The dual-energy X-ray absorptiometry (DEXA) is the most commonly used technique for bone mass density (DMO), although the quantitative calcaneus bone ultrasonometry (USQ) shows good results as a predictor for fracture risk. We compared the results obtained by these two methods in patients referred to the Endocrine Division at the Universidade Federal de São Paulo for DEXA evaluation. A total of 189 patients were studied, 165 women / 24 men, with ages from 20 to 84 years (Mi: 51 and 53, respectively for women and men) with distinct diagnosis. All were submitted on the same day to DEXA (Lunar,DPX-L) for lumbar spine (LOMB), neck (COLO) and major throcanter (TROC) and to USQ of calcaneus (Lunar, Aquilles), measuring speed of sound (SOS) and broadband ultrasound attenuation (BUA). A significant positive correlation was found between DEXA values in all sites and USQ. The best correlation was seen in men, between TROC and SOS (r=0.82). When only individuals 50 years or older (n=102) were evaluated, the coefficient of correlation was lower than in the younger than 50, but still significant. In evaluating the utility of USQ as a screening for DEXA measurement, we found that 21.4% of patients with normal values for T score on USQ were osteopenic or osteporotic on TROC. This discrepancy was even more evident on LOMB, where 29.9% of the patients with normal DMO presented T<-1 on USQ, and 35.8% of the patients with normal USQ had T<-1 on DMO of the same region. The coefficient of variation of USQ obtained after 9 measurements in the same person on different days was 0.66% for SOS and 2.75% for BUA. In conclusion, the USQ is only moderately related to DMO and has little utility as a screening for DEXA examination. Its value to determine fracture risk is already established, however prospective studies are necessary to evaluate its usefulness in the diagnosis and follow-up of osteoporosis.
Bone ultrasonometry; Bone densitometry; Bone mass
