Characterizing post-stroke changes in brain microstructure using the mean apparent propagator model
4 affiliations
- 1Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
- 2Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- 3Department of Neurosurgery, Medical College of Wisconsin and Froedtert Hospital, Milwaukee, Wisconsin, USA
- 4Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
Abstract
This study investigated regional and whole-brain microstructural alterations following stroke using diffusion tensor imaging (DTI) and Mean Apparent Propagator MRI (MAP-MRI). Multi-shell diffusion and T1-weighted MRI data were analyzed from participants with chronic stroke and healthy controls. DTI-derived fractional anisotropy (FA) and mean diffusivity (MD), and MAP-MRI-derived return-to-origin (RTOP), return-to-axis (RTAP), and return-to-plane (RTPP) probabilities were quantified across 13 predefined regions in native diffusion space. Regional group differences were assessed using participant-level median values with Benjamini–Hochberg false discovery rate (BH-FDR) correction across all 65 ROI × diffusion-metric comparisons and age- and sex-adjusted sensitivity analyses. Complementary lesion-relative whole-brain analyses used nonparametric permutation testing with threshold-free cluster enhancement and family-wise error correction.
MAP-MRI demonstrated widespread regional abnormalities, with significant group differences in 11 of 13 regions for RTOP, 12 of 13 for RTAP, and 10 of 13 for RTPP, compared with 8 of 13 for FA and all 13 regions for MD. After adjustment for age and sex, significant differences remained in 11, 10, and 9 regions for RTOP, RTAP, and RTPP, respectively, compared with 6 for FA and all 13 for MD. Whole-brain analyses demonstrated significant corrected abnormalities across all five diffusion metrics, with RTOP and RTAP showing the most spatially extensive Control > Stroke effects, followed by RTPP and FA, whereas MD showed extensive effects in the opposite, Stroke > Control direction. Regional discrimination varied by anatomical region and metric, without a uniform advantage of MAP-MRI over DTI. Exploratory diffusion–function analyses identified several nominal associations, but none survived correction across all comparisons.
These findings demonstrate complementary, region- and metric-specific sensitivity of MAP-MRI and DTI to chronic stroke-related microstructural abnormalities. MAP-MRI identified distributed abnormalities across regional and whole-brain analyses, while MD remained highly sensitive to widespread tissue differences. The differing spatial distributions and regional discriminative performance of MAP-MRI and DTI suggest that these approaches capture partially distinct features of the post-stroke diffusion environment. Together, these findings support their complementary use for characterizing distributed microstructural abnormalities following chronic stroke.
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BibTeX
@article{vega2026characterizing,
title = {{Characterizing post-stroke changes in brain microstructure using the mean apparent propagator model}},
author = {Ricardo J. Vega and Wesely T. Richerson and Max O. Krucoff and Brian D. Schmit},
journal = {NeuroImage: Clinical},
year = {2026},
month = oct,
doi = {10.1016/j.nicl.2026.104076},
url = {https://doi.org/10.1016/j.nicl.2026.104076},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Characterizing post-stroke changes in brain microstructure using the mean apparent propagator model
AU - Ricardo J. Vega
AU - Wesely T. Richerson
AU - Max O. Krucoff
AU - Brian D. Schmit
PY - 2026
DA - 2026/10/21
JO - NeuroImage: Clinical
DO - 10.1016/j.nicl.2026.104076
UR - https://doi.org/10.1016/j.nicl.2026.104076
AB - This study investigated regional and whole-brain microstructural alterations following stroke using diffusion tensor imaging (DTI) and Mean Apparent Propagator MRI (MAP-MRI). Multi-shell diffusion and T1-weighted MRI data were analyzed from participants with chronic stroke and healthy controls. DTI-derived fractional anisotropy (FA) and mean diffusivity (MD), and MAP-MRI-derived return-to-origin (RTOP), return-to-axis (RTAP), and return-to-plane (RTPP) probabilities were quantified across 13 predefined regions in native diffusion space. Regional group differences were assessed using participant-level median values with Benjamini–Hochberg false discovery rate (BH-FDR) correction across all 65 ROI × diffusion-metric comparisons and age- and sex-adjusted sensitivity analyses. Complementary lesion-relative whole-brain analyses used nonparametric permutation testing with threshold-free cluster enhancement and family-wise error correction. MAP-MRI demonstrated widespread regional abnormalities, with significant group differences in 11 of 13 regions for RTOP, 12 of 13 for RTAP, and 10 of 13 for RTPP, compared with 8 of 13 for FA and all 13 regions for MD. After adjustment for age and sex, significant differences remained in 11, 10, and 9 regions for RTOP, RTAP, and RTPP, respectively, compared with 6 for FA and all 13 for MD. Whole-brain analyses demonstrated significant corrected abnormalities across all five diffusion metrics, with RTOP and RTAP showing the most spatially extensive Control > Stroke effects, followed by RTPP and FA, whereas MD showed extensive effects in the opposite, Stroke > Control direction. Regional discrimination varied by anatomical region and metric, without a uniform advantage of MAP-MRI over DTI. Exploratory diffusion–function analyses identified several nominal associations, but none survived correction across all comparisons. These findings demonstrate complementary, region- and metric-specific sensitivity of MAP-MRI and DTI to chronic stroke-related microstructural abnormalities. MAP-MRI identified distributed abnormalities across regional and whole-brain analyses, while MD remained highly sensitive to widespread tissue differences. The differing spatial distributions and regional discriminative performance of MAP-MRI and DTI suggest that these approaches capture partially distinct features of the post-stroke diffusion environment. Together, these findings support their complementary use for characterizing distributed microstructural abnormalities following chronic stroke.
SN - 2213-1582
ER -