Diagnostic disagreement of imaging quantitative sonography of the calcaneus with dual X-ray absorptiometry of the spine and femur.

Abstract

This study evaluates the diagnostic agreement between imaging quantitative sonography of the calcaneus and dual X-ray absorptiometry of the spine and femur for diagnosing osteoporosis. In 498 female patients (56 +/- 18 years old), bone mineral density measurements by dual X-ray absorptiometry of the lumbar spine (posteroanterior, L1--L4) and the proximal femur and imaging quantitative sonography of the calcaneus were performed. The percentage of patients having T-scores less than or equal to a threshold of -2.5 standard deviations below a young normal reference was used to compare quantitative sonography with dual X-ray absorptiometry. The diagnostic agreement was assessed using kappa scores. Approximately 30% of the patients had a T-score less than or equal to -2.5 standard deviations as assessed by imaging quantitative sonography (broadband ultrasound attenuation), 26.5% as assessed by dual X-ray absorptiometry of the spine, and 16.7--56.4% as assessed by dual X-ray absorptiometry of the different regions of interest at the femur. Kappa analysis showed that severe diagnostic disagreement exists among broadband ultrasound attenuation and dual X-ray absorptiometry (kappa = 0.28-0.42). Considerable diagnostic disagreement exists between imaging quantitative sonography and dual X-ray absorptiometry of the spine and femur. The disagreement is in the same range as that reported recently in comparisons of dual X-ray absorptiometry and nonimaging quantitative sonography. In general, no distinct advantage for imaging quantitative sonography could be found when compared with other techniques.