Real-Time Flap Viability Monitoring during Facial Transplantation using SFDI

描述（由申请人提供）：随着最近全脸移植的引入，确保移植移植物的存活比以往任何时候都更重要。然而，皮瓣活力目前仅使用主观临床标准或活检进行评估。同样，头颈部重建手术领域正在努力减少高达14%的总皮瓣损失率。除了明显的失败，并发症发生率从21%到43%不等，使患者在ICU停留时间延长，生活质量下降，并增加医疗费用。每年，美国有超过87，000名患者接受某种类型的头颈部重建，迫切需要能够在术中和术后客观、无创地评估皮瓣活力的新技术。 指导这项研究的假设是，近红外（NIR）光与活组织成分（即氧合血红蛋白，脱氧血红蛋白，脂质和水）深入相互作用，提供生理参数的定量测量，如氧合，代谢和水合作用。这些信息可以用于以非侵入性的方式和真实的时间监测术中和术后的面部皮瓣移植存活率。最先进的近红外内源性成像包括多光谱空间频域成像（SFDI），可以在大视场范围内准确提供组织成分的定量图像。我们建议开发的技术类似于脉搏血氧仪。但是，它不是用NIR光对身体的单个点进行采样，而是提供皮肤表面组织氧合和灌注的完整图像，甚至可以分离氧合血红蛋白和脱氧血红蛋白对氧饱和度的贡献。 为了测试NIR光学成像是否有潜力监测面部皮瓣的生存能力，我们组建了一个由图像引导手术、临床翻译、SFDI和重建手术专家组成的多机构团队。加州大学欧文分校的布鲁斯特罗姆伯格博士是生物医学光学领域的国际领导者，他的实验室首先开发了SFDI技术。伯纳德李博士是一个积极的，董事会认证的整形和重建外科医生在BIDMC。我们在BIDMC的团队在术中近红外成像方面有着长期而富有成效的记录，特别关注整形和重建手术。 通过利用专家的这种强有力的合作，我们的研究旨在解决面部重建手术中的一个长期问题，即使用NIR光在术中和术后对组织移植进行无创监测。具体目标包括优化SFDI技术，以允许面部移植的实时成像（<每秒1帧），包括校正面部的复杂几何形状，开发移植状态的定量光学度量，以及在接近人类大小的大型动物上验证优化方法。这些目标的实现有可能彻底改变头颈外科手术，特别是面部移植，为外科医生提供关键的反馈，从而使他们能够识别组织损害并在并发症发生之前预防并发症。

DESCRIPTION (provided by applicant): With the recent introduction of full-face transplantation, it is more important than ever to ensure survival of a transplanted graft. However, flap viability is currently assessed using only subjective clinical criteria or biopsy. Similarly, the field of head and neck reconstructive surgery is struggling to reduce a total flap loss rate as high as 14%. In addition to overt failures, complication rates range from 21% to 43%, leaving patients with a prolonged stay in the ICU, decreased quality of life, and additional healthcare costs. Every year, over 87,000 patients in the US undergo some type of head and neck reconstruction, and new technology that permits objective, noninvasive assessment of flap viability intraoperatively and postoperatively is desperately needed. The hypothesis guiding this study is that near-infrared (NIR) light interacts deeply with living tissue constituents, namely oxyhemoglobin, deoxyhemoglobin, lipids, and water, providing quantitative measurement of physiological parameters, such as oxygenation, metabolism, and hydration. Such information can be used to monitor facial flap transplant viability intraoperatively and postoperatively, in a noninvasive manner and in real time. State-of-the-art NIR endogenous imaging consists of multispectral spatial frequency domain imaging (SFDI) that can accurately provide quantitative images of tissue constituents over large fields of view. The technology we propose to develop is analogous to pulse oximetry. But, rather than sample a single point of the body with NIR light, it provides a complete image of tissue oxygenation and perfusion over the skin surface, and can even separate the contributions of oxyhemoglobin and deoxyhemoglobin to oxygen saturation. To test whether NIR optical imaging has the potential to monitor facial flap viability, we have assembled a multi-institutional team of experts from image-guided surgery, clinical translation, SFDI, and reconstructive surgery. Dr. Bruce Tromberg at UC Irvine is an international leader in biomedical optics whose laboratory first developed the SFDI technique. Dr. Bernard Lee is an active, board-certified plastic and reconstructive surgeon at BIDMC. Our own team at BIDMC has a long and productive track record in intraoperative NIR imaging, with a particular focus on plastic and reconstructive surgery. By leveraging this strong collaboration of experts, our study aims to solve a longstanding problem in facial reconstructive surgery, namely the noninvasive monitoring of tissue transplants intraoperatively and postoperatively using NIR light. Specific aims include optimization of the SFDI technology to permit real-time imaging (< 1 frame per second) of facial transplants, including correction for the complex geometry of the face, the development of a quantitative optical metric of the transplant status, and validation of the optimized method on large animals approaching the size of humans. Completion of these aims has the potential to revolutionize head and neck surgery, especially facial transplants, by providing critical feedback to surgeons, thus permitting them to identify tissue compromise and prevent complications before they occur.