{
  "abstract": "The corpus callosum (CC) is a major white-matter structure and a well-established marker of brain aging, but most studies quantify it using scalar summaries that discard its boundary geometry. We present a Riemannian shape-space framework \\cite{fletcher2013geodesic-regression} for analyzing age-related morphological change in the midsagittal CC, applied to the OASIS-1 cohort. Each contour is represented by $128$ landmarks and embedded into Kendall shape space, where translation, rotation, and scale are removed. We derive a multivariate geodesic regression with exact Riemannian gradients and use the fitted age-velocity field to localize age-related deformation to five anatomical sub-regions. In the cognitively normal cohort ($n = 252$), geodesic regression outperforms the Euclidean linear benchmark ($R^2 = 0.1355$ vs.\\ $0.1216$). Regional energy is anterior-dominant: the Genu carries $46.1\\%$ and the Anterior Body $23.3\\%$ of total age-related shape change, together accounting for $\\sim 69\\%$ despite comprising only $\\sim 41\\%$ of landmarks. Signed projections confirm the ordering (Genu $r = 0.562$; Anterior Body $r = 0.507$). In contrast, age explains less than $0.5\\%$ of shape variance in Alzheimer's disease ($n = 88$), indicating that the disease disrupts the healthy aging trajectory. A tangent-space classifier achieves an age-group AUC of $0.791$ from the 2D contour alone, exceeding a recent volumetric benchmark ($0.67$).",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.05326",
  "author_total": 2,
  "authors": [
    {
      "name": "Olakunle S. Abawonse"
    },
    {
      "name": "Fatou Fall"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/b1vs1ej5r4010.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.05326",
  "fulltext_url": null,
  "id": "b1vs1ej5r4010",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.05326",
  "language": null,
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cs.CV"
    ],
    [
      "arxiv",
      "math.DG"
    ],
    [
      "arxiv",
      "math.OC"
    ],
    [
      "openalex",
      "1707|Medical Image Segmentation Techniques"
    ]
  ],
  "openalex": "W7220736937",
  "pdf_url": "https://arxiv.org/pdf/2610.05326",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/b1vs1ej5r4010.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:40Z",
      "native_id": "2610.05326",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.05326"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.DG",
      "subfield": "geometry-topology"
    },
    {
      "field": "mathematics",
      "origin": "arxiv:math.OC",
      "subfield": "optimisation-control"
    }
  ],
  "title": "Riemannian Shape Analysis of the Corpus Callosum in Kendall Space: Aging and Alzheimer's Disease",
  "title_text": "Riemannian Shape Analysis of the Corpus Callosum in Kendall Space: Aging and Alzheimer's Disease",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:40Z",
  "url": "https://research.draconitic.com/paper/b1vs1ej5r4010",
  "venue": "arXiv",
  "versions": []
}