Increased Brownian Motion of Water Molecules in Livers With Advanced Fibrosis: Preclinical and Clinical Observations...

Area of Science:

• Biomedical Imaging
• Medical Physics
• Hepatology

Background:

• Liver fibrosis is characterized by increased water content, yet apparent diffusion coefficient (ADC) typically decreases.
• This decrease is attributed to T2 shine-through, where prolonged T2 in fibrosis reduces signal decay between low and high b-value images.
• Slow diffusion coefficient (SDC) is proposed to overcome T2 shine-through by focusing on Brownian motion.

Purpose of the Study:

• To evaluate the utility of SDC in assessing liver fibrosis.
• To compare ADC and SDC changes in induced liver fibrosis models in rats and human data.
• To investigate the relationship between fibrosis stage and diffusion metrics.

Main Methods:

• Calculated ADC and SDC in a rat model of liver fibrosis induced by biliary duct ligation (BDL).
• Analyzed ADC and SDC from three human liver fibrosis datasets (male subjects only).
• Correlated diffusion metrics with fibrosis progression over time (rats) and severity (humans).

Main Results:

• Rat study: Liver ADC decreased stepwise post-BDL, while SDC increased stepwise.
• Human studies: All three datasets showed lower ADC and higher SDC in advanced fibrosis compared to earlier stages.
• Results consistently indicate SDC as a sensitive indicator of liver fibrosis progression.

Conclusions:

• SDC is a more robust metric than ADC for evaluating liver fibrosis, unaffected by T2 shine-through.
• Increased SDC correlates with the severity of liver fibrosis.
• SDC holds potential as a non-invasive biomarker for liver fibrosis assessment.