Microwave ablation is a minimally invasive technique whose planning relies on manufacturer tables derived from ex vivo models that do not account for patient or tumor-specific factors. In clinical practice, the actual ablation volume often differs from the planned volume due to liver characteristics, vascular proximity, and tumor biology.

This study aims to assess the variability between ablation small axis during percutaneous microwave ablation of liver lesions. The influence of patient-related (fibrosis, steatosis, portal flow) and tumor-related factors (location, histology, prior treatment) will be evaluated. Small axis and volume will be compared with volumes measured on immediate post-procedural CT and on CT/MRI at 6-12 weeks, accounting for expected tissue shrinkage.

Inclusion Criteria:

• Adult patients
• Treated with percutaneous hepatic microwave ablation under CT or ultrasound guidance
• Adult treated for one or more liver lesions
• Patients with available follow-up imaging

Exclusion Criteria:

• Two treatment cycles on the same lesion during the same session.
• Reoperation on the same lesion.
• Planned volume not available (no manufacturer data, not specified in the surgical report).
• No control imaging injected between 1 and 4 months post-procedure.
• Final ablation volume not measurable (e.g., artifacts, no injection on MRI).
• No definitive diagnosis of the nature of the tumor on imaging and no histology available.

Adult patients treated with percutaneous hepatic microwave ablation under CT or ultrasound guidance for one or more liver lesions with followed up imaging availables