Early response evaluation of radiosurgery in intracranial meningiomas: insights from dynamic contrast‑enhanced MRI

Abstract

Early assessment of treatment response following radiosurgery in intracranial meningiomas is critical for guiding patient management. Conventional evaluation based on tumor volume may not reliably reflect early treatment effects. Objective This study aimed to evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting tumor response during the early post-treatment period. Methods Seventeen meningiomas in 15 patients treated with Gamma Knife radiosurgery were included. DCE-MRI was performed before radiosurgery and at 1- and 6-month post-radiosurgery. Perfusion parameters (Ktrans, Kep, Ve) were analyzed using dedicated software, and tumor volume was calculated from morphological sequences. DCE-MRI parameters were compared with volumetric data to assess early treatment response. Results No significant change in average tumor volume was observed at 1-month post-radiosurgery. Although there was a decrease in the average tumor volume at 6 months, all cases remained classified as stable disease according to RANO criteria. Ktrans decreased significantly at both 1- and 6-month post-radiosurgery. Kep showed a significant change at 6 months compared to pre-treatment. The proportional decrease in Ktrans was more pronounced than changes in tumor volume at both time points. Conclusion Morphological evaluation alone may be insufficient for early assessment of treatment response in meningiomas post-radiosurgery. DCE-MRI provides functional insights that may allow early prediction of therapeutic response, supporting its role as a complementary imaging tool in post-radiosurgery follow-up.