MR imaging of the breast

The results of clinical investigation suggest that MR imaging can provide clinically important information that cannot be obtained with conventional imaging methods, and that this modality will, in the future, be an invaluable adjunctive breast imaging tool, just as breast imaging is today. MR imaging as a method to detect, diagnose, and stage breast cancer remains in the investigational stage, but is emerging as perhaps the most promising imaging modality for breast cancer detection.     

High-resolution MR imaging of the breast

Investigation into the use of MRI as a breast imaging tool is ongoing. Several studies have shown that MRI is a very accurate imaging method for the identification of implant failure in the symptomatic patient with augmented breasts. In this clinical setting, MRI may be the study of choice. Imaging techniques, and the MRI appearance of normal and abnormal implants, are described. The use of MRI for the detection of breast cancer is not as straightforward. Preliminary results suggest that this technique can be used as an adjunct to mammography for the detection and diagnosis of breast cancer. However, it is premature to draw firm conclusions regarding the role that MRI should play in the management of women with breast disease because of the wide variability of imaging techniques, protocols, and patient populations in the studies reported to date. In this overview, the current state of MR imaging of the breast is discussed. Technical requirements are described, and potential clinical applications—including the differentiation of benign from malignant lesions, breast cancer staging, detection of recurrence after breast conservation therapy, and detection of cancer in patients presenting with positive axillary lymph nodes with an unknown primary—are reviewed. Many of these potential clinical applications will require an accurate MR-guided biopsy system, and the implementation of such a system as well as its inherent limitations are discussed.     

Cancer staging with breast MR imaging

Breast MR imaging is a useful tool for staging breast cancer patients, and staging is more accurate with MR imaging than with conventional imaging techniques. MR imaging is the preferred imaging test for the accurate staging of breast cancer before surgery and for assessment of patients with positive axillary adenopathy and negative mammogram and physical examination. There are many important questions regarding the role of MR imaging in breast cancer staging that must be addressed by future research and involvement of MR imaging of the breast in clinical trials.     

三阴型乳腺癌的MRI特征

目的探讨三阴型乳腺癌(TNBC)的MRI(包括动态增强DCE及扩散加权成像DWI)特征。方法收集符合要求的病例入组,比较TNBC组与Luminal组的MR形态学、动态参数及DWI的ADC值的差异。结果 44例TNBC及183例Luminal型患者,TNBC组和Luminal B型组的形态学特征及DCE参数差异均无统计学意义,而两者的ADC值差异有统计学意义,TNBC组的ADC值较高(P=0.001)。结论 TNBC存在一定的DWI特征性。相对于Luminal型来说,TNBC倾向出现较高的ADC值。     

乳腺单纯型黏液癌的MR影像学表现

目的 分析乳腺单纯型黏液癌(PMBC)的MRI影像学表现。方法 回顾性分析经手术病理证实的23例PMBC患者的MRI特点。结果 PMBC的MR多表现为卵圆形肿块(18/23,78.26%),多数病灶边缘光整(15/23,65.22%);T1WI呈等低信号(22/23,95.65%)或均匀低信号(1/23,4.35%)。肿瘤的强化方式为环形强化(15/23,65.22%)、不均匀强化(7/23,30.43%)及无强化(1/23,4.35%)。早期增强率为(103.90±50.50)%。时间-信号强度曲线以流入型为主(17/22,77.27%);T2WI呈明显高信号(23/23,100%),多伴内部低信号分隔(21/23,91.30%)。DWI均呈明显高信号,ADC值为(2.05±0.38)×10^-3 mm²/s。结论 PMBC的MR表现具有一定特征性。     

Concepts for differential diagnosis in breast MR imaging

There is broad agreement in that breast MR imaging, compared with all other contemporary breast imaging techniques, offers the highest sensitivity for primary and recurrent invasive breast cancer. For a long time, however, the modality suffered from the reputation of offering only a limited specificity. In addition, the allegedly low sensitivity for intraductal breast cancer hampered the more widespread use of breast MR imaging. More recent results, however, suggest that the specificity and positive predictive value of breast MR imaging are at least equivalent to those of mammography and that the sensitivity for ductal carcinoma in situ (DCIS) is at least comparable to mammography, if not higher. Apart from increasing reader experience, this progress is mainly attributable to the fact that in parallel with improved MR imaging technology, more refined interpretation criteria became available. These criteria allow a substantially improved diagnosis of malignant masses and of DCIS. This article provides an overview on the current status of the diagnosis criteria that are used for differential diagnosis in breast MR imaging and on the diagnostic accuracy that is achievable with breast MR imaging.     

乳腺MR动态增强扫描联合扩散加权成像的临床应用评价

目的探讨动态增强扫描联合扩散加权成像对乳腺病变定性诊断临床应用价值.方法35例临床或钼靶X线可疑恶性发现的病人,获得病理证实的41个病灶,其中良性病灶13个,恶性病灶28个.同时进行动态增强扫描和扩散加权成像,MR扫描采用3D快速扰相位梯度回波(FSPGR)和单次激发EPI,b*1000 s/mm2.由两名医生共同在ADW工作站Functool 2软件进行图像分析,观察病变形态和动态增强表现,绘制时间-信号强度曲线,根据病变的形态特征、时间-信号强度曲线采用评分法对病变性质进行判断,分为恶性,可疑恶性及良性三种.参照动态增强病变位置确定扩散图像病变所在,描记扩散图像上病变的感兴趣区,由软件计算获得表观扩散系数(ADC)值.采用ROC曲线法确定ADC值的诊断阈值,并进行性质判断.联合动态增强扫描和ADC值,采用评分法根据积分情况进行综合定性诊断.比较动态增强扫描、DWI ADC值及联合应用对乳腺病变定性诊断效能.结果动态增强扫描(病灶形态学表现结合时间-信号强度曲线)诊断乳腺病变的敏感性、特异性和准确性分别为96.4%(26/27)、61.5%(8/13)和85.4%(35/41).ROC曲线分析确定ADC诊断阈值为1.42×10-3 mm2/s,曲线下面积为0.690.ADC值诊断敏感性、特异性和准确性分别为89.3%(25/28)、61.5%(8/13)和80.5%(33/41).动态增强扫描和DWI-ADC值联合诊断的敏感性、特异性和准确性分别为89.3%(25/28)、76.9%(10/13)和85.4%(35/41).有50%(14/28)的恶性病灶动态增强扫描表现不典型,通过ADC值得到进一步确定诊断.结论动态增强扫描联合扩散加权成像有助于提高乳腺病变定性诊断的特异性,可为动态增强扫描不能确定诊断的病灶提供更有价值的信息.     

乳腺叶状肿瘤的MRI表现分析

目的 分析乳腺叶状肿瘤(PTs)的MRI表现.材料与方法 回顾性分析经手术病理证实的10例PTs MRI表现,包括形态学、平扫信号强度、增强扫描病变内部强化特征及时间-信号强度曲线(TIC)类型、DWI信号及表观扩散系数(ADC)值.采用配对设计资料￡检验比较PTs和正常乳腺组织ADC值的差异.结果 10例乳腺PTs术后病理诊断良性6例,交界性3例,恶性1例.MRI上6例表现为分叶状,4例为椭圆形;7例边界清晰,3例欠清;10例PTsMRI平扫T1WI均呈较低信号;T2WI脂肪抑制或STIR呈较高信号,其中2例肿瘤内见低信号分隔,2例见不规则囊性极高信号影;PTs于动态增强初始期呈快速强化,初始期后TIC 2例呈Ⅰ型,8例呈Ⅱ型;9例行DWI检查,肿瘤均表现为高信号,平均ADC值为(1.32±0.18)×10-3 mm3/s;正常乳腺组织ADC值为(1.90±0.21)×10-3 mm3/s,二者差异有统计学意义(t=2.33,P＜0.05).结论 乳腺PTs的MRI表现有一定的特点,但这些表现为非特征性,确诊仍需依靠组织病理学检查.     

Fusion of contrast-enhanced breast MR and mammographic imaging data

Increasing use is being made of Gd-DTPA contrast-enhanced magnetic resonance imaging for breast cancer assessment since it provides 3D functional information via pharmacokinetic interaction between contrast agent and tumour vascularity, and because it is applicable to women of all ages as well as patients with post-operative scarring. Contrast-enhanced MRI (CE-MRI) is complementary to conventional X-ray mammography, since it is a relatively low-resolution functional counterpart of a comparatively high-resolution 2D structural representation. However, despite the additional information provided by MRI, mammography is still an extremely important diagnostic imaging modality, particularly for several common conditions such as ductal carcinoma in situ (DCIS) where it has been shown that there is a strong correlation between microcalcification clusters and malignancy. Pathological indicators such as calcifications and fine spiculations are not visible in CE-MRI and therefore there is clinical and diagnostic value in fusing the high-resolution structural information available from mammography with the functional data acquired from MRI imaging. This paper presents a novel data fusion technique whereby medial-lateral oblique (MLO) and cranial-caudal (CC) mammograms (2D data) are registered to 3D contrast-enhanced MRI volumes. We utilise a combination of pharmacokinetic modelling, projection geometry, wavelet-based landmark detection and thin-plate spline non-rigid 'warping' to transform the coordinates of regions of interest (ROIs) from the 2D mammograms to the spatial reference frame of the contrast-enhanced MRI volume. Of key importance is the use of a flexible wavelet-based feature extraction technique that enables feature correspondences to be robustly determined between the very different image characteristics of X-ray mammography and MRI. An evaluation of the fusion framework is demonstrated with a series of clinical cases and a total of 14 patient examples.     

磁共振动态增强及扩散加权成像诊断乳腺纤维腺瘤

目的 探讨乳腺纤维腺瘤的动态增强MR及DWI特点。方法 回顾性分析59例经手术或穿刺病理证实的乳腺纤维腺瘤患者的MRI资料,观察病灶的形态特征、MR平扫、增强及DWI信号特点、时间-信号强度曲线类型,测量 ADC值。结果 59例共检出62个纤维腺瘤病灶,其中类圆形29个,分叶状33个;58个病灶边缘光滑;12个(12/62,19.35%)病灶于压脂T2WI 上可见低信号分隔。在动态增强图像上,2个病灶无或轻度强化,60个明显强化,其中34个(34/60,56.67%)可见低信号分隔,35个(35/60,58.33%)病灶呈离心模式强化。时间-信号强度曲线类型:I型43个(43/62,69.35%),Ⅱ型15个(15/62,24.19%),Ⅲ型2个(2/62,3.22%),Ⅳ型2个(2/62,3.22%)。DWI上高信号病灶45个(45/62,72.58%),等信号17个(17/62,27.42%)。共测量52个病灶的ADC值,为(0.79~2.78)×10^-3 mm²/s,平均ADC值为(1.67±0.38)×10^-3 mm²/s,95%可信区间为(1.56~1.78)×10^-3 mm²/s。结论 乳腺纤维腺瘤具有特征性MRI表现,结合ADC值有助于鉴别诊断。     

An overview of interpretation strategies for breast MR imaging

This article provides an overview of the different approaches to the interpretation of breast MR imaging. It provides an overview of the use of architectural features for breast MR imaging interpretation. It also includes a discussion of the various types of contrast kinetic data that are used for breast MR imaging interpretation. Approaches to combine architectural and kinetic features are also discussed. This article serves as an introduction to the other articles in this issue that discuss specific interpretation and strategies.     

不同MRI序列显示乳腺病变的比较

目的比较不同MRI序列显示乳腺病变的价值.方法对79例乳腺癌和68例乳腺良性疾病患者采用自旋回波(SE)序列、快速自旋回波(TSE)序列、脂肪抑制(FS)成像、快速小角度激发(FLASH)序列、静态或动态增强扫描,比较不同MRI序列对乳腺病变的显示检出情况.结果脂肪抑制成像序列对乳腺病变的检出率高于SE序列,SE序列有利于病灶病理解剖关系的显示,MR增强扫描可检出所有乳腺病灶且有助于明确病灶的内部结构、浸润范围及其血供情况.结论 SE、TSE应为乳腺MR检查的常规序列,脂肪抑制成像序列必不可少,MR增强扫描对病灶的定性诊断很有价值,尤其是FLASH动态增强扫描.     

Vascularity assessment of breast lesions with gadolinium-enhanced MR imaging

Gadolinium-enhanced MR imaging of the breast can be used to characterize both tumor morphology and vascularity. An empirical three-point method using high resolution three-dimensional MR imaging that combines high spatial resolution with an estimate of tumor pharmacokinetics is described. This technique appears to improve diagnostic specificity of breast MR imaging and may provide a noninvasive method of tumor characterization of prognostic value.     

Ki-67表达与乳腺MRI成像特点的相关性研究

目的 对比研究乳腺癌磁共振成像特点与Ki-67表达的关系.方法 回顾性分析140例行MR检查并经手术病理证实为乳腺癌患者,80例Ki-67表达阳性,60例阴性.结果 乳腺癌Ki-67阳性组比阴性组肿瘤大(P＜0.05),更倾向于显示肿块型病变(P＜0.05),且更容易出现腋下淋巴结转移(P＜0.05).阳性组的ADC均值比阴性组稍高,但没有统计学意义(P=0.65).结论 乳腺癌Ki-67表达阳性者肿块更大,更易出现淋巴结转移,这可能与细胞增殖活跃相关,也提示患者预后不良.     

VIBRANT多时相增强MRI鉴别乳腺良恶性病变的应用研究

目的 探讨VIBRANT多时相增强MRI鉴别乳腺良、恶性病变的临床价值。方法 采用GE1.5T MR仪及4通道乳腺相控阵线圈，对53例（57灶）患者双侧乳腺平扫后用Gd-DTPA（磁显葡胺0.1mmol/kg）以2.0ml/s静脉团注，注药后约15秒开始第1次采集，采集时间约57秒，连续无间隔采集8-10次。结果 除1例外，所有乳腺脂肪抑制均匀。乳腺病变形态是否规则及边缘是否有毛刺与病变良、恶性关系显着（P〈0.05）。边缘毛刺征特异度95%（19/20）。恶性病变1分钟早期增强率高于良性病变（P〈0.05），诊断灵敏度及特异度分别为91.89%及65%。恶性病变时间-信号强度曲线Ⅰ型（单相型）10.81%（4/37），Ⅱ型（平台型）2.7%（1/37），Ⅲ型（流出型）86.49%（32/37）;良性病变Ⅰ型65%（13/20），Ⅱ型5%（1/20），Ⅲ型10%（2/20），Ⅳ型（环状或无明显强化）20%（4/20）。以Ⅱ型或Ⅲ型为恶性标准，诊断灵敏度、特异度分别为89.19%及85%。形态学与血流动力学相结合，灵敏度、特异度及准确率分别为91.89%（34/37），85%（17/20），89.47%（51/57）。结论 应用VIBRANT进行乳腺多时相增强MRI脂肪抑制较好，可以得到较好的形态学和血流动力学信息。时间-信号强度曲线是鉴别乳腺良、恶性病变比较有效的方法。1分钟早期增强率诊断灵敏度较高，边缘毛刺征特异度较高。形态学与血流动力学相结合，可以提高诊断准确率。     

乳腺MRI技术操作规范探讨

目的：乳腺MRI具有良好的软组织分辨率、多平面成像和无辐射性,现已成为高危人群普查、乳腺癌早期诊断、判断疗效、评估预后等不可或缺的检查手段的重要方法。该文简要介绍乳腺MRI的适应证、常用技术的规范和图像影响因素,以期对乳腺MRI技术的临床应用提供参考。     

MRI评价乳腺癌脑膜转移

目的探讨乳腺癌脑膜转移的MRI表现特点及转移途径。方法回顾性分析21例经临床病理证实的乳腺癌脑膜转移患者的临床及MRI资料。结果 MRI表现:平扫仅3例表现为条片状或结节状异常信号。增强后18例表现为硬脑膜-蛛网膜型,3例为软脑膜-蛛网膜型。12例伴有颅骨骨质破坏,6例伴有脑内转移。乳腺癌脑膜转移途径:11例经邻近颅骨转移灶直接侵犯邻近硬脑膜;5例脑实质表浅部位的转移瘤侵犯邻近硬脑膜;4例经血行直接转移至硬脑膜和(或)柔脑膜,1例经血行转移至脑脊液后播散至柔脑膜。结论 MR增强扫描是乳腺癌脑膜转移的重要检查方法。经颅骨转移瘤侵犯邻近硬脑膜是乳腺癌脑膜转移的主要途径和特点。     

Pre-processed image reconstruction applied to breast and brain MR imaging

Magnetic resonance imaging (MRI) has emerged as a powerful tool in medical diagnosis and research. Although high spatial resolution images are essential in medical diagnosis and image analysis, high temporal resolution is equally important in applications of dynamic contrast-enhanced MRI or functional brain MRI. In particular, in breast MRI the ability to differentiate between benign and malignant lesions depends, in part, on the temporal resolution of the dynamic image acquisition. New applications of MRI such as multi-feature analysis of image time series data and full 3D functional MRI or event-related functional MRI require high spatial and high temporal resolution for accurate image analysis on a voxel-by-voxel basis. Currently available partial Fourier reconstruction techniques. which effectively improve the time resolution, suffer from a reduced signal to noise ratio in the reconstructed image, a decrease in spatial resolution or reconstruction artefacts, making numerical image analysis difficult. In this work we present an image reconstruction algorithm based on image recovery theory which effectively doubles the temporal resolution and results in an image quality sufficient for further numerical analysis. The developed algorithm requires a full Fourier space acquisition of a pre-contrast or baseline image prior to the reconstruction procedure of the time series partial Fourier data.     

MR imaging for assessment of breast cancer response to neoadjuvant chemotherapy

Contrast-enhanced MR imaging is being used increasingly because of its high sensitivity to breast cancer and superior ability to demonstrate the extent and distribution of disease. In addition to this direct clinical use, MR imaging in the neoadjuvant treatment setting allows exploration of its potential value in quantifying primary tumor response. The high sensitivity and staging accuracy of MR imaging may yield more accurate classification of objective tumor response using RECIST criteria than clinical examination or mammography. Functional measurements hold the promise of greater sensitivity for detecting biologic effects of targeted treatments than simple anatomic methods.