Reconstruction of three-dimensional organ of Corti micromechanical motion patterns via optical coherence tomography

光学相干断层成像技术（OCT）用于耳蜗力学研究中的成像和测量 Corti复合器官（OCC）中的振动，OCC是耳蜗内螺旋的感觉组织。OCT可以 可用于同时测量沿光轴沿着的许多点处的亚纳米振动。 然而，该光轴通常不具有与解剖结构的直接关系。 耳蜗这导致两个模糊性：1）所测量的运动是真实三个运动的投影， 在解剖学上不重要的轴上的三维运动，以及2） 测量的结构仅沿光轴沿着是已知的，这不足以使结构相关 从解剖学上讲这导致对OCT数据的解释的限制，因为在两个位置进行测量， 不同的取向不能合理地相互比较。即使同时测量 不能充分比较单个测量中的结构，因为它们的相对位置不 必须知道。这个项目的目的是克服当代OCT的这些局限性 实验并获得沙鼠耳蜗底部微观力学的完整三维图像。 这些定量的三维测量将揭示机械性能， 耳蜗调谐和传导，如OCC有效质量和静纤毛旋转。目标1： 建议在三个月内在沙鼠耳蜗基底的体积中使用密集间隔的OCT测量， 不同的方向来重建三维OCC运动。在目标2中，我们建议使用 压缩感测，以减少该重建所需的空间样本的数量，以及 从而减少该三维振动数据的采集时间。目标2基于 期望-将在本项目中进行测试-可以表达OCC的运动模式 稀疏地存在于某个基函数集合中，例如小波基。找到这样一个基础， 重要的洞察力的空间结构在体内耳蜗微观力学。该方法将在 通过公共GitHub存储库提供。

Optical coherence tomography (OCT) is used in cochlear mechanics research to image and measure vibrations in the organ of Corti complex (OCC), the sensory tissue that spirals within the cochlea. OCT can be used to measure sub-nanometer vibrations at many points along the optical axis simultaneously. However, this optical axis does not generally bear a straightforward relation to the anatomy of the cochlea. This results in two ambiguities: 1) the measured motion is a projection of the true three- dimensional motion onto an axis that is not anatomically important, and 2) the relative locations of measured structures are known only along the optical axis, which is not sufficient to relate the structures anatomically. This results in limitations for the interpretation of OCT data, as measurements taken at two different orientations cannot be reasonably compared to one another. Even simultaneously measured structures in a single measurement cannot be adequately compared, as their relative locations are not necessarily known. The purpose of this project is to overcome these limitations of contemporary OCT experiments and gain a full three-dimensional picture of micromechanics in the base of the gerbil cochlea. These quantitative three-dimensional measurements will reveal mechanical properties governing cochlear tuning and transduction, such as the OCC effective mass and stereocilia pivoting. In Aim 1, we propose the use of densely spaced OCT measurements in a volume of the gerbil cochlea base at three different orientations to reconstruct the three-dimensional OCC motion. In Aim 2, we propose the use of compressed sensing to reduce the number of spatial samples required for this reconstruction, and consequently reduce the acquisition time of this three-dimensional vibration data. Aim 2 is based in the expectation - which will be tested in this project - that the motion pattern of the OCC can be expressed sparsely in some set of basis functions, for example, a wavelet basis. Finding such a basis would give significant insight into the spatial structure of in vivo cochlear micromechanics. The method will be made available through a public GitHub repository.