Very-High-Frequency Ultrasound Imaging With Coded Signals and Annular Arrays

描述（由申请人提供）：超高频超声提供分辨率优于100 μ m的非侵入性诊断成像。甚高频超声（VHFU）对皮肤、眼睛、胃肠道粘膜和动脉斑块等浅表组织的成像非常有用。VHFU的两个主要限制因素是小的景深和频率相关的衰减。小景深允许仅在焦点周围的小轴向范围内获得精细分辨率的图像，并且频率依赖性衰减限制了VHFU在浅层成像中的应用。我们建议开发信号处理和VHFU成像策略，以减轻这两个限制因素。具体来说，我们将联合收割机编码激励算法与环形阵列技术相结合。用于VHF超声波的编码信号的特定设计将增加信噪比（SNR），这将允许增加VHF超声波的穿透深度。VHFU环形阵列允许动态聚焦，可以显著增加景深，而不需要线性阵列中所需的大量元件;这大大简化了电子设备，便于临床扫描的实施。超声中的编码激励从未在非常高的频率下被研究过，也没有将其与最先进的环形阵列相结合。我们计划扩展的方法，以获得定量的组织微观结构的信息。这种定量的超声信息将导致一种新的手段来区分病变组织和正常组织，并监测疾病的进展或消退。虽然本项目中开发的技术和方法对浅表组织成像具有普遍适用性，但本研究计划将在眼科学的背景下开发。拟议的研究可以显著改善眼科病理的评估，如青光眼，玻璃体膜，出血，脉络膜肿瘤，视网膜和脉络膜脱离，这些都是具有挑战性的图像与传统的高频超声。如果成功，拟议的研究也将导致诊断超声在其他临床专业的显着改善。它将允许获得具有精细分辨率、增加的景深和更大的穿透深度的医学图像，并导致改进诊断成像和疾病管理的新能力。

DESCRIPTION (provided by applicant): Ultrasound at very-high-frequency provides non-invasive diagnostic imaging with resolution better than 100 urn. Very-high-frequency ultrasound (VHFU) is of great interest for imaging superficial tissues, such as skin, eye, gastrointestinal mucosa, and arterial plaque. The two main limiting factors for VHFU are the small depth of field and the frequency-dependent attenuation. The small depth of field allows fine-resolution images over only a small axial range about the focus, and the frequency-dependent attenuation limits application of VHFU to shallow imaging. We propose to develop signal-processing and VHFU imaging strategies that will mitigate these two limiting factors. Specifically, we will combine coded-excitation algorithms with annular-array technologies. The specific design of coded signals for VHFU will increase signal-to-noise ratio (SNR), which will permit an increased depth of penetration of VHFU waves. VHFU annular arrays allow dynamic focusing that can significantly increase the depth of field without requiring the large number of elements needed in linear arrays; this greatly simplifies electronics and facilitates implementation for clinical scanning. Coded excitation in ultrasound has never been investigated at very high- frequencies nor has it been combined with state-of-the-art annular arrays. We plan to extend the methodologies to obtain quantitative information about tissue microstructures. This quantitative ultrasound information will lead to a new means of distinguishing diseased from normal tissue and of monitoring disease progression or regression. While the technology and methodology to be developed in this project have general applicability for imaging superficial tissues, this research program will be developed in the context of ophthalmology. The proposed research can lead to significant improvement in evaluation of ophthalmic pathologies such as glaucoma, vitreous membranes, hemorrhage, choroidal tumors, and retinal and choroidal detachment that are challenging to image with conventional high-frequency ultrasound. If successful, the proposed research also will lead to significant improvement of diagnostic ultrasound in other clinical specialties. It will allow obtaining medical images with exquisite resolution, increased depth of field and a greater depth of penetration, and lead to new capabilities for improved diagnostic imaging and disease management.