Noninvasive photoacoustic tomography of human peripheral joints toward diagnosis of inflammatory arthritis

Photoacoustic and ultrasound dual-modality imaging of human peripheral joints

“…Ex vivo studies in the rat tail and human finger joints and an in vivo study in osteoarthritis demonstrated the capability of PA imaging in achieving submillimeter resolution and identifying optical properties in articular tissues and variations induced by inflammation. [7][8][9][10] However, utilizing single or limited number of transducer elements and home-fabricated sophisticated devices for signal acquisition, as in most current PA imaging systems, undermines the system compactness and imaging speed as well as repeatability of imaging findings which drastically hinders quick adaptation of novel photoacoustic tomography (PAT) techniques to clinical settings. 4,7,9 Achieving new PA imaging functions, through a commercial US unit, could accelerate the clinical acceptance of novel PAT techniques.…”

First assessment of three‐dimensional quantitative photoacoustic tomography for in vivo detection of osteoarthritis in the finger joints

“…By using 1 MHz transducers, the joint cavity can be clearly identified and be measured in this study. As shown previously in photoacoustic imaging of cadaver joints, 22 PAT was capable of imaging other interesting joint structures as well, including volar plate, tendon, and aponeurosis, when a high frequency transducer was used. In a recent study of wholebody mouse imaging using 3-D PAT, 36 both relatively large organs in centimeter size such as liver, kidney, and spleen, and small structures in millimeter size such as spinal cords, ovarian vessel, abdominal aorta, and femoral veins were clearly imaged when multiscale wavelet filter was used along with a 64-element 3.1 MHz ultrasound array.…”

“…that are absent from other imaging modalities. [18][19][20][21][22][23][24][25] While pure-optical imaging techniques, such as diffuse optical tomography, are able to detect the optical absorption/scattering abnormalities associated with soft tissues in OA and RA joints, its spatial resolution is relatively low (about 3-5 mm) for imaging tissues in approximately centimeter depth. [18][19][20][21] Photoacoustic tomography (PAT), which combines both the high optical absorption contrast and high ultrasound resolution, is able to visualize the same sensitive "color" abnormality (optical absorption contrast) with significantly improved spatial resolution (0.5 mm or better, adjustable with ultrasound frequency) for deep-tissue imaging in optically diffusive regime.…”

“…For example, tendon, aponeurosis, volar plate, subcutaneous tissue, phalanx, and other tissues around DIP joints were well differentiated when a cadaver human finger was photoacoustically scanned in cross section with a 10 MHz transducer. 22 Up to now, PAT has shown its potential to detect breast cancer, to assess vascular and skin diseases, to monitor epilepsy in small animals, to image finger joints, to visualize fluorescent proteins, and to evaluate exogenous contrast agents in molecular imaging. 22,23,[26][27][28] By combining a light transport model with the conventional PAT method, quantitative PAT (qPAT) is able to provide quantitative tissue absorption coefficient and physiological/functional parameters including hemoglobin concentration, blood oxygenation, and water content when multispectral light is used, which can further quantify the neoangiogenesis and hypoxia in diseased finger joints for more accurate diagnosis and better understanding of OA development.…”

“…22 Up to now, PAT has shown its potential to detect breast cancer, to assess vascular and skin diseases, to monitor epilepsy in small animals, to image finger joints, to visualize fluorescent proteins, and to evaluate exogenous contrast agents in molecular imaging. 22,23,[26][27][28] By combining a light transport model with the conventional PAT method, quantitative PAT (qPAT) is able to provide quantitative tissue absorption coefficient and physiological/functional parameters including hemoglobin concentration, blood oxygenation, and water content when multispectral light is used, which can further quantify the neoangiogenesis and hypoxia in diseased finger joints for more accurate diagnosis and better understanding of OA development. [39][40][41][42][43] The goal of this paper is to present a pilot clinical study that aims to assess the potential of 3-D qPAT as a sensitive detection method of OA in the finger joints.…”