Advanced IVUS imaging with MUTs

血管内超声（IVUS）成像是一种能够对动脉壁进行实时断层成像评估的技术，它越来越多地被用于辅助选择和评估治疗干预措施。虽然新的导管设计已经开发出来，但目前的超声换能器阵列制造和电子集成技术限制了图像质量的提高和体内检测动脉粥样硬化疾病进展的先进技术的进一步发展。在过去的两年中，在NIH的资助下，我们专注于改进用于IVUS的电容式微机械超声换能器（CMUT）技术，并消除了实现高性能阵列的重大障碍：我们开发了具有与单晶压电换能器阵列元件相匹配的效率和带宽的新型双电极CMUT，更重要的是，我们展示了前端成像电子器件和CMUT阵列在同一硅芯片上的单片集成。我们还利用在20-50MHz范围内工作的CMUT-IVUS阵列对医学相关样本进行了初步成像研究，并建立了基础设施和合作，以实现CMUT-IVUS原型导管。基于这些进展，在这一竞争性更新应用中，我们寻求证明在临床环境中使用集成电子器件的高性能CMUT的IVUS导管的可行性，并进一步开发CMUT设计和阵列，以应对具有挑战性的IVUS应用。我们将开发用于IVUS的高性能质量负载双电极环形CMUT相控阵，其单片集成电子器件工作在30-50MHz范围内，以提供血管-血管成像所需的高分辨率和穿透深度，以及改进成分成像的带宽和分辨率。我们建议实现一个环形阵列的原型侧视CMUT-IVUS导管，并将其用于相关成像模型进行验证。这项研究将促进革命性的无铅CMUT技术的研究转化为临床研究，用于冠状动脉和外周动脉疾病的检测和管理。这项研究也将为广泛的超声成像应用提供范例，这些应用将受益于集成电子的先进换能器技术。

Intravascular ultrasound (IVUS) imaging is a technology that enables realtime tomographic assessment of the arterial wall and it is increasingly employed to assist in selecting and evaluating therapeutic interventions. While new catheter designs have been developed, the current technology for ultrasound transducer array fabrication and electronics integration has limited the improvement of image quality and further development of advanced techniques for in vivo detection of the progression of atherosclerotic disease. Over the past two years, with NIH funding, we focused on improving Capacitive Micromachined Ultrasonic Transducer (CMUT) technology for IVUS, and removed significant barriers for implementation of high performance arrays: We developed novel dual-electrode CMUTs with efficiency and bandwidth rivaling single crystal piezoelectric transducer array elements, and more importantly, we demonstrated monolithic integration of front-end imaging electronics and CMUT arrays on the same silicon chip. We also performed initial imaging studies on medically relevant samples with CMUT-IVUS arrays operating in the 20-50MHz range and established infrastructure and collaborations for implementation of a prototype CMUT-IVUS catheter. Based on these advances, in this competitive renewal application we seek to demonstrate the feasibility of IVUS catheters using high performance CMUTs with integrated electronics for clinical settings, and further develop CMUT designs and arrays for challenging IVUS applications. We will develop high performance mass loaded dual-electrode annular CMUT phased arrays for IVUS with monolithic integrated electronics operating in the 30-50MHz range to provide the high resolution and penetration depth required for vasa-vasorum imaging and the bandwidth and resolution for improved composition imaging. We propose to implement a prototype side looking CMUT-IVUS catheter with annular arrays, and use it on relevant imaging phantoms for validation. This study will facilitate translation of research on revolutionary, lead free CMUT technology into clinical studies for detection and management of coronary and peripheral arterial diseases. This study will also serve as a paradigm for a broad range of ultrasound imaging applications that would benefit from advanced transducer technology with integrated electronics.