DWI诊断小儿幕下脑肿瘤

Diffusion weighted imaging in diagnosis of infratentorial brain tumors in children

目的评价扩散加权成像（DWI）和表观扩散系数（ADC）值诊断及鉴别诊断小儿幕下脑肿瘤的价值。方法 58例经病理证实的幕下脑肿瘤患儿均接受常规MR平扫、增强和DWI扫描,并测量实质病变的ADC值。结果髓母细胞瘤25例,ADC均值（6.73±1.55）×10-4mm2/s;星形细胞瘤（Ⅰ-Ⅱ级）24例,ADC均值（14.80±2.61）×10-4mm2/s;室管膜瘤8例,ADC均值（11.08±1.60）×10-4mm2/s;少突胶质瘤1例,ADC均值（15.10±2.73）×10-4mm2/s。对前三种肿瘤实质部分ADC值进行方差分析（F检验）和t检验,其ADC值差异有统计学意义（P〈0.01）。结论 DWI及ADC值可评估小儿幕下脑肿瘤实质病变,是术前诊断及鉴别诊断后颅窝肿瘤的简单可靠的检查方法,对鉴别诊断髓母细胞瘤与星形细胞瘤有明显优势。

Objective To observe the value of diffusion weighted imaging（DWI） and ADC value in the diagnosis and differential diagnosis of pediatric infratentorial brain tumors.Methods Fifty-eight patients with pediatric infratentorial brain tumors confirmed pathologically underwent conventional MR,contrast-enhanced MR and DWI,and the ADC value was calculated in the solid part of tumor.Results Among all 58 pediatric infratentorial brain tumors,there were 25 cases of medulloblastomas with ADC mean（6.73±1.55）×10-4 mm2/s,24 cases of astrocytomas（Ⅰ—Ⅱ grade） with ADC mean（14.80±2.61）×10-4 mm2/s,8 cases of ependymoma with ADC mean（11.08±1.60）×10-4 mm2/s,and 1 case of oligodendrocytes glioma with ADC（15.10±2.73）×10-4 mm2/s.F-test and t-test were used to analyze the ADC values of the first three kinds of tumors.Differences of ADC values among these three different types of tumors were statistically significant（P0.01）.Conclusion The assessment of the DWI and ADC values in the solid part of pediatric infratentorial brain tumor provides a simple and reliable method for preoperative diagnosis and differential diagnosis of posterior fossa tumors,especially in differential diagnosis of medulloblastoma and astrocytoma.