多序列MRI对热射病的诊断价值初探

Preliminary study of MRI in diagnosis of heat stroke

目的 探讨热射病的MRI表现和1H-MRS在监测临床转归中的变化.方法 回顾性分析临床确诊的热射病患者6例.首诊按照格拉斯哥昏迷评分（GCS）分为重度昏迷4例（2例昏迷4h后清醒、2例持续昏迷）、中度昏迷2例.所有患者均行T1WI、T2WI、液体衰减反转恢复（FLAIR）序列、DWI、磁敏感加权成像（SWI）、多体素脑1H-MRS扫描,定量分析病变区N-乙酰天冬氨酸（NAA）/肌酸（Cr）、胆碱（Cho）/Cr、NAA/Cho比值.1例重度昏迷患者MR检查次日死亡,其他5例患者首次检查后7、15d,随访影像表现和脑1H-MRS数值与病情的转归的变化.结果 重度昏迷患者MRI表现为T1WI等信号,T2WI、FLAIR高信号,DWI高信号,ADC高低混杂信号,病变分别位于幕下小脑半球、齿状核和小脑臂（3例）,幕上位于海马旁回（2例）、顶叶（2例）、颞叶（1例）,可累及多部位,其中以小脑和海马旁回多见,随访SWI灶状出血1例,病灶位于脑干和顶叶.中度昏迷2例患者MRI表现未见异常.首次检查,重度昏迷患者NAA/Cr、Cho/Cr、NAA/Cho比值分别为0.67±0.09、0.94±0.16、0.70±0.12,中度昏迷患者对应比值分别为0.87±0.12、0.95±0.13、0.94±0.08,重度昏迷较中度昏迷NAA/Cr、NAA/Cho降低,Cho/Cr轻度降低.1例持续昏迷患者随访病变范围扩大,首诊后15d时NAA/Cr、NAA/Cho分别为0.63±0.07、0.67±0.10,比值降低,Cho/Cr为0.96±0.05;2例病变缩小,NAA/Cr、NAA/Cho分别为1.02±0.13、0.96±0.11,比值升高,GCS评分恢复为14分.中度昏迷NAA/Cr、NAA/Cho比值为1.17±0.10、1.21±0.07.结论 重度热射病可伴有脑肿胀、脑出血,1H-MRS对可作为监测热射病病情变化重要指标,昏迷持续时间越长预后越差.

Objective To investigate MRI features of heat stroke （HS） and 1H-MRS in monitoring clinical outcome.Methods Six cases（4 males,2 females） of HS patients,aged 43-75 years old were retrospectively studied.The patients were divided into 4 severe cases （2 cases with coma for 4 hours,2 patients with persistent coma） and 2 moderate cases according to initial Glasgow coma scale （GCS） at the time of hospital admission.All patients underwent T1WI,T2WI,FLAIR,DWI,SWI,multi voxel 1H-MRS scans and the ratios of NAA/Cr,Cho/Cr,and NAA/Cho were calculated.One case of severe coma died on the next day.Follow-up imaging and brain 1H-MRS were performed on other 5 patients on the 7th and 15th day after the first examination.The imaging results were compared with clinical outcome.Results MRI features of HS for severe coma patients were iso-intensity on T1WI,hyper-intensity on T2WI,FLAIR and DWI,heterogeneous signal intensity on ADC.The infratentorial lesions distributed in the cerebellum,dentate nucleus and cerebellar arm （3 cases）,and the supratentorial lesions distributed in the parahippocampal gyrus （2 cases）,parietal lobe （2 cases）,and temporal lobe （1 cases）.The lesions could be multiple,and the cerebellum and the parahippocampal gyrus were most common involved.SWI showed focal hemorrhage in 2 cases,which located in the brainstem and parietal lobe.No obvious MRI abnormality was found in 2 cases of moderate coma patients.The ratios of NAA/Cr,Cho/Cr,and NAA/Cho for severe coma patients were 0.67 ±0.09,0.94 ±0.16 and 0.70±0.12,respectively,which for moderate coma patients were 0.87±0.12,0.95±0.13,and 0.94±0.08,respectively.The NAA/Cr and NAA/Cho ratios decreased and Cho/Cr mild decreased in the severe coma patients when compared with the moderate coma patients.One patient with persistent coma had expanded lesions on follow-up study.NAA/Cr,NAA/Cho and Cho/Cr were 0.63± 0.07,0.67 ±0.10,and 0.96 ±0.05,respectively.Two cases had smaller lesions on follow-up study with NAA/Cr and NAA/Cho ratio increased,which were 1.02±0.13 and 0.96±0.11,respectively.GCS was turned to 14.NAA/Cr and NAA/Cho for moderate coma patients were 1.17±0.10 and 1.21 ±0.07,respectively.Conclusions Severe HS patients present with cerebral edema and hemorrhage.1H-MRS can be an important index for monitoring the severity of HS.The longer the duration of coma,the worse prognosis may happen.