High-frequency-ultrasound annular arrays for ophthalmic and small-animal imaging

描述（由申请人提供）：本研究的目标是开发和评估先进的环形阵列换能器技术，用于重要的医学研究应用中的快速、高清成像。该研究将评估高频超声（HFU, = 20 MHz）环形阵列在两个重要应用中的应用：1)成像小动物（如小鼠胚胎）的微观结构；2)成像与糖尿病视网膜病变相关的后玻璃体脱离（pvd），根据美国防盲协会，糖尿病视网膜病变是美国工作年龄人口失明的主要原因。由于各种技术和成本原因，目前的HFU仪器不使用线性阵列进行此类应用。相反，目前的HFU仪器使用机械扫描的单元件换能器，在非常有限的景深（DOF）内提供高分辨率的图像。对于小动物应用，较浅的DOF会导致标本中的大多数解剖边界定义不清；因此，精确的微观结构和体积分析几乎是不可能的。对于眼科应用，与聚焦区域相比，浅DOF导致大多数眼部解剖成像清晰度较差；因此，由于在给定时间内只有一小部分眼睛处于聚焦状态，因此诸如PVD等眼部疾病的检测和评估容易出现不准确和假阴性的结果。环形阵列换能器提供了一种很有前途的方法，可以显着扩展DOF并增加提供精细横向分辨率的深度范围。该提案旨在继续在EY014371拨款下启动的HFU环形阵列研究，该研究证明了合成聚焦环形阵列在兔眼、小鼠胚胎和人眼库中的成像能力的提高。拟议的项目将通过开发和验证一种实时HFU，基于环形阵列的快速成像系统来扩展先前的研究，该系统能够1)以bbb10fps的速率动态接收显示成像；2)单帧合成聚焦成像数据采集时间< 0.2 s；3) < 20 s的3D数据采集。拟议的系统将是模块化的，以方便升级系统组件和功能。我们将通过动物实验和人体实验来验证系统的性能。首先，采用兔眼进行体内动物实验，评估40 mhz环形阵列用于前段成像和20 mhz环形阵列用于后段和全球成像。我们还将利用40 mhz环形阵列对小鼠胚胎进行体内3D成像和体积分割研究。其次，我们将验证20 mhz环形阵列提高PVD检测的假设。验证这一假设将显著提高我们评估糖尿病视网膜病变疾病状态的能力。

DESCRIPTION (provided by applicant): The goal of this study is to develop and evaluate advanced annular-array transducer technology for rapid, high-definition imaging in significant medical-research applications. The study will assess high frequency ultrasound (HFU, = 20 MHz) annular arrays in two important applications: 1) imaging microstructure in small animals (e.g., mouse embryos); and 2) imaging posterior vitreous detachments (PVDs) associated with diabetic retinopathy, the leading cause of blindness in the US working-age population according to Prevent Blindness America. Current HFU instruments do not use linear arrays for such applications because of a variety of technical and cost reasons. Instead, current HFU instruments use mechanically scanned, single-element transducers, which provide fine-resolution images over a very limited depth of field (DOF). For small-animal applications, a shallow DOF causes most anatomical boundaries in the specimen to be poorly defined; therefore, accurate micro-structural and volumetric analyses are nearly impossible. For ophthalmic applications, a shallow DOF causes most ocular anatomy to be imaged with poor definition compared to the in-focus region; therefore, because only a small portion of the eye is in focus at a given time, detection and assessment of ocular conditions such as PVD are prone to inaccuracies and false-negative determinations. Annular-array transducers offer a promising approach to significantly extend DOF and to increase the depth range over which fine-lateral resolution is provided. This proposal seeks to continue the HFU annular-array studies initiated under grant EY014371 that demonstrated the improved imaging capability of synthetically-focused annular arrays using in vivo rabbit eyes, in vivo mouse embryos, and human eye-bank eyes. The proposed project will extend those previous studies by developing and validating a real-time HFU, annular-array-based, rapid-imaging system capable of 1) dynamic-receive display imaging at a rate of > 10 fps; 2) data acquisition in < 0.2 s for single-frame, synthetically-focused imaging; and 3) 3D data collection in < 20 s. The proposed system will be modular to facilitate upgrading system components and features. We will validate system performance using animal experiments and human-subject examinations. First, in vivo animal experiments will be conducted with rabbit eyes to evaluate a 40-MHz annular array for anterior-segment imaging and a 20-MHz annular array for posterior segment and full-globe imaging. We also will utilize the 40-MHz annular array to perform in vivo 3D imaging and volumetric segmentation studies with mouse embryos. Second, we will test the hypothesis that 20-MHz annular arrays improve detection of PVD. Validation of this hypothesis will significantly improve our ability to assess disease status in diabetic retinopathy.