Diffusion Tensor Imaging of Normal-Appearing White Matter as Biomarker for Radiation-Induced Late Delayed Cognitive Decline

• DOI: 10.1016/j.ijrobp.2011.01.068
• Publication Date: 2011-05-20T21:50:41Z
• Authors: Christopher H. Ch...; Vijaya Nagesh; Pia C. Sundgren; Henry Buchtel; Thomas L. Chenevert; Larry Junck; Theodore S. Lawrence; Christina I. Tsien; Yue Cao
• Keywords: Adult; Male; Time Factors; Radiotherapy Dosage; Middle Aged; Hippocampus; Temporal Lobe; 03 medical and health sciences; Diffusion Tensor Imaging; 0302 clinical medicine; Mental Recall; Quality of Life; Humans; Female; Prospective Studies; Cognition Disorders; Radiation Injuries

To determine whether early assessment of cerebral white matter degradation can predict late delayed cognitive decline after radiotherapy (RT).Ten patients undergoing conformal fractionated brain RT participated in a prospective diffusion tensor magnetic resonance imaging study. Magnetic resonance imaging studies were acquired before RT, at 3 and 6 weeks during RT, and 10, 30, and 78 weeks after starting RT. The diffusivity variables in the parahippocampal cingulum bundle and temporal lobe white matter were computed. A quality-of-life survey and neurocognitive function tests were administered before and after RT at the magnetic resonance imaging follow-up visits.In both structures, longitudinal diffusivity (λ(‖)) decreased and perpendicular diffusivity (λ(⊥)) increased after RT, with early changes correlating to later changes (p < .05). The radiation dose correlated with an increase in cingulum λ(⊥) at 3 weeks, and patients with >50% of cingula volume receiving >12 Gy had a greater increase in λ(⊥) at 3 and 6 weeks (p < .05). The post-RT changes in verbal recall scores correlated linearly with the late changes in cingulum λ(‖) (30 weeks, p < .02). Using receiver operating characteristic curves, early cingulum λ(‖) changes predicted for post-RT changes in verbal recall scores (3 and 6 weeks, p < .05). The neurocognitive test scores correlated significantly with the quality-of-life survey results.The correlation between early diffusivity changes in the parahippocampal cingulum and the late decline in verbal recall suggests that diffusion tensor imaging might be useful as a biomarker for predicting late delayed cognitive decline.