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: 6949538
• 负责人: ERIK C WIENER
• 金额: $ 42.3万
• 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/6949538
• 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）： 磁共振乳房摄影（MRM）是一种正在开发的成像技术，以克服X射线乳房X线摄影的局限性。一种方法使用从动态对比增强（DCE）数据得出的渗透性 - 表面面积（PS）产品来提高特异性。该技术获得的特异性为37％至97％是有争议的。 DCE需要高的时间分辨率来收集动力学信息，而以空间分辨率为代价。没有人报告是否由部分体积效应引起的PS产物的平均值限制了使用PS产物分化和等级肿瘤的有效性。我们正在检验以下假设：人DCE MRM中使用的空间分辨率会导致部分体积平均，从而显着降低了可使用从DCE-MRM数据计算出的PS产品获得的预后信息，并降低了基于一个参考图像PS的产生图像的PS产品，该方法降低了与部分参考图像产生的图像。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-硝基雷氏肿瘤区域中GD（III）-DTPA的PS产物来实现这些目标，从而与平面分辨率和切片厚度相关的大鼠乳腺肿瘤诱导的大鼠乳腺肿瘤。 PS值是通过平面分辨率的两个隔室模型计算的，该模型在包括临床上使用的6.25 mm2，以及用于分析血管密度0.74和0.152 mm2的“显微镜场”大小。 PS值与通过体外组织化学方法获得的肿瘤等级，血管密度和血管通透性因子相关。我们采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，并表明从这些图像中计算出的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。该算法使用通用串联方法，并具有前对比度和后对比度增强参考图像Trigr。用低平面分辨率获得的动态数据被重建为Trigr的高空间分辨率。这保持了高时间分辨率。然后，该方案与DCE MRM和基于树枝状聚合物的对比剂一起使用，以区分良性与恶性肿瘤，并与组织学方法进行比较。