眼眶神经鞘瘤的MRI诊断

目的　研究眼眶神经鞘瘤的MRI表现特征 ,提出对眼眶神经鞘瘤诊断与鉴别诊断的依据。方法　对 2 3例经手术病理证实的眼眶神经鞘瘤患者分别行MRI矢状位、横轴位、冠状位的TSE序列T1加权、T2 加权扫描 ,平扫不压脂 ,增强扫描均压脂。结果　 14例位于肌锥内 ;5例位于肌锥外 ,均呈边缘清楚锐利的椭圆形或长条状 ;4例位于眼眶与海绵窦 ,呈哑铃形 ,跨眶尖 ,为颅眶沟通性神经鞘瘤。结论　MRI的三维立体扫描能准确地显示肿瘤的位置、形态、大小、内部结构、与邻近组织关系以及增强表现 ,并能作出定位、定性诊断

MRI Diagnosis of Orbital Neurilemoma

Objective To investigate the MRI characteristics of orbital neurilemoma, and put forward the evidence of diagnosis and differential diagnosis about orbital neurilemoma. Methods Twenty three cases of orbital neurilemoma confirmed by pathology were scanned by MRI with T 1WI and T 2WI of sagittal transverse and coronal TSE sequence. No fat saturation was on pre contrast images, but post contrast images were all with fat saturation. Results Intraconal masses were found in 14 cases, extraconal masses in 5 cases and they were demonstrated as well marginated, ovoid fusiform masses. Orbitocranial communicating masses in 4 cases showed like dumb bell in shape. MRI revealed 17 cases low to intermediate signal intensity on T 1WI and high intensity on T 2WI with respect to brain gray matter, and ring or half ring long T 2 signal intensity were showed on margin. Homogeneous signal on T 1WI and non homogeneous on T 2WI were found with little cystic regions. 5 cases of multiple cysts were found on T 2WI with star shape cystic low signal in the central or eccentrical areas on T 1WI. One case was an entire cyst with thick wall. Homogeneous enhancement was found in 15 cases, multicyst wall and non enhancement in cystic cavity on post contrast images in 5 cases, significant enhancement on the envelope in one case was also detected. Conclusion Three dimensional scanning of MRI could accurately demonstrate the location, appearance, size, internal structure, relation to neighborhood tissues and enhancement of the tumor.