Xiang Liu, Presenter: Nothing to Disclose

Wei Tian MD, PhD, Abstract Co-Author: Nothing to Disclose

Balasubramanya Kolar MD, Abstract Co-Author: Nothing to Disclose

Sven E. Ekholm MD, Abstract Co-Author: Nothing to Disclose

Background and Purpose: Malignant, non-enhancing gliomas, and mixed neuronal-glial tumors (NEGNGT) are sometimes misdiagnosed as low grade tumors based on convention MR imaging. The aim of this study was to evaluate the value of imaging parameters calculated from Diffusion tensor imaging (DTI), MR perfusion weighted imaging(PWI) and MR spectroscopy (MRS) in preoperative grading of supratentorial NEGNGT and their correlation with the Ki67 index.

Method and materials: A total of 61 patients (mean age 40±13) with histology confirmed supratentorial NEGNGT were included. There were 38 patients with low grade tumor and 23 patients had high grade. The parameters, including age, sex, tumor size, maximal relative cerebral blood volume (rCBV), maximal and mean Fractional anisotropy (FA), mean and minimal ADC, Choline/Creatine (Cho/Cr) and Choline/N-acetylaspartate (Cho/NAA) ratios were compared for the low and high grade NEGNGT using Mann-Whitney U test. The receiver operating characteristic (ROC) analysis was performed for optimal grading threshold. The correlations of imaging parameters with ki67 index were analyzed.

Results: The values of mean FA and maximal FA in high grade NEGNGT were significant higher than the values in low grade (p<0.05), but there was no significance for age, sex, tumor size, maximal rCBV, mean ADC, minimal ADC, Cho/Cr and Cho/NAA ratios. (p>0.05). The ROC analysis showed that the maximal FA cutoff value of 0.235 differentiated between low and high grade with a sensitivity of 93.8% and a specificity of 78.9%, which is better than the other imaging parameters. No significant correlation could be found for maximal rCBV, minimal ADC, Cho/Cr, Cho/NAA ratios and Ki-67 index. However, the mean FA, maximal FA and mean ADC correlated with Ki67 index (p values were <0.001, 0.0168 and 0.0204, respectively).  

Conclusions: The results suggest that the maximal FA value is the best parameter for grading of NEGNGT, better than other imaging parameters. The maximal FA value could serve as an adjuvant tool to differentiate between low and high grade non-enhancing supratentorial gliomas and neuronal-glial tumors.

Maximal FA value is useful in preoperative grading non-enhancing gliomas, and mixed neuronal-glial tumors, and significantly correlates with Ki67 index.

Liu, X, Tian, W, Kolar, B, Ekholm, S, Preoperative Grading Nonenhancing Cerebral Gliomas and Neuronal- Glial Tumors by Multiple Parameters of Diffusion Tensor Imaging, MR Perfusion Imaging, and MR Spectroscopic Imaging, and Their Correlation with ki67 Index.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016746.html