论文部分内容阅读
Background: Gliomas are the most common brain tumor in human beings and 80%of malignant brain tumors are gliomas which are often diffuse and difficult to diagnosis without biopsy.Early accurate diagnosis is important to the patients.Mutations in isocitrate dehydrogenases 1 and 2(IDH1 and IDH2)have been shown to be present in 86%World Health Organization grade 2 and grade 3 gliomas in adults.These mutations are associated with the accumulation of 2-hydroxyglutarate(2HG)in the tumor which may prove to be a valuable diagnostic and prognostic biomarker.Recently,two-dimensional correlated spectroscopy(2DCOSY)have demonstrated in gliomas.Unlike conventional MRS studies,the second dimension is spectral and not spatial allowing for up to 35 different metabolites The goal of this study was to compare the efficacy of CSI and 2D-COSY in detecting of 2-Hydroxyglutarate in Gliomas Methods: 24 subjects with pathologically confirmed gliomas with IDH mutate were recruited in Brigham and Womens hospital of Harvard Medicine School from 2014 to 2015,including 9 females and 15 males,All of the subjects were examined on a 3T Siemens Skyra using a 32 channel head.In this study we utilize two methods of characterizing MRS: 1)2D-COSY was acquired using 64 increments of 0.8 ms with a starting TE=30 ms and 8 averages as previously described.Voxel size is 30×30×30mm,the total time is 12 minutes for it.2)CSI: semi-LASER CSI spiral sequence,available clinically,TE=97 ms,TR=1.7 sec,3 averages,16x16 grid with 10 mm2 resolution and 15 mm slice thickness 2D-COSY was processed using commercially available software(FelixNMR).Crosspeaks at 1.90~4.02ppm and 4.02~1.90ppm were measured for 2HG.Using the MR software package of 2D-CSI spectral image processing,determination of 2HG/Cr ratio and drawn into the colorful display.Results: All the data of 2D-COSY were analysed by Felix software.Crosspeaks of F1 and F2 at 1.90-4.02ppm were found signal in 12 subjects.Crosspeaks of F1 and F2 at 1.90-4.02ppm were found signal in 13 subjects.4 subjects were found in both of these two crosspeaks.2 subjects found no 2HG signal in 2D-COSY and the positive rate of 2HG is 91.67%.The finding of CSI showed positive results of 2HG/Cr in 13 subjects,the positive rate of CSI is 54.16%.Only one case neither detective by 2D-COSY nor CSI.Low signal to noise ratio,water suppression problem and T1 ridging effects are the most reasons of failing in 2D-COSY.Phasing and baseline artifacts reduce 2HG signal and mapping only measures integration height are the fail reasons for CSI.Conclusion: Our results demonstrate that 2D-COSY methods and CSI may provide additional information that can be of diagnostic or prognostic value of gliomas.Specific to IDH-mutated gliomas,that may provide additional pathophysiological information.