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Diffuse optical tomography: Imaging multiple structural and functional features.

机译：漫射光学层析成像：成像多个结构和功能特征。

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摘要

Diffuse Optical Tomography has drawn more and more interests in the biomedical field over the recent couple of decades due to its ability to noninvasively recover not only tissue structural information but also functional and molecular properties. The contrasts that optical parameters could demonstrate in DOT are usually higher than those of the conventional methods. Based on these contrasts, different approaches had been developed applying DOT for imaging, and so far lots of efforts were spent on detecting breast cancer by imaging tissue absorption and scattering coefficients as well as hemoglobin concentration and oxygen saturation level.;In this work, we tried to expand the ability of DOT in breast cancer detection by introducing Phase-contrast diffuse optical tomography (PCDOT). PCDOT uses near-infrared diffusing light to non-invasively reconstruct tissue refractive index (RI) distribution. RI depends on the tissue’s physical and chemical properties and previous study revealed that it might serve as a promising imaging parameter in breast cancer detection. We’ve first developed a 2-step method to improve the PCDOT image both qualitatively and quantitatively at single-wavelength; then we’ve introduced a multispectral PCDOT algorithm to more efficiently reconstruct RI simultaneously with other tissue functional parameters and attempted to improve this algorithm by different structural regularization methods.;Measuring hemodynamic changes, oxygen delivery and cerebral blood flow is important for locating and interpreting pathological variations associated with epileptic disorders. We then further expanded the application of DOT by presenting a method of dynamic, noninvasive and functional diffuse optical brain imaging that is conducted simultaneously with hippocampus CA1 local field potential recordings for anesthetized rats under resting conditions and during acute chemoconvulant provoked seizures. By illuminating the scalp with near-infrared light and recovering, the backward scattered light were collected and three-dimensional (3D) absolute tissue optical absorption images with high temporal resolution were obtained using a finite-element based reconstruction algorithm. The measured tissue absorption changes were validated with optic-intrinsic-signals measurement. In the focal seizure model, the seizure focus could be identified using the technique denoted by local variations of tissue absorption level as well as hemoglobin and cerebral blood flow changes. The findings are consistent with general observations in seizures of significant local cerebral metabolism increase. Successive absorption images along with EEG signals demonstrated linearity relationships from the neurovascular coupling study, suggesting cerebral metabolism closely matches demand from neuronal changes. This preclinical study suggests that this technique is feasible to be applied to human study and can provide insights into brain function and mechanisms of seizure disorders.
机译：由于其无创地恢复组织结构信息以及功能和分子特性的能力，近几十年来，漫射光学层析成像技术在生物医学领域引起了越来越多的兴趣。光学参数可以在DOT中显示的对比度通常高于常规方法。基于这些对比，已经开发出了将DOT应用于成像的不同方法，到目前为止，人们已经通过对组织的吸收和散射系数以及血红蛋白浓度和血氧饱和度水平成像来检测乳腺癌。试图通过引入相衬漫射光学层析成像（PCDOT）来扩大DOT在乳腺癌检测中的能力。 PCDOT使用近红外漫射光以非侵入性方式重建组织折射率（RI）分布。 RI取决于组织的物理和化学性质，以前的研究表明，RI可以作为乳腺癌检测中有希望的成像参数。我们首先开发了一种两步法来从单波长定性和定量地改善PCDOT图像；然后我们引入了一种多光谱PCDOT算法，可以更有效地同时重建RI和其他组织功能参数，并尝试通过不同的结构调整方法来改进该算法。测量血液动力学变化，氧气输送和脑血流量对于定位和解释病理学很重要与癫痫病有关的变异。然后，我们通过提出一种动态，无创和功能性弥散性光学脑成像方法，进一步扩展了DOT的应用，该方法与麻醉大鼠在休息条件下以及在急性化学惊厥引起的癫痫发作中同时进行的海马CA1局部场电势记录。通过用近红外光照射头皮并进行恢复，收集了向后散射的光，并使用基于有限元的重建算法获得了具有高时间分辨率的三维（3D）绝对组织光学吸收图像。所测量的组织吸收变化通过光学-内在信号测量得到验证。在局灶性癫痫发作模型中，可以使用组织吸收水平的局部变化以及血红蛋白和脑血流变化所表示的技术来识别癫痫发作的焦点。该发现与癫痫发作中局部脑新陈代谢显着增加的一般观察结果一致。连续的吸收图像和EEG信号证明了神经血管耦合研究的线性关系，表明脑代谢与神经元变化的需求紧密匹配。这项临床前研究表明，该技术是可行的，可以应用于人体研究，并且可以提供有关脑功能和癫痫发作机制的见解。

著录项

  • 作者

    Jiang, Ruixin.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Engineering Biomedical.;Health Sciences Oncology.;Health Sciences Radiology.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 134 p.
  • 总页数 134
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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