The effects of white matter disease on the accuracy of automated segmentation.

Automated segmentation of the brain is challenging in the presence of brain pathologies such as white matter hyperintensities (WMH). A late-life depression population was used to demonstrate the effect of WMH on brain segmentation and normalization. We used an automated algorithm to detect WMH, and either filled them with normal-appearing white-matter (NAWM) intensities or performed a multi-spectral segmentation, and finally compared the standard approach to the WMH filling or multi-spectral segmentation approach using intra-class correlation coefficients (ICC). The presence of WMH affected segmentations for both approaches suggesting that studies investigating structural differences in populations with high WMH should account for WMH. We also investigated how functional data contrasts are affected using normalization between the standard compared to fill and multi-spectral approach. We found that the functional data was not affected. While replication with a larger sample is needed, this study shows that WMH can significantly affect the results of segmentation and these areas are not limited to those affected by WMH. It is clear that to study gray matter differences that some correction should be made to account for WMH. Future studies should investigate which methods for accounting for WMH are most effective.