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Main Authors: Zhang, Yilin, Harvey, Nicholas C., Fuggle, Nicholas R., Attar, Rahman
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.22649
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author Zhang, Yilin
Harvey, Nicholas C.
Fuggle, Nicholas R.
Attar, Rahman
author_facet Zhang, Yilin
Harvey, Nicholas C.
Fuggle, Nicholas R.
Attar, Rahman
contents Dual-energy X-ray absorptiometry (DXA) is widely used for large-scale skeletal assessment, yet learning controllable and interpretable factor-specific anatomical variation remains challenging. We propose a metadata-conditioned causal hierarchical variational autoencoder (CHVAE) for causally consistent generation of anteroposterior (AP) spine DXA images from the UK Biobank (UKB). The model is trained on 3,743 raw AP spine scans from the first imaging visit and conditioned on basic participant attributes and lumbar morphometry. Causal consistency is evaluated in a baseline-to-follow-up setting using abduction--action--prediction (AAP): latent variables are abducted from baseline images, age is intervened to the repeat-imaging value, and the resulting counterfactual follow-up morphometry is compared with observed repeat-imaging measurements. Results show strong absolute-level agreement for key vertebral morphometry variables under age intervention, supporting intervention-aligned synthesis of anatomically plausible DXA images.
format Preprint
id arxiv_https___arxiv_org_abs_2605_22649
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle From Baseline to Follow-Up: Counterfactual Spine DXA Image Synthesis in UK Biobank Using a Causal Hierarchical Variational Autoencoder
Zhang, Yilin
Harvey, Nicholas C.
Fuggle, Nicholas R.
Attar, Rahman
Computer Vision and Pattern Recognition
Machine Learning
Dual-energy X-ray absorptiometry (DXA) is widely used for large-scale skeletal assessment, yet learning controllable and interpretable factor-specific anatomical variation remains challenging. We propose a metadata-conditioned causal hierarchical variational autoencoder (CHVAE) for causally consistent generation of anteroposterior (AP) spine DXA images from the UK Biobank (UKB). The model is trained on 3,743 raw AP spine scans from the first imaging visit and conditioned on basic participant attributes and lumbar morphometry. Causal consistency is evaluated in a baseline-to-follow-up setting using abduction--action--prediction (AAP): latent variables are abducted from baseline images, age is intervened to the repeat-imaging value, and the resulting counterfactual follow-up morphometry is compared with observed repeat-imaging measurements. Results show strong absolute-level agreement for key vertebral morphometry variables under age intervention, supporting intervention-aligned synthesis of anatomically plausible DXA images.
title From Baseline to Follow-Up: Counterfactual Spine DXA Image Synthesis in UK Biobank Using a Causal Hierarchical Variational Autoencoder
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2605.22649