Shape Quantification

Quantitative shape biomarkers for cortical morphology and brain disorders

Method

LGI: Cortical Shape-Adaptive Local Gyrification Index

Local Gyrification Index heatmap on cortical surface
Shape-adaptive LGI heatmap visualization on cortical surface

The amount of cortical folding, or gyrification, is typically measured within local cortical regions covered by an equidistant geodesic or nearest neighborhood-ring kernel. Without careful design, such a kernel can easily cover multiple sulcal and gyral regions that may not be functionally related, resulting in blurring of local gyrification measurements. We propose a novel kernel shape for locally quantifying cortical gyrification within sulcal and gyral regions. We adapt wavefront propagation to generate a spatially varying kernel that encodes cortical folding patterns, including neighboring gyral crowns, sulcal fundi, and sulcal banks. To achieve this, we perform anisotropic wavefront propagation by solving a static Hamilton–Jacobi partial differential equation. The resulting kernel adaptively elongates along gyral crowns and sulcal fundi, while maintaining a uniform shape over flat regions such as sulcal banks.

Applications

Brain Disorder / Disease / Developmental Studies

Autism Spectrum Disorder cortical gyrification
Autism Spectrum Disorder
Huntington's Disease cortical gyrification
Huntington's Disease
  • Long-term effects of preterm birth on cortical folding trajectories in early childhood

    Yong Hun Jang, Jongmin Kim, Bong Gun Lee, Jeong-Kyu Hoh, Gang Yi Lee, Hyun Ho Kim, Ilwoo Lyu, Hyun Ju Lee

    Brain Communications, 8(3), fcag097, 2026

  • Local Gyrification Index and Sulcal Depth as Imaging Markers of Cognitive Decline in Alzheimer's Disease

    Yongsik Sim, Changmin Seo, Young-gun Lee, Byoung Seok Ye, Ilwoo Lyu, Beomseok Sohn

    Frontiers in Aging Neuroscience, 17, 1635861, 2025

  • Comprehensive Shape Analysis of the Cortex in Huntington's Disease

    Zachary Stoebner, Kilian Hett, Ilwoo Lyu, Hans Johnson, Jane Paulsen, Jeffrey Long, Ipek Oguz

    Human Brain Mapping, 44(4), 1417–1431, 2023

  • Cortical Morphology in Autism: Findings from a Cortical Shape-Adaptive Approach to Local Gyrification Indexing

    Alisa Zoltowski, Ilwoo Lyu, Michelle Failla, Lisa Mash, Kacie Dunham, Jacob Feldman, Tiffany Woynaroski, Mark Wallace, Laura Barquero, Tin Nguyen, Laurie Cutting, Hakmook Kang, Bennett Landman, Carissa Cascio

    Cerebral Cortex, 31(11), 5188–5205, 2021

  • Sulcal Depth-based Cortical Shape Analysis in Normal Healthy Control and Schizophrenia Groups

    Ilwoo Lyu, Hakmook Kang, Neil Woodward, Bennett Landman

    SPIE Medical Imaging 2018, SPIE10574, 1057402, Houston, TX, 2018 · oral presentation