| Objective: To explore the value of multimodal functional MR imaging for differentiation of recurrent glioma from radiation necrosis by discussing the performances and optimum indicators of 3.0T MR diffusion MR imaging, perfusion MR imaging and magnetic resonance spectroscopy.Materials and methods: 54 brain glioma patients who had undergone conventional MR imaging, DWI, dynamic contrast-enhanced T2*-weighted PWI and MRS on a SIEMENS 3.0T scanner were confirmed by the secondary surgical pathology or MRI follow-up. 34 cases were in the recurrent glioma group while 20 in the radiation necrosis group. Using SWI images as the reference images to avoid hemorrhage, calcification and small veins, the ADC, r ADC, r CBV, r CBF, r MTT, PH, r PH, r PSR, Cho/NAA, Cho/Cr, and NAA/Cr measurements were obtained from regions of the enhanced area and the corresponding opposite white matter respectively. An analysis of the imaging findings including the diffusion indicators, the perfusion indicators and the magnetic resonance spectroscopy was done. Unpaired two-tailed Student t test were performed to compare the DWI, PWI and MRS between two groups. Receiver operating characteristic(ROC) analyse curves were performed to determine optimum thresholds for differentiation and also to calculate the sensitivity, specificity. Sensitivity, specificity of the associating screening of DWI, PWI and MRS were obtained finally.Results:(1) Group of glioma recurrence abnormal enhancement of the lesion ADC values(1.00×10-3±0.21mm2/s) and r ADC values(1.39×10-3±0.35mm2/s) were lower than those of radiation necrosis group(1.28×10-3±0.19mm2/s and 1.84×10-3±0.27mm2/s)(P<0.05).(2) The r CBV and r CBF values of the glioma recurrence group were 6.01±3.01, 5.98±3.23, respectively, which were significantly higher than those of radiation necrosis group(1.96±1.20, 1.89 ±1.84)(P<0.05), but the r MTT values were not significant statistical differences(P>0.05). The PH value(405.43±157.36) and r PH value(4.08±1.85) of the glioma recurrence group were significantly higher than those of radiation necrosis group(189.34±97.15, 1.75±1.04), respectively(P<0.05).The PSR value(0.69±0.16) and r PSR value(0.92±0.26) of the glioma recurrence group were significantly lower than those of radiation necrosis group(0.81±0.26, 1.22±0.73), respectively(P<0.05).(3) The Cho/NAA and Cho/Cr values of the glioma recurrence group were 4.62±1.77 and 2.64±1.25, respectively, which were significantly higher than those of radiation necrosis group(1.78±0.56 and 1.63±0.49)(P<0.05), while the NAA/Cr values of the glioma recurrence group(0.63±0.32) were lower than those of radiation necrosis group(0.98±0.33)(P <0.05).(4) The maximum Youden index was chosen to determine the optimum thresholds of all the indicators in ROC analyses. Statistical analysis demonstrated a threshold value of 1.22 and 1.57 for ADC and r ADC of the two groups to provide sensitivity, specificity of 73.3%, 84.4% and 86.7%, 72.9%, and a threshold values of 3.11, 2.16, 218.55, 0.717 and 0.91 for r CBV, r CBF, PH, PSR, r PSR of the two groups to provide sensitivity and specificity of 85.3% and 84.2%, 94.1% and 78.9%, 85.3% and 78.9%, 85.3% and 79.4%, 68.4% and 58.8%, 68.4% and 64.7%, as well as a threshold value of 2.67, 1.78 and 0.760 for Cho/NAA, Cho/Cr and NAA/Cr of the two groups to provide sensitivity, specificity of 78.9% and100%, 73.7% and 75.0%, 87.5% and 78.9%, respectively.(4) Sensitivity and specificity were 94.7%, 100% when combining the r ADC, r CBV and Cho/NAA of the differentiation with DWI, PWI and MRS, respectively.Conclusion:The value of r ADC, rCBV, Cho/NAA are the optimal indicators of DWI, PWI and MRS in the differentiation.Combined with multimodal functional imaging can significantly improve the sensitivity and specificity of the differentiation of glioma recurrence and radiation necrosis. |
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