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

PURPOSE: 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.
MATERIALS AND METHODS: Forty PSC patients (50 ± 12.6 years) and ten controls (49.5 ± 13.0 years) were scanned using a DWI spin echo echo-planar sequence (b-factors 0-800 s/mm2) on a 3-T MRI system and DXA (76 kVp). The apparent diffusion coefficient (ADC) and T-score were correlated to laboratory and clinical details using Pearson correlation.
RESULTS: In DXA-diagnosed osteoporosis (n = 3) and osteopenia (n = 12), the mean ADC was decreased (0.26 ± 0.03 and 0.30 ± 0.07 × 10-3 mm2/s) compared to patients with normal DXA scan results (n = 25; 0.32 ± 0.06 × 10-3 mm2/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).
CONCLUSION: 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.