Diffusion weighted imaging in breast MRI: comparison of two different pulse sequences

RATIONALE AND OBJECTIVES: Comparison of two different diffusion weighted (DW) sequences in breast MRI regarding the differentiation between benign and malignant lesions. MATERIALS AND METHODS: Breast MRI including two different DW sequences was performed in 165 consecutive women. Inclusion criteria for DW imaging and ADC evaluation were histologically proven focal mass lesions with a diameter of more than 5 mm in dynamic contrast-enhanced MRI. The DW sequences were pre-contrast echo-planar imaging with spectral fat saturation (EPI fs) and DW EPI with inversion recovery (EPI STIR) (b-values: 50, 400, and 800). Lesions were analyzed regarding visibility in DW sequences and ADC values. RESULTS: Inclusion criteria were fulfilled in 56 women with 69 lesions. Five lesions could not be evaluated for different reasons. Finally, DW sequences were evaluated in 51 women with 64 focal mass lesions (15 benign, 49 malignant). The visibility of the lesions was significantly better in the EPI fs sequence (P<0.05). The ADC values (10(-3) mm(2)/s) in the EPI fs were 1.76, 2.58, and 1.21 (mean, maximum, minimum, respectively) for benign lesions and 0.90, 1.19, and 0.34 for malignant lesions. Respective values in the EPI STIR sequence were 1.92, 3.20, 1.10, and 0.91, 1.43, 0.35. Only in the EPI fs sequence there was no overlap in ADC values between benign and malignant lesions. CONCLUSION: The DW MRI of the breast with EPI fs and EPI STIR sequences has a high potential to differentiate between benign and malignant breast lesions. Due to better lesion visibility and selectivity, the EPI fs sequence should be preferred.     

Breast diffusion-weighted MRI: comparison of tetrahedral versus orthogonal diffusion sensitization for detection and localization of mass lesions

Purpose:

To evaluate the potential of tetrahedral diffusion‐weighted imaging (DWI) compared to orthogonal DWI for detection and localization of early enhanced breast mass lesions at 1.5T.

Materials and Methods:

Sixty‐seven consecutive patients (mean age 51.7 years, range 14–84 years) with 68 solitary early enhanced breast lesions suspicious for cancer on dynamic contrast‐enhanced magnetic resonance imaging (MRI) were enrolled in this retrospective study. Two radiologists independently observed maximum intensity projection images of orthogonal and tetrahedral DWI and the diagnostic accuracy and background tissue visibility between two DWI techniques were compared. Contrast‐enhanced MRI was used as the reference standard. Background tissue visibility was assessed based on whether the “breast quadrant” and “skin line” were determined. A phantom validation study for apparent diffusion coefficient (ADC) values was also conducted.

Results:

Sensitivity (93%) and specificity (96%) on tetrahedral DWI were equivalent to those on orthogonal DWI (sensitivity, 88%; specificity, 95%). Background tissue was more easily determined with tetrahedral DWI (breast quadrant, 90%; skin lines, 95%) than with orthogonal DWI (breast quadrant, 61%; skin lines, 16%). ADC values of tetrahedral DWI were highly correlated with those of orthogonal DWI.

Conclusion:

Tetrahedral DWI provided equivalent detectability of mass lesions with improved visibility of surrounding anatomical structure. J. Magn. Reson. Imaging 2011;33:1375–1381. © 2011 Wiley‐Liss, Inc.     

Diffusion tensor MRI: Preliminary anisotropy measures and mapping of breast tumors

Purpose:

To investigate whether diffusion tensor imaging (DTI) measures of anisotropy in breast tumors are different from normal breast tissue and can improve the discrimination between benign and malignant lesions.

Materials and Methods:

The study included 81 women with 105 breast lesions (76 malignant, 29 benign). DTI was performed during breast MRI examinations, and fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured for breast lesions and normal tissue in each subject. FA and ADC were compared between cancers, benign lesions, and normal tissue by univariate and multivariate analyses.

Results:

The FA of carcinomas (mean ± SD: 0.24 ± 0.07) was significantly lower than normal breast tissue in the same subjects (0.29 ± 0.07; P < 0.0001). Multiple logistic regression showed that FA and ADC were each independent discriminators of malignancy (P < 0.0001), and that FA improved discrimination between cancer and normal tissue over ADC alone. However, there was no difference in FA between malignant and benign lesions (P = 0.98).

Conclusion:

Diffusion anisotropy is significantly lower in breast cancers than normal tissue, which may reflect alterations in tissue organization. Our preliminary results suggest that FA adds incremental value over ADC alone for discriminating malignant from normal tissue but does not help with distinguishing benign from malignant lesions. J. Magn. Reson. Imaging 2010; 31: 339–347. © 2010 Wiley‐Liss, Inc.     

Quantitative diffusion imaging in breast cancer: a clinical prospective study

PURPOSE: To study the correlation between apparent diffusion coefficient (ADC) and pathology in patients with undefined breast lesion, to validate how accurately ADC is related to histology, and to define a threshold value of ADC to distinguish malignant from benign lesions. MATERIALS AND METHODS: Seventy-eight patients (110 lesions) were referred for positive or dubious findings. Three-dimensional fast low-angle shot (3D-FLASH) with contrast injection was applied. EPI diffusion-weighted imaging (DWI) with fat saturation was performed, and ROIs were selected on subtraction 3D-FLASH images before and after contrast injection, and copied on an ADC map. Inter- and intraobserver analyses were performed. RESULTS: At pathology 22 lesions were benign, 65 were malignant, and 23 were excluded. The ADCs of malignant and benign lesions were statistically different. In malignant tumors the ADC was (mean +/- SEM) 0.95 +/- 0.027 x 10(-3)mm(2)/second, and in benign tumors it was 1.51 +/- 0.068 x 10(-3)mm(2)/second. According to receiver operating characteristic (ROC) curves, we found a threshold between malignant and benign lesions for highest sensitivity and specificity (both 86%) around 1.13 +/- 0.10 x 10(-3)mm(2)/second. For a threshold of 0.95 +/- 0.10 x 10(-3)mm(2)/second, specificity was 100% but sensitivity was very low. Inter- and intraobserver studies showed good reproducibility. CONCLUSION: The ADC may help to differentiate benign and malignant lesions with good specificity, and may increase the overall specificity of breast MRI.     

Improved diagnostic accuracy of breast MRI through combined apparent diffusion coefficients and dynamic contrast‐enhanced kinetics

This study investigated the relationship between apparent diffusion coefficient (ADC) measures and dynamic contrast‐enhanced magnetic resonance imaging (MRI) kinetics in breast lesions and evaluated the relative diagnostic value of each quantitative parameter. Seventy‐seven women with 100 breast lesions (27 malignant and 73 benign) underwent both dynamic contrast‐enhanced MRI and diffusion weighted MRI. Dynamic contrast‐enhanced MRI kinetic parameters included peak initial enhancement, predominant delayed kinetic curve type (persistent, plateau, or washout), and worst delayed kinetic curve type (washout > plateau > persistent). Associations between ADC and dynamic contrast‐enhanced MRI kinetic parameters and predictions of malignancy were evaluated. Results showed that ADC was significantly associated with predominant curve type (ADC was higher for lesions exhibiting predominantly persistent enhancement compared with those exhibiting predominantly washout or plateau, P = 0.006), but was not significantly associated with peak initial enhancement or worst curve type (P > 0.05). Univariate analysis showed significant differences between benign and malignant lesions in both ADC (P < 0.001) and worst curve (P = 0.003). In multivariate analysis, worst curve type and ADC were significant independent predictors of benign versus malignant outcome and in combination produced the highest area under the receiver operating characteristic curve (0.85 and 0.78 with 5‐fold cross validation). Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Differentiation of clinically benign and malignant breast lesions using diffusion-weighted imaging

PURPOSE: To evaluate the value of diffusion-weighted imaging (DWI) in distinguishing between benign and malignant breast lesions. MATERIALS AND METHODS: Fifty-two female subjects (mean age = 58 years, age range = 25-75 years) with histopathologically proven breast lesions underwent DWI of the breasts with a single-shot echo-planar imaging (EPI) sequence using large b values. The computed mean apparent diffusion coefficients (ADCs) of the breast lesions and cell density were then correlated. RESULTS: The ADCs varied substantially between benign breast lesions ((1.57 +/- 0.23) x 10(-3) mm(2)/second) and malignant breast lesions ((0.97 +/- 0.20) x 10(-3) mm(2)/second). In addition, the mean ADCs of the breast lesions correlated well with tumor cellularity (P < 0.01, r = -0.542). CONCLUSION: The ADC would be an effective parameter in distinguishing between malignant and benign breast lesions. Further, tumor cellularity has a significant influence on the ADCs obtained in both benign and malignant breast tumors.     

IVIM成像与DWI在乳腺良恶性病变鉴别诊断中的比较

目的 比较体素内不相干运动(IVIM)成像双指数模型、拉伸指数模型与扩散加权成像(DWI)单指数模型各参数在乳腺良恶性病变鉴别诊断中的价值.方法 回顾性分析257例经病理证实的乳腺病变患者(共276个病灶,包括197个恶性病变,79个良性病变).所有患者均行MRI常规检查及多b值DWI检查,获得传统DWI及IVIM各参数.比较各参数在正常乳腺组织、乳腺良性病变及恶性病变中的统计学差异,采用受试者工作特征(ROC)曲线确定各参数诊断乳腺恶性病变的阈值以及曲线下面积(AUC)、诊断敏感性和特异性.结果 正常乳腺组织、乳腺良性病变及恶性病变的表观扩散系数(ADC)、慢速表观扩散系数(slow ADC)、快速表观扩散系数(fast ADC)、灌注分数(f)、扩散分布指数(DDC)及扩散异质性指数(α)值均有统计学差异(P<0.001).ADC、slow ADC、f、DDC和α的AUC分别为0.865、0.861、0.742、0.85和0.735;ADC、slow ADC、DDC和α的最佳诊断阈值分别为1.105×10-3 mm2/s,0.883×10-3 mm2/s,1.025×10-3 mm2/s和0.842,slow ADC敏感性最高(90.3%),DDC特异性最高(79.5%).双指数模型中slow ADC与fast ADC联合诊断的AUC为0.882;拉伸指数模型DDC与α联合诊断的AUC为0.853.结论 3种模型对于乳腺病变良恶性的鉴别都具有较高的价值,传统ADC的诊断准确性较高,slow ADC敏感性较高,DDC特异性较高.双指数模型中slow ADC与fast ADC联合诊断具有较高的价值.     

磁共振扩散加权成像在乳腺良恶性病变中的诊断价值

目的探讨磁共振扩散加权成像在乳腺良恶性病变中的诊断价值。方法收集我院2010年2—8月经手术病理证实或穿刺活检证实的50例乳腺癌患者和50例乳腺良性病变患者。DWI扫描b值分别为400、600、8001、000 s/mm2,测量病灶区域的ADC值,并比较各组之间的差异。结果 b值分别为400、6008、001、000时乳腺癌及良性病变的ADC值,恶性组ADC值明显低于良性组(P<0.05)。四组不同b值的良恶性病变分别做ROC曲线,以b=1 000 s/mm2时,AUC最大,诊断价值最高,以ADC值为1.23×10-3mm2/s作为良恶性病变的诊断阈值,敏感性为90.0%,特异性为89.8%,准确性为89.9%。结论 DWI结合ADC值测量,对乳腺良恶性病变的鉴别诊断具有较高的临床应用价值。     

Menstrual cycle variation of apparent diffusion coefficients measured in the normal breast using MRI

Recent investigations have shown that tumors may be distinguished from benign lesions in the breast based on differences in apparent diffusion coefficient (ADC) values. The goal of this study was to assess the magnitude of normal variations in the measured ADC of breast parenchyma during the menstrual cycle. Eight healthy female subjects were scanned once a week for 4 weeks, using a diffusion-weighted single-shot fast spin-echo (DW-SSFSE) sequence. The ADC of breast fibroglandular tissue was calculated for each woman at each time point. Results showed a trend of decreased ADC during the second week of the cycle, and increased ADC during the final week. However, no significant influence of menstrual cycle on breast ADC values was identified. The results of this study show that the normal fluctuation of breast ADC is relatively small, and the coefficient of variation was determined to be 5.5% for our group of volunteers during a menstrual cycle. Nonetheless, breast diffusion measurements for tumor differentiation and evaluation of treatment response should be interpreted with consideration of normal variability.     

乳腺DCE-MRI与ADC值及ADC差值的临床应用价值

目的 探讨动态增强磁共振成像(DCE-MRI)、扩散加权成像(DWI)对鉴别乳腺良恶性病变的临床应用价值.方法 对临床拟诊乳腺病变的60例患者行MR检查,将病灶形态学、早期增强率、时间-信号曲线(TIC)、表观扩散系数(ADC)值、病灶周围组织与病灶ADC的差值诊断结果进行比较分析.结果 早期增强率、TIC、ADC值、ADC差值受试者工作特征(ROC)曲线的曲线下面积(AUC)分别为0.741、0.808、0.882、0.959,早期增强率、ADC值、ADC差值最佳诊断阈值分别为163％、1.30×10-3mm2/s、0.47×10-3 mm2/s.形态学、早期增强率、Ⅲ型曲线、Ⅱ型及Ⅲ型曲线、ADC值、ADC差值鉴别诊断乳腺良恶性病变的敏感性分别为53.1％、59.4％、43.8％、90.6％、93.8％、96.9％,特异性分别为85.7％、82.1％、89.3％、57.1％、75.0％、82.1％,阳性预测值分别为81.0％、79.2％、82.4％、70.7％、81.1％、86.1％,阴性预测值分别为61.5％、63.9％、58.1％、84.2％、91.3％、95.8％,准确率分别为68.3％、70.0％、65.0％、75.0％、85.0％、90.0％.结论 DCE MRI与DWl对乳腺良恶性病变的鉴别诊断有重要作用,其中ADC差值诊断效能最高,需多种方法综合诊断互补不足,以提高诊断准确性.     

1.5TMR乳腺扩散加权成像b值的优化

目的 通过分析水模、正常乳腺腺体、乳腺良性及恶性病变的ADC值及图像信噪比(SNR)随b值的变化规律,探讨1.5 TMR乳腺DWI合理的b值取值范围.方法 对32例经病理证实的乳腺病变(恶性18例,良性14例)及对侧正常腺体进行乳腺MR检查,采用EPI-DWI序列;b值分别采用0、50、100、200、400、600、800、1000、1200、1400、1600、1800、2000、2200、2400、2600 s/mm2.测量不同b值下水模、正常乳腺腺体、乳腺良性及恶性病变的平均ADC值和图像SNR,采用Pearson相关分析法分析不同b值时的变化规律.结果 DWI的SNR均随b值的增加逐渐下降,二者呈负相关(r=-0.802,P＜0.01),乳腺良、恶性病变的ADC值均随着b值的增加而下降(r=-0.923和-0.855,P＜0.01);当b值取800～1000 s/mm2时,恶性病变与良性病变和正常腺体之间的ADC值差异最大(0.7×10-3mm2/s);当b值＞1400 s/mm2,差异逐渐减小.结论 取b值800～ 1000 s/mm2时,既能取得良好的图像质量,又能有效地鉴别乳腺良、恶性病变,是1.5 TMR乳腺DWI最合理的b值取值范围.     

磁共振扩散加权成像在胆管癌及肝占位性病变鉴别诊断中的应用价值

目的 探讨磁共振扩散加权成像在胆管癌及肝良、恶性占位性病变鉴别诊断中的应用价值。方法 采用DWI技术对胆管癌患者及肝良、恶性占位性病变患者进行了鉴别和诊断,探讨DWI对胆管癌定性诊断中的作用,及其与肝其他占位性病变进行鉴别比较研究过程中的特点。结果 肝细胞癌组、肝转移瘤组的ADC值与胆管癌组比较无明显差异。肝血管瘤组、肝囊肿组及正常肝组织的ADC值则明显高于胆管癌组,且差异具有统计学意义。胆管癌组的ADC值与与肝恶性病变比较无明显差异;但是胆管癌组的ADC值明显低于肝良性病变组,且差异具有统计学意义。结论 DWI序列速度快,通过DWI图像特点及量化分析ADC值,对胆管癌及肝良、恶性占位性病变可提供定量的诊断信息,可作为上腹部平扫的补充检查序列,应列为MRI常规序列之一。     

Characterization of malignancy of adnexal lesions using ADC entropy: Comparison with mean ADC and qualitative DWI assessment

Purpose:

To establish the utility of apparent diffusion coefficient (ADC) entropy in discrimination of benign and malignant adnexal lesions, using histopathology as the reference standard, via comparison of the diagnostic performance of ADC entropy with mean ADC and with visual assessments of adnexal lesions on conventional and diffusion‐weighted sequences.

Materials and Methods:

In all, 37 adult female patients with an ovarian mass that was resected between June 2006 and January 2011 were included. Volume‐of‐interest was drawn to incorporate all lesion voxels on every slice that included the mass on the ADC map, from which whole‐lesion mean ADC and ADC entropy were calculated. Two independent radiologists also rated each lesion as benign or malignant based on visual assessment of all sequences. The Mann–Whitney test and logistic regression for correlated data were used to compare performance of mean ADC, ADC entropy, and the visual assessments.

Results:

No statistically significant difference was observed in mean ADC between benign and malignant adnexal lesions (P = 0.768). ADC entropy was significantly higher in malignant than in benign lesions (P = 0.009). Accuracy was significantly greater for ADC entropy than for mean ADC (0.018). ADC entropy and visual assessment by the less‐experienced reader showed similar accuracy (P ≥ 0.204). The more experienced reader's accuracy was significantly greater than that of all other assessments (P ≤ 0.039).

Conclusion:

ADC entropy showed significantly greater accuracy than the more traditional metric of mean ADC for distinguishing benign and malignant adnexal lesions. Although whole‐lesion ADC entropy provides a straightforward and objective measurement, its potential benefit decreases with greater reader experience. J. Magn. Reson. Imaging 2013;37:164–171. © 2012 Wiley Periodicals, Inc.     

MR扩散加权成像鉴别乳腺良恶性病变的研究

目的　探讨磁共振扩散加权成像(diffusion weightedMRimaging, DW MRI)的表观扩散系数(apparentdiffusioncoefficient, ADC)在乳腺病变鉴别诊断中的价值。方法　DW- MRI采用单次激发平面回波成像(echo planarimaging, EPI)技术, 扩散敏感系数(b值)分别为0、500、1000s/mm2。计算26个正常乳腺、手术病理证实的24个恶性病灶、30个良性病灶分别在b=1000~0、1000~500、500~0s/mm2 时的ADC值,比较良恶性病变、正常腺体间ADC值差异的统计学意义及b=1000~0、1000~500、500~0s/mm2 间ADC值差异的统计学意义。结果　乳腺良、恶性病变、正常腺体间ADC值差异均有统计学意义(F= 565. 74,P<0 .01),恶性病变ADC值明显低于良性病变和正常腺体组织,良性病变ADC值明显低于正常腺体组织; 3组b值间ADC值差异均有统计学意义(F=21. 30,P<0 .01),b值越低,ADC值越大;把恶性肿瘤ADC值95%可信区间上界( 1. 01×10-3 )mm2 /s定为良恶性病变鉴别的界值,诊断敏感性为64 .0%,特异性为96 .7%。结论　根据ADC值可以对乳腺良恶性病变做出鉴别诊断,其特异性较高,但敏感性较低。     

表观扩散系数在乳腺病变诊断中的应用价值

目的:对比乳腺良、恶性病变的表观扩散系数(apparent diffusion coefficient,ADC),探讨DWI在乳腺病变中的诊断价值.材料和方法:搜集术前行MR检查并经病理证实的236例乳腺病变,采用平面回波-扩散加权成像序列(EPH)WI);测量病变区和对侧正常乳腺腺体的ADC值,应用t检验比较良、恶性病变及正常腺体ADC值的差异,采用接收者工作特征曲线(receiver operating characteristic curve,ROC)确定良、恶性病变的ADC界值;根据BI-RADS MRI将乳腺病变分为肿块性病变和非肿块性病变,比较ADC值在两组病变中定性诊断效能.结果:236例乳腺病变中,恶性病变ADC值[(1.08±0.32)X 10-3mm2/s]显著低于良性病变[(1.48±0.35)×102mm2/s],差异有统计学意义(P=0.01);根据ROC曲线确定ADC界值为1.25×10-2mm2/s,诊断敏感性和特异性分别为78.2%和77.5%.肿块性病变良、恶性ADC界值为1.15×10-3mm2/s(敏感性和特异性分别为79.8%和81.8%),非肿块性病变良、恶性ADC界值为1.35×10-3mm2/s(敏感性和特异性分别为78%和72%).绪论:根据ADC界值可以鉴别乳腺良、恶性病变;对肿块性病变和非肿块性病变应采用不同的ADC界值;DWI对肿块性病变的诊断效能优于非肿块性病变.     

Differential diagnosis of mammographically and clinically occult breast lesions on diffusion‐weighted MRI

Purpose:

To investigate the diagnostic performance of diffusion‐weighted imaging (DWI) for mammographically and clinically occult breast lesions.

Materials and Methods:

The study included 91 women with 118 breast lesions (91 benign, 12 ductal carcinoma in situ [DCIS], 15 invasive carcinoma) initially detected on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and assigned BI‐RADS category 3, 4, or 5. DWI was acquired with b = 0 and 600 s/mm². Lesion visibility was assessed on DWI. Apparent diffusion coefficient (ADC) values were compared between malignancies, benign lesions, and normal (no abnormal enhancement on DCE‐MRI) breast tissue, and the diagnostic performance of DWI was assessed based on ADC thresholding.

Results:

Twenty‐four of 27 (89%) malignant and 74/91 (81%) benign lesions were hyperintense on the b = 600 s/mm² diffusion‐weighted images. Both DCIS (1.33 ± 0.19 × 10^?3 mm²/s) and invasive carcinomas (1.30 ± 0.27 × 10^?3mm²/s) were lower in ADC than benign lesions (1.71 ± 0.43 × 10^?3mm²/s; P < 0.001), and each lesion type was lower in ADC than normal tissue (1.90 ± 0.38 × 10^?3mm²/s, P ≤ 0.001). Receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.77, and sensitivity = 96%, specificity = 55%, positive predictive value (PPV) = 39%, and negative predictive value (NPV) = 98% for an ADC threshold of 1.60 × 10^?3mm²/s.

Conclusion:

Many mammographically and clinically occult breast carcinomas were visibly hyperintense on diffusion‐weighted images, and ADC enabled differentiation from benign lesions. Further studies evaluating DWI while blinded to DCE‐MRI are necessary to assess the potential of DWI as a noncontrast breast screening technique. J. Magn. Reson. Imaging 2010;1:562–570. © 2010 Wiley‐Liss, Inc.

     

ADC mapping of benign and malignant breast tumors.

PURPOSE: The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) value in differentiating benign and malignant breast lesions and evaluating the detection accuracy of the cancer extension. MATERIALS AND METHODS: We used DWI to obtain images of 191 benign and malignant lesions (24 benign, 167 malignant) before surgical excision. The ADC values of the benign and malignant lesions were compared, as were the values of noninvasive ductal carcinoma (NIDC) and invasive ductal carcinoma (IDC). We also evaluated the ADC map, which represents the distribution of ADC values, and compared it with the cancer extension. RESULTS: The mean ADC value of each type of lesion was as follows: malignant lesions, 1.22+/-0.31 x 10(-3) mm2/s; benign lesions, 1.67+/-0.54 x 10(-3) mm2/s; normal tissues, 2.09+/-0.27 x 10(-3) mm2/s. The mean ADC value of the malignant lesions was statistically lower than that of the benign lesions and normal breast tissues. The ADC value of IDC was statistically lower than that of NIDC. The sensitivity of the ADC value for malignant lesions with a threshold of less than 1.6 x 10(-3) mm2/s was 95% and the specificity was 46%. A full 75% of all malignant cases exhibited a near precise distribution of low ADC values on ADC maps to describe malignant lesions. The main causes of false negative and underestimation of cancer spread were susceptibility artifact because of bleeding and tumor structure. Major histologic types of false-positive lesions were intraductal papilloma and fibrocystic diseases. Fibrocystic diseases also resulted in overestimation of cancer extension. CONCLUSIONS: DWI has the potential in clinical appreciation to detect malignant breast tumors and support the evaluation of tumor extension. However, the benign proliferative change remains to be studied as it mimics the malignant phenomenon on the ADC map.     

Role of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) in differentiating between benign and malignant breast lesions

Objective

To assess the role of DWI and ADC in differentiating between benign and malignant breast lesions.

Materials and methods

51 patients (age range 24–66 years; mean age 48 years) were included in our study. MRI was done using bilateral fat-suppressed T2- weighted fast spin-echo, STIR, axial T1-weighted fast spin-echo. DWI series were acquired using echo planar imaging pulse sequences incorporated with diffusion gradients and finally dynamic contrast enhancement study was done.

Results

Sixty three lesions were detected in 51 patients included in our study. Twenty one lesions were malignant, three lesions were intermediate and twenty two lesions were fibroadenoma according to the final histopathological study and seventeen lesions were breast cysts. A total of 21 lesions showed lower ADC values than benign lesions and were in the range of 0.76–1.29 × 10⁻³ mm²/s and were diagnosed as malignant breast lesions. The sensitivity and specificity for DWI in the differentiating malignant from benign breast lesions were calculated and showed 95.4% and 97.5%, respectively.

Conclusion

DWI is easy to obtain in short scan time and easy to evaluate, and ADC values can differentiate between benign and malignant breast lesions with high sensitivity and specificity.     

高b值MR扩散加权成像在乳腺良恶性病变诊断中的应用价值

目的 评价高b值MR DWI及ADC值在乳腺良恶性病变诊断中的应用价值.方法 165例患者在行乳腺MR动态增强扫描前行不同b值(分别为500、1500 s/mm2)的DWI扫描,对171个怀疑或高度怀疑恶性病变者行回顾性分析.以正常乳腺组织为参考基准,选择增强图像中异常强化的高信号病变,同时在高b值(b= 1500 s/mm2)DWI中视觉判定是高信号的病变定义为恶性病变阳性结果,否则为良性病变阴性结果.对其中111个DWI视觉判定阳性结果的病变计算ADC值.依据全部病变穿刺活检病理诊断结果,应用Fisher精确检验和Wilcoxon秩和检验对比分析高b值DWI视觉评估中恶性和良性病变的阳性和阴性病灶数,以ADC值=1.13×10-3 mm2/s作为临界值,计算诊断的特异度和敏感度.结果 乳腺病变穿刺活检病理证实的171个乳腺病变中,91个恶性病变,80个良性病变.高b值DWI视觉评估,139个阳性结果中,恶性病变83个,良性病变56个;32个阴性结果中,良性病变24个,恶性病变8个(非肿块性导管原位癌),差异有统计学意义(P＜0.01).所有浸润性癌和肿块样导管原位癌(DCIS)在DWI视觉判定中为阳性,8例非肿块性DCIS判定为假阴性,总体的敏感度为91.2％ (83/91),特异性为30.0％ (24/80).110个肿块样病变和1个局灶性病变DWI视觉评估阳性结果的病变中,63个恶性病变平均ADC值为(0.73±0.24)×10-3 mm2/s,48个良性病变平均ADC值为(1.19±0.42)×10-3mm2/s,差异有统计学意义(Z=5.818,P＜0.01).以ADC值=1.13×10-3mm2/s作为临界值时,61个恶性病变为阳性结果,2个黏液癌为假阴性结果;27个良性病变为阴性结果,21个良性病变为假阳性,诊断敏感度是96.8％(61/63),特异度为56.2％ (27/48).结论 高b值DWI及ADC值对乳腺良恶性病变的鉴别诊断有一定的作用,但在诊断非肿块性乳腺病变时仍需慎重.     

ADC值和相对ADC鉴别乳腺良恶性病变的价值

目的探讨ADC值和相对ADC(relative ADC,rADC)鉴别乳腺良恶性病变的价值。方法回顾性分析2011年1月~2018年12月济宁医学院附属医院通过病理或活检证实的乳腺病变,其中良性病变组31例,恶性病变组41例,测量病变区ADC值及其周围正常腺体ADC值,并计算rADC(病变ADC值/周围正常腺体ADC值),将良性病变组ADC值和恶性病变组ADC值;良性病变组rADC和恶性病变组rADC分别做独立样本t检验,比较组间差异,并绘制ROC曲线。结果良性病变组ADC(1.33±0.24)×10^-3 mm²/s,恶性病变组ADC(0.94±0.25)×10^-3 mm²/s(t=-6.755,P<0.001);良性病变组rADC 0.71±0.12,恶性病变组rADC 0.50±0.12,(t=-7.389,P<0.001)。ADC值最佳诊断分界点为1.264×10^-3 mm²/s,ROC曲线下面积为0.856,灵敏度为80.5%,特异度为80.7%,rADC最佳诊断分界点为0.624,ROC曲线下面积为0.893,灵敏度为85.4%,特异度为90.3%。结论ADC值、rADC可以鉴别乳腺良恶性病变,rADC的诊断准确性更高。