MRI常规扫描结合扩散加权成像诊断眼眶淋巴瘤的价值

Value of conventional MRI and diffusion-weighted imaging in diagnosis of orbital lymphoma

目的探讨眼眶淋巴瘤常规磁共振成像(magnetic resonance imaging,MRI)及扩散加权成像(diffusion-weighted imaging,DWI)特点,以提高其术前诊断准确率。方法经手术病理检查证实的眼眶淋巴瘤18例,术前均行常规MRI及DWI检查,回顾性分析其影像学表现。结果18例患者中14例为单侧发病,4例为双侧发病。13例位于眼眶前部,边界清楚;5例累及肌锥内外呈弥漫生长。15例平扫及增强扫描信号均匀,与眼外肌相比,T1WI/T2WI均为等信号,增强扫描病灶中等度强化;3例患者病变信号不均,T1WI为等-低混杂信号,T2WI为等-高信号。DWI均为稍高信号,扩散系数值为(0.71±0.32)×10-3mm2.s-1。结论常规MRI结合DWI扫描有利于眼眶淋巴瘤的定性诊断。

Objective To investigate the characteristics of conventional magnetic resonance imaging（MRI） and diffusion-weighted imaging in diagnosis of orbital lymphoma for improving the diagnostic accurate rate. Methods Eighteen cases of orbital lymphoma confirmed by pathology underwent conventional MRI and diffusion-weighted imaging. Imaging manifestations of all cases were retrospectively analyzed. Results The lesions of 14 cases were unilateral and 4 cases were bilateral. The lesions of 13 cases were seen in the anterior part of orbit with clear boundary and 5 cases were seen in intra- and extra-myopyramid with diffuse growth. Fifteen cases showed even plain scanning and enhancement scanning signals, iso-intensity on T1WI and T2WI, and moderate strengthening of focus of infection with enhancement scanning. Three cases showed uneven signal with iso-intensity or hypo-intensity on T1 WI and iso-intensity or hyper-intensity on T2WI. All cases showed hyper-intensity on DWI,and the mean apparent diffusion coefficient was （0.71 ± 0.32） ×10^-3 mm^2 . s-1. Conclusion Conventional MRI combined with diffusion-weighted imaging is useful for the diagnosis of orbital lymphomas.