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1、Diffusion-weighted Imaging of the Breast: Principles and Clinical Applications,何杰 2013年12月25日,乳腺弥散加权成像：原理和临床应用,Diffusion-weighted imaging is a modality that makes use of magnetic resonance (MR) imaging to depict the diffusivity of water molecules in a defined voxel by means of the application of mot
2、ion-probing gradients. This imaging property is unique and provides a different contrast mechanism than that observed on conventional T1- and T2-weighted MR images. Evaluation of breast images acquired with sensitization to the diffusion of water molecules has the potential to play an adjunct role i
3、n the assessment of breast tissue. DWI是一种通过运动-探测梯度磁场的应用的方式，在一个有限的像素内，利用磁共振来检测水分子弥散的方法。这种成像方式是唯一，并且与常规的T1和T2加权MR图像相比，提供一个不同的对比机制。乳腺图像的获取来源于对水分子的扩散敏感，其拥有在乳腺组织的评估中发挥辅助作用的潜力。 。,Introduction,Diffusion-weighted imaging was initially applied in the clinical setting in the mid-1990s for the diagnosis of acu
4、te stroke. At that time, diffusion-weighted imaging demonstrated a high diagnostic utility, not only in the investigation of acute stroke, but also in developing the differential diagnosis for other brain abnormalities, including tumors and abscesses. 弥散加权成像在临床上最初的应用是90年代中期对急性脑卒中的诊断，不仅用于检测急性脑卒中，而且发展
5、到别的脑部异常病变的鉴别诊断，包括肿瘤和脓肿。,Introduction,Subsequent technical advances in MR imaging, including the development of ultrafast imaging sequences and the proliferation of array coils and of imagers with higher magnetic field strength (which increase signal-to-noise ratio SNR per unit time) have led to a re
6、duction in the impact of motion artifacts and the investigation of organs other than the brain. 在MR成像随后的技术进步，包括超快成像序列的发展和较高磁场强度阵列线圈和成像器的发展（这提高了每单位时间的信噪比），导致了运动伪影的影响的减少,Introduction,Diffusion-weighted imaging has subsequently been used in the evaluation of disease processes in various anatomic locati
7、ons (eg, chest, liver, pancreas, prostate gland) that had previously not been studied due to difficulties resulting from movement during patient respiration, peristalsis, and low inherent SNR . 弥散加权成像随后被用于不同的解剖部位疾病过程的评价（如胸部，肝脏，胰腺，前列腺），这些以前从未研究过，因为病人呼吸，蠕动所导致的困难和低的信噪比。,Introduction,In 1997, Englander
8、et al addressed the possibility of applying diffusion-weighted imaging to the human breast. Since that time, clinical studies have been undertaken, and several studies have shown diffusion-weighted imaging to be highly sensitive for the evaluation of breast cancer and a possible means of differentia
9、ting between benign and malignant tumors 在1997年，Englander等人探讨了DWI应用于人体乳腺的可能性。从那时起，一些临床研究开始进行，并且一些研究表明DWI在评估乳腺癌上有高的敏感性，是一种鉴别诊断良恶性肿瘤的可能的方法。,Introduction,As a result of these findings, diffusion-weighted breast imaging has attracted greater interest among breast imagers, with many clinicians advocating
10、 applications beyond just clinical research. However, the incorporation into clinical decision making of information gleaned from diffusion-weighted breast imaging has been slow compared to the use of information obtained from diffusion-weighted imaging of other organs. 由于这些发现，乳腺弥散加权成像吸引了乳腺影像学家越来越多的
11、注意，许多医生主张应用不仅仅是临床研究。然而，与其他器官的弥散加权图像的使用相比，应用在乳腺上比较缓慢。,Introduction,One reason is that the diagnostic role of diffusion-weighted imaging in breast imaging has not been incorporated into the already established Breast Imaging and Reporting Data System lexicon (11). Contrast materialenhanced breast MR i
12、maging is currently accepted as the most sensitive imaging technique for the diagnosis and staging of breast cancer. However, several studies have noted that conventional breast MR imaging, including T2-weighted imaging and contrast-enhanced T1-weighted imaging, is limited in terms of specificity in
13、 the assessment of breast tumors 原因之一是弥散加权成像在乳腺成像上的诊断作用还没有纳入到已经确定的BI-RADS系统中。对比增强乳腺磁共振是目前公认是最敏感的用于乳腺癌诊断和分级的成像技术。然而，然而，一些研究表明常规乳腺磁共振成像，包括T2加权像和T1对比增强磁共振在评价乳腺肿瘤的特异性方面作用有限。,Introduction,Consequently, there has been considerable interest in the development of adjunct MR imaging methods to improve the sp
14、ecificity of dynamic contrast-enhanced breast MR imaging, and diffusion-weighted breast imaging is being investigated for its potential to improve breast disease diagnosis at the cost of a small increase in examination time. 因此，在发展辅助磁共振成像方法用来提高动态对比增强乳腺磁共振的特异性上，引起了研究者很大的兴趣，研究者正在研究DWI乳腺成像，探讨其耗费最小的检查时间
15、增加乳腺疾病诊断率的潜力。,Introduction,In this PPT we discuss the principles of diffusion-weighted imaging, offer suggestions for optimizing diffusion-weighted breast imaging technique, and discuss the clinical implementation of diffusion-weighted breast imaging. 在这个PPT里，我们讨论DWI的原理，提出优化DWI乳腺成像技术的建议，并且讨论DWI乳腺成像的
16、临床应用,Introduction,Principles of Diffusion-weighted Imaging,DWI的原理,Proton Diffusion in Biologic Tissue,Diffusion is the random and thermal (Brownian) motion of water molecules (or any other type of molecule). This motion is affected by the local tissue environment and the presence of barriers (eg, cell membranes and semipermeable membranes). The motion of water molecules is more restricted in tissues with a high cellular density 弥散是水分子（或其他分子类型）的无规则的热运动（布朗运动）。这种运动受局部组织环境和障碍的影响（如细胞膜和半透膜）。组织中的水分
