Ultrasound Radiation Force Noninvasive Bone Assessment

In this work, a novel ultrasound-guided remote measurement technique is proposed for bone quality assessment. The technique utilizes an acoustic radiation force (ARF) excitation source to generate vibrational waves from the bone, and the ensuing radiating acoustic pressure is captured for analysis. Of particular interest, are extracting acoustic features related to the bone mechanical properties. Ex-vivo experiments of demineralized and intact (non-demineralized) bones are conducted, in order to determine the best acoustic features delineating the effects of demineralization. Mechanical tests demonstrate a reduction in the bone elastic modulus with demineralization. The acoustic waves from the intact bones travel faster than the demineralized bones. The spectra of the acoustic response of the demineralized bones exhibit higher attenuation for frequencies below 200 kHz in comparison to the intact bones. A time-frequency analysis exhibits a frequency shift with demineralization. Acoustic features related to these observations are extracted from the acoustic response of the bare bone experiments. Thereafter, attempts are made to recover these features from bone phantom experiments with overlaying tissue-like material. The results are summarized and discussed.