Kendall空间中胼胝体的黎曼形状分析：衰老与阿尔茨海默病
Riemannian Shape Analysis of the Corpus Callosum in Kendall Space: Aging and Alzheimer's Disease
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中文总结 AI 辅助
提出Kendall空间黎曼形状框架分析胼胝体衰老形态变化，定位后部亚区，优于线性基准，并揭示阿尔茨海默病破坏健康衰老轨迹。
中文摘要 AI 辅助
胼胝体（CC）是主要的白质结构，也是公认的脑衰老标志物，但大多数研究使用标量摘要对其进行量化，忽略了其边界几何形状。我们提出了一种黎曼形状空间框架，用于分析正中矢状面胼胝体的年龄相关形态变化，并将其应用于OASIS-1队列。每个轮廓由128个地标点表示，并嵌入Kendall形状空间，在该空间中平移、旋转和缩放被去除。我们推导了具有精确黎曼梯度的多元测地线回归，并使用拟合的年龄-速度场将年龄相关变形定位到五个解剖亚区。在认知正常队列（n=252）中，测地线回归优于欧几里得线性基准（R²=0.1355对比0.1216）。区域能量呈后部主导：压部承载了年龄相关形状变化的41.4%，峡部承载了23.8%，两者合计约占65%，尽管它们仅包含约35%的地标点。符号投影确认了排序（压部r=0.570；峡部r=0.473）。相比之下，在阿尔茨海默病（n=88）中，年龄解释了不到0.5%的形状方差，表明该疾病破坏了健康的衰老轨迹。仅从2D轮廓出发，切空间分类器实现了年龄组AUC为0.791，超过了最近的体积基准（0.67）。
英文摘要
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 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 posterior-dominant: the Splenium carries $41.4\%$ and the Isthmus $23.8\%$ of total age-related shape change, together accounting for $\sim 65\%$ despite comprising only $\sim 35\%$ of landmarks. Signed projections confirm the ordering (Splenium $r = 0.570$; Isthmus $r = 0.473$). 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 ($0.67$).
发表机构
- African Institute for Mathematical Sciences (AIMS), Rwanda（非洲数学科学研究所（卢旺达））
- African Institute for Mathematical Sciences (AIMS), Senegal（非洲数学科学研究所（塞内加尔））
机构由 AI 辅助整理，请以论文原文为准。
