In vivo pulse-echo measurement of apparent broadband attenuation and Q factor in cortical bone: a preliminary study

• Published in: Physics in medicine & biology Vol. 66; no. 15; pp. 155002 - 155014
• Main Authors: Minonzio, Jean-Gabriel, Han, Chao, Cassereau, Didier, Grimal, Quentin
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 07.08.2021
• Subjects: Bone and Bones - diagnostic imaging; Bone Density; broadband ultrasonic attenuation; cortical bone; Cortical Bone - diagnostic imaging; factor; Humans; Life Sciences; measurement; orthogonal matching pursuit; quantitative ultrasound; Radius - diagnostic imaging; sparse reconstruction; Ultrasonography; quantitative ultrasound; Q factor; broadband ultrasonic attenuation; in vivo measurement; sparse reconstruction; cortical bone; orthogonal matching pursuit; Orthogonal Matching Pursuit; Quantitative Ultrasound
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/1361-6560/ac1022

Quantitative ultrasound (QUS) methods have been introduced to assess cortical bone health at the radius and tibia through the assessment of cortical thickness (Ct.Th), cortical porosity and bulk wave velocities. Ultrasonic attenuation is another QUS parameter which is not currently used. We assessed the feasibility of measurement of ultrasonic attenuation in cortical bone with a broadband transducer with 3.5 MHz center frequency. Echoes from the periosteal and endosteal interfaces were fitted with Gaussian pulses using sparse signal processing. Then, the slope of the broadband ultrasonic attenuation (Ct.nBUA) in cortical bone and quality factorQ11-1were calculated with a parametric approach based on the center-frequency shift. Five human subjects were measured at the one-third distal radius with pulse-echo ultrasound, and reference data was obtained with high-resolution x-ray peripheral computed tomography (Ct.Th and cortical volumetric bone mineral density (Ct.vBMD)). Ct.Th was used in the calculation of Ct.nBUA whileQ11-1is obtained solely from ultrasound data. The values of Ct.nBUA (6.7 ± 2.2 dB MHz .cm ) andQ11-1(8.6 ± 3.1%) were consistent with the literature data and were correlated to Ct.vBMD (R2=0.92,p<0.01, RMSE = 0.56 dB.MHz .cm , andR2=0.93,p<0.01, RMSE = 0.76%). This preliminary study suggests that the attenuation of an ultrasound signal propagating in cortical bone can be measured at the one-third distal radius and that it provides an information on bone quality as attenuation values were correlated to Ct.vBMD. It remains to ascertain that Ct.nBUA andQ11-1measured here exactly reflect the true (intrinsic) ultrasonic attenuation in cortical bone. Measurement of attenuation may be considered useful for assessing bone health combined with the measurement of Ct.Th, porosity and bulk wave velocities in multimodal cortical bone QUS methods.