Biological processes like growth, aging, and disease progression are generally studied with follow-up scans taken at different time points, i.e., with image time series (TS) based analysis. Comparison between TS representing a biological process of two individuals/populations is of interest. A metric to quantify the difference between TS is desirable for such a comparison. The two TS represent the evolution of two different subject/population average anatomies through two paths. A method to untangle and quantify the path and inter-subject anatomy(shape) difference between the TS is presented in this paper. The proposed metric is a generalized version of Fr\'echet distance designed to compare curves. The proposed method is evaluated with simulated and adult and fetal neuro templates. Results show that the metric is able to separate and quantify the path and shape differences between TS.

翻译：生物过程如生长、衰老及疾病进展通常通过不同时间点的随访扫描（即基于图像时间序列的分析）进行研究。比较代表两个个体/群体生物过程的时间序列（TS）具有重要研究意义。为实现此类比较，需构建一种量化TS间差异的度量方法。两个TS分别代表两个不同受试者/群体平均解剖结构沿两条路径的演变过程。本文提出一种解耦并量化TS之间路径差异与受试者间解剖结构（形状）差异的方法。所提出的度量是用于比较曲线的Fréchet距离的广义版本。通过模拟实验及成人与胎儿神经模板数据对方法进行验证。结果表明该度量能够有效分离并量化TS间的路径差异与形状差异。