颅内原发性淋巴瘤MRI诊断价值分析

Value of MRI in the diagnosis of primary intracranial lymphoma

目的分析颅内原发淋巴瘤的MRI征像特点,旨在提高对该病的诊断正确率,降低误诊率。方法回顾性分析苏州大学附属第一医院在2013年～2017年期间收治并经手术病理确诊的32例颅内原发性淋巴瘤患者的MRI资料,并对颅内原发性淋巴瘤患者的病变发生部位、大小、信号等MRI表现进行综合分析。结果本组共检出病灶60个,病灶单发20例,多发12例,以单发为主。病灶分布具有幕上为主,幕下相对少见的特征,其中额顶叶18例,颞叶11例,枕叶2例,小脑半球1例,基底节区4例,丘脑1例,胼胝体5例。多发病灶具有"卫星样"分布的特征。肿瘤周围水肿形态可呈斑片状,指套状。MRI平扫瘤体T_1WI呈等或稍低信号,T_2WI及FLAIR呈等或稍高信号。DWI多表现为高或稍高信号,增强扫描明显强化,多呈握拳样、团块状或开环样强化,"脐凹征""尖角征"及"蝶翼征"也是颅内淋巴瘤较为特异性的影像学表现。颅内原发淋巴瘤的MRS表现为胆碱(Cho)峰升高,N-乙酰天门冬氨酸(NAA)峰降低,脂质(Lip)峰高耸。结论颅内原发淋巴瘤具有特定的MRI征像,对这些征像的综合细致观察分析,有助于提高诊断正确率。

Objective To analyze the MRI features of primary intracranial lymphoma, so as to enhance diagnostic accuracy and to lower misdiagnosis rate. Methods We retrospectively analyzed MRI data of 32 patients with primary intracranial lymphoma proved by operation and pathology in the hospital from January, 2013 to July, 2017. And comprehensive analysis of location, lesion size and signal were made. Results 60 lesions were detected in 32 cases, there are 20 cases with solitary lesion, 12 cases with multiple lesions, and the focal distribution was mainly single. The distribution of the lesions was mainly supratentorial, and the lesions under tentorium were relatively rare. Site of lesion was fronto-parietal lobe (18 cases), temporal lobe (11 cases), occipital lobe (2 cases), cerebellum (1 case), basal ganglia (4 cases), thalamus (1 case) and corpus callosum (5 cases). Multiple lesions had the characteristics of "satellite like" distribution. And the edema around the tumor was found to be patchy or finger shaped. Among all the cases, T 1WI showed isointense or slightly hypointense signal, T 2WI and FLAIR showed isointense or slightly hypointense signal, and DWI showed hyperintense signa1. After contrast scanning, all the cases were markedly enhanced and the main enhanced shape was characterized by typical fist sign, lump sign or open-loop sign. Additionally,"umbilicus sign""spike sign" and "butterfly sign" were also the specific imaging manifestations of primary intracranial lymphoma. MR spectroscopy demonstrated the increased Cho, decreased NAA, and high Lip. Conclusion Primary intracranial lymphoma has characteristic MRI findings, comprehensive and careful analysis of MRI features contribute to the improvement of diagnostic accuracy.