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加重要。然而，目前评估皮瓣活力仅使用主观临床标准或活检。同样，头颈部重建手术领域也在努力降低高达14%的皮瓣总损失率。除了明显的失败外，并发症发生率从21%到43%不等，使患者在ICU的住院时间延长，生活质量下降，并增加了医疗费用。在美国，每年有超过87,000名患者接受某种类型的头颈部重建，因此迫切需要能够在术中和术后对皮瓣生存能力进行客观、无创评估的新技术。指导本研究的假设是，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，为氧合、代谢和水合作用等生理参数提供定量测量。这些信息可用于术中和术后监测面部皮瓣移植的生存能力，以无创的方式和实时。最先进的近红外内源性成像由多光谱空间频域成像（SFDI）组成，可以在大视场上准确地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，它不是用近红外光对人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，甚至可以分离出氧合血红蛋白和脱氧血红蛋白对氧饱和度的贡献。为了测试近红外光学成像是否具有监测面部皮瓣活力的潜力，我们召集了一个来自图像引导手术、临床翻译、SFDI和重建手术的多机构专家团队。加州大学欧文分校的Bruce Tromberg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。Bernard Lee博士是BIDMC的一名活跃的、董事会认证的整形和重建外科医生。我们在BIDMC的团队在术中近红外成像方面有着悠久而富有成效的记录，特别是在整形和重建手术方面。通过与专家的紧密合作，我们的研究旨在解决面部重建手术中一个长期存在的问题，即使用近红外光对术中和术后组织移植进行无创监测。具体目标包括优化SFDI技术，以实现面部移植的实时成像（每秒< 1帧），包括对面部复杂几何形状的校正，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。通过向外科医生提供关键反馈，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，这些目标的完成有可能彻底改变头颈部手术，特别是面部移植。

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.