磁共振灌注成像的序列选择

The sequence selection in MR perfusion weighted imaging

目的 探讨磁共振灌注成像时成像序列的最佳选择。方法 16例健康自愿者和 42例胶质瘤患者 ,以SE EPI或GE EPI序列进行灌注成像 ,观察图像的质量 ,计算正常脑组织的最大信号强度下降百分比 (SRRmax)和肿瘤的相对局部脑血流容积 (rrCBV)。结果 SE EPI和GE EPI灌注图像脑白质的信噪比分别为 2 3 .2、17.8;白质的SRRmax则为 8.0 7%、13 .68%;SE EPI首幅图像信号明显高于其后对比剂进入前图像 ,而GE EPI未见此表现。SE EPI测得低、高级胶质瘤的rrCBV间无显著差异 ,而GE EPI测得低、高级胶质瘤的rrCBV间差异显著。结论 脑肿瘤的灌注研究应采用GE EPI序列 ,但研究非肿瘤性病变 ,或肿瘤较小并位于鞍区、颅底时 ,可考虑用SE EPI。

Objective To define the best sequence in MR perfusion weighted imaging(PWI).Methods 16 health subjects and 42 patients with gliomas were recuited into this study. PWI was performed with SE EPI or GE EPI, image quality was observed, and the perfusion data were deconvoluted to calculate maximum signal reduction ratio (SRR max ) of white matter and relative regional cerebral blood volume (rrCBV) of gliomas.Results The signal to noise ratio of white matter was 23.2 in SE EPI, which was higher than 17.8 in GE EPI. SRR max of white matter in SE EPI and GE EPI was 8.07%, 13.68%, respectively. The signal of first picture was obviously higher than the others in SE EPI, but it wasn't been seen in GE EPI. The rrCBV had no obvious discrepancy between low and high grade gliomas in SE EPI, but difference was statistically significant in GE EPI. Conclusion GE EPI should be used in PWI of brain tumors. In non tumor disease, or small tumor located in sellar region or skull base, SE EPI could be regarded as choice.