| Objective: To test the hypothesis that brain regions with normal metabolite levels can be discriminated from brain regions with abnormal metabolite levels in MRSâ… data from patients with glioma by using a iterative-exclusive method and a linear model of choline versus NAA; To assess the clinical value of the imaging maps of the Cho/NAA residual Z-scores; To discuss the value of Z-score for histological grading of glioma, for evaluating the invasion of glioma, and for delineating the target area of radiation therapy. Materials and Methods: The method was tested on data from healthy volunteers and patients with gliomas proven by histology. Our subjects included 15 healthy volunteers and 26 patients with gliomas (including 4 cases of grade-â… gliomas ; 6 cases of grade-â…¡gliomas; 8 cases of grade-â…¢gliomas; 8 cases of grade-â…£gliomas). All gliomas were entirely on supratentorial area. Conventional MR imaging and 2D PROBE/SI PRESS were performed in all subjects. NAA, Cho, Cr/PCr , Lac , Lip were observed . Using the method, Z-score imaging maps, the distributional maps of Lac and Lip, the mean and standard deviation of the Z-score from the excluded voxels in each patient' s examination, the maximal Z-score, and the contours of AI(Z-score abnormality index) and the contours of LA (enhanced T1Wâ… area) of gliomas between any group of glioma were obtained. Results: There was a significance for the maximal Z-scores between the grade-â…¢ glioma and grade- â… , â…¡ glioma , between grade-â…¢ glioma and grade-â…£ glioma (p<0. 05). 7 cases of gliomas(n=26) exhibited abnormal lactate, 1 case of grade- â… , â…¡ gliomas(n=10) showed lactate, 2 cases of grade-â…¢ gliomas(n=8) showed lactate, 4 cases of grade-IV gliomas(n=8) showed lactate. 7 cases of gliomas(n=26) exhibited Lip, no case of grade- â… , â…¡gliomas showed Lip, 2 cases of grade-â…¢ gliomas(n=8) showed Lip, 5 cases ofgrade-â…£ gliomas (n=8) showed Lip. There was a significance for the (AI area-T1A area)/ T1A area(%) between grade- â… , â…¡glioma and grade-â…¡ glioma; between grade-â…¢ glioma and grade-â…£ glioma(p<0.05). Conclusion: The imaging maps of Z-score display abnormal metabolism of brain tissue. There is a difference between the grade-â…¢ glioma and grade- â… , â…¡glioma for the maximal Z-score, the lowest maximal Z-score observed in the grade-â…£ glioma most likely results from the presence of necrosis, with simultaneous presence of Lac, Lip. 1HMRS could more accurately define the contour of lesion , delineate the target lesion area for radiation therapy planning of gliomas, evaluate invasive ability of gliomas. |
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