眼眶孤立性纤维瘤的MRI诊断

MRI diagnosis of solitary fibrous tumor in the orbit

目的探讨眼眶孤立性纤维瘤的特征性MRI表现。方法回顾性分析7例经手术病理证实的眼眶孤立性纤维瘤的MRI资料，7例均行MR平扫、增强及动态增强检查。扫描序列包括T1WI、T2WI及三维快速扰相梯度回波（FSPGR）动态增强扫描序列。结果肿瘤发生于右侧眼眶5例，左侧2例；位于泪腺周围肌锥外间隙6例（内上方5例、外下方1例），眼球后肌锥内间隙颞侧1例。病变边界均清楚，呈椭圆形6例，分叶状1例；病变最大径18～40mm，平均31mm。与脑实质相比，MR T1WI呈较均匀等信号6例；T2WI呈不均匀低信号5例，等信号1例，高信号（多发囊变）1例；增强后病变呈较均匀显著强化6例，不均匀显著强化1例。7例动态增强扫描的时间一信号强度曲线（TIC）均为速升缓降型。结论T2WI呈低信号、增强扫描明显强化、动态增强扫描TIC显示速升流出型为眼眶孤立性纤维瘤的典型MRI征象。

Objective To explore the MRI features of solitary fibrous tumor （SFF） in the orbit. Methods The MRI findings of 7 patients with SFT in the orbit confined by histopathology were analyzed retrospectively. Results Of the 7 lesions, 5 occurred in the right orbit and 2 in the left orbit. Six lesions were located in the extraconal space near the lacrimal gland fossa, including 5 in the superomedial region and 1 in the inferolateral region. The other one was located in the retrobulbar intraconal space. The lesions with well-defined margin showed elliptic shape in 6 cases and lobulated configuration in 1. The maximum diameter of the lesions ranged from 18 to 40 mm （mean, 31 mm）. The lesions showed homogeneous isointense relative to gray matter on T1 -weighted images in 6 patients. On T2-weighted images, the lesions showed heterogeneous hypointense in 5 patients, isointense and hyperintense in one patient respectively. SFT demonstrated markedly homogeneous enhancement in 6 patients and inhomogeneous enhancement in one patient. The time-intensity curves （TIC） of 7 patients exhibited a rapidly enhancing and rapid washout pattern on dynamic contrast-enhanced （DCE） MRI. Conclusion Hypointense signal on T2WI, marked enhancement on contrast-enhanced Tl WI, and a rapidly enhancing and rapid washout pattern TIC on DCE MRI are the typical MRI features of orbital SFT.