IMPROVING THE DIAGNOSTIC POTENTIAL OF OCT FOR VULNERABLE

该项目是麻省总医院、国王学院和麻省理工学院研究人员之间持续合作的延续。这项工作的长期目标是开发一种新的高分辨率血管内成像方法，以克服目前心脏诊断中的局限性，主要是识别可能发生破裂的冠状动脉病变。大多数心肌梗死(MIs)是由于冠状动脉中的小斑块而不是大斑块破裂造成的。这些斑块含有较多的脂质，并有较薄的内膜帽。当这些斑块破裂时，它们会释放血栓物质进入血液，形成血栓，血管闭塞。这些小斑块超出了目前任何可用的成像设备的检测极限。因此，临床上确实需要一种能够在破裂前识别这些病变的成像技术。光学相干层析成像(OCT)是一种新的高分辨率成像方法，在评估高危斑块方面显示出巨大的潜力。OCT类似于超声波，测量的是红外线而不是声音的强度。它的分辨率目前比目前分辨率最高的临床技术高频超声(30 MHz)高出25倍。OCT的优点除了分辨率外，还包括紧凑的便携设计、较小的导管直径和接近实时的成像速度。这项工作的总体假设是，几项进展可以显著提高OCT表征不稳定斑块的能力，并改善患者的风险分层。这些进展包括提高渗透率，将OCT与光谱学相结合，以及处理数据以获得更好的解释。每个特定的目标都将解决一个独立的假设，以提高OCT的诊断能力。其具体目标是：(目标1)通过指数匹配增加对血液的渗透率，(目标2)利用吸收和偏振光谱来表征组织，(目标3)减少超声的多次散射，以及(目标4)通过图像处理改善数据解释。

This program is a continuation of an ongoing collaboration between investigators at Massachusetts General Hospital, King's College, and Massachusetts Institute of Technology. The long term objective of this work is to develop a new method of high resolution intravascular imaging to overcome current limitations in cardiac diagnostics, principally the identification of coronary lesions likely to undergo rupture. Most myocardial infarctions (MIs) result from the rupture of small rather than large plaques in the coronary arteries. These plaques contain a relatively large amount of lipid and have thin intimal caps. When these plaques rupture, they release thrombogenic material into the blood, clot forms, and the vessel occludes. These small plaques are beyond the detection limit of any currently available imaging modality. Therefore, a true clinical need exists for an imaging technology capable of identifying these lesions prior to rupture. Optical coherence tomography (OCT), a new method of high resolution imaging, has demonstrated great potential for the assessment of high-risk plaque. OCT is analogous to ultrasound, measuring the intensity of infrared light rather than sound. Its resolution is currently up to 25X higher than high frequency ultrasound (30MHz), the current clinical technology with the highest resolution. Advantages of OCT, in addition to its resolution, are its compact portable design, small catheter diameter, and near real time imaging rate. The general hypothesis of this work is that several advances could substantially improve the ability of OCT to characterize unstable plaque and improve patient risk stratification. These advances include improving penetration, combining OCT with spectroscopy, and processing data for superior interpretation. Each specific aim will address an independent hypothesis that improves the diagnostic capabilities of OCT. The specific aims are: (Aim 1) To Increasing the Penetration through Blood with Index Matching, (Aim 2) To Characterize Tissue with Absorption and Polarization Spectroscopy, (Aim 3) To Reduce Multiple Scattering with Ultrasound, and (Aim 4) To Improve Data Interpretation through Image Processing.