Izawa Daisuke, Matsumoto Hiroyuki, Nishiyama Hirokazu, Toki Naotsugu, Nakao Naoyuki
Department of Neurological Surgery, Kishiwada Tokushukai Hospital, Kishiwada, Osaka, Japan.
Department of Neurological Surgery, Wakayama Medical University, Wakayama, Wakayama, Japan.
J Neuroendovasc Ther. 2021;15(9):574-582. doi: 10.5797/jnet.oa.2020-0100. Epub 2021 Jan 14.
Early recanalization of acute stroke caused by large vessel occlusion (LVO) may improve high signal intensity (HSI) on diffusion-weighted imaging (DWI). In this study, we investigated whether subtraction of reversible ischemic lesions (RIL) from the HSI lesions on DWI improves the diagnostic accuracy for the ischemic core.
A total of 35 patients from April 2013 and December 2019 were included in this study. These patients presented acute ischemic stroke due to anterior circulation LVO and underwent thrombectomy. All patients underwent DWI within 48 hours after thrombectomy. HSI ratios were calculated, and compared between ischemic lesions and contralateral normal tissue. Ischemic lesions with improvement in the HSI ratio from initial to postoperative DWI were defined as RIL. Based on a receiver operating characteristic (ROC) curve analysis that compared the HSI ratio of all ischemic lesions, the cutoff value of HSI ratio of RILs was calculated.
In all, 127 ischemic lesions were identified in 35 patients. HSI ratios of RILs were significantly lower than those of irreversible ischemic lesions (IILs) (p <0.0001). Based on a ROC curve analysis that compared the HSI ratio of all 127 lesions, the cutoff value of the HSI ratio of RILs was 1.4. After applying this cutoff value to the 127 ischemic lesions of the 35 patients, 20 patients (57%) were identified as having RILs with a HSI ratio of <1.4. In this 20 patients, the postoperative National Institutes of Health Stroke Scale (NIHSS) score at 24 hours was significantly lower (p = 0.007) and improvement in the NIHSS score was significantly higher (p = 0.018) than in the other patients.
A HSI ratio of <1.4 on preoperative DWI may reflect ischemic reversibility. In this study, the HSI ratio correlated with clinical findings associated with cerebral ischemia, and our method may be useful in assessing ischemic cores.
大血管闭塞（LVO）所致急性卒中的早期再通可能改善扩散加权成像（DWI）上的高信号强度（HSI）。在本研究中，我们调查了从DWI上的HSI病变中减去可逆性缺血性病变（RIL）是否能提高缺血核心的诊断准确性。
本研究纳入了2013年4月至2019年12月期间的35例患者。这些患者因前循环LVO出现急性缺血性卒中并接受了血栓切除术。所有患者在血栓切除术后48小时内接受了DWI检查。计算HSI比值，并在缺血性病变与对侧正常组织之间进行比较。从初始DWI到术后DWI的HSI比值有所改善的缺血性病变被定义为RIL。基于比较所有缺血性病变HSI比值的受试者操作特征（ROC）曲线分析，计算RIL的HSI比值的临界值。
35例患者共识别出127个缺血性病变。RIL的HSI比值显著低于不可逆缺血性病变（IIL）（p<0.0001）。基于比较所有127个病变HSI比值的ROC曲线分析，RIL的HSI比值的临界值为1.4。将该临界值应用于35例患者的127个缺血性病变后，20例患者（57%）被确定为具有HSI比值<1.4的RIL。在这20例患者中，术后24小时的美国国立卫生研究院卒中量表（NIHSS）评分显著更低（p=0.007），且NIHSS评分的改善显著更高（p=0.018），高于其他患者。
术前DWI上HSI比值<1.4可能反映缺血可逆性。在本研究中，HSI比值与脑缺血相关的临床发现相关，我们的方法可能有助于评估缺血核心。
