Quantitative volumetric ultrasonic and photoacoustic tomography

摘要 我们的中心目标是创建一个结合超声(US)和光声(PA)的体积实时系统 用于高分辨率结构和功能成像的层析成像(USPAT)。HIGH的最新发展 声道计数超高速美国系统创造了以高帧速率捕获音量的机会。 断层摄影术，定义为用于显示穿过人体的横截面的表示的技术， 通过有效旋转US点扩散函数以减少 绕射效应。我们已经开发出一种超快的美国能力，与一组断层扫描传感器相匹配 并通过机动化采集进行深度扫描。利用超高速功能提供了 在1分钟内获取体积、功能的乳房图像。捕获由1024相干控制 Verasonics成像系统的通道(将增加到2048)，并包括用于实时的嵌入式GPU 成像和分析。当以5 mhz运行时，所产生的空间分辨率在平面上几乎是各向同性的 分辨率约为半个波长(在本例中为约150微米)。与通过以下方式获取的美国图像相比 常规成像，图像质量大大提高。超声波方法很有吸引力，可以集成到 乳房管理由于其在引导活检方面的实用性和很高的 可达到的灵敏度(97.3%) 通过将超声波与常规筛查相结合。 透射层析模式和反射层析模式都将 进行评估，以促进高分辨率反射模式和高定量传输 成像。PA成像(PAI)特别适合补充US和改进诊断成像 胸部。我们的近期目标是减少接受乳房筛查的女性所需的活检次数。 光声断层成像(PAT)提高了图像的信噪比和形态可视化 常规PAI。健康的乳房组织具有低的光吸收和US散射，从而实现高效 帕特。由于肿瘤部位血管和血红蛋白的异常增加会产生强烈的内源性 与光声对比，PAT非常适合于血管生成的可视化。此外，PAT可以评估亲属 一个区域的氧合作用。通过我们的组合策略，我们将评估基于以下各项的表征算法 每项功能-血流、氧合和结构变化，评估个体和 综合成像功能。在小鼠从癌前到恶性的模型中首次研究了这项技术 我们将确定USPAT是否可以增加 MRI对病变定性的敏感性和特异性。我们由此产生的具体目标是：1)实施和 将血液测绘、超声断层扫描和PAT用于乳房成像，2)评估敏感性和特异性 在乳腺癌的啮齿动物模型中应用所产生的系统，以及3)将这些新功能应用于成像患者 有MRI检查异常者，建议做活检。

Abstract Our central goal is to create a volumetric real-time system combining ultrasound (US) and photoacoustic (PA) tomography (USPAT) for high resolution structural and functional imaging. The recent development of high channel count ultrafast US systems creates the opportunity to capture volumes at a high frame rate. Tomography, defined as a technique for displaying a representation of a cross section through a human body, facilitates high resolution (lamba/2) imaging by effectively rotating the US point spread function to reduce the effect of diffraction. We have developed an ultrafast US capability mated to a tomographic ring of transducers and scanned in depth by motorized acquisition. Leveraging the ultrafast capability provides the opportunity for acquisition of volumetric, functional breast images within 1 minute. The acquisition is controlled by 1024 coherent channels of Verasonics imaging systems (to be increased to 2048) and includes embedded GPUs for real-time imaging and analysis. When operated at 5 MHz, the resulting spatial resolution is nearly isotropic in plane with resolution of ~ half a wavelength (in this case ~150 microns). Compared to US images acquired with conventional imaging, the image quality is far improved. Ultrasound methods are attractive for integration into breast management due to their utility in guiding biopsy and the very high sensitivity (97.3%) that can be achieve by combining ultrasound with conventional screening. Both transmission and reflection tomography modes will be evaluated in order to facilitate both high resolution reflective modes and highly quantitative transmission imaging. PA imaging (PAI) is particularly well suited to complement US and improve diagnostic imaging of the breast. Our immediate goal is to reduce the number of biopsies required in women undergoing breast screening. Photoacoustic tomography (PAT) enhances the signal to noise ratio and visualization of morphology over conventional PAI. Healthy breast tissue has low optical absorption and US scattering, allowing for highly efficient PAT. Since abnormally increased vasculature and hemoglobin at tumor sites produces strong intrinsic photoacoustic contrast, PAT is ideally suited for visualizing angiogenesis. Further, PAT can assess the relative oxygenation of a region. With our combined strategy, we will evaluate characterization algorithms based on each feature – blood flow, oxygenation and structural changes, assessing the sensitivity of individual and combined imaging features. With a first study of this technique in a mouse model of premalignant to malignant transformation and a human study of lesion characterization, we will determine whether USPAT can add to the sensitivity and specificity of lesion characterization by MRI. Our resulting specific aims are to: 1) implement and integrate blood mapping, US tomography, and PAT for breast imaging, 2) assess the sensitivity and specificity of the resulting system in a rodent model of breast cancer, and 3) apply these new capabilities to image patients with MRI detected abnormalities recommended for biopsy.