Imaging liver metastases: review and update

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Radiologic diagnosis of liver metastasis involves detection, characterization, and staging.
• Histopathologic knowledge guides accurate interpretation of imaging findings.
• Choosing appropriate imaging methods is critical for radiologists.

Purpose of the Study:

• To emphasize the importance of histopathologic knowledge in liver metastasis diagnosis.
• To discuss the optimal use of contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) phases.
• To highlight the role of advanced MRI techniques and liver-specific contrast agents.

Main Methods:

• Review of imaging characteristics of liver metastases based on histopathology.
• Discussion of contrast-enhanced CT and MRI imaging phases (hepatic arterial, portal venous, delayed).
• Exploration of MRI's capabilities in assessing metastasis composition and diffusion.

Main Results:

• Routine hepatic arterial dominant-phase imaging is often not necessary for hypovascular metastases.
• Portal venous phase imaging is essential for metastasis detection, vessel invasion assessment, and evaluating necrosis/fibrosis.
• Delayed-phase imaging aids in detecting intratumoral fibrosis and tissue characterization.
• MRI provides comprehensive data on vascularity, water content, hemorrhage, fibrosis, necrosis, and diffusion.
• Liver-specific contrast agents enhance MRI diagnostic accuracy for liver metastases.

Conclusions:

• Histopathologic understanding is key to selecting appropriate imaging techniques for liver metastases.
• Portal venous and delayed-phase imaging are critical for comprehensive assessment.
• MRI, especially with liver-specific contrast agents, offers advanced diagnostic capabilities for liver metastases.