Brain Imaging With Chemical Exchange Saturation Transfer Technique And Clinical Application

Background:Brain metastasis of lung cancer is very common and serious,and is also one of the common causes of treatment failure.How to monitor the changes of metabolites in the course of brain metastases by using the new technique of chemical exchange saturation,transfer(CEST)provides a new method for early diagnosis and prognosis of brain metastases.Purpose:To investigate the CEST technique of 3.0T magnetic resonance imaging(MRI)for brain metastases of lung cancer and to evaluate its clinical application.Method:From January to July 2018,26 cases of lung cancer brain metastases,15 cases of gliomas and 20 cases of normal controls were collected.The MTR image of 3.5ppm magnetic metastasis rate obtained by GRE EPI CEST sequence using ASSET technique and APT software was observed according to the lesion parenchyma and edema area.MTR values were measured in non-focus areas.ANOVA and t test of independent samples were performed,and the test standard was P<0.05.At the same time,the MTR image was compared with the MRI plain scan,and the DWI/DKI/DKI/SWI was compared.Result:In the metastatic tumor group,the parenchyma,edema and non-focus areas were red and yellow,yellowish green,and green-blue respectively,and the MTR values were 3.29 ± 1.14%,1.28 ± 0.36%,1.26 ± 0.31%respectively.In glioma group,the lesion parenchyma,edema and non-focus areas were red,red and yellow respectively,and the MTR values of green and blue were 6.29 ± 1.580%,2.87 ± 0.65%,1.03 ± 0.30%respectively.The MTR values of the corresponding areas in the normal group were 1.07 ± 0.22%,1.04 ± 0.23%,1.06 ± 0.24%respectively.Traditional MR images are black and white contrast,no metabolic information display.The MTR values of three regions in metastatic tumor group and normal group and glioma group were significantly different(P<0.05),and the parenchymal area and edema area in metastatic tumor group were significantly different(P<0.05).There were significant differences in MTR values between the non-lesion and edema areas(P<0.05),but there was no significant difference between the MTR values in the edema area and the non focus area(P>0.05).In glioma group,there were significant differences in MTR values between the parenchymal and edema areas and the non-focus areas(P<0.05),and the MTR values between the edema and non-focus areas were significantly different(P<0.05).Conclusion:CEST imaging technology can obtained the pseudo-color images,which can reflect protein metabolism.In metastatic tumor group,the parenchymal area was red-yellow,green-blue,and the MTR value was lower than that of glioma group,higher than that of normal group.Observed the MTR image color and MTR value,the early diagnosis of brain metastases and the prognosis evaluation can be achieved on the molecular imaging level.