MRI检查中SWI和DTI序列对弥漫性轴索损伤诊断和预后评价的作用

Role of susceptibility-weighted imaging and diffusion tensor imaging sequence of MRI in diagnosis and prognosis evaluation of diffuse axonal injury

目的探讨MRI检查中SWI和DTI序列在弥漫性轴索损伤（DAI）诊断和预后评价中的临床应用价值。方法采用回顾性病例系列研究分析2015年1月-2017年12月收治的16例DAI患者临床资料，其中男9例，女7例；年龄（56．3±4．1）岁。格拉斯哥昏迷评分（GCS）：3～8分7例，9—12分8例，13分1例。入院时行头颅CT检查，1周内行头颅MRI检查，记录CT和MRI中T1WI、T2WI、DWI和SWI序列上的病灶数；在DTI序列上选取5个区，分别是大脑半球皮层下脑白质区、胼胝体、丘脑、小脑和脑干部位，测量表观弥散系数（ADC）和部分各向异性分数（FA）值。伤后6个月行格拉斯哥预后评分（GOS）。将ADC、FA值与入院时GCS和6个月后GOS行线性相关分析。结果16例DAI患者CT、T1WI、T2WI、DWI及SWI的DAI病灶数检出率分别为25．6％（43／168）、30．4％（51／168）、44．0％（74／168）、51．8％（87／168）、100％（P〈0．01）。皮层下脑白质区胼胝体、丘脑、小脑、脑干区域ADC值分别为0．830±0．148，0．536±0．169，0．838±0．596，0．708±0．157，0．713±0．135；FA值分另0为0．487．±0．103，0．142±0．040，0．293±0．089，0．212±0．045，0．366±0．797。入院时GCS为（8．9±3．3）分，6个月后GOS为（4．2±1．0）分。相关性分析结果显示，皮层下脑白质区和小脑区ADC值、FA值与GCS、GOS无相关性（P〉0．05），各区域ADC值与GCS相关性程度依次是丘脑、胼胝体和脑干（P〈0．05或0．01），各区域ADC值与GOS相关性程度依次是胼胝体、丘脑和脑干（P〈0．05或0．01）。各区域FA值与GCS、GOS相关性程度依次是丘脑、胼胝体和脑干（P〈0．05或0．01）。结论SWI检测DAI病灶的敏感度优于CT和常规MRI序列，DTI可精确、客观和可视化检测大脑白质纤维的完整性。SWI和DTI均能对DAI作出早期诊断并较准确评价DAI患者的预后。

Objective To evaluate the clinical application of SWI and DTI of MRI in the diagnosis and prognosis of diffuse axonal injury （DAI）. Methods A retrospective case series study was conducted on the clinical data of 16 patients with DAI admitted from January 2015 to December 2017. There were nine males and seven females, aged （ 56.3 ± 4.1 ） years. According to Glasgow Coma Scale （GCS）, there were seven patients with 3-8 points, eight with 9-12 points, and one with 13 points. All patients received head CT examination on admission and then received head MRI examination within one week to record the number of lesions on T1WI, T2WI, DWI, and SWI in CT and MRI examination. On the DTI sequence, five regions including the subcortical white matter, the corpus callosum, the thalamus, the cerebellum, and the brain stern were selected for measurement of the apparent diffusion coefficient （ADC） and partial fraction of anisutropy （FA） values. The Glasgow outcome scale （GOS） was evaluated 6 months after injury. The linear correlation between ADC, FA values, GCS, and GOS on admission and after 6 months were analyzed. Results The statistical analysis of CT, T1WI, T2WI, DWI and SWI in 16 patients showed that the detection rates of DAI lesions were 25.6% （43/168）, 30.4% （51/168） , 44.0% （74/168）, 51.8% （87/168）, and 100% , respectively （P 〈0.01）. The ADC values of the subcortical white matter, the corpus callosum, the thalamus, the cerebellum, and the brain stem were 0. 830 -0. 148, 0.536 ±0. 169, 0. 838 ±0. 596, 0. 708 ±0. 157, and 0. 713 ±0. 135, respectively, and FA values were 0. 487 ± 0. 103,0. 142± 0. 040, 0. 293 ± 0. 089, 0. 212 ± 0. 045, and 0. 366 ± 0. 797, respectively. The GCS on admission was （8.9 ± 3.3 ）points, and GOS was （4. 2 ± 1. 0）points six months after injury. The correlation analysis showed that the ADC value and FA value of subeortieal white matter and cerebellum were not related to GCS and GOS （ P 〉 0.05 ）. The correlation strength of ADC values in each region with the GCS score in descending order was the thalamus, the corpus eallosum, and the brain stem （P 〈 0.05 or 0.01 ） ; for ADC with the GOS score, it was the corpus eallosum, the thalamus and the brain stem （P 〈0.05 or 0.01 ） ; for FA with GCS and GOS scores, it was thalamus, corpus callosum, and brainstem （ P 〈 0. 05 or 0.01 ）. Conclusion The SWI has better sensitivity to detect DAI lesions than CT and conventional MRI sequences. DTI can accurately, objectively and visually detect the integrity of cerebral white matter fibers. Both SWI and DTI can help make early diagnosis and evaluate the prognosis of DAI patients accurately.