目的 分析常规磁共振成像(MRI) 征象及3D多平面重建增强在原发性中枢神 经系统淋巴瘤(PCNSL)诊断中的价值。方 法 2014年4月-2018年4月期间本院经病 理证实的57例PCNSL患者术前均接受常规 MRI检查，并行常规增强扫描，其中35例 进行3D多平面重建增强成像。观察病变的 一般MRI征象、T1WI、T2WI上的信号强度、 强化形态及强化特征等。结果 57例PCNSL 患者共检出79个病灶，多位于幕上脑实 质，其次为幕下，多为类圆形、结节状或 斑片状浸润病灶，最大径2-7.5cm。MR平 扫病灶信号多均匀，T1WI呈等信号或稍低 信号，T2WI呈稍高信号或等信号，DWI上 呈高信号，且ADC值为(0.75±0.15)×10- 3 mm2 /s，与对侧半球正常脑白质的ADC值 (0.91±0.19)×10-3mm2 /s对比，差异有统 计学意义(P＜0.05)。常规增强扫描显示 病灶多呈团块状、结节状、片状、环形明 显强化或轻中度强化，少数病灶内可见明 显的坏死、囊变区。接受3D增强后重建的 患者在清晰显示PCNSL病灶或病灶周围的 “马蹄征”、“软脑膜强化征”、“室管 膜强化征”、“病灶内血管包绕征”、 “病灶旁血管包绕征”及“蝴蝶征”方面 效果明显优于常规增强扫描(P＜0.05)。 结论 PCNSL的常规MRI征象如病灶位置、 大小、信号强度等具有一定特征，3D多平 面重建增强后可丰富强化信息，继而可作 为PCNSL的诊断依据，提高诊断率。

Objective To analyze the value of conventional magnetic resonance imaging (MRI) and 3D multi-planar reconstruction and enhancement in the diagnosis of primary central nervous system lymphoma (PCNSL). Methods Fifty-seven patients with PCNSL confirmed by pathology during the period from April 2014 to April 2018 were examined by conventional MRI before surgery, and MRI conventional enhanced scan was also performed. Among them, 35 cases underwent 3D multi-planar reconstruction and enhanced imaging. The general MRI findings, the signal intensity, enhancement morphology and enhancement sign on T1WI and T2WI were observed. Results A total of 79 lesions were detected in 57 patients with PCNSL, mostly in the supratentorial brain parenchyma, followed by the subcolumn. Most of them were round, nodular or patchy infiltrative lesions with a maximum diameter of 2 to 7.5 cm. MR plain scan showed that most lesions were homogeneous, with equal or slightly lower signal on T1WI, slightly higher or equal signal on T2WI, high signal on DWI and an ADC value of (0.75±0.15)×10-3mm2 /s. Compared with the ADC value of normal white matter in the contra lateral hemisphere (0.91±0.19)×10-3mm2 /s, there was significantly different (P<0.05). The conventional enhanced scan found that most lesions showed clumpy, nodular, flaky and ring-like enhancement or mild to moderate enhancement, and a few lesions showed necrosis and cystic lesion. The effect of 3D enhanced reconstruction after enhancement is significantly better than that of conventional enhanced scan in displaying the "Horseshoe sign", "Soft meningeal enhancement sign", "Ependymal enhancement sign", "Vessel encapsulation sign in the lesion", "Vessel encapsulation sign beside the lesion" and "Butterfly sign" of the lesion(P<0.05). Conclusion The conventional MRI findings of PCNSL, such as lesion location, size and signal intensity are characteristic. The 3D multiplanar reconstruction and enhancement can enrich the enhancement information which can be used as a diagnostic basis for PCNSL to improve the diagnostic rate.