扩散加权成像在小儿脑肿瘤诊断中的价值

Diagnostic Value of Diffusion Weighted Imaging in Brain Tumors in Children

目的:探讨磁共振扩散加权成像在小儿脑肿瘤诊断中的应用价值。方法:回顾性分析60例经病理证实不同类型的小儿脑肿瘤扩散加权成像及ADC图像,其中包括神经胶质瘤36例,室管膜瘤11例,髓母细胞瘤13例。结果:正常脑白质ADC值在三组间无统计学差别,均值为(0.76±0.06)×10-3mm2/s。三组肿瘤实质的ADC值及rADC(肿瘤实质/正常白质)值如下:胶质瘤为(1.18±0.33)×10-3mm2/s、1.54±0.44;室管膜瘤为(0.97±0.19)×10-3mm2/s、1.26±0.26;髓母细胞瘤为(0.62±0.09)×10-3mm2/s、0.84±0.16。三组肿瘤的ADC及rADC值存在显著性差异,胶质瘤高于室管膜瘤,髓母细胞瘤最低。I-II级胶质瘤为(1.32±0.32)×10-3mm2/s、1.71±0.43;III-IV级胶质瘤为(1.02±0.28)×10-3mm2/s、1.35±0.37,两者之间也有显著性差异,前者高于后者。结论:DWI对于小儿上述三类脑肿瘤的鉴别诊断有一定的帮助。ADC及rADC值能较为可靠地鉴别小儿常见颅内肿瘤以及区分I-II与III-IV级胶质瘤。

Purpose：To evaluate MR diffusion weighted imaging（DWI） in diagnosing pediatric brain tumors.Methods：Sixty cases including 36 gliomaes,11 ependymaes and 13 medulloblastomaes were enrolled in our study. The DWI signal intensity and ADC value for each case were analyzed retrospectively.Results：The ADC values of normal-looking white matter,with average of 0.76±0.06×10-3mm2/s,in three types of tumors showed no statistical difference. The ADC values and rADC（ADC of tumoral parenchyma to that of normal white matter） for gliomaes,ependymaes,medulloblastomaes were 1.18±0.33×10-3mm2/s（1.54±0.44）、0.97±0.19×10-3mm2/s（1.26±0.26）、0.62±0.09×10-3mm2/s（0.84±0.16）,respectively. The difference among the 3 type tumors was statistically significant. The ADC or rADC value for glioma was the highest,while that for medulloblastoma was the lowest. The ADC values and rADC for grade I-II and III-IV gliomaes were 1.32±0.32×10-3mm2/s（1.71±0.43）、1.02±0.28×10-3mm2/s（1.35±0.37）,respectively.The difference between them was statistically significant. Conclusion：DWI has some value in differential diagnosis of pediatric brain tumors. ADC value and rADC are of great value in differential diagnosing pediatric brain tumors and distinguishing high grade from low grade gliomaes.