Purpose: To evaluate if the relative tumor blood volume (rTBV) using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) can aid in distinguishing low- from high-grade nonenhancing astrocytomas.
Materials and methods: Seventeen patients with histologically proven astrocytomas underwent MRI including DSC-MRI. Maximum TBV regions of interest were recorded from each neoplasm and normalized to contralateral normal white matter. Demographic features, diagnostic MRI findings including tumor volumes, and the normalized rTBV ratios were compared between low-grade (I and II, LGA, n = 6) and high-grade (III) astrocytomas (HGA, n = 11) using Mann-Whitney's U-test and receiver operating characteristic (ROC) analysis.
Results: Maximum rTBV ratios were statistically higher for HGA (1.11 ± 0.13) than LGA (0.66 ± 0.17, P < 0.005) with the best cutoff threshold at 0.94 (sensitivity of 90.9%, specificity of 100%). Differences in mean age and tumor volume on fluid-attenuated inversion recovery (FLAIR) imaging between the two groups did not reach statistical difference (P = 0.22, 0.36).
Conclusion: The addition of DSC-MRI can aid in accurate grading of nonenhancing astrocytomas with high sensitivity and specificity.