视交叉病变的MRI分析

目的 分析视交叉病变的MRI表现，探讨MRI对视交叉病变的诊断价值。方法 回顾性分析经临床或病理证实的117例视交叉病变的MRI表现。男54例，女63例，年龄9个月至67岁，平均37．4岁。117例均行MR扫描，101例同时行增强扫描。结果 直接累及视交叉的病变24例，占20．5％。其中胶质瘤11例，表现为视交叉增粗或肿块，伴有视神经或(和)视束受累；炎性病变5例，表现为视交叉弥漫性增粗伴周围结构异常强化，特别是脑膜的炎症；转移瘤5例，其中4例表现为球内肿块沿视神经向球后及颅内侵犯累及视交叉，1例表现为视交叉边缘线状强化伴广泛脑膜强化；脑膜瘤1例，表现为视交叉局限性强化伴视神经肿块；外伤1例，表现为视交叉形态异常伴额叶软化灶；出血1例，表现为视交叉不规则增粗，呈短T1、长T2信号。引起视交叉移位的病变93例，占79．5％，其中视交叉向上移位51例，向前移位2例，向下移位10例，向后移位1例。视交叉一侧受压13例，视交叉显示不清16例。结论 MRI能清晰地显示视交叉病变的特点，对临床诊断与治疗有重要价值。

Analysis of the optic chiasmal lesions by MRI

Objective To analyze the MRI findings of the optic chiasmal lesions, and to evaluate the value of MRI in demonstrating the optic chiasmal lesions. Methods MRI findings in 117 cases of optic chiasmal lesions confirmed by clinical data or pathology were analyzed retrospectively. There were 54 males and 63 females, with the age from 9 months to 67 years, mean 37.4 years. Results There were 24 (20.5%) cases with direct involvement of the optic chiasms. 11 of them were gliomas of the optic chiasm which showed enlargement or mass of the optic chiasms with involvement of optic nerves and/or optic tracts. Diffuse enlargement of optic chiasm with inflammation of adjacent structures, particularly meninges, was found in 5 cases of inflammation. Metastases were found in 5 cases, of which optic chiasm involved by retinoblastoma spreading along optic nerves were found in 4 cases, and linear enhancement of optic chiasm was found in 1 case. Circumscribed enhancement of the optic chiasm with mass of optic nerve was found in 1 meningioma. Abnormal shape of optic chiasm with encephalomalacia of the frontal lobe was found in 1 case of trauma. Irregular enlargement of the optic chiasm showing short T 1 and long T 2 signal was found in 1 case of intrachiasmal hemorrhage. The displacement of the optic chiasms compressed by the lesions arising from adjacent structures was revealed on MRI in 93 (79.5%) cases. Of which superior displacement of the optic chiasms was found in 51 patients, anterior displacement in 2 cases, inferior displacement in 10 cases, and posterior displacement in 1 patient. Only one aspect of the optic chiasms was compressed by the lesions in 13 cases, and the optic chiasms were poorly defined in 16 patients. Conclusion MRI could accurately show the optic chiasmal lesions, which could contribute to clinical diagnosis and treatment.