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

Abstract

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.

Diffusion‐weighted imaging of hyperpolarized [13C]urea in mouse liver

“…Our results for ADC measurements of water and urea in solution agree with those of prior studies, as do the results for the water ADC of normal mouse liver . Using a spectroscopic DW sequence, Sogaard et al observed a similar compartmentalization effect in muscle with HP [1‐ 13 C]pyruvate as the extracellular agent, and HP [1‐ 13 C]lactate as the intracellular compound.…”

“…One possible reason that we did not detect a change with progression of fibrosis is that there was not severe enough liver fibrosis in this mouse model to detect a significant change (maximum fibrosis grade was 3 on a scale from 0 to 6). This possibility is supported by the fact that we did not observe a decrease even in the proton ADC, which has been observed by other researchers using similar but more severe animal models of liver fibrosis and in humans with advanced fibrosis . In a study performed in a CCl 4 rat model of liver fibrosis, 1 H ADC decreased from ∼(1.5 ± 0.3) × 10 −3 mm 2 /s in healthy livers to ∼(1.0 ± 0.2) × 10 −3 mm 2 /s in fibrotic livers with 14% fibrosis volume density .…”

“…In a study performed in a CCl 4 rat model of liver fibrosis, 1 H ADC decreased from ∼(1.5 ± 0.3) × 10 −3 mm 2 /s in healthy livers to ∼(1.0 ± 0.2) × 10 −3 mm 2 /s in fibrotic livers with 14% fibrosis volume density . Similarly, in another study where CCl 4 was administered to rats for up to 8 weeks, the ADC decreased when compared to baseline, although there was also a large variability of the results: ADCs at baseline ranged between 0.6 and 1.1 (×10 −3 mm 2 /s); ADCs in stage 2–3 fibrotic livers (4 weeks post‐treatment) were between 0.4 and 1.0 (×10 −3 mm 2 /s); and ADCs in cirrhotic livers (8 weeks post‐treatment) ranged between 0.5 and 0.9 (×10 −3 mm 2 /s) . In all these studies, and also in ours, measurements were performed at least 2 days after the final CCl 4 injection to exclude acute toxicity and inflammation effects in the results.…”

“…Conventionally, DWI is performed using endogenous water molecules. In clinical and preclinical settings, DWI has been used to measure molecular movement of water in order to study tissue microstructure …”

The effects of ageing on mouse muscle microstructure: a comparative study of time‐dependent diffusion MRI and histological assessment

“…This effect was used to estimate myofibre size and sarcolemmal permeability. Since then, other studies have measured the time dependence of diffusivity in skeletal muscle, other organs and other pathologies . More recently, structural parameters, such as fibre size and membrane permeability of human calf muscles, have been quantified in both adult healthy subjects and patients using a biophysical model applied to time‐dependent diffusion measurements.…”