9例脑原发淋巴瘤的MRI影像特征

Magnetic Resonance Imaging Features of Primary Brain Lymphoma:A Report of Nine Cases

背景与目的:脑原发淋巴瘤少见,术前常被误诊为恶性胶质瘤或转移瘤。由于脑原发淋巴瘤对化学治疗及放射治疗敏感,因此术前明确诊断具有重要意义。本研究回顾性分析9例经病理证实的免疫状态正常人脑原发淋巴瘤的MRI表现,以提高对本病的诊断及鉴别诊断能力。方法:分析9例脑原发淋巴瘤MRI表现特征(包括病灶的数目、位置、信号强度、瘤周水肿、占位效应程度及瘤体强化特点)。结果:9例病变均为单发,病灶位于幕上者8例,同时累及幕上幕下者1例。平扫T1WI上呈低信号8例,等信号1例;平扫T2WI上等信号6例,低信号1例,稍高信号2例。2例病灶中见坏死改变。瘤周水肿轻度5例,中度3例,重度1例。增强后肿瘤呈团块状强化4例,分叶状强化3例,环状强化2例。结论:免疫状态正常人脑原发淋巴瘤具有较典型的MRI征象,结合患者影像学及临床资料,术前可作出明确诊断。

BACKGROUND ＆ OBJECTIVE. Primary brain lymphoma, a rare tumor, is often misdiagnosed as malignant glioma or metastases before operation. A definite preoperative diagnosis of primary brain lymphoma is of great significance because of its sensitive to chemotherapy and irradiation. This study was to analyze the magnetic resonance imaging （MRI） features of primary brain lymphoma to improve the diagnosis and differential diagnosis accuracy. METHODS.. MRI findings in 9 patients with pathologically proved primary brain lymphoma were analyzed for the number of lesions, tumor site, signal intensity, peritumoral edema, mass effect and contrast enhancement patterns. RESULTS： Of the 9 patients, 8 had supratentorial solitary lesion, and 1 had supratentorial and infratentorial solitary lesion. On plain MRI, 8 lesions were hypo-intense and 1 iso-intense on T1WI, while 6 displayed iso-intense, 1 hypo-intense and 2 slightly hyper-intense on T2WI. Necrosis was seen in 2 lesions. The peritumoral edema was mild in 5 lesions, moderate in 3 lesions, and severe in 1 lesion. On Gd-DTPA- enhanced MR1, 4 lesions displayed obvious homogeneous mass-like enhancement, 3 Iobular enhancement and 2 ring-like enhancement. CONCLUSIONS, Primary brain lymphoma in immunocompetent patients has typical MRI features. Correct diagnosis could be made before operation when imaging findings are considered together with clinical data.