视神经胶质瘤的CT与MRI表现

目的 分析视神经胶质瘤CT和MBI表现，并探讨其在诊断和鉴别诊断中的价值。资料与方法回顾性分析经手术及病理证实的视神经胶质瘤16例，其中CT检查15例，MRI检查6例，CT MRI检查4例。结果16例中肿瘤位于眶内段13例，眶内段累及视神经管内2例，其中1例涉及颅内，另1例位于视神经管内。肿瘤表现为眼球后肌锥内肿块占位，梭形8例，条索状与椭圆形各3例，梨形及结节状各1例。CT检查15例，2例平扫与脑实质呈等密度，14例密度均匀，边界清晰，与视神经无法区分，增强后(13例)肿瘤大多呈轻至中等强化，1例CT扫描示视神经管扩大。MRI检查6例，3例肿瘤位于眶内段，2例涉及视神经管内，其中1例蔓延至颅内显示为视交叉前视神经增粗，另1例肿瘤位于视神经管内呈结节状；肿瘤在T1WI上呈低信号，T2WI呈高信号，注射对比剂肿瘤可强化，1例肿瘤内伴有囊性变。结论 CT与MRI均能显示眶内段视神经胶质瘤，但MRI较CT能够获得更多的肿瘤内部信息，为管内及颅内视神经胶质瘤首选的影像学检查方法。

CT and MRI Manifestations of Optic Glioma

Objective To discuss CT and MRI findings of the optic glioma and their value in its diagnosis and differentiation.Materials and Methods Imaging findings in 16 patients with pathologically-proved optic glioma were retrospectively analyzed. CT scanning was performed in 14 cases, and MRI in 6 cases. Four cases underwent both CT and MRI scanning.Results The lesion was located in intraorbital segment (n=13), or in intraorbital segment with the involvement of optic canal (n=2), or within the optic canal (n=1). The lesions took the form of shuttle-shaped (n=8), cord-like (n=3), ellipse (n=3), pear-shaped (n=1) or nodular (n=1) mass in retrobulbar ocular muscles with space-occupying effect. On CT scans, the mass was homogeneous with clear border and could not be distinguished from the optic nerve (n=14). Slight to moderate enhancement after contrast injection was seen in 13 cases. On MRI, the lesion showed low signal on T 1WI, while high signal on T 2WI. Conclusion Both CT and MRI can detect the optic glioma in intraorbital segment. MRI is superior to CT in being able to obtain more information concerning the tumor, and MRI is the choice of examination for intracranial and intracanal optic glioma.