Real-Time Flap Viability Monitoring during Facial Transplantation using SFDI

描述(申请人提供)：随着最近全面部移植的引入，确保移植后的移植物存活比以往任何时候都更加重要。然而，目前仅使用主观的临床标准或活组织检查来评估皮瓣存活。同样，头颈重建外科领域也在努力降低高达14%的总瓣膜损失率。除了明显的失败，并发症的发生率从21%到43%不等，这使得患者在ICU停留时间更长，生活质量下降，并增加了医疗成本。在美国，每年有超过8.7万名患者接受某种类型的头颈重建，迫切需要新的技术来客观、非侵入性地评估术中和术后的皮瓣存活能力。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、脂类和水深度相互作用，提供对生理参数的定量测量，如氧合作用、新陈代谢和水合作用。这些信息可以用来在术中和术后以非侵入性的方式实时监测面部皮瓣移植的活力。最先进的近红外内源成像包括多光谱空间频域成像(SFDI)，它可以在大视野内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一个点进行采样，而是提供皮肤表面组织氧合和灌流的完整图像，甚至可以区分氧合血红蛋白和脱氧血红蛋白对血氧饱和度的影响。为了测试近红外光学成像是否具有监测面部瓣存活的潜力，我们组建了一个由图像引导手术、临床翻译、SFDI和重建外科的多机构专家组成的团队。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。伯纳德·李博士是BIDMC的一名活跃的、获得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长期和富有成效的记录，尤其是在整形和重建手术方面。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外科中的一个长期问题，即术中和术后使用近红外光对组织移植进行非侵入性监测。具体目标包括优化SFDI技术以实现面部移植的实时成像(1帧/秒)，包括校正面部的复杂几何形状，开发移植状态的定量光学测量，以及对接近人类大小的大型动物验证优化方法。这些目标的完成有可能给头颈部手术，特别是面部移植带来革命性的变化，因为它向外科医生提供了关键的反馈，从而使他们能够在组织损害发生之前识别组织损害并预防并发症。

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.