Improving the Specificity of Breast MRI Through Improved DWI

描述（由申请人提供）：乳房MRI正在获得广泛的临床认可，用于筛查高危妇女，并进一步调查可疑的超声波或乳房x光检查结果。动态对比增强（DCE）成像中局部增强模式的观察是乳腺MRI检查的支柱，具有接近完美的病变检测灵敏度。然而，目前的方案显示出不理想的特异性；根据报告，多达五分之四的阳性MRI检查可能导致阴性活检和心烦意乱的患者。最近提出的一种提高乳房MRI特异性和减少假阳性和阴性活检数量的方法是扩散加权成像（DWI），这种方法可以在几微米的尺度上探测水分子的流动性。新兴研究，主要在1.5T时进行，指出DWI有可能减少高达33%的DCE阳性活检结果，而不会遗漏任何癌症。随着3T扫描仪成为临床标准，DWI采集能在多大程度上提高DCE方案对乳腺癌诊断的特异性还有待确定。在高视场下进行乳房解剖成像的许多问题，如图像阴影、B0不均匀性引起的伪影、不当的脂肪抑制和低通道计数的商业乳房射频接收线圈，使3T DWI空间分辨率在10-40ml范围内，与1.5T相似，明显低于3T DCE MRI方案的典型1ml分辨率。我们提出的研究代表了一个多方面的，全面的方法来了解3T DWI的最终潜力，以提高乳腺癌检测的特异性。更具体地说，我们建议开发一种技术，可以在不到5分钟的时间内获得减少的伪影，高空间分辨率和扩散加权图像。为了保证均匀的信号激励，高灵敏度的信号接收，以及减轻主场不均匀性对扩散加权图像质量的影响，我们将研究一些方法。开发的硬件和软件将借给我们的临床合作伙伴贝斯以色列女执事医疗中心，在那里，单独的DWI测量以及作为DCE MRI辅助诊断乳腺癌的性能将在临床研究中进行评估。

DESCRIPTION (provided by applicant): MRI of the breast is gaining widespread clinical acceptance, being used to screen high-risk women and to further investigate questionable ultra-sound or mammography findings. The observation of the local pattern of enhancement in dynamic contrast enhanced (DCE) imaging is the pillar of the MRI breast exams, yielding close to perfect lesion detection sensitivity. Less than ideal specificity, however, is exhibited by the current protocols; depending on the report, up to 4 out of 5 positive MRI exams may result in negative biopsies and distraught patients. One of the methods recently proposed for increasing breast MRI specificity and reducing the number of false positives and negative biopsies is diffusion weighted imaging (DWI), an approach which probes the mobility of water molecules on a scale up to a few microns. Emerging studies, mainly performed at 1.5T, point to the potential of DWI to reduce up to 33% of the biopsies warranted by positive DCE results, without missing any cancers. As 3T scanners become the clinical standard, the extent of the improvement in specificity of breast cancer diagnosis that can be imparted to a DCE protocol by DWI acquisitions is yet to be determined. A number of problems associated with imaging the breast anatomy at high fields, such as image shading, artifacts due to B0 inhomogeneities, improper fat suppression and low channel count breast RF receive coils available commercially, have left the 3T DWI spatial resolution in the 10-40ml range, similar to 1.5T, and significantly below the 1ml resolution typical of 3T DCE MRI protocols. The research we propose represents a multi-faceted, comprehensive approach toward understanding the ultimate potential of 3T DWI to improve the specificity of breast cancer detection. More specifically, we propose to develop technology resulting in the acquisition of reduced artifact, high spatial resolution, and diffusion weighted images in less than 5 minutes. A number of approaches for insuring homogeneous signal excitation, high sensitivity signal reception, and mitigating the impact of main field inhomogeneity on diffusion weighted image quality will be studied. The hardware and software developed will be loaned to our clinical partner, Beth Israel Deaconess Medical Center, where the performance of DWI measurements alone and as an adjuvant to DCE MRI in diagnosing breast cancer will be assessed in a clinical study.