Quantitative two-dimensional photoacoustic tomography of osteoarthritis in the finger joints.

We present for the first time in vivo experimental evidence that quantitative photoacoustic tomography (qPAT) has the potential to detect osteoarthritis (OA) in the finger joints. In this pilot study, 2 OA patients and 4 healthy volunteers were enrolled, and their distal interphalangeal (DIP) joints were examined photoacoustically by a PAT scanner. Tissue absorption coefficient images of all the examined joints, which were unavailable from the conventional PAT, were recovered using our finite element based qPAT approach. The recovered quantitative photoacoustic images revealed significant differences in the tissue absorption coefficient of the joint cavity (cartilage and synovial fluid) between the OA and normal joints.