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，用于筛查高危女性，并进一步调查可疑的超声或乳房X线检查结果。动态对比增强（DCE）成像中局部增强模式的观察是MRI乳腺检查的支柱，可产生接近完美的病变检测灵敏度。然而，目前的方案显示出不太理想的特异性;根据报告，5次阳性MRI检查中多达4次可能导致阴性活检和心烦意乱的患者。最近提出的用于增加乳腺MRI特异性和减少假阳性和阴性活检数量的方法之一是扩散加权成像（DWI），这是一种在高达几微米的尺度上探测水分子的流动性的方法。主要在1.5T下进行的新兴研究指出，DWI有可能减少高达33%的阳性DCE结果所需的活检，而不会遗漏任何癌症。随着3 T扫描仪成为临床标准，DWI采集可赋予DCE协议的乳腺癌诊断特异性的改善程度尚未确定。与在高场下对乳房解剖结构进行成像相关的许多问题，例如图像阴影、由于B 0不均匀性引起的伪影、不适当的脂肪抑制和市售的低通道数乳房RF接收线圈，使得3 T DWI空间分辨率在10- 40 ml范围内，类似于1.5T，并且显著低于3 T DCE MRI协议典型的1 ml分辨率。我们提出的研究代表了一种多方面的，全面的方法，以了解3 T DWI的最终潜力，以提高乳腺癌检测的特异性。更具体地说，我们建议开发的技术，导致收购减少伪影，高空间分辨率，扩散加权图像在不到5分钟。将研究用于确保均匀信号激励、高灵敏度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的许多方法。开发的硬件和软件将借给我们的临床合作伙伴Beth Israel Deaconess Medical Center，在那里，DWI测量单独和作为DCE MRI诊断乳腺癌的辅助手段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.