Dynamic MRM: Source of Specificity Errors and Solutions

动态 MRM：特异性错误的来源和解决方案

• 批准号: 6803126
• 负责人: ERIK C WIENER
• 金额: $ 41.07万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-24 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6803126
• 关键词: bioimaging /biomedical imaging; chemical synthesis; cyclic compound; diagnosis quality /standard; histochemistry /cytochemistry; histology; image enhancement; laboratory rat; magnetic resonance imaging; mammography; mathematics; neoplasm /cancer diagnosis; noninvasive diagnosis; prognosis; technology /technique development

DESCRIPTION (provided by applicant): Magnetic resonance mammography (MRM) is an imaging technique under development to overcome the limitations of X-ray mammography. One method uses permeability-surface area (PS) products derived from dynamic contrast enhancement (DCE) data to improve specificity. The specificity, 37 to 97%, obtained by this technique is controversial. DCE requires high temporal resolution to collect the kinetic information at the expense of spatial resolution. No one has reported if the averaging of the PS product, induced by partial volume effects, limits the effectiveness in using PS products to differentiate and grade tumors. We are testing the hypothesis that the spatial resolution used in human DCE MRM results in partial volume averaging that significantly reduces the prognostic information obtainable with PS products calculated from DCE-MRM data, and that reduced encoding methods that reconstruct images based on one reference image produce PS-products with partial volume averaging. We then demonstrate a technique to obtain images with both high temporal and spatial resolutions. We will accomplish these goals by studying the PS product of Gd(III)-DTPA in tumor region of interests in N-ethyI-N-nitrosourea induced rat mammary tumors as a function of both the in plane resolution and slice thickness. The PS values are calculated with a two compartment model at in plane resolutions that include those used clinically, 6.25 mm2, and at the "microscopic field" sizes used to analyze vascular density, 0.74 and 0.152 mm2, in vitro. PS values are correlated to tumor grade, vascular density, and vascular permeability factor obtained by in vitro histochemical methods. We apply a reduced encoding method to obtain DCE MRM data with both high temporal and spatial resolutions, and show that the PS product calculated from these images are accurate relative to those obtained with standard high spatial resolution techniques. The algorithm uses a generalized series method with both pre and post contrast enhanced reference images, TRIGR. The dynamic data obtained with low in plane resolution is reconstructed to high spatial resolution with TRIGR. This maintains the high temporal resolution. The protocol is then used with DCE MRM and a dendrimer based contrast agent to differentiate benign from malignant tumors and compared against histological methods.

描述（由申请人提供）： 磁共振乳房X线摄影（MRM）是一种正在开发的成像技术，旨在克服X射线乳房X线摄影的局限性。一种方法使用从动态对比度增强 (DCE) 数据导出的渗透率-表面积 (PS) 产品来提高特异性。通过该技术获得的 37% 至 97% 的特异性存在争议。 DCE 需要高时间分辨率来收集动力学信息，但会牺牲空间分辨率。没有人报告由部分体积效应引起的 PS 产品的平均是否限制了使用 PS 产品区分和分级肿瘤的有效性。我们正在测试这样的假设：人类 DCE MRM 中使用的空间分辨率会导致部分体积平均，从而显着减少使用根据 DCE-MRM 数据计算的 PS 产品可获得的预后信息，并且基于一幅参考图像重建图像的简化编码方法会产生具有部分体积平均的 PS 产品。然后，我们演示了一种获得具有高时间和空间分辨率的图像的技术。我们将通过研究 N-乙基-N-亚硝基脲诱导的大鼠乳腺肿瘤中感兴趣的肿瘤区域中 Gd(III)-DTPA 的 PS 产物作为平面分辨率和切片厚度的函数来实现这些目标。 PS 值使用两室模型计算，平面分辨率包括临床使用的分辨率 6.25 mm2，以及用于体外分析血管密度的“显微镜视野”尺寸 0.74 和 0.152 mm2。 PS值与通过体外组织化学方法获得的肿瘤分级、血管密度和血管通透性因子相关。我们应用简化的编码方法来获得具有高时间和空间分辨率的 DCE MRM 数据，并表明从这些图像计算的 PS 产品相对于使用标准高空间分辨率技术获得的 PS 产品是准确的。该算法使用具有前后对比增强参考图像的广义序列方法 TRIGR。使用 TRIGR 将低平面分辨率获得的动态数据重建为高空间分辨率。这保持了高时间分辨率。然后将该方案与 DCE MRM 和基于树枝状聚合物的造影剂一起使用，以区分良性肿瘤和恶性肿瘤，并与组织学方法进行比较。