Glioma-grade diagnosis using in-phase and out-of-phase T1-weighted magnetic resonance imaging: A prospective study

Purpose: The purpose of this prospective study was to determine whether chemical shift gradient-echo magnetic resonance imaging (MRI) could predict glioma grade.

Materials and methods: A total of 69 patients with 69 gliomas were prospectively included. There were 41 men and 28 women with a mean age of 50±(SD) years (range: 16-82years). All patients had MRI of the brain including chemical shift gradient-echo sequence, further referred to as in- and out-of phase sequence (IP/OP). Intravoxel fat content was estimated by signal loss ratio (SLR=[IP-OP]/2IP), between in- and out-of-phase images, using a region of interest placed on the viable portion of the gliomas. Association between SLR and glioma grade was searched for using Wilcoxon and Mann-Whitney U tests and diagnostic capabilities using area under the receiver operating characteristic (AUROC) curves.

Results: A significant association was found between SLR value and glioma grade (P<0.0001). SLR>9‰ allowed complete discrimination between grade III and grade II glioma with 100% specificity (95% CI: 85-100%), 100% sensitivity (95% CI: 78-100%) and 100% accuracy (95% CI: 90-100%) (AUROC=1). A SLR>20‰ allowed discriminating between grade IV and grade III glioma with 75% specificity (95% CI: 57-89%), 73% sensitivity (95% CI: 45-92%) and 72% accuracy (95% CI: 57-84%) (AUC=0.825, 95% CI: 0.702-0.948). The AUROC for the diagnosis of high-grade glioma (grade III and IV vs. grade II) was 1.

Conclusion: Chemical shift gradient echo MRI provides accurate grading of gliomas. This simple method should be used as a biomarker to predict glioma grade.