Measurement of blood flow in tissue provides vital information for the diagnosis and therapeutic monitoring of various vascular diseases. A noncontact, camera-based, near-infrared speckle contrast diffuse correlation tomography (scDCT) technique has been recently developed for 3D imaging of blood flow index (αD_B) distributions in deep tissues up to a centimeter. A limitation with the continuous-wave scDCT measurement of blood flow is the assumption of constant and homogenous tissue absorption coefficient (μ_a). The present study took the advantage of rapid, high-density, noncontact scDCT measurements of both light intensities and diffuse speckle contrast at multiple source-detector distances and developed two-step fitting algorithms for extracting both μ_a and αD_B. The new algorithms were tested in tissue-simulating phantoms with known optical properties and human forearms. Measurement results were compared against established near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) techniques. The accuracies of our new fitting algorithms with scDCT measurements in phantoms (up to 16% errors) and forearms (up to 23% errors) are comparable to relevant study results (up to 25% errors). Knowledge of μ_a not only improved the accuracy in calculating αD_B but also provided the potential for quantifying tissue blood oxygenation via spectral measurements. A multiple-wavelength scDCT system with new algorithms is currently developing to fit multi-wavelength and multi-distance data for 3D imaging of both blood flow and oxygenation distributions in deep tissues.

中文翻译：

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从散斑对比扩散相关断层扫描 (scDCT) 测量中提取组织光学特性和血流

组织中血流的测量为各种血管疾病的诊断和治疗监测提供了重要信息。最近开发了一种非接触式、基于相机的近红外散斑对比漫反射相关断层扫描 (scDCT) 技术，用于对深达一厘米的深层组织中的血流指数 (αDB) 分布_{进行3D 成像。}血流的连续波 scDCT 测量的一个限制是假设组织吸收系数 ( μ _a ) 恒定且均匀。本研究利用快速、高密度、非接触式 scDCT 测量多个光源 - 探测器距离处的光强度和漫反射散斑对比度的优势，并开发了两步拟合算法来提取两个μ_a和 αD _B。新算法在具有已知光学特性和人类前臂的组织模拟体模中进行了测试。测量结果与已建立的近红外光谱 (NIRS) 和扩散相关光谱 (DCS) 技术进行了比较。我们新的拟合算法在体模（高达 16% 的误差）和前臂（高达 23% 的误差）中的 scDCT 测量的准确性与相关研究结果（高达 25% 的误差）相当。μ _{a 的}知识不仅提高了计算αD _{B的准确性}但也提供了通过光谱测量量化组织血氧合的潜力。目前正在开发一种具有新算法的多波长 scDCT 系统，以适应多波长和多距离数据，以对深部组织中的血流和氧合分布进行 3D 成像。