1、Diffusion-weighted MR imaging of the breast:Comparison of apparent diffusion coefficient values of normal breast tissue with benign and malignant breast lesions,乳房MR扩散加权成像：比较正常乳腺组织与良性和恶性乳腺病变表观扩散系数值 XIA WANJUN,The specificity of conventional magnetic resonance (MR) imaging is lower than its high sens
2、itivity. 传统的磁共振（MR）成像灵敏度低。 Diffusion-weighted imaging (DWI), based on alterations in the microscopic motion of water molecules, promises improved specificity for breast MR imaging.In this study, we aimed to determine the diagnostic potential of DWI to differentiate between benign and malignant breas
3、t lesions and normal breast tissue.弥散加权成像（DWI）的基础是水分子的微观运动，是特殊的乳腺磁共振成像技术。本项研究的目的是探讨DWI对区分良性和恶性乳腺病变及正常乳腺组织的潜在诊断性。,Dynamic contrast-enhanced breast MR imaging and DWI were applied to 108 women. Apparent diffusion coefficient (ADC) values were obtained for normal breast tissue (n = 183), benign lesions
4、 (n = 66) and malignant lesions (n = 58). The results were compared with the patients final diagnoses. 对108名妇女进行动态对比增强乳腺磁共振成像和弥散加权成像。对正常乳腺组织（N= 183例），良性病变组（n =66例），恶性病变（N =58例）分别进行表观扩散系数（ADC）值测定。然后与患者的最终诊断结果进行比较。,The mean age of the patients was 44.9 (range 1977) years. There was no difference betwe
5、en the mean age of patients with malignant and benign lesions (45.0 years vs. 44.8 years, p = 0.9;Students t-test). The ADC measurements of normal breast tissue were obtained from 183 breasts. 患者的平均年龄为44.9岁（范围19-77）。恶性和良性患者的平均年龄之间无显着差异（45.0岁vs44.8年，P = 0.9;t分布检验 ）。正常乳腺组织的ADC测量有183例。,On histopatholog
6、ical examination, 58 lesions proved to be malignant in 42 patients: invasive ductal carcinoma (IDC) n = 31; invasive lobular carcinoma (ILC) n = 1; mixed invasive lobular and ductal carcinoma (IDC+ILC) n = 3; ductal carcinoma in situ n = 2; mix IDC + mucinous carcinoma n = 1;IDC and pleomorphic carc
7、inoman = 1; medullary carcinoma n = 1; 对42位患者58例病变进行病理组织学检查，发现恶性乳腺浸润性导管癌（IDC）31位患者，浸润性小叶癌（ILC）1位患者，浸润性导管癌和浸润性小叶癌（IDC+ ILC）3位患者;导管原位癌2位患者;浸润性导管癌+黏液腺癌 1位患者;浸润性导管癌和多形性癌1例，髓样癌1位患者，,malignant phyllodes tumour n = 1; diffuse leukaemic infiltration of the breast n = 1 . 恶性叶状肿瘤1位患者，弥漫性白血病浸润乳腺1位患者。 The mean
8、size of the malignant lesions was 41.3 34.3 mm. 恶性病变的平均大小为41.334.3毫米。 A total of 66 benign lesions in 44 patients were included in the study. 44位患者66例良性病变的研究。,35 lesions were histopathologically diagnosed as benign fibroadenoma (n = 18) , cystosarcoma phyllodes tumour (n = 2), fibrocystic changes (n
9、 = 4), seroma (n = 6), fat necrosis (n = 2), ductal hyperplasia (n = 1), papilloma (n = 1) and haematoma (n = 1). 35例病变组织病理学诊断为良性纤维腺瘤18例，分叶状囊肉瘤2例，纤维囊性变4例，血清肿组6例，脂肪坏死2例，导管上皮增生1例，乳头状瘤1例和血肿1例。,31 benign lesions had typical BI-RADS (Breast Imaging Reporting and Data System) 2 findings on DCE-MRI and wer
10、e diagnosed as cyst (n = 7), fibroadenoma (n = 20) and intramammarian lymph node (n = 4) . DCE-MRI检查对31例典型的良性病变定BI-RADS分级（乳腺影像报告和数据系统）2 ，并诊断为囊肿7例，纤维腺瘤20例和乳房淋巴结4例。,Resu lts：Mean ADC values for benign and malignant breast lesions were 1.04 103 0.29 103 mm2/s and 2.00 103 0.55 103 mm2/s, respectively (
11、p = 0.001, Students t-test), while that for normal breast tissue was 1.78 103 0.33 103 mm2/s. With a cut-off value of 1.46 103 mm2/s for ADC in receiver operating characteristic analysis,95% sensitivity and 85% specificity were achieved for differentiating between benign and malignant lesions. 结果 乳腺
12、良、恶性病变的ADC值平均值分别为1.0410-30.29103mm2/s和2.001030.5510-3 mm2/s，（P = 0.001，t分布检验），而正常乳腺组织1.781030.33103 mm2/s。根据受试者特征取1.46103 mm2/s的ADC为区分良性和恶性病变的临界值，得到敏感性为95和特异性85。,Conclusion DWI of the breast can help differentiate benign and malignant breast lesions from normal breast tissue. 结论 乳房DWI检查可以帮助区分良性、恶性乳腺
13、病变与正常乳腺组织。 DWI, which can be easily introduced into standard breast MR imaging protocols without increasing imaging times,promises to increase the accuracy of breast MR imaging without contrast media. 。 DWI在不增加成像时间，通常作为常规的乳房MR成像检查方法之一，增加乳腺磁共振成像的准确性而无需造影剂。,Since the specificity of conventional MR ima
14、ging, which uses morphological and kinetic criteria, is relatively lower than its high sensitivity, advanced MR imaging application has a potential role to play in the diagnosis of breast lesions. 常规磁共振成像，它采用形态学和动力学的标准，其灵敏度低于相对先进的磁共振成像，先进的磁共振成像技术在乳腺病变的诊断中具有潜在的作用。 Diffusion-weighted imaging (DWI) pro
15、mises improved specificity of breast MR imaging.弥散加权成像（DWI）能够提高乳腺磁共振成像的特异性。,DWI is an advanced MR imaging technique based on the diffusion signal of tissues, which reflects the amount of random motion of water molecules into tissues due to thermal agitation (Brownian motion). DWI是一种先进的磁共振成像技术，基于组织的扩
16、散信号，反映了组织中水分子的随机热运动（布朗运动）。 DWI was first introduced for acute cerebral infarction, for which it has become one of the primary imaging modalities. DWI最初引入急性脑梗塞，并已成为主要成像方式之一。,However, it is now being used for other clinical applications over the entire body, and holds great promise for the detection a
17、nd characterisation of tumours of other organs such as the ovaries, pancreas, prostate and breast. 然而，现在被用于整个身体部位的临床检查，它在检测卵巢，胰腺，前列腺癌和乳腺肿瘤及描述肿瘤征象方面拥有巨大潜力。 DWI helps in the investigation of breast masses by providing information about the biological behaviour of the tumour.Several studies have evalua
18、ted breast lesions using DWI.DWI有助于提供乳腺肿块的生物学行为。一些学者采用DWI评估乳腺病变。,DWI has been reported to be a useful technique for the discrimination of benign and malignant lesions.已报道DWI是一种区别良性和恶性病变有用的技术。 Malignant lesions with tightly packed cells have a reduced extracellular space, resulting in decreased diffu
19、sion of water. The result is a high DWI signal intensity and a lower ADC value, indicating restricted diffusion on an ADC map (Figs. 13). 恶性病变的细胞排列紧密，减少外的空间，从而降低水的扩散。其结果是高DWI信号强度和低ADC值，ADC图（图1-3）上显示扩散受限制。,（图1-3）,1a,Fig. 1 Histopathological f indings in a 43-year-old woman with invasive ductal carcin
20、oma浸润性导管癌. (a) Postcontrast T1-W fat-saturated sagittal image and (b) MIP image of the breast in the axial plane show an enhancing BI -RADS 5 lesion with irregular margins (arrows). (c) DWI with b = 600 and (d) ADC map show a mass with restricted diffusion that was hyperintense on DWI and hypointens
21、e on ADC map (arrows). Mean ADC value = 0.95 103 mm2/s. ADC: apparent diffusion coefficient ; BI-RADS: B reast Imaging Repor t ing and Data System; DWI : diffusion-weighted imaging;MIP: maximum intensity projection,1b,1c,1d,Fig. 2 Histopathological f indings in a 43-year-old woman with locally advan
22、ced invasive ductal carcinoma浸润性导管癌. Sagittal MIP reconstructions obtained from the f irst series of post-contrast dynamic images (a) before and (b) after neoadjuvant chemotherapy show minimal decrease in the size of tumour, axillary lymph nodes and vascularity. ADC maps of DWI (c) before (b = 0) an
23、d (d) af ter (b =600) neoadjuvant chemotherapy are also seen (black and white arrows show the margin of the lesion). Mean ADC value: before, 0.93 103 mm2/s; after, 1.08 1033 mm2/s. Post-therapy measurements were not included in the study.ADC: apparent dif fusion coef ficient; DWI: dif fusion-weighte
24、d imaging; MIP: maximum intensity projection,2a,2b,2c,2d,（图4和图5）。,3a,3b,3c,3d,Fig. 3 Histopathologicalf indings in a 32-year-old woman showing leukemic infiltration 白血病浸润of the breast . (a) T2-W sagittal and(b) post-contrast T1-W fat-saturated subtracted sagit tal images show a huge lesion with cent
25、ral areas of necrosis坏死. (c) DWI with b = 600 and (d) ADC map show solid portions of the mass with restricted dif fusion that were hyperintense on DWI and hypointense on ADC map. Mean ADC value = 0.31 103 mm2/s. The necrotic central part of the tumour, with relatively higher diffusion, was not inclu
26、ded in the ROI during measurements.ADC: apparent diffusion coefficient; DWI: dif fusion-weighted imaging; ROI: region of interest,On the contrary, benign lesions with a larger extracellular space have water molecules that are more mobile, and thus higher ADC values (Figs. 4 & 5). 相反，良性病变有更大范围内的细胞外的空
27、间有更多的水分子移动，因此ADC值增高（图4和图5）。,Fig. 4 His topathologic al f indings in a 39-year-old woman with fibroadenoma纤维腺瘤 . (a) Post-contrast T1-W fat-saturated subtracted sagittal image shows a BI-RADS 2 solid mass typical of a fibroadenoma with macrolobulated contour, smooth margins, darkinternal septa and ty
28、peI enhancement characteristics (arrow). (b)DWI with b = 600 and (c) ADC map show a fibroadenoma (arrows)that exhibited no restriction of dif fusion. Mean ADC value of 2.17 103 mm2/s was higher than that of neighbouring glandular tissue(1.97 103 mm2/s).ADC: apparent diffusion coef ficient; BI-RADS:
29、B reast Imaging Reporting and Data System; DWI: diffusion-weighted imaging,4a,4b,4c,Fig. 5 Histopathological f indings in a 61-year-old woman with intramammarian lymph node乳房淋巴结. (a) A xial STIR image shows an intramammarian lymph node (arrow), with a typical hilar notch, that was stable on screenin
30、g mammograms. (b) ADC map shows a mean ADC value = 2.14 103 mm2/s of the lymph node (arrow).ADC: apparent diffusion coefficient; STIR: shor t tau inversion recovery,5a,5b,Similar to the findings of other reports in the literature, our finding, which was based on the ADC values of 58 malignant lesion
31、s,66 benign lesions and 183 normal breast tissues, supports the consensus that DWI can successfully differentiate between benign and malignant lesions 与其他文献报告相似，我们对58个恶性病变，66个良性病变和183例正常乳腺组织的ADC值的研究，也发现，DWI可以很好的区分良性和恶性病变。,In a meta-analysis of 12 studies, Tsushima et al reported that the ADC values
32、of benign breast tumours were between 1.41 103mm2/s and 2.01 103mm2/s, and those of malignant lesions were in the range of 0.90 103mm2/s to 1.61 103mm2/s. 12项研究的综合分析，对马等报道，良性乳腺肿瘤的ADC值介于1.41103mm2 / s和2.01103 mm2/ s，和那些恶性病变范围在0.90103mm2/ s到1.61103mm2/ s,The mean ADC values of normal breast tissue in
33、our study were in the range of 1.51 103 mm2/s to 2.37 103mm2/s. The mean ADC value for malignant lesions was found to be 1.04 103 0.29 103mm2/s, which was compatible with that reported in the literature. 我们的研究正常乳腺组织的ADC值的范围为1.51103mm2/ s到2.37103mm2/ s。恶性病变平均ADC值被认为1.041030.29103mm2/ s，这是与在文献中报告相相似。,
34、The findings of statistical analysis in our series were similar to those in the literature. The mean ADC of benign lesions in our study also showed a value within the reported range, although it was at the higher end. 统计分析的结果，与该系列其它文献相似。 虽然良性病变平均ADC高，但也是在我们的研究结果的范围内。 It is possible that the inclusio
35、n of patients with fibrocystic changes and seromas in the study population may have increased the mean ADC value slightly.纤维囊性变和血清肿可能稍增加病灶的平均ADC值。,Due to the wide range of ADC values reported in patients with inflammatory diseases and the false positive results known in this group of patients, these
36、 patients were not included in the benign group for statistical analysis in our study. 因为炎性疾病ADC值范围广，且会造成诊断的假阳性，所以它不被列入良性研究对象。 Mucinous carcinomas with high mucine content have also been reported to contribute to high ADC values. 黏液腺癌粘蛋白含量高，导致ADC值高。,On the contrary, the mucinous and medullary carcin
37、omas in our series exhibited low ADC values. 但是相反，我们的研究，粘液性和髓样癌ADC值低。 As ADC values have been reported to be higher in the central necrotic areas of malignant tumours, they were measured from the periphery of necrotic tumours in our series. 由于已报道中恶性肿瘤中央坏死ADC值是较高的，而我们的研究中坏死区在肿瘤周边。,The microscopic mov
38、ement of biological tissues consist of molecular diffusion in the extracellular compartment and microcirculation of blood in the capillary network (flow). Therefore, perfusion is another factor that affects ADC values. 生物组织的微观运动包括在细胞外和微循环的血液中的毛细管网络的水分子扩散（流量）。因此，灌注是另一个影响ADC值的因素。 ADC values also diffe
39、r with various b-values, as seen in the literature. Images with low b-values result in less diffusion-weighted images, as a lower gradient is applied. 文献报道ADC值因b值的不同而不同。图像的低b值，导致扩散加权图像较低的梯度。,Also, the extension of microvascular structures in malignant lesions may increase the perfusion effect on ADC
40、 values in images with low b-values. 此外，在恶性病变微血管结构灌注增加可能会影响低b值的ADC值。 However, the signal-to-noise ratio in these images is higher than that in diffusion images with high b-values. 低b值的信号噪声比高于高b值所在扩散图像。,Typically, at least two b-values should be used during DWI in order to enable meaningful ADC inter
41、pretation,although accuracy increases when more b-values are used. 虽然使用更多的b值提高精确度，通常情况下至少两个b值。 In our study, we had used b-values of 0 s/mm2 and 600 s/mm2 in order to limit the examination time. 我们的研究使用0 s/mm2和600 s/mm2 b值，以限制测试时间。,Pereira et al, however, reported no significant difference between t
42、he ADC values of benign and malignant lesions when different combinations of b-values were used, and thus concluded that using multiple b-values in a DWI sequence was unnecessary. 但是Pereira等人报告，不同的b值测量D的不同ADC值,对区别良性和恶性病变没有明显差异。因而认为，使用多个b值在DWI序列是不必要的。 Wood hams et al reported that b 750 mm2/s was hig
43、hly efficient detecting breast masses. Woodhams等报道，B 750 mm2 / s可以高效检测乳腺肿块。,The diagnostic accuracy of DWI for breast can only be ascertained once technical parameters and post-processing procedures are standardised for the modality. DWI对乳腺的诊断准确率在于技术参数和后处理程序方法的标准化。 Major technical limitations associ
44、ated with it are distortion of the images secondary to susceptibility, chemical shift, motion artefacts and low spatial resolution. 与它相关的主要技术限制是敏感性低的失真的图像，化学位移，运动伪影和低空间分辨率。,Even under optimal circumstances, small lesions may not be visualised on ADC maps, as Kinoshita et al have reported that lesion
45、s 10 mm in diameter cannot be demonstrated by DWI. 即使在最理想的情况下，小的病灶可能不会ADC图上可见，木下等人报道，病灶直径10毫米的病灶DWI显示欠佳。 Another limitation is that of nonmass-like enhancing lesions that form large and non-compact lesions with normal parenchyma intervening within the tumour. 另一个限制是非肿块型增强的病变，该病变肿瘤细胞排列不紧密，病灶范围广中间夹杂正常
46、组织成分。,Non-IDCs, lobular carcinoma in situ, atypical ductal hyperplasia, papillomas, hormonal changes and fibrocystic disease may show this type of enhancement.非乳腺浸润性导管癌，小叶原位癌，导管上皮不典型增生，乳头状瘤，荷尔蒙的变化和纤维囊性疾病，可能会出现该类型的强化。 According to Guo et al and Sinha et al, the mean ADC value is inversely proportiona
47、l to cellular density, and therefore, these lesions may exhibit less restriction of diffusion. 根据Guo和Sinha等的研究，平均ADC值是与细胞密度成反比，因此，这些病变较少表现出限制扩散。,When the range of ADC values was considered, a slight overlap was observed in the ADC values of benign and malignant lesions, both in the literature and in
48、 our series. 无论文献还是我们的研究发现，良性和恶性病变的ADC值的范围有一个轻微的重叠。 Some benign conditions,such as haematomas, abscesses, fibrosis and inflammatory lesions, are known to exhibit low ADC values. 一些良性病灶，如血肿，脓肿，纤维化和炎症改变具有低ADC值。,The Finally, it should be noted that DWI cannot replace dynamic breast MR imaging with contrast, but can be used as a complementary technique to evaluate breast masses. 最后，应注意的是，DWI不能取代动态乳腺MR成像当做增强对比，但可以用作一个互补的技术来评估乳腺肿块。 DWI may also provide a useful alternative in cases where contrast media is contraindicated for patients. DWI对造影剂禁忌患者可以做一种替代检查。,
