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

Jean-Gabriel Minonzio (1, 2) , Chao Han (1) , Didier Cassereau (1) , Quentin Grimal (1)

1 LIB - Laboratoire d'Imagerie Biomédicale [Paris]
2 Universidad de Valparaiso [Chile]

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 (Ct.Po) and bulk wave velocities. Ultrasonic attenuation is another QUS parameter which is not currently used. We assess the feasibility of in vivo 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 factor Q11-1 were 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 while Q11-1 is obtained solely from ultrasound data. The values of Ct.nBUA (6.7 ± 2.2 dB.MHz-1.cm-1) and Q11-1 (8.6±3.1 %) were consistent with the literature data and were correlated to Ct.vBMD (R2 =0.92, p<0.01, RMSE = 0.56dB.MHz-1.cm-1, and R2 =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 in vivo at the one-third distal radius and that it provides an information on bone quality as attenuation values highly correlated to Ct.vBMD. It remains to ascertain that Ct.nBUA and Q11-1 measured 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 cortical thickness, porosity and bulk wave velocities in multimodal cortical bone QUS methods.

Mots clés: cortical bone; broadband ultrasonic attenuation; Quantitative Ultrasound; in vivo measurement; Orthogonal Matching Pursuit; sparse reconstruction; Q factor

Domaines: Sciences du Vivant [q-bio]

Jean-Gabriel Minonzio, Chao Han, Didier Cassereau, Quentin Grimal. In vivo pulse-echo measurement of apparent broadband attenuation and Q factor in cortical bone: a preliminary study. Physics in Medicine and Biology, 2021, ⟨10.1088/1361-6560/ac1022⟩. ⟨hal-03276444⟩