A new system for clincial ultrasound assessment of bone

A new ultrasound device for noninvasive assessment of bone known as the QRT 2000 for Quantitative Real-Time—that is entirely self-contained, portable, and handheld is described. The QRT 2000 is powered by 4 AA rechargeable batteries and permits near real-time evaluation of a novel set of ultrasound parameters and their on-line display to the user. A clinical study has just been completed with the QRT 2000 in which 60 female subjects ranging in age from 25 to 88 were ultrasonically interrogated at their heels. The same heel was measured also using DEXA (PIXI, GE Medical Systems) and the bone mineral content (BMC) was compared with one ultrasound parameter which has been found to be extremely sensitive to bone mass. The parameter, known as the net time delay (NTD), and BMC had an associated R-squared value of 0.73, about a 13% improvement over presently marketed devices. This, coupled with the lower cost and portability of the system, makes the QRT 2000 ideally suited for use by primary care physicians in this country and abroad, and including for use in the developing world. Further improvements are being pursued through array methods (to improve reproducibility and correlations with BMD) and by incorporating other parameters particularly sensitive to architectural structure. [This research was supported by SBIR Grant No. 2R44AR045150 from the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the NIH.]