急性脑梗死患者磁共振弥散加权成像阴性的相关因素分析

Analysis of correlation factors of MR diffusion-weighted imaging in patients with acute cerebral infarction

目的 探讨急性脑梗死患者头颅MRI弥散加权成像阴性的相关因素.方法 收集同济大学附属东方医院2015年1-12月350例因急性脑梗死住院并完成头颅MRI的患者一般情况、既往病史及卒中相关因素,按首次弥散加权成像（DWI）是否存在异常信号分为DWI阳性组及阴性组,对两组进行相关因素对比分析.DWI阴性组的患者于首次头颅MRI检查1周后复查.结果 350例急性脑梗死患者中首次MRI DWI阴性的患者有34例（9.7%）,其中5例患者1周后复查头颅MR存在阳性病灶.多因素Logistic回归分析提示：患者入院首次血压≥140/90 mmHg（P=0.033）、入院首次空腹血糖≥7.0 mmol/L（P=0.028）、首次头颅MRI检查时间距发病时间〉24 h的患者容易出现DWI阳性病灶（P=0.013）,后循环梗死的患者较前循环梗死的患者更易出现首次头颅MRI阴性结果（P=0.001）.结论 脑梗死急性期患者中确有一部分患者首次头颅DWI呈阴性结果,不仅与检查时间有关,也与脑梗死的部位有关,检查时间距发病时间越近,越有可能获得阴性结果.后循环梗死的患者较前循环梗死的患者更易出现首次头颅MRI阴性结果.而入院首次血压以及首次血糖水平升高的患者更易出现DWI阳性病灶.在发病时间窗以内的急性脑梗死患者,即使DWI显示为阴性,临床充分评估后应采取积极的溶栓等治疗,避免延误治疗.

Objective To explore the correlation factors of cranial magnetic resonance diffusion weighted imaging（DWI） in patients with acute cerebral infarction.Methods A total of 350 patients with acute cerebral infarction who underwent MR imaging were divided into DWI positive group and negative group according to whether the first diffusion weighted imaging was abnormal or not.The clinical and radiological data of the two groups were retrospectively collected and analyzed.patients with negative DWI on initial MRI were re-examined 1 week later.Result Thirty-four（9.7%） patients were DWI-negative in 350 patients with acute cerebral infarction on initial MRI,and 5 patients in DWI-negative group had positive lesions on the re-examine MRI.Multivariate logistic regression analysis indicated the patients with first blood pressure of admission≥ 140/90 mmHg（P=0.033）,first blood glucose of admission≥ 7.0 mmol/L（P=0.028） and the time from the onset to initial MRI〉24 h were more likely showed DWI-positive on initial MRI（P=0.013）.Patients with posterior circulation infarcts were more likely to have negative DWI findings than patients with anterior circulation infarction（P=0.001）.Conclusion Some patients with acute cerebral infarction may show DWI negative results on initial MRI,which is related with the time from onset to initial MRI and the site of cerebral infarction.Patients with posterior circulation infarcts are more likely to have first negative MR findings than patients with anterior circulation infarction.Patients with elevation of the admission blood pressure or blood glucose are more likely to have DWI positive lesions.Patients with acute cerebral infarction within the time window should received be thrombolytic therapy after carefully assessment to avoid delay in treatment even if the DWI negative results.