Diffusion-weighted MRI for detection of hepatic osteodystrophy in primary sclerosing cholangitis: a comparison study with dual-energy X-ray absorptiometry.

Abstract

Osteodystrophy is a frequent complication in primary sclerosing cholangitis (PSC). The aim was to test the feasibility of vertebral bone diffusion-weighted imaging (DWI) in routine liver MRI for detection of osteoporosis using dual-energy X-ray absorptiometry (DXA) as gold standard. Forty PSC patients (50±12.6years) and ten controls (49.5±13.0years) were scanned using a DWI spin echo echo-planar sequence (b-factors 0-800s/mm2) on a 3-T MRI system and DXA (76kVp). The apparent diffusion coefficient (ADC) and T-score were correlated to laboratory and clinical details using Pearson correlation. In DXA-diagnosed osteoporosis (n=3) and osteopenia (n=12), the mean ADC was decreased (0.26±0.03 and 0.30±0.07×10-3mm2/s) compared to patients with normal DXA scan results (n=25; 0.32±0.06×10-3mm2/s). No significant correlation of the ADC and T-score (r=0.24; p=0.13) was found, but the T-score correlated significantly to disease duration (r=-0.33; p=0.04). In patients with prednisolone therapy (n=7), the DXA T-score was significantly lower (-1.46±0.49 vs. -0.16±0.23; p=0.03). Diffusion-weighted MRI of the vertebral spine is a feasible technic to detect diffusion alterations caused by osteoporosis but lacks diagnostic capacities for diagnosing minor reductions of the bone mineral density detected by DXA.