An all-optical photacoustic imaging system for the eye

一种全光学眼部光声成像系统

• 批准号: 8902618
• 负责人: Parag Vijay Chitnis
• 金额: $ 22.32万
• 依托单位: GEORGE MASON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-30 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8902618
• 关键词: Address; Age related macular degeneration; Anatomy; Animal Model; Animals; Applications Grants; Attenuated; Blood; Blood Circulation; Blood Vessels; Blood flow; Choroid; Clinical; Clinical assessments; Coupling; Crystalline Lens; Data; Detection; Development; Diabetic Retinopathy; Diagnosis; Diagnostic; Disease; Elements; Evaluation; Eye; Frequencies; Functional Imaging; Fundus; Generations; Glaucoma; Goals; Health; Hemoglobin; Hemoglobin concentration result; Histology; Image; Imagery; Imaging Techniques; Interferometry; Lasers; Lateral; Life; Light; Liquid substance; Maps; Measures; Methods; Microscope; Modality; Modification; Mus; Noise; Optic Nerve; Optical Coherence Tomography; Optics; Oryctolagus cuniculus; Oxygen; Performance; Physiologic pulse; Physiology; Property; Resolution; Retina; Retinal; Retinal Diseases; Scanning; Scheme; Signal Transduction; Stress; Structure; Structure of retinal pigment epithelium; Surface; System; Techniques; Thick; Three-Dimensional Image; Time; Tissues; Transducers; Ultrasonography; absorption; base; chromophore; disease diagnosis; image reconstruction; imaging modality; improved; in vivo; indexing; insight; instrumentation; neovasculature; novel; photoacoustic imaging; pre-clinical; pre-clinical research; pressure; response; sensor; signal processing; sound; submicron; tomography

DESCRIPTION (provided by applicant): The proposed study will assess the feasibility of a novel, all-optical technique for photoacoustic imaging that employs a photorefractive crystal (PRC) and potentially can provide anatomical and functional images of the retina, choroid, and the optic nerve with ultra-fine-resolution. Detailed visualization of retinal substructures and the optic nerve is critical for evaluation of ophthalmic diseases such as diabetic retinopathy (DR), age-related macular degeneration (AMD) and glaucoma. However, vascular function and local oxygen delivery also are relevant indicators of the diseased state. Existing diagnostic modalities such as optical coherence tomography (OCT) and ultrasound (US) do not provide this information. Our PRC-based implementation of PAI will address the shortcomings of other imaging modalities while providing sub-micron image resolution and an imaging depth that is 3 to 5 times that of OCT. Furthermore, PAI also can provide functional information such as the level of hemoglobin-oxygen saturation, which can improve clinical assessment of ophthalmic diseases. Our approach does not require fluid coupling or physical contact required by US. Because the proposed holographic implementation of PAI employs a continuous-wave laser and CCD-based full-field interferometry for detecting the photoacoustic (PA) signal, it potentially can acquire 3D-image data in 500 ms (limited only by the frame rate of the camera and the desired bandwidth for PA-signal detection). The CCD- based implementation also facilitates modification of the field of view (FOV) and resolution simply by changing the microscope objective employed to direct the optical beams to the retina. A prescribed FOV can be achieved by adjusting the distance between the ocular lens and the external objective. The performance of a prototypical system will be characterized using tissue-mimicking phantoms. Subsequently, using live animals, we will demonstrate the ability of our techniques to depict retinal/choroidal micro-circulation and the retinal-pigmented epithelium microstructure as well as functional changes related to altered oxygen saturation. Images obtained using the proposed methods will be compared with optical fundus images and histology- based ground truth. Successful completion of the proposed study will establish a basis for developing a versatile system for ophthalmic imaging that can be employed in pre-clinical research using a variety of animal models, and ultimately in clinical imaging.

描述（由申请人提供）：拟议的研究将评估一种新型全光学光声成像技术的可行性，该技术采用光折射晶体（PRC），并可能提供具有超精细分辨率的视网膜、脉络膜和视神经的解剖和功能图像。视网膜亚结构的详细可视化和 视神经对于评估眼科疾病如糖尿病性视网膜病变（DR）、年龄相关性黄斑变性（AMD）和青光眼至关重要。然而，血管功能和局部氧气输送也是疾病状态的相关指标。现有的诊断模式，如光学相干断层扫描（OCT）和超声（US）不提供此信息。我们基于PRC的派实现将解决其他成像模式的缺点，同时提供亚微米图像分辨率和3至5倍的OCT成像深度。此外，派还可以提供功能信息，如血红蛋白-氧饱和度水平，这可以改善眼科疾病的临床评估。我们的方法不需要美国要求的流体耦合或物理接触。由于所提出的派的全息实现采用连续波激光器和基于CCD的全场干涉测量法来检测光声（PA）信号，因此其潜在地可以 在500 ms内采集3D图像数据（仅受相机帧速率和PA信号检测所需带宽的限制）。基于CCD的实现方式还便于简单地通过改变用于将光束引导到视网膜的显微镜物镜来修改视场（FOV）和分辨率。通过调节目镜透镜和外部物镜之间的距离可以实现规定的FOV。原型系统的性能将使用组织模拟体模进行表征。随后，使用活体动物，我们将证明我们的技术描绘视网膜/脉络膜微循环和视网膜色素上皮显微结构以及与氧饱和度改变相关的功能变化的能力。使用所提出的方法获得的图像将与眼底图像和基于组织学的地面实况进行比较。拟议研究的成功完成将为开发一种多功能眼科成像系统奠定基础，该系统可用于使用各种动物模型的临床前研究，并最终用于临床成像。