中枢神经系统原发淋巴瘤和高级别星形细胞瘤MR灌注成像的对比研究

The comparative study of perfusion MR imaging in primary central nervous system iymphomas and high grade astrocytomas

目的探讨MR灌注成像鉴别中枢神经系统原发淋巴瘤（PCNSL）和高级别星形细胞瘤的价值。方法PCNSL患者12例，高级别星形细胞肿瘤患者23例，手术前行常规MR检查及MR灌注检查，比较其MR灌注伪彩图像和灌注曲线，测量肿瘤实质部分最大相对脑血容量（rCBV），将所测量数值进行t检验。结果PCNSL实质部分rCBV平均为1．8±0．5；高级别星形细胞瘤实质部分rCBV平均为3．9±0．9，二者之间差异有统计学意义（P〈0．05）。PCNSL实质区域时间-信号曲线对比剂首过后曲线逐渐接近基线，12例中有7例超过基线水平。高级别星形细胞瘤实质区域时间-信号曲线对比剂首过后曲线逐渐向基线水平靠拢，但均不能完全恢复到基线水平。结论MR灌注成像有助于鉴别PCNSL和高级别星形细胞瘤。

Objective To investigate the value of perfusion MR imaging in differential diagnosis between primary central nervous system lymphomas （PCNSL）and high grade astrocytomas. Methods Twelve patients with PCNSL and 23 patients with high grade astrocytomas were preoperatively examined using a 1.5T MR unit. Routine MR sequences were performed followed by dynamic susceptibility contrastenhanced MR perfusion imaging. The perfusion color images and the time-signal intensity curves of the two tumor groups were compared. The relative cerebral blood volume （rCBV） within the tumor parenchyma was measured and the data were analyzed with unpaired Student＇s t-test. Results The rCBVs within the tumor parenchyma of the PCNSL and high grade astrocytomas were 1.78± 0. 51 and 3. 87 ±0. 87 respectively. The rCBV in the PCNSL was significantly lower than that of the high grade astrocytoma （ P 〈 0. 05 ）. When the time-signal intensity curves were compared, the PCNSL showed a trend towards the baseline after the first pass and the curves even overshot above the baseline in 7 out of 12 cases, whereas the high grade astrocytoma showed a trend to be close to the baseline but couldn＇t return to the baseline completely. Conclusion The MR perfusion imaging can be very useful in distinguishing the PCNSL from high grade astrocytomas.