To evaluate the correlation between the grades of glioma and quantitative analysis of ADC (Apparent diffusion coefficient) values and normalised ADC values on DWI (Diffusion weighted imaging). Retrospective cross-sectional study including fifty adult patients with glioma, who underwent pre-operative DW-MRI followed by surgical intervention for biopsy or resection. Multiple ADC values measured in lesion and normalised ADC values calculated, were correlated with histopathology grading of the surgical specimen. ADC min , ADC mean , nADC min , nADC mean were greater for low-grade tumors than high-grade tumors and this difference was statistically significant. ROC analysis showed that both ADC min and ADC mean are good measures to differentiate high and low-grade tumors with a ADC min value below 0.85 x 10 -3 mm 2 /sec indicating high-grade tumor with an 85% sensitivity and 90% specificity and ADC mean values below 0.93 x 10 -3 mm 2 /sec indicating high-grade tumor with a 85% sensitivity and 90% specificity. nADC min and nADC mean also differentiated high and low-grade tumors with a nADC min value below 1.14 indicating a high-grade tumor with 90% sensitivity and 82.5% specificity and nADC mean values below 1.4 indicating high-grade tumor with an 80% sensitivity and 85% specificity. This study concludes that ADC values are good measures to distinguish high-grade gliomas and low-grade gliomas. Normalised ADC values have similar sensitivity and specificity in differentiating high-grade gliomas and low-grade gliomas and can be used in indeterminate cases.
Gourishetty et al. (Sun,) studied this question.