Body Charts from CT Segmentations across the Adult Lifespan: Large-scale Cross-sectional and Longitudinal Analyses

Purpose To model the distribution of CT-derived whole-body anatomic volumes across adulthood and establish comprehensive cross-sectional and longitudinal reference charts, addressing the current lack of non-brain CT-based whole-body standards. Materials and Methods Retrospective CT scans acquired from March 2017 to April 2025 (189,710 scans, 106,563 patients) from the institutional PACS and two external datasets (19,393 and 1,158 patients, respectively), were automatically segmented into 104 structures (totaling 7.8 million volumes). An automated quality control pipeline, incorporating a novel outlier removal strategy based on strong correlation between organ sizes, ensured data reliability. Cross-sectional normative models were constructed using Generalized Additive Models for Location, Scale, and Shape (GAMLSS) to capture non-linear age effects through fractional polynomial functions. A Generalized Additive Mixed Model (GAMM) was employed for longitudinal analyses to assess within-subject changes over follow-up visits. Results All anatomic structures followed complex, non-linear age trajectories, with marked sex differences and distinct CT contrast effects on vascular structures. Bootstrap resampling confirmed the stability and precision of these volume trajectories in both central tendency and variability. An exemplary cardiomegaly case-control analysis showed significantly increased centile scores ( P < .001) for heart volume. The longitudinal analysis further revealed significant age-sex interactions influencing within-subject trajectories. Conclusion Cross-sectional and longitudinal reference models were developed from CT-derived anatomic volumes that map the trajectories of body structural change across adulthood. These body charts facilitate robust quantification of individual deviations via centile scores. ©RSNA, 2025