合成MRI技术研究基于弛豫时间的脑恶性肿瘤异质性

Synthetic MRI to Study the Heterogeneity of Brain Malignancy Based on Relaxation Time

目的与脑恶性肿瘤常规MRI成像相比,分析合成MRI(SyMRI)技术对病灶的显示及评价基于弛豫时间肿瘤异质性的价值。方法收集确诊的高级别胶质瘤(HGG)和脑转移瘤(BM)患者51例,行头颅SyMRI和常规序列平扫及增强扫描,重建SyMRI序列对比加权像,比较两种序列病灶信号与周围组织信号强度对比度。在SyMRI定量参数图测量并比较HGG和BM肿瘤实质及瘤周组织的平扫T1、T2、PD值及增强T1值。结果平扫SyMRI-T2FLAIR及增强T1FLAIR肿瘤-瘤周对比度高于相应常规MRI加权像,HGG肿瘤实质平扫T1值、增强前、后T1值变化百分比大于BM,增强T1值小于BM,瘤周组织平扫T1值小于BM(P均<0.05)。Logistic回归分析显示肿瘤实质增强T1值是区别HGG和BM的独立因素。结论平扫SyMRI-T2FLAIR及增强T1FLAIR在显示恶性脑肿瘤方面优于常规MRI加权像。SyMRI定量参数能够借助弛豫时间的差异评估脑恶性肿瘤的异质性,为临床诊断、治疗和预后评估予以影像学信息。

Objective Compared with conventional MRI imaging of brain malignant tumors,the value of the analysis of Synthetic MRI(SyMRI)technology in lesion display and evaluation based on the tumor heterogeneity of relaxation time is discussed.Methods A total of 51 patients with diagnosed high grade glioma(HGG)or brain metastasis(BM)were collected.Before and after intravenous administration of gadolinium contrast agents,SyMRI and conventional sequence scanning were performed.Reconstruction of SyMRI sequence contrast weighted image images,and the signal intensity contrast between the two sequences of lesions and surrounding tissues was compared.The normal T1,T2PD and enhanced T1values of tumor parenchyma and peri-tumor tissues of HGG and BM were measured and compared by SyMRI quantitative parameter map.Results The tumorperitumoral contrast of SyMRI-T2FLAIR and enhanced T1FLAIR were higher than that of conventional images,T1value of HGG tumor parenchyma and the percentage change of T1value before and after enhancement were greater than BM,and T1value after enhancement was less than BM,T1value of HGG peritumor tissue was less than that of BM(P<0.05).Logistic regression analysis showed that T1value after tumor parenchymal enhancement was an independent factor in differentiating HGG and BM.Conclusion SyMRI-T2FLAIR and enhanced T1FLAIR were superior to conventional MRI sequences in the detection of brain malignancy.SyMRI quantitative parameter values can be used to evaluate the heterogeneity of brain malignant tumors through the difference of relaxation time,and provide imaging information for clinical diagnosis,treatment and prognosis evaluation.