Purpose. This study was designed to establish whether the
measurement of apparent diffusion coefficients (ADCs) is
clinically accurate in diagnosing liver fibrosis in a selected series
of cirrhotic patients.
Materials and methods. Twenty-eight cirrhotic patients (mean age
58.1 years) with histologically proven liver fibrosis and 29 healthy
controls (mean age 43.8 yeas) underwent liver diffusion-weighted
magnetic resonance (MR) using a 1.5-Tesla (T) magnet equipped
with a phased-array coil. Diffusion studies with parallel imaging
[generalized autocalibrating partially parallel acquisitions
(GRAPPA)] were performed within a single breath-hold using a
single-shot spin-echo echo-planar sequence (TE 74 ms) using four
b values: b=0, 150, 250 and 400 s/mm2. A unidirectional diffusion
gradient was applied. ADCs were measured on ADC maps.
Results. Mean ADC was significantly lower in cirrhotic livers
than in controls (1.11±0.16 vs. 1.54±0.12×10-3mm2/s) (p<0.0001).
Receiver operating characteristic (ROC) analysis showed an area
under the curve (AUC) of 0.96 [confidence interval (CI)
95%:(0.87; 0.94)], demonstrating higher sensitivity and specificity
(92.9% and 100%, respectively) for an ADC cutoff of
1.31×10-3mm2/s. Positive predictive value (PPV), negative
predictive value (NPV) and overall accuracy were 100%, 99.9%
and 96.4%, respectively.
Conclusions. Diffusion-weighted MRI is an accurate tool in
evaluating advanced liver fibrosis if an optimised single-shot spinecho
echo-planar sequence with maximum intermediate b value is
used. The ADC threshold for liver fibrosis was 1.31×10-3mm2/s.
