四肢神经源性肿瘤的MRI表现

MR imaging features of neurogenic tumor in extremities

目的探讨四肢神经源性肿瘤的MRI表现特点。方法回顾性分析我院1997年至2004年收治的22例神经源性肿瘤患者(47个肿瘤)的MRI表现。22例患者均行常规MRI扫描,包括T_1WI、T_2WI轴位、冠状位和矢状位扫描,并对其中20例行增强扫描。结果在T_1WI 15例神经鞘瘤、4例神经纤维瘤、1例恶性神经源性肿瘤呈等信号,1例神经纤维瘤、1例恶性神经源性肿瘤呈不均质的低/中等信号。在T_2WI 22例肿瘤均呈高信号,5例神经鞘瘤信号轻度不均,1例恶性神经源性肿瘤信号中度不均匀,1例恶性神经源性肿瘤信号明显不均匀。10例病灶位于皮下,12例病灶位于肌间。所有病变均呈梭形,其中9例两端出现"鼠尾征"。5例出现"靶征"。1例恶性神经源性肿瘤侵犯邻近骨。结论 MRI信号特点可提示神经源性肿瘤的诊断,MRI信号明显不均匀及邻近组织的侵犯可提示恶性神经源性肿瘤。

Objective To analyze MR imaging （MRI） features ofneurogenic tumor in extremities. Methods A total of 22 patients （tumors, n=47） with neurogenic tumor in extremities treated in our hospital from 1997 to 2004 were involved. A retrospective analysis was conducted on their MR/manifestations. All these patients underwent routine MRI scanning, including T1Wi and TEW1 in axial, sagittal, and coronal positions. Among them, 20 patients were performed with weighted MR/scanning. Results According to the T1W1 results, equal signal was found in 15 schwannomas, 4 neurofibromas, and lmaligrtant neurogenic tumor, while low and medium signal was found in 1 neurofibroma and 1 malignant neurogenic tumor. With respect to the T2WI results, all 22 cases showed high signal, whereas 5 schwannomas had mildly unequal signal, 1 malignant neurogenic tumor demonstrated moderately unequal signal, and 1 malignant neurogenic tumor illustrated significantly unequal signal. Of the lesions, 10 cases were subcutaneous （8 schwannomas and 2 neurofibromas）, 12 cases （7 schwannomas, 3 neurofibromas and 2 malignant neurogenic tumors） were intermuscular. All of the tumors were spindle-shaped. Among them, 9 cases presented rat-tail sign （7 schwannomas and 2 neurofibromas）, 5 cases showed target sign, and 1 case with malignant neurogenic tumor invaded adjacent bones. Conclusions MRI signal features can suggest the diagnosis of neurogenic tumor. The significant unequal signal of MRI and invasion of adjacent tissues can help diagnoze the malignant neurogenic tumors.