Quantitative Photoacoustic Reconstruction of the Optical Properties of Intervertebral Discs Using a Gradient Descent Scheme

Photonics

Anabela Da Silva¹  Antoine Capart¹  Julien Wojak¹  Olivier Boiron²  Roman Allais²  Moncef Ghiss³ 

[1] Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France;CNRS, Centrale Marseille, IRPHE, Aix Marseille University, 13013 Marseille, France;Mechanical Laboratory of Sousse, National Engineering School of Sousse, University of Sousse, Sousse 4054, Tunisia;

关键词: intervertebral disc;    inverse problem;    photoacoustic imaging;    quantitative photoacoustic tomography;    gradient descent;   

DOI  :  10.3390/photonics9020116

来源: DOAJ

【 摘 要 】

The intervertebral discs (IVD) are among the essential organs of the human body, ensuring the mobility of the spine. These organs possess a high proportion of water. However, as the discs age, this content decreases, which can potentially lead to various diseases called degenerative disc diseases. This water content is therefore an important indicator of the well-being of the disc. In this paper, we propose photoacoustic imaging as a means of probing a disc and quantitatively recovering its molecular composition, which should allow concluding on its state. An adjoint-assisted gradient descent scheme is implemented to recover the optical absorption coefficient in the disc, from which, if spectroscopic measurements are performed, the molecular composition can be deduced. The algorithm was tested on synthetic measurements. A realistic numerical phantom was built from magnetic resonance imaging of an actual IVD of a pig. A simplified experiment, with a single laser source, was performed. Results show the feasibility of using photoacoustics imaging to probe IVDs. The influences of exact and approximate formulations of the gradient are studied. The impact of noise on the reconstructions is also evaluated.

【 授权许可】

Unknown