Study (year) (ref) Group ( Average age (years) Imaging modality (method or model; parameter analysis) Indexes Results Limitations Maia et al. (2005) [35 ] Grade II (13) 36 DSC-MRI (leakage effect uncorrected; ROI-based analysis) rCBV Positive correlation between rCBV and tumor grade and VEGF expression Impact of leakage effect on rCBV accuracy; small sample size Boxerman et al. (2006) [38 ] Grade II (11) 52 DSC-MRI (algorithm for leakage correction; ROI-based analysis) rCBV Significant correlation between tumor grade and corrected rCBV rCBV threshold to discriminate tumor grade was not provided Law et al. (2007) [41 ] Grade II (31) 43 DSC-MRI (γ -variate function for leakage correction; histogram analysis) rCBV Positive correlation between all parameters and tumor grade; more specific than rCBV Histogram was based on whole tumor ROI probably including normal brain tissues Emblem et al. (2008) [42 ] LGG (24) 52 DSC-MRI (γ -variate function for leakage correction; histogram analysis) rCBV Increased diagnosis accuracy and interobserver agreement were obtained using histogram method Only the peak height of histogram distribution was measured Server et al. (2011) [39 ] Grade II (18) 57 DSC-MRI (algorithm for leakage correction; ROI-based analysis) rCBV All parameters were correlated with tumor grade; the diagnostic power of rCBV was better than Influence of steroid treatment on correlation between Yoon et al. (2014) [57 ] LGG (12) 50 DSC-MRI (γ -variate function for leakage correction; ROI-based analysis) rCBV Significant difference of rCBV between HGG and LGG Subjectivity and neglect of the heterogeneity using ROI-based analysis Aprile et al. (2015) [45 ] HGG (31) 55 DSC-MRI (preload for leakage correction; ROI-based analysis) PSR Both the two parameters were significantly different between LGG and HGG; PSR was better than rCBV for grading The relative small sample number of grade III glioma Smitha et al. (2015) [46 ] HGG (25) 38 DSC-MRI (leakage effect uncorrected; ROI-based analysis) rPSR Positive correlation between all parameters and tumor grade; the diagnosis performance of rPSR was better than rCBV and rCBF Impact of leakage effect on rCBV accuracy Choi et al. (2013) [47 ] LGG (10) 51 DCE-MRI (ETK model; ROI-based analysis), DWI Significant difference in Small sample size Zhao et al. (2015) [52 ] LGG (9) 46 DCE-MRI (TK model; ROI-based analysis), DWI Significant difference of all parameters between LGG and HGG; Small sample size; lack of correlation between histopathology and imaging biomarkers Jung et al. (2014) [53 ] Grade II (7) 49 DCE-MRI (ETK model; histogram analysis) Positive correlation between all parameters and tumor grade Small sample size of LGG; lack the percentile of parameters ranging from 0 to 50 Li et al. (2015) [48 ] Grade II (15) 42 DCE-MRI (TK model; ROI-based analysis), SWI All parameters could distinguish tumor grade except for grade III and grade IV Small sample size; lack of voxel-to-voxel correlation between imaging features and pathological specimens Nguyen et al. (2015) [54 ] Grade II (9) 57 DCE-MRI (ETK model, phase-derived AIF; ROI-based analysis), DSC-MRI (bookend method; ROI-based analysis) Significant difference between all parameters and tumor grade; improved diagnostic power of parameters using phase-derived AIF method Only 2 flip angles were used for estimation of the precontrast T1 map; sampling error of histopathological biopsy; some patients received steroids before imaging Santarosa et al. (2016) [49 ] Grade II (9) 55 DCE-MRI (ETK model; histogram/ROI-based analysis), DSC-MRI (algorithm for leakage correction; histogram/ROI-based analysis) Significant difference of all parameters between HGG and LGG; histogram analysis is better than ROI-based method Small sample size
