颅内原发性B细胞淋巴瘤MRI表现

目的 探讨免疫功能正常患者颅内原发性B细胞淋巴瘤的常规MRI征象及DWI和PWI特点.方法 结合病理特征分析21例颅内原发性B细胞淋巴瘤的常规MRI表现,并分析其中10例DWI表现,9例PWI特征.结果 21例患者中发现24个病灶,其中19例为单发,2例为多发.颅内原发性B细胞淋巴瘤常规MRI表现为病灶好发于大脑半球,主要位于脑室旁深部白质区、皮质下、基底节,病灶均为类圆形肿块或结节影,T1WI多呈稍低或等信号,T2WI呈等或稍高信号,信号较均匀, 瘤周水肿与占位效应均以轻、中度为主,呈团块状和结节状均匀明显强化,可出现较有特征性"缺口征"、"尖角征".10例颅内原发性B细胞淋巴瘤行DWI检查,其肿瘤实质DWI多呈均匀高信号,ADC值平均值为(79.73±10.21)×10-5] mm2/s.9例行PWI检查,肿瘤实质最大rCBV比值为0.85～2.55,平均值为1.71±0.59,呈低灌注趋势.结论 结合常规MRI表现和DWI、PWI特点可提高MRI对颅内原发性B细胞淋巴瘤的诊断水平.

MRI findings of intracranial primary B-cell lymphoma

Objective To evaluate the conventional MRI, DWI and PWI findings of intracranial primary B-cell lymphoma in immunocompetent patients. Methods The conventional MRI features were retrospectively analyzed in 21 cases of intracranial primary B-cell lymphoma proved by operation and pathology, while DWI features of 10 cases and PWI features of 9 cases were retrospectively studied in combination with their histopathological characteristics. Results Twenty-four lesions were identified in 21 cases, in which, ninteen cases had single lesion, and 2 cases had multiple lesion. The conventional MRI characteristics of intracranial primary B-cell lymphoma were as follows: The primary intracranial lymphoma tended to be located in para-ventricular deep white matter or the subcortical area or basal ganglia. Usually, the lesions were presented as an oval mass or nodule which appeared slight low signal or iso-signal on T1-weighted images and slight high signal or iso-signal on T2-weighted images. The para-tumorous edema and space-occupying effect were slight or moderate. Obvious homogeneous mass-like or nodular enhancement was seen on Gd-DTPA enhanced MRI, and the presence of "incision sign" or "angular sign" were specific. The lesions usually showed high signal on DWI, and the ADC value of intracranial primary lymphoma was ( ×10^-5) mm²/s. PWI features showed that the maximum rCBV ratio of primary B-cell intracranial lymphoma in tumor parenchyma was (0.85-2.55), and the average was (1.71±0.59). The intracranial primary B-cell lymphoma had a tendency to have low perfusion. Conclusion Combining the conventional MRI appearance with DWI and PWI features can improve MRI diagnostic accuracy of intracranial primary B-cell lymphoma.