Development of super resolution ultrasound for detecting microcalcifications

项目摘要 大量的研究表明，癌症的早期发现可以改善患者的预后。通过 早期发现癌症，当肿瘤处于原发阶段时，可以在转移之前进行治疗 已经发生了。微钙化（MC）的存在表明乳腺恶性肿瘤， 用现代成像技术提高检测MC的能力仍然是一个悬而未决的问题。存在 与乳腺癌的存在有关，即，30-50%的不可触及的乳腺癌 使用乳房X线照片检测的乳腺癌是基于识别MC的存在。因此，改善 检测乳腺MC的成像技术的灵敏度将为早期乳腺癌提供重要作用。 检测和诊断乳腺癌。 最近，我们开发了一种新的非线性波束形成技术的超声阵列， 超声波图像的超分辨率（分辨率提高25倍）。波束形成技术， 称为零减成像（NSI），利用波束图案中的零值来使用超声创建图像。 由NSI提供的横向分辨率增益伴随着所有波束中存在的旁瓣的减少 模式和增加的信号噪声比（SNR）。使用NSI构建的超声图像导致 斑点伪影的抑制和奇异目标的强化。因此，我们假设NSI 成像对于检测组织中MC的特定成像任务将表现良好。创新和 通过两个目的验证NSI用于乳腺癌动物模型中MC的成像和检测。 在第一个目标中，我们将量化NSI在动物模型中检测MC的能力， 常规超声和X射线成像技术。我们假设使用NSI将导致 与常规超声方法相比，在动物模型中定量改善MC检测 和X射线成像。传统的超声方法使用延迟和求和来进行波束形成，并且可以使用 不同的信号处理工具，以提高MC检测。常规超声B型成像 成像和X射线CT将用于检测乳腺癌大鼠模型中的MC， 将比较性能（灵敏度和特异性）。 在第二个目标中，我们将开发和验证接收方法，以增加扫描线的密度 使用NSI时。我们假设使用NSI可以充分增加扫描线密度，而不需要 物理地平移换能器。由于与NSI相关的成像光束非常窄， 传统的线性顺序扫描技术在每一步将光束平移一个间距 未被询问的光束之间的空间。为了确保在手术过程中不会遗漏任何组织区域， 扫描时，有必要增加询问组织的光束密度。这可以通过以下方式实现： 通过使用常规方法来增加扫描线密度，即，插值或网格聚焦。

Project Summary Abundant research demonstrates that early detection of cancer leads to improved patient prognosis. By detecting cancer earlier, when tumors are in their primary stages, treatment can be applied before metastases have occurred. The presence of microcalcifications (MCs) is indicative of malignancy in the breast and improving the ability to detect MCs with modern imaging technology remains an open question. The presence of MCs is associated with presence of cancer in the breast, i.e., 30-50% of all nonpalpable breast cancers detected using mammograms are based on identifying the presence of MCs. Therefore, improving the sensitivity of imaging techniques to detect MCs in the breast will provide an important role for the early detection and diagnosis of breast cancer. Recently, we developed a novel nonlinear beamforming technology for ultrasonic arrays that provides super resolution of ultrasonic images (up to 25 times improvements in resolution). The beamforming technique, called null subtraction imaging (NSI), utilizes nulls in the beam pattern to create images using ultrasound. Lateral resolution gains provided by NSI are accompanied by a reduction in side lobes present in all beam patterns and increases in the signal-to-noise ratio (SNR). Ultrasonic images constructed with NSI result in suppression of speckle artifacts and an intensification of singular targets. Therefore, we hypothesize that NSI imaging will perform well for the specific imaging task of detection of MCs in tissues. We will develop and validate NSI for imaging and detecting MCs in an animal model of breast cancer through two aims. In the first aim we will quantify the ability of NSI to detect MCs in an animal model compared to conventional ultrasonic and X-ray imaging techniques. We hypothesize that the use of NSI will result in a quantifiably improved detection of MCs in animal models compared to conventional ultrasound approaches and X-ray imaging. Conventional ultrasound approaches use delay and sum to do beam formation and can use different signal processing tools to improve MC detection. Conventional ultrasound B-mode imaging, NSI imaging and X-ray CT will be used to detect MCs in a rat model of breast cancer and their detection performance (sensitivity and specificity) will be compared. In the second aim we will develop and validate approaches on receive to increase the density of scan lines when using NSI. We hypothesize that the scan line density can be sufficiently increased using NSI without physically translating the transducer. Because the imaging beam associated with NSI is so narrow, conventional linear sequential scanning techniques that translate a beam at each step by one pitch cause spaces between the beams that are not interrogated. To ensure that no tissue region is missed during scanning, it is necessary to increase the density of beams interrogating tissue. This can be accomplished on receive by using conventional methods to increase scan line density, i.e., interpolation or gird focusing.