VERY-HIGH-FREQUENCY ULTRASOUND ARRAYS FOR OPHTHALMOLOGY

描述(申请人提供)：这项研究的最终目标是通过为临床医生提供显著改进的整个前眼的超声图像来改善对包括青光眼、眼部创伤和肿瘤以及视力缺陷在内的眼部疾病和紊乱的护理。这项拟议的研究将先进的高频、高分辨率超声环形阵列换能器与新的数字信号处理概念结合在一起，专门设计用于克服传统高频超声系统所达到的几个限制；例如，阵列将焦深提高了10倍。阵列在数字合成孔径模式下运行，允许对发射的脉冲和接收的回波信号进行动态聚焦。动态聚焦使眼球前部的微结构在整个组织深度内都是“聚焦”的；目前，只有亚毫米焦深才能获得非常高的分辨率(30微米)。该方案还使用数字频率均衡处理技术来提高聚焦光束和接收回波的空间均匀性；该技术为成像组织微观结构提供了统一的灵敏度。合成孔径和频率均衡技术结合在一起，强化了数字增强轴向分辨率(优于25微米)的概念，用于角膜和卓越图像细节的生物测定分析。这些技术还用于改善斑点抑制和图像对比度，提供复杂微结构节段的稳定、特征灰度图像，例如睫状体和前部眼部肿瘤。所提出的方法允许近乎实时地生成眼睛的2-D图像。 为了实现其目标，该计划将全面的数字模拟和换能器设计、换能器制造、集成数字处理和显示以及实验室测试相结合。通过对体外猪眼和活体兔眼的扫描，验证和提炼了概念。

DESCRIPTION (provided by applicant): The ultimate objective of this research is to improve the care of ocular diseases and disorders, including glaucoma, ocular trauma and tumors, and vision deficiencies by providing clinicians with dramatically improved ultrasonic images of the entire anterior eye. The proposed research combines advanced high frequency, high-resolution ultrasonic annular-array transducers with novel digital signal processing concepts specifically designed to overcome several limits that have been reached with conventional high-frequency ultrasound systems; for example, the arrays improve the depth of focus by a factor of 10. The arrays are operated in a digital synthetic-aperture mode that permits dynamic focusing of both transmitted pulses and received echo signals. The dynamic focusing permits the microstructure of the anterior of the eye to be "in focus" throughout the entire tissue depth; currently, very high resolution (30 mu m) is available only in sub-millimeter focal depths. The program also uses digital frequency-equalization processing techniques to improve the spatial uniformity of focused beams and received echoes; this technique provides uniform sensitivity for imaging tissue microstructure. Synthetic-aperture and frequency-equalization techniques are combined to potentiate concepts that digitally enhance axial resolution (to better than 25 mu m) for biometric assays of the cornea and superior image detail. These techniques are also used to improve speckle suppression and image contrast, providing stable, characteristic grayscale images of complex microstructural segments e.g., the cilliary body and anterior ocular tumors. The proposed methods permit near real-time generation of 2-D images of the eye. To reach its goals, the program combines thorough digital simulations and transducer design, transduce fabrication, integrated digital processing and display, and laboratory testing. Concepts are validated and refined using scans of in-vitro porcine eyes and in-vivo rabbit eyes.