Dynamic contrast-enhanced magnetic resonance imaging as a biomarker for prediction of radiation-induced neurocognitive dysfunction

Purpose: To determine whether early assessment of cerebral microvessel injury can predict late neurocognitive dysfunction after brain radiation therapy (RT). Experimental Design: Ten patients who underwent partial brain RT participated in a prospective dynamic contrast-enhanced magnetic resonance imaging (MRI) study. Dynamic contrast- enhanced MRI was acquired prior to, at weeks 3 and 6 during, and 1 and 6 months after RT. Neuropsychological tests were done pre-RTand at the post-RT MRI follow-ups. The correlations between early delayed changes in neurocognitive functions and early changes in vascular variables during RT were analyzed. Results: No patients had tumor progression up to 6 months after RT. Vascular volumes and blood-brain barrier (BBB) permeability increased significantly in the high-dose regions during RT by 11% and 52% (P < 0.05), respectively, followed by a decrease after RT. Changes in both vascular volume and BBB permeability correlated with the doses accumulated at the time of scans at weeks 3 and 6 during RT and 1 month after RT (P < 0.03). Changes in verbal learning scores 6 months after RT were significantly correlated with changes in vascular volumes of left temporal (P < 0.02) and frontal lobes (P < 0.03), and changes in BBB permeability of left frontal lobes during RT (P < 0.007). A similar correlation was found between recall scores and BBB permeability. Conclusion: Our data suggest that the early changes in cerebral vasculature may predict delayed alterations in verbal learning and total recall, which are important components of neurocognitive function. Additional studies are required for validation of these findings.