The Longitudinal Abdominal CT Dataset with Expert-Validated Liver and Metastasis Segmentations

A longitudinal collection of contrast-enhanced abdominal CT scans was retrospectively assembled from 54 patients with liver metastases who underwent systemic chemotherapy. Each case includes:• CT.nii — preprocessed contrast-enhanced CT volume (NIfTI format) • LiverMask.nii — expert-validated liver segmentation • MetastasisMask.nii — expert-validated metastasis segmentation we have added the imaging acquisition dates and scan intervals to the accompanying metadata.csv file. This enhancement enables more precise longitudinal timing analysis while preserving patient anonymity. This dataset provides a unique resource for developing and evaluating methods in liver segmentation, deformable image registration, and longitudinal tumor tracking. **Ethics statement:** This data release was approved by the Institutional Review Board of the participating medical sciences university (IRB approval number provided in the full title page), with a waiver of written informed consent due to the retrospective design and complete de-identification of imaging data. **License:** This dataset is released under the Creative Commons Attribution 4.0 International (CC BY 4.0) license, allowing unrestricted use, distribution, and reproduction with appropriate citation.