Effect of diffusion time on liver DWI: an experimental study of normal and fibrotic livers

Magn Reson Med. 2014 Nov;72(5):1389-96. doi: 10.1002/mrm.25035. Epub 2013 Nov 20.


Purpose: To investigate whether diffusion time (Δ) affects the diffusion measurements in liver and their sensitivity in detecting fibrosis.

Methods: Liver fibrosis was induced in Sprague-Dawley rats (n = 12) by carbon tetrachloride (CCl(4)) injections. Diffusion-weighted MRI was performed longitudinally during 8-week CCl(4) administration at 7 Tesla (T) using single-shot stimulated-echo EPI with five b-values (0 to 1000 s/mm(2)) and three Δs. Apparent diffusion coefficient (ADC) and true diffusion coefficient (D(true)) were calculated by using all five b-values and large b-values, respectively.

Results: ADC and D(true) decreased with Δ for both normal and fibrotic liver at each time point. ADC and D(true) also generally decreased with the time after CCl(4) insult. The reductions in D(true) between 2-week and 4-week CCl(4) insult were larger than the ADC reductions at all Δs. At each time point, D(true) measured with long Δ (200 ms) detected the largest changes among the 3 Δs examined. Histology revealed gradual collagen deposition and presence of intracellular fat vacuoles after CCl(4) insult.

Conclusion: Our results demonstrated the Δ dependent diffusion measurements, indicating restricted diffusion in both normal and fibrotic liver. D(true) measured with long Δ acted as a more sensitive index of the pathological alterations in liver microstructure during fibrogenesis.

Keywords: b-value; diffusion time; liver fibrosis; rat; restricted diffusion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diffusion Magnetic Resonance Imaging / methods*
  • Disease Models, Animal
  • Echo-Planar Imaging
  • Liver Cirrhosis / pathology*
  • Rats
  • Rats, Sprague-Dawley
  • Sensitivity and Specificity
  • Time Factors