静脉溶栓后急性脑梗死患者DWI阴性的临床 特征及预后意义

Clinical Characteristics and Prognostic Significance of Diffusion-Weighted Imaging Negativity in Acute Ischemic Stroke following Intravenous Thrombolysis

摘要: 目的：磁共振弥散加权成像(DWI)是诊断急性脑梗死的重要工具，但部分患者在接受静脉溶栓(IVT)后表现为DWI阴性。这种现象是否代表未发生脑梗死，还是提示血管已再通或影像学敏感性不足，尚存争议。本研究旨在探讨静脉溶栓后急性脑梗死患者DWI阴性的临床特征、预测因素及二级预防意义。方法：回顾性分析2017年1月到2023年6月在重庆医科大学附属第一医院卒中中心接受静脉溶栓治疗的急性脑梗死患者的临床资料，根据溶栓后1周内MRI结果分为DWI阳性组和阴性组。采用单因素分析、二分类Logistic回归及机器学习模型分析临床特征的预测价值。对DWI阴性患者进行电话随访，记录其服药依从性、卒中复发及死亡情况，并采用Fine-Gray竞争风险模型分析复发危险因素。结果：溶栓后DWI阴性患者占22.74%。发病至溶栓时长(ONT)、发病至首次MRI时长(OMT)、住院1周时NIHSS评分(NIHSS-1w)、高脂血症及心房颤动与DWI阳性显著相关(p < 0.05, OR > 1)。既往脑梗死病史和血小板数量与DWI阳性呈负相关(p < 0.05, OR < 1)。TOAST分型对DWI表现有显著影响(p = 0.01)。机器学习模型提示心房颤动和高脂血症预测价值最高。随访结果显示，DWI阴性患者短期内复发风险高，半年的复发率达6.35%，TOAST分型可能与复发风险相关。结论：临床上，DWI阴性并不代表无急性脑梗死事件。小卒中、早期MRI检查、早期溶栓治疗、无高脂血症及心房颤动与DWI阴性相关。合并心房颤动和高脂血症患者更易有DWI阳性表现。DWI阴性患者在短期内卒中复发风险高，需避免因影像学阴性而中断二级预防治疗。

Abstract: Objectives: Diffusion-weighted imaging (DWI) is a cornerstone in the diagnosis of acute ischemic stroke. However, a subset of patients demonstrates DWI negativity following intravenous thrombolysis (IVT). Whether this phenomenon represents the absence of cerebral infarction, successful vascular recanalization, or the limited sensitivity of imaging remains controversial. This study aimed to investigate the clinical characteristics, predictors, and implications for secondary prevention of DWI negativity in acute ischemic stroke patients after IVT. Methods: In this retrospective study, we analyzed clinical data from patients thrombolyzed for acute ischemic stroke at the Stroke Center of The First Affiliated Hospital of Chongqing Medical University (January 2017~June 2023). Patients were stratified by one-week post-procedural MRI findings into DWI-positive and DWI-negative cohorts. Predictors were evaluated using univariate analysis, binary Logistic regression, and machine learning algorithms. DWI-negative patients underwent telephone follow-up for medication adherence, stroke recurrence, and mortality; recurrence risk factors were assessed with a Fine-Gray competing risk model. Results: Among patients thrombolyzed for acute ischemic stroke, 22.74% were DWI-negative. Positive predictors of DWI lesions (p < 0.05, OR > 1) included longer onset to needle time (ONT) and onset to first MRI time (OMT), higher NIHSS score at one week (NIHSS-1w), hyperlipidemia, and atrial fibrillation, while prior stroke recurrence and platelet count were negative predictors. TOAST classification significantly affected DWI outcomes (p = 0.01). Machine learning models ranked atrial fibrillation and hyperlipidemia as the top predictors. The follow-up results showed that patients with negative DWI had a high risk of recurrence in the short term, with a recurrence rate of 6.35% within six months. The TOAST classification might be related to the risk of recurrence. Conclusions: Clinically, DWI negativity must be interpreted with caution, as it does not rule out an acute ischemic event. It is linked to minor stroke severity, early MRI examination, early thrombolytic therapy, and the absence of hyperlipidemia or atrial fibrillation conditions that themselves promote DWI-positivity. Patients with atrial fibrillation and hyperlipidemia are more likely to have positive DWI manifestations. Importantly, DWI-negative status carries a high short-term recurrence risk, underscoring the imperative to maintain secondary prevention regardless of the initial imaging phenotype.