Calcaneal ultrasound bone densitometry in inflammatory bowel disease--a comparison with double x-ray densitometry of the lumbar spine.

OBJECTIVE: The aim of this study was to measure ultrasound (US) densitometric parameters [Broadband Ultrasound Attenuation (BUA), Speed of Sound (SOS), and stiffness of the os calcis] in patients with inflammatory bowel disease (IBD) and to compare the results with those obtained with conventional x-ray absorptiometry (DXA) of the lumbar spine.
METHODS: Twenty-two patients with Crohn's disease (13 with ileal and nine with ileocolonic disease), 11 patients with ulcerative colitis (eight with left-sided and three with pancolitis), and 18 healthy controls. US densitometry of the right heel and DXA of the lumbar spine were performed within the same day.
RESULTS: Compared to controls, IBD patients had significantly lower values with both methods, US and DXA. Forty-nine percent of patients had a lumbar T score below -1. Calcaneal SOS and stiffness of these patients were significantly reduced (p < 0.03 and p < 0.05, respectively). Positive significant correlations were found between lumbar DXA and calcaneal US parameters. Lumbar bone density and calcaneal US stiffness correlated inversely with the lifetime prednisone intake (p < 0.03 andp < 0.05, respectively), but not with age or duration of disease. A cut-off level of 80 dB/MHz for calcaneal BUA predicted axial osteopenia correctly in 74%, but some underestimation of spinal BMD was observed, especially in female patients with Crohn's disease.
CONCLUSION: US evaluation of the os calcis gives results similar to those of conventional DXA and therefore may be used for screening IBD patients for axial osteoporosis. Because US does not expose patients to radiation, repeated measurements are possible and may be used to assess short term variations and the effect of treatment of IBD-associated bone disease.