Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA.
Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA.
Sci Rep. 2017 Nov 3;7(1):15026. doi: 10.1038/s41598-017-15147-5.
By using our dual-modality system enabling simultaneous real-time ultrasound (US) and photoacoustic (PA) imaging of human peripheral joints, we explored the potential contribution of PA imaging modality to rheumatology clinic. By performing PA imaging at a single laser wavelength, the spatially distributed hemoglobin content reflecting the hyperemia in synovial tissue in metacarpophalangeal (MCP) joints of 16 patients were imaged, and compared to the results from 16 healthy controls. In addition, by performing PA imaging at two laser wavelengths, the spatially distributed hemoglobin oxygenation reflecting the hypoxia in inflammatory joints of 10 patients were imaged, and compared to the results from 10 healthy controls. The statistical analyses of the PA imaging results demonstrated significant differences (p < 0.001) in quantified hemoglobin content and oxygenation between the unequivocally arthritic joints and the normal joints. Increased hyperemia and increased hypoxia, two important physiological biomarkers of synovitis reflecting the increased metabolic demand and the relatively inadequate oxygen delivery in affected synovium, can both be objectively and non-invasively evaluated by PA imaging. The proposed dual-modality system has the potential of providing additional diagnostic information over the traditional US imaging approaches and introducing novel imaging biomarkers for diagnosis and treatment evaluation of inflammatory arthritis.
利用我们的双通道系统，实现了对人体外周关节的实时超声（US）和光声（PA）成像，我们探索了 PA 成像在风湿病学临床中的潜在应用。通过在单一激光波长下进行 PA 成像，对 16 名患者的掌指（MCP）关节滑膜组织充血的血红蛋白含量分布进行成像，并与 16 名健康对照者的结果进行比较。此外，通过在两个激光波长下进行 PA 成像，对 10 名患者炎性关节缺氧的血红蛋白氧合程度的分布进行成像，并与 10 名健康对照者的结果进行比较。PA 成像结果的统计分析表明，在明确的关节炎关节和正常关节之间，血红蛋白含量和氧合的定量存在显著差异（p<0.001）。充血增加和缺氧增加，这两个反映受累滑膜代谢需求增加和供氧相对不足的滑膜炎重要生理生物标志物，均可通过 PA 成像进行客观和非侵入性的评估。双通道系统有可能为传统 US 成像方法提供额外的诊断信息，并为炎症性关节炎的诊断和治疗评估引入新的成像生物标志物。
