Dynamic OCE with acoustic micro-tapping for in vivo monitoring of skin graft surgeries

摘要 该项目的目标是开发一种非接触，非侵入性的临床工具，以表征，成像和 使用定量、体积、亚毫米分辨率的杨氏图谱监测皮肤移植手术 基于光学相干弹性成像（OCE）的模量。 与皮肤弹性有关或直接由皮肤弹性定义的因素（如收缩力和剪切力）是 全层皮肤移植（FTSG）手术最常见的并发症之一。此外，收件人 当其弹性与移植的供体组织相匹配时，部位功能最佳。拥有数千万 仅在美国每年进行的美容手术中，外科美容显然是至关重要的，特别是 当在面部、颈部或乳房上进行手术时。目前还没有临床工具，甚至 方法，可以定量映射皮肤的杨氏模量和各向异性在体内。我们建议绘制这些 使用非接触、完全无创的方法，以亚毫米的空间分辨率测量皮肤中的参数， 几乎是真实的时间。我们假设，量化皮肤弹性在体内将使显着的创新， 整形外科、烧伤外科、肿瘤外科和皮肤科的所有领域都可以改变患者的组织 通过医疗、放射或手术干预，获得高质量和弹性的产品。 为了实现我们的目标，我们提出了一种新的非接触OCE方法。我们的方法是基于：（一）声学 微敲击（AµT），使用在空气中传播的超声波在软介质中发射机械波， 最高的效率和最好的分辨率在所有非接触波激发方法，（ii）国家的最先进的真实的- 时间4-D PhS-OCT成像以跟踪波传播，以及（iii）杨氏体积图的重建 模量和各向异性使用成像的波场在皮肤分析与横向各向同性模型。 SA 1将专注于完善以前开发的机械波分析和数值模型 传播在皮肤考虑其分层各向异性结构，并开发算法来重建 皮肤模量然后，SA 2将开发一种用于体内皮肤测量的自动化AµT-OCE成像系统， 临床环境。我们将进行常规测量皮肤弹性模量在体内健康 志愿者了解皮肤弹性特性的正常变化，在正常的代表性人口 以帮助定义在匹配皮肤弹性特性中可能的预期改善水平 在FTSG程序中。SA 3将重点关注在移植过程中移植皮肤弹性特性的体内监测变化。 临床移植程序，包括术前绘制供体皮肤的弹性特性， FTSG的基本结构和弹性参数的受体位点和映射纵向变化 和周围组织的影响如果成功，这个项目可以成为 多个连续项目测试是否可以使用 OCE的信息，以帮助选择最佳的供体组织移植和指导手术后的程序。

Abstract The goal of this project is a develop a non-contact, non-invasive clinical tool to characterize, image and monitor skin grafting procedures using quantitative, volumetric, sub-mm resolved maps of Young's modulus based on Optical Coherence Elastography (OCE). Factors related to or directly defined by skin's elastic properties (such as contractions and shearing forces) are among the most common complications of full thickness skin graft (FTSG) procedures. In addition, the recipient site functions best when its elastic properties are matched by transplanted donor tissue. With tens of millions of aesthetic procedures performed every year in the USA alone, surgical cosmesis is clearly critical, especially when procedures are performed on the face, neck or breast. Currently there are no clinical tools, or even methods, that can quantitatively map skin's Young's modulus and anisotropy in vivo. We propose to map these parameters in skin using a non-contact, fully non-invasive method, with sub-mm spatial resolution and nearly in real time. We hypothesize that quantifying skin elasticity in vivo will enable significant innovation within all areas of plastic surgery, burn surgery, oncologic surgery, and dermatology that modify a patient's tissue quality and elastic properties through medical, radiologic, or surgical intervention. To achieve our objective, we propose a new non-contact OCE method. Our approach is based on: (i) acoustic micro-tapping (AµT) using ultrasound propagating in air to launch mechanical waves in soft media with the highest efficiency and best resolution among all non-contact wave-excitation methods, (ii) state-of-the-art real- time 4-D PhS-OCT imaging to track wave propagation, and (iii) reconstruction of volumetric maps of Young's modulus and anisotropy using imaged wavefields in skin analyzed with a transversally isotropic model. SA1 will focus on refining previously developed analytic and numerical models of mechanical wave propagation in skin considering its layered anisotropic structure, and developing algorithms to reconstruct skin's moduli. Then, SA2 will develop a robotized AµT-OCE imaging system for in vivo skin measurements in a clinical environment. We will perform routine measurements of skin elastic moduli in vivo on healthy volunteers to understand normal variability in skin elastic properties in a representative population of normal human subjects to help define the level of expected improvements possible in matching skin elastic properties in FTSG procedures. SA3 will focus on in vivo monitoring changes in grafted skin elastic properties during grafting procedures in the clinic, including pre-operative mapping of skin's elastic properties in donor and recipient sites and mapping longitudinal changes in fundamental structural and elastic parameters of FTSGs and surrounding tissue over the reconstruction process. If successful, this project can be the starting point for multiple continuation projects testing whether new methods and clinical protocols can be developed using information from OCE to help select the best donor tissue for grafting and guide post-surgery procedures.