The origin of the hepatic artery is known to be highly variable, as reported by Michels in 1966 and other authors. This variability has an indisputable impact regarding hepatic, pancreatic and upper gastro-intestinal surgery.

As the investigators go deeper into the liver's parenchyma, full-liver and segment IV studies have also found high levels of variability. Only few cadaveric studies have analyzed the entire liver and with limited sample size.

The current CT technology allows for an accurate analysis of the arterial branching thanks to the 0.625mm voxel.

The aim of this CT study is to describe the anatomy of hepatic arterial segmental branching from the origin of the hepatic artery.

Inclusion Criteria:

• patients undergoing CT with arterial abdominal imaging

Exclusion Criteria:

• imaging with radiological artefact (movement, biliary prothesis,..)
• hepatic resection (except small non anatomic resections)

Systematic inclusion of patients undergoing CT imaging with arterial abdominal contrast between November 2019 and April 2020