroke (AIS). This study aimed to ascertain whether the ratio of different CBF thresholds derived from computed tomography perfusion (CTP) is an independent risk factor for HT after mechanical thrombectomy (MT). A retrospective single center cohort study was conducted on patients with AIS undergoing MT at the First Affiliated Hospital of Wenzhou Medical University from August 2018 to December 2023. The perfusion parameters before thrombectomy were obtained according to CTP automatic processing software. The low blood flow ratio (LFR) was defined as the ratio of brain volume with relative CBF <20 % over volume with relative CBF <30 %. HT was evaluated on the follow-up CT images. Binary logistic regression was used to analyze the correlation between parameters that differ between the two groups with regards to HT occurrence. The predictive efficacy was assessed utilizing the receiver operating characteristic curve. In total, 243 patients met the inclusion criteria. During the follow-up, 46.5 % of the patients (113/243) developed HT. Compared with the Non-HT group, the HT group had a higher LFR (0.47 (0.34–0.65) vs. 0.32 (0.07–0.56); < 0.001). According to the binary logistic regression analysis, the LFR (aOR: 6.737; 95 % CI: 1.994–22.758; = 0.002), Hypertension history (aOR: 2.231; 95 % CI: 1.201–4.142; = 0.011), plasma FIB levels before MT (aOR: 0.641; 95 % CI: 0.456–0.902; = 0.011), and the mismatch ratio (aOR: 0.990; 95 % CI: 0.980–0.999; = 0.030) were independently associated with HT secondary to MT. The area under the curve of the regression model for predicting HT was 0.741. LFR, a ratio quantified via CTP, demonstrates potential as an independent risk factor of HT secondary to MT.

中文翻译：

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低血流比与急性缺血性脑卒中患者机械取栓继发出血转化相关

脑血流量（CBF）显着减少是急性缺血性卒中（AIS）发生出血性转化（HT）的危险因素。本研究旨在确定计算机断层扫描灌注 (CTP) 得出的不同 CBF 阈值的比率是否是机械血栓切除术 (MT) 后发生 HT 的独立危险因素。对2018年8月至2023年12月在温州医科大学附属第一医院接受MT的AIS患者进行回顾性单中心队列研究。根据CTP自动处理软件获取取栓前的灌注参数。低血流比（LFR）定义为相对CBF<20%的脑体积与相对CBF<30%的脑体积之比。根据后续 CT 图像评估 HT。使用二元逻辑回归分析两组之间关于 HT 发生的不同参数之间的相关性。利用受试者工作特征曲线评估预测功效。总共有 243 名患者符合纳入标准。随访期间，46.5%的患者（113/243）出现HT。与非 HT 组相比，HT 组的 LFR 较高（0.47 (0.34–0.65) vs. 0.32 (0.07–0.56)；< 0.001）。根据二元 Logistic 回归分析，LFR（aOR：6.737；95 % CI：1.994–22.758；= 0.002）、高血压病史（aOR：2.231；95 % CI：1.201–4.142；= 0.011）、治疗前血浆 FIB 水平MT（aOR：0.641；95% CI：0.456–0.902；= 0.011）和错配率（aOR：0.990；95% CI：0.980–0.999；= 0.030）与继发于 MT 的 HT 独立相关。预测 HT 的回归模型的曲线下面积为 0.741。 LFR 是通过 CTP 量化的比率，显示出作为继发于 MT 的 HT 独立危险因素的潜力。