原发性中枢神经系统淋巴瘤常规及功能磁共振成像特点

目的探讨原发性中枢神经系统淋巴瘤(PCNSL)常规MRI及fMRI特点。方法回顾性分析21例经病理证实的PCNSL的常规MRI及DWI、1 H-MRS、PWI表现。结果 21例患者共39个PCNSL病灶的ADC值为(0.78±0.14)×10-3 mm2/s,对侧半球正常脑白质ADC值为(0.89±0.21)×10-3 mm2/s,二者差异有统计学意义(t=1.24,P0.05)。相对于正常脑白质,PCNSL病灶1 H-MRS波谱表现为Cho/Cr值增高(4.62±2.05vs 0.83±0.25)、Cho/NAA值增高(6.86±2.36vs 0.63±0.34)、NAA/Cr值减低(0.67±1.73vs 0.63±.034),差异均有统计学意义(P均0.05)。PCNSL病灶PWI表现为相对低灌注,脑血容量低于周围正常脑实质。结论采用MR DWI、1 H-MRS、PWI可从不同方面反映PCNSL的特征,结合常规MRI征象可进一步提高诊断准确率。

Features of conventional and functional MRI of primary central nervous system lymphoma

Objective To investigate the conventional and functional MRI features of primary central nervous system lymphoma (PCNSL). Methods The conventional MRI, DWI, ¹H-MRS and PWI data of 21 patients with PCNSL confirmed pathologically were analyzed retrospectively. Results There were 39 lesions in 21 cases. The mean ADC value of the PCNSL lesions and the contralateral hemisphere normal white matter was (0.78±0.14)×10^-3 mm²/s and (0.89 + 0.21)×10^-3 mm²/s, respectively. The difference of ADC value between PCNSL lesions and the contralateral hemisphere normal white matter was statistically significant (t=1.24, P<0.05). Compared with the normal brain white matter, the PCNSL lesions showed abnormally high Cho/Cr ratio (4.62±2.05 vs 0.83±0.25), high Cho/NAA ratio (6.86±2.36 vs 0.63±0.34) and low NAA/Cr ratio (0.67±1.73 vs 0.63±.034) on ¹H-MRS (all P<0.05). PCNSL lesions showed relatively low perfusion on PWI. And the cerebral blood volume of PCNSL lesion was lower than that of the surrounding normal brain parenchyma. Conclusion MR DWI, ¹H-MRS and PWI can reflect the features of PCNSL from different profiles. Combined with routine MRI signs, the accuracy of diagnosis can be further improved.