Efficacy of 1H-MRSI and DWI for Non-invasive Grading of Brain Gliomas
Background:
Distinguishing low-grade from high-grade gliomas can aid in optimal treatment planning and prognostication. Diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) have been applied in several studies for non-invasive glioma grading. However, these studies focused on limited aspects of these imaging techniques and used different study setups, resulting in occasionally inconsistent and incomparable conclusions in the literatureObjectives:
This study was designed to introduce the optimal imaging setup and the most reliable and applicable imaging parameters in glioma grading, using DWI and MRS.Patients and Methods:
During this prospective study, using a 3T-MR scanner, 55 glioma patients underwent brain MRS with short, intermediate, and long echo times (TEs), as well as DWI using low, intermediate, and high b-values. Postoperatively, all of the specimens were graded pathologically using light microscopy.Results:
We found that Max (Chol/Cr)/ Min (NAA/Cr) ((maximum choline to creatine ratio)/(minimum N-acetyl aspartate to creatine ratio)), followed by Max (Chol/ Cr), both in long-TE, were the most reliable metabolite ratios on MRS for accurate glioma grading. These had values for area under the curve (AUC) of 0.92 (P < 0.05) and 0.89 (P = 0.001), respectively, compared to conventional MR imaging (cMRI), which had an AUC of 0.83 (P < 0.05). DWI at maximal accuracy showed an AUC of 0.80 (P < 0.05).Conclusion:
Max (Chol/Cr)/Min (NAA/Cr) in long-TE was the most reliable of all of the MRS parameters studied, while DWI showed no superiority over cMRI in glioma grading. No significant differences existed among the various b-values applied, or between the minimum and mean tumor apparent diffusion coefficient values used in DWI-based glioma grading
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