MRI-Based Elasticity Imaging

基于 MRI 的弹性成像

基本信息

批准号：
6616320
负责人：
JOHN B WEAVER
金额：
$ 16.87万
依托单位：
DARTMOUTH COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-01 至 2003-07-31
项目状态：
已结题

项目摘要

Breast cancer is the second leading cause of death in women and, despite some questions, it is generally agreed that early detection of malignancies improves the chances of successful treatment. There is mounting evidence to suggests that tissue elasticity might be a means to detect and classify breast lesions because hardness is a property strongly associated with cancer. This rationale is underscore by the prominent place that physical examination has and continues to hold in breast cancer screening. The principle hypotheses which underpins Project I is that breast tissue elastic properties are sensitive and specific predictors of pathology. We will address five specific aims: 1) Advance our data acquisition techniques to (i) induce larger displacements in more mass of tissue, (ii) decrease the image acquisition time through improved pulse sequence designs, and (iii) acquire data using a continuous vibration mode of operation. 2) Advance our model-based image reconstruction methodology in collaboration with the Computational Core to include (i) tissue dampening, (ii) multi-valued property recovery, (iii) transient effects and (iv) overlapping zone optimization, first in two and then in three dimensions. 3) Conduct transient effects and (iv) overlapping zone optimization, first in two and then in three-dimensions. 3) Conduct extensive simulations and phantom imaging experiments under controlled conditions to identify optimal mechanical stimulation, image acquisition and property estimation options from those investigated in Aims #1 and #2. 4) Develop a clinical system to estimate the mechanical properties of both breasts in reasonable times, demonstrate its feasibility and refine procedural protocols on a limited number of volunteers. 5) Recover the mechanical properties of breast tissue on patients with normal and abnormal mammograms, first through a test phase of evaluation followed by a prospective validation study executed in collaboration with the Clinical Core. Project I pursues a synthesis of existing and novel ideas which will address many of the current problems associated with breast elasticity imaging. First, harmonic mechanical stimuli which produce compressional or dilatational displacements will be developed. Phase contrast measurements of harmonic displacement will also serve to reduce patient motion artifacts while the use of multi-spectral vibrational stimuli will afford the opportunity to account for dissipational effects. Second, model-based property reconstruction methods will be deployed to exploit the multi-dimensional displacement field gradients which can be accurately measured in three dimensions. Further, the volumetric subsurface displacement data provided by the proposed MR system provides tissue response observations that are more extensive than those typically available in the model-based image reconstruction context which is likely to translate into improved spatial and contrast resolutions relative to those which have been achieved with elasticity imaging to date.

乳腺癌是女性死亡的第二大原因，尽管有一些疑问，但人们普遍认为，早期发现恶性肿瘤可改善成功治疗的机会。有越来越多的证据表明，组织弹性可能是检测和分类乳房病变的一种手段，因为硬度是与癌症密切相关的特性。体格检查在乳腺癌筛查中所拥有并继续保持的关键位置是强调的。基础I的主要假设是，乳腺组织弹性特性是敏感和特定的病理学预测指标。我们将解决五个具体目的：1）将数据采集技术提高到（i）在更多组织中诱导更大的位移，（ii）通过改进的脉冲序列设计减少图像采集时间，（iii）使用连续的振动模式获取数据。 2）通过与计算核心合作，推进了基于模型的图像重建方法，包括（i）组织抑制，（ii）多价值属性回收，（iii）瞬态效应和（iv）重叠区优化，首先是两次，然后在三个维度中进行。 3）进行瞬态效应和（iv）重叠的区域优化，首先是一分为一分，然后在三维中进行。 3）在受控条件下进行大量的模拟和幻影成像实验，以确定AIMS＃1和2中研究的人的最佳机械刺激，图像采集和财产估计选项。 4）开发一个临床系统，以估计合理时期两种乳房的机械性能，证明其可行性和在有限数量的志愿者身上进行了完善的程序方案。 5）恢复乳腺组织对正常和异常乳房X线照片患者的机械性能，首先是通过评估的测试阶段，然后是与临床核心合作执行的前瞻性验证研究。项目I追求现有和新思想的综合，这些想法将解决与乳房弹性成像相关的许多当前问题。首先，将开发产生压缩或扩张位移的谐波机械刺激。谐波位移的相比对比测量也将有助于减少患者运动伪像，而使用多光谱振动刺激将有机会考虑耗散效应。其次，将部署基于模型的属性重建方法来利用可以在三个维度中准确测量的多维位移磁场梯度。此外，所提出的MR系统提供的体积地下位移数据提供的组织响应观测值比基于模型的图像重建环境中通常可用的体积响应观测值更广泛，这些观察可能会转化为相对于与弹性成像所实现的那些相对于已经实现的空间和对比度分辨率。