磁共振扩散加权成像对瓦斯爆炸所致苍白球及海马病变的动态研究

Dynamic study on lesions in globus pallidus and hippocampus caused by gas explosion using MR diffusion-weighted image

目的分析瓦斯爆炸伤后不同时期苍白球及海马磁共振扩散加权成像（DWI）及表观扩散系数（ADC）值的动态变化。方法使用常规T1WI、T2WI及DWI序列,对49例瓦斯爆炸伤患者脑部进行动态观察,20例正常志愿者进行对照检查;测量苍白球及海马的ADC值,对正常对照组（A组）、患者爆炸后1~3天（B组）及爆炸后2个月（C组）的测量结果进行对照分析。结果爆炸后1~3天内脑部MR检查显示,苍白球病变（12例23侧）及海马病变（7例13侧）呈T1WI等或低信号、T2WI及DWI均呈高信号。A组苍白球区域、B组病变苍白球、B组正常苍白球、C组病变苍白球以及C组正常苍白球ADC值（×10-4mm2/s）分别为6.78±0.24、5.12±1.07、6.83±0.54、8.57±2.26、6.74±0.41;B组病变苍白球ADC值明显低于A组ADC值（P〈0.05）,C组病变苍白球ADC值高于A组ADC值（P〈0.05）,B组正常苍白球、C组正常苍白球及A组苍白球三组之间ADC值均无统计学差异（P〉0.05）;A组海马、B组病变海马、B组正常海马、C组病变海马以及C组正常海马ADC值（×10-4mm2/s）分别为8.75±0.35、6.00±0.64、8.47±0.57、8.95±2.23、8.72±0.69;B组病变海马ADC值明显低于A组（P〈0.05）,B组正常海马ADC值低于A组（P〈0.05）,C组病变海马、C组正常海马与A组ADC值之间均无统计学差异（P〉0.05）。结论苍白球及海马是瓦斯爆炸伤后最易受累的脑区,海马损伤更为普遍。MRI是有效的诊断及评价手段,ADC值有助于定量评价脑损伤的程度。

Objective To analyze the dynamic changes in the lesions of globus pallidus （GP） and hippocampus caused by gas explosion using MR diffusion-weighted imaging （DWI） and apparent diffusion coefficient （ADC）. Methods A serial MR study was performed in 49 victims of gas explosion using conventional T1WI, T2WI, and DWI.Twenty healthy volunteers were studied as the control group. ADC values of GP and hippocampus were measured, and the data of control group （group A）, 1-3 day post-explosion patient group （group B）, and 2 month post-explosion patient group （group C） were compared. Results In patients within 1-3 days after explosion （group B）, the involved GP （12 cases, 23 sides） and hippocampus （7 cases, 13 sides） showed iso- or hypointense signal on T1WI, hyperintense signal on both T2WI and DWI. ADC values （×10-4 mm2/s） of GP in group A, abnormal GP in group B, normal GP in group B, abnormal GP in group C, and normal GP in group C were 6.78±0.24, 5.12±1.07, 6.83±0.54, 8.57±2.26, and 6.74±0.41, respectively. ADC value of abnormal GP in group B was markedly lower than that in group A （P〈0.05）. ADC value of abnormal GP in group C was markedly higher than that in group A （P〈0.05）. ADC values showed no statistical differences among normal GP in group B, normal GP in group C, and GP in group A （P〉0.05）. ADC value of hippocampus in group A, abnormal hippocampus in group B, normal hippocampus in group B, abnormal hippocampus in group C, and normal hippocampus in group C were 8.75±0.35, 6.00±0.64, 8.47±0.57, 8.95±2.23, and 8.72±0.69, respectively. ADC value of abnormal hippocampus in group B was markedly lower than that in group A （P〈0.05）. ADC value of normal hippocampus in group B was lower than that in group A （P〈0.05）. ADC values showed no statistical differences among abnormal hippocampus in group C, normal hippocampus in group C, and hippocampus in group A （P〉0.05）. Conclusion Globus pallidus and hippocampus are the most vulnerable areas in victims of gas explosion, and injuries of hippocampus are more frequently encountered. MRI is a useful method of choice for the diagnosis and evaluation, and ADC value is helpful in quantitatively assessing the degree of brain injury.