Local and Global Function Model of the Liver.

Area of Science:

• Medical Imaging and Radiation Oncology
• Computational Biology and Bioinformatics
• Hepatology

Background:

• Individualized adaptive radiation therapy (RT) requires precise assessment of organ function.
• Liver function varies regionally and can be affected by treatments like RT.
• Developing models to predict liver function is crucial for optimizing RT strategies.

Purpose of the Study:

• To create a local and global liver function model.
• To support individualized adaptive radiation therapy (RT) planning.
• To correlate regional and organ function measurements with RT outcomes.

Main Methods:

• Developed a liver function model incorporating functional volume and subunit variations.
• Modeled local function probabilities using sigmoid functions based on MRI-derived portal venous perfusion.
• Fitted the global function model to indocyanine green retention rates and validated using cross-validation and patient subgroups (HCC vs. non-HCC).

Main Results:

• Established perfusion thresholds for local liver function probability (0.5 at 68.6 mL/(100 g·min), 0.9 at 98 mL/(100 g·min)).
• Identified loss of global function contribution below a perfusion of 38 mL/(100 g·min).
• Demonstrated stable model parameters via cross-validation and showed reduced local function probability per perfusion unit in HCC patients.

Conclusions:

• The developed liver function model enables better assessment of individual and regional hepatic function dose-responses.
• Provides guidance for individualized treatment planning in radiation therapy.
• Facilitates more precise and effective RT strategies for liver cancer patients.