Wavelet-based signal processing of in vitro ultrasonic measurements at the proximal femur

被引:12
作者
Dencks, Stefanie
Barkmann, Reinhard
Padilla, Frederic
Haiat, Guillaume
Laugier, Pascal
Glueer, Claus-C.
机构
[1] Univ Klinikum Schleswig Holstein, Klin Diagnost Radiol, D-24105 Kiel, Germany
[2] Univ Paris 06, Lab Imagerie Parametr, Paris, France
[3] Univ Paris 12, Lab Mecan Phys, F-94010 Creteil, France
关键词
quantitative ultrasound; speed-of-sound; proximal human femur; wavelets;
D O I
10.1016/j.ultrasmedbio.2006.12.002
中图分类号
O42 [声学];
学科分类号
070206 ; 082403 ;
摘要
To estimate osteoporotic fracture risk, several techniques for quantitative ultrasound (QUS) measurements at peripheral sites have been developed. As these techniques are limited in the prediction of fracture risk of the central skeleton, such as the hip, we are developing a QUS device for direct measurements at the femur. In doing so, we noticed the necessity to improve the conventional signal processing because it failed in a considerable number of measurements due to multipath transmission. Two sets of excised human femurs (n = 6 + 34) were scanned in transmission mode. Instead of using the conventional methods, the radio-frequency signals were processed with the continuous wavelet transform to detect their time-of-flights for the calculation of speed-of-sound (SOS) in bone. The SOS-values were averaged over a region similar to the total hip region of dual X-ray absorptiometry (DXA) measurements and compared with bone mineral density (BMD) measured with DXA. Testing six standard wavelets, this algorithm failed for only 0% to 6% of scan in test set 1 compared with 29% when using conventional algorithms. For test set 2, it failed for 2% to 12% compared with approximately 40%. SOS and BMD correlated significantly in both test sets (test set 1: r(2) = 0.87 to 0.92, p < 0.007; test set 2: r(2) = 0.68 to 0.79, p < 0.0001). The correlations are comparable with correlations recently reported. However, the number of evaluable signals could be substantially increased, which improves the perspectives of the in vivo measurements.
引用
收藏
页码:970 / 980
页数:11
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