Major Metabolite Levels of Preoperative Proton Magnetic Resonance Sectroscopy and Intraoperative Fluorescence Intensity in Glioblastoma

Abstract

Objective To compare the intraoperative major metabolite level of preoperative proton magnetic resonance spectroscopy(¹H-MRS)and fluorescence intensity marked with fluorescein sodium(FLs)in glioblastoma(GBM)and thus provide an objective basis for fluorescence surgical treatment of GBM. Methods All newly diagnosed patients by plain and enhanced magnetic resonance imaging from the April 1,2014 to December 31,2015 were enrolled in this study.All of them received ¹H-MRS and marked with FLs.The expression of Ki67 in tumor boundary were confirmed by postoperative pathology and determined by immunostaining assay.The relationship between ¹H-MRS metabolite levels and tumor fluorescence intensity was analyzed. Results Totally 33 patients were included in the study.Preoperative ¹H-MRS revealed high-grade gliomas in 25 cases.The N-acetylaspartate(NAA)decreased significantly and choline(Cho)increased significantly in high-grade gliomas.The ratios of Cho/NAA,NAA/creatine(Cr),and Cho/Cr significantly differed in different tumor regions(P=0.02,P=0.01,and P=0.00,respectively).Surgical results were marked with FLs intraoperatively.Tissue fluorescence were clearly seen.There were 29 patients undergoing total resection and 4 cases undergoing subtotal resection.No acute encephalocele occured after operation,while 2 patients suffered from epilepsy.Postoperative pathology results included:28 cases were diagnosed as GBM(22 cases consistent with ¹H-MRS diagnosis).The results of GBM fluorescence imaging included:the level of fluorescence intensity in tumor parenchyma was significantly higher than that in tumor boundary and peritumoral edema(P=0.01).The result of ¹H-MRS metabolite analysis included:The kurtosis of NAA and of Cho and the ratio of Cho/NAA were significantly different according the fluorescence intensity in tumor parenchyma(P=0.01,P=0.02,and P=0.01).While there was no difference in the kurtosis of NAA,the kurtosis of Cho and the ratio of Cho/NAA were significantly different according the fluorescence intensity in tumor boundary(P=0.02, P=0.00).In peritumoral edema,there was no significant different in kurtosis of NAA and of Cho and in the ratio of Cho/NAA(P=0.23,P=0.09,P=0.14).Immunohistochemistry in GBM tumor boundary showed different Ki67 expressions according to different fluorescence imaging(P=0.03). Conclusions The fluorescence intensity in GBM parenchyma is higher than that in other tumor regions,and there are different metabolic levels in different fluorescence intensity.The metabolic information marked by FLs and provided by ¹H-MRS before operationis are important,and the correlation between them should be further investigated.