Diagnostic efficacy of apparent diffusion coefficient measurements in differentiation of malignant intra-axial brain tumors.

PURPOSE: To evaluate diagnostic efficacy of the apparent diffusion coefficient measurements from tumor (ADCt) and tumor circumference hyperintensities (ADCtch) in different types of malignant intra-axial brain tumors.

MATERIALS AND METHODS: Between April 2013 - June 2017, 125 patients (52 females (41.6%) and 73 males (58.4%); mean age, 53 years; age range, 14-81 years), who underwent diffusion-weighted imaging (DWI) with intracranial mass, were retrospectively evaluated. The mean ADCt and ADCtch values and ratios were measured.

RESULTS: Of the 125 patients, 22 (17.6%) had a low-grade glioma (LGG), 55 (44%) had a high-grade glioma (HGG), 32 (25.6%) had metastasis, and 16 (12.8%) had lymphoma diagnosis. There was a statistically significant difference LGG and HGG in terms of mean ADCt and mean ADCtch values and ratios. ADCtch values and ratios showed a statistically significant difference in the differentiation of HGG and metastasis and in the differentiation of HGG and lymphoma. According to ROC curve analysis, a cut-off value of 1.49 × 10?3 mm2/s for the mean ADCtch value generated the best combination of sensitivity 70% and specificity 71% for differentiation of HGGs and metastasis. The mean ADCtch value had the highest statistical predictive value for differentiation of HGGs and lymphoma with a sensitivity of 78% and a specificity of 76% for the optimal cut-off value of 0.82 x 10?³ mm²/s.

CONCLUSION: The mean ADCt ratio allowed reliable differentiation of LGG and high grade brain tumors, including HGGs, metastases, and lymphoma. The mean ADCtch might be a better imaging biomarker in the differentiation of HHG from metastasis and lymphoma.