Synthetic MRI Studies The Relaxation Time Of Brain Malignant Tumors And Its Clinical Significance

Objective:The synthetic magnetic resonance imaging(SyMRI)technology is used to analyze the quantitative parameter values of SyMRI in tumor parenchyma and peritumor tissues of high grade glioma(HGG)and brain metastasis(BM).Compared with conventional MRI imaging,the ability of SyMRI imaging to display lesions and the value of differentiating HGG and BM are discussed.Methods:Patients who underwent MRI examination and were confirmed as HGG or BM by surgery and pathology or follow-up from May 2020 to March 2021 were collected.All patients underwent SyMRI scan and conventional sequence scan before and after intravenous injection of contrast agent.The obtained images were processed by the host computer to obtain the SyMRI images and MAP images.The contrast of signal intensity between the two sequences of lesions and surrounding tissues was compared,and the T1value(pre-T1),T2 value(pre-T2)and PD value(pre-PD)of tumor parenchyma and peritumoral edema of HGG and BM,and T1 value(post-T1),T2 value(post-T2)and PD value(post-PD)after enhancement were measured on MAP.Paired sample t-test or Wilcoxon signed rank test were used to analyze the contrast difference between the SyMRI image and the conventional image.The unpaired t-test analysis or Mann-Whitney U test was used to analyze the differences between T1,T2 and PD values,and the independent predictors of HGG were analyzed by multivariate Logistic regression method,and the receiver operating characteristic curve was plotted.Significance indicated by P<0.05.Results:51 patients were eventually included in the analysis,including 20 patients with HGG and 31 patients with BM.SyMRI-T2 FLAIR and enhanced SyMRI-T1 FLAIR of brain tumors in 51 patients were higher than those in the corresponding conventional MRI weighted images,and the differences were statistically significant(t=4.018,P=0.010;z=3.180,p=0.001).There was no statistically significant difference in tumor-peritumoral contrast between SyMRI-T1 FLAIR 、 SyMRI-T2 WI scan and conventional MRI images(P > 0.05).HGG tumor parenchyma pre-T1 was higher than BM,while HGG tumor parenchyma post-T1 was lower than BM,and the percentage change of T1 value before and after enhancement of HGG tumor parenchyma was higher than BM(t=2.272,P=0.030;t=2.754,P=0.010;and t=4.374,P<0.001).There was no significant difference in PD at T2 between HGG patients and BM patients before and after tumor parenchymal enhancement.HGG peripheral edema Pre-T1 was lower than BM(t=2.198,P=0.036).There was no statistically significant difference in peripheral edema,pre-T2,pre-PD,post-T1,post-T2,post-PD,between HGG patients and BM patients.Multivariate Logistic regression analysis of tumor parenchyma post-T1 was an independent predictor of HGG(OR=1.010,95%CI=1.001～1.020,P=0.039).The area under ROC curve of HGG and BM tumor parenchyma post-T1 was 0.857(P=0.007,95%CI=0.696～1.000),the optimal cut-off point was 543.5ms,the sensitivity was 76%,and the specificity was83.3%.Conclusion:SyMRI-T2 FLAIR and enhanced SyMRI-T1 FLAIR were better than conventional MRI images in the diagnosis of brain malignancy.The value of quantitative parameters of SyMRI is helpful to reflect the heterogeneity of HGG and BM,and the post-T1 of tumor parenchyma can be used as an independent influencing factor for the differentiation of HGG and BM.