| Part 1:Title:Differentiation of Radiation-Injuries and Tumor Recurrence Using MR Spectroscopy.Purpose To evaluate the MR Spectroscopy imaging in Distinction between Radiation-injuries and Tumor Recurrence.Materials and Methods 9 patients with previously resected and irradiated glioma received 2D 1H-MRS examination with 3.0T GE Signa Scanner.The volumes of interest(VOIs) were placed on enhanced regions based on contrast-enhanced axial T1 weighted image.Metabolite values were calculated automatically from the area under each metabolite peak by SAGE software. Metabolite ratios(Cho/Cr,Cho/NAA,NAA/Cr,Lip/Cr,Lac/Cr)were manually calculted.Results The ratios(mean±SD) of Cho/Cr,Cho/NAA,NAA/Cr,Lip/Cr,Lac/Cr in the recurrent tumor group were 3.1931±1.4316,3.6051±3.0985,1.2037±0.5584,1.4069±1.6793,9.7090±17.0099 respectively,while the ratios(mean±SD) of Cho/Cr,Cho/NAA,NAA/Cr,Lip/Cr,Lac/Cr in the radiation-injuries group were 1.5287±1.1814,1.4102±1.0594,1.1662±0.7943,1.0670±1.2637,5.9089±6.3380 respectively.Five ratios of MRS had no significantly statistical difference(p＞0.05) between the radiation-injuries group and recurrent tumor group.Conclusion The ratios of Cho/Cr,Cho/NAA in 1H-MRS maybe valuabe in differentiating recurrent glioma and radiation-injuries.However,the statistical difference was not significant in this study becauese of insufficient sample size. Part 2:Title:Differentiation of Radiation-Injuries and Tumor Recurrence Using ADC valuePurpose To evaluate the ADC value in differentiating radiation-injuries and tumor recurrence.Materials and Methods 12 patients with previously resected and irradiated glioma were imaged by 3.0T GE Signa Scanner.The examination included conventional MRI and DWI.Postprocessing of ADC maps was performed by using Functool software(AW 4.3,GE Healthcare),regions of interest were drawn manually on the ADC maps in the area corresponding to the contrast-enhancing area on contrast-enhanced axial Tl-weighted images.The ADC values were calculated automatically.ADC values were measured 3 times in order to reduce errors.Results The mean ADC value of the recurrent tumor group were 1.31±0.35×10-3 mm2/s,while the Radiation-injuries group were 1.51±0.48×10-3 mm2/s. There was no significantly statistical difference(p＞0.05) between the radiation-injuries group and recurrent tumor group.Conclusion ADC values of radiation-injuries group were slightly higher than those of recurrent tumor group,but no stastistical difference was found which maybe owing to insufficient sample size. Part 3:Title:Differentiation of Radiation-Injuries and Tumor Recurrence Using Perfusion-weighted imagingPurpose To evaluate the perfusion-weighted imaging in the distinction between radiation-injuries and tumor recurrence.Materials and Methods 12 patients with previously resected and irradiated glioma were included.All the patients were performed on 3.0T GE Signa Scanner by GRE-EPI series with 8-channel head coil.On the mean transit time(MTT), relative cerebral blood flow(rCBF) and relative cerebral blood volume(rCBV) map calculated by software employing decovolution algorithms,the regions of interest(ROIs) were placed on the area corresponding to the contrast-enhancing area on contrast-enhanced axial T1-weighted images and contralateral normal white matter,ROI sizes were 20-40mm2.The MTT,rCBF and rCBV ratios of the patients were calculated as abnormal side against contralateral side.These values were measured 3 times in order to reduce errors.Results The ratios(mean±SD) of rCBV of the recurrent tumor group were 3.45±2.27,while those of the radiation-injuries group were 0.76±0.42.There was significantly statistical difference(p＜0.05) between two groups.The ratios of rCBF and MTT had no statistical difference between the radiation-injuries group and recurrent tumor group(p＞0.05);using 1.579 as the cutoff point of rCBV ratio,the diagnostic sensitivity and specificity were 74%and 100% respectively.Conclusion Perfusion-weighted imaging should be the prior choice in distinction of radiation-injuries and tumor recurrence.The ratios of rCBV has important clinical value in differentiating them. |
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