BACKGROUND Available data proving the value of DWI for breast cancer diagnosis is mainly for enhancing masses; DWI may be less sensitive and specific in non-mass enhancement (NME) lesions. The objective of this study was to assess the diagnostic accuracy of DWI using different ROI measurement approaches and ADC metrics in breast lesions presenting as NME lesions on dynamic contrast-enhanced (DCE) MRI. METHODS In this retrospective study, 95 patients who underwent multiparametric MRI with DCE and DWI from September 2007 to July 2013 and who were diagnosed with a suspicious NME (BI-RADS 4/5) were included. Twenty-nine patients were excluded for lesion non-visibility on DWI (n = 24: 12 benign and 12 malignant) and poor DWI quality (n = 5: 1 benign and 4 malignant). Two readers independently assessed DWI and DCE-MRI findings in two separate randomized readings using different ADC metrics and ROI approaches. NME lesions were classified as either benign (> 1.3 × 10-3 mm2/s) or malignant (≤ 1.3 × 10-3 mm2/s). Histopathology was the standard of reference. ROC curves were plotted, and AUCs were determined. Concordance correlation coefficient (CCC) was measured. RESULTS There were 39 malignant (59%) and 27 benign (41%) lesions in 66 (65 women, 1 man) patients (mean age, 51.8 years). The mean ADC value of the darkest part of the tumor (Dptu) achieved the highest diagnostic accuracy, with AUCs of up to 0.71. Inter-reader agreement was highest with Dptu ADC max (CCC 0.42) and lowest with the point tumor (Ptu) ADC min (CCC = - 0.01). Intra-reader agreement was highest with Wtu ADC mean (CCC = 0.44 for reader 1, 0.41 for reader 2), but this was not associated with the highest diagnostic accuracy. CONCLUSIONS Diagnostic accuracy of DWI with ADC mapping is limited in NME lesions. Thirty-one percent of lesions presenting as NME on DCE-MRI could not be evaluated with DWI, and therefore, DCE-MRI remains indispensable. Best results were achieved using Dptu 2D ROI measurement and ADC mean.

中文翻译：

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DWI在弥漫性乳腺病变中表现为弥散性增强的动态弥散增强MRI在乳腺病变中具有明显扩散系数作图的作用有限。

背景技术可用的数据证明DWI在乳腺癌诊断中的价值主要是为了增加肿块。DWI对非质量增强（NME）病变的敏感性可能较低，且特异性较高。这项研究的目的是评估在动态对比增强（DCE）MRI上表现为NME病变的乳腺病变中使用不同ROI测量方法和ADC指标的DWI的诊断准确性。方法在这项回顾性研究中，纳入了2007年9月至2013年7月接受DCE和DWI的多参数MRI诊断并诊断为可疑NME（BI-RADS 4/5）的95例患者。二十九名患者因DWI不可见病变（n = 24：12良性和12恶性）和差的DWI质量（n = 5：1良性和4恶性）而被排除。两名读者使用不同的ADC指标和ROI方法在两个单独的随机读数中独立评估了DWI和DCE-MRI的发现。NME病变分为良性（> 1.3×10-3 mm2 / s）或恶性（≤1.3×10-3 mm2 / s）。组织病理学是参考标准。绘制ROC曲线，并确定AUC。测量一致性相关系数（CCC）。结果66例（65名女性，1名男性）患者（平均年龄51.8岁）中有39例恶性（59％）和27例良性（41％）病变。肿瘤最暗部分的平均ADC值（Dptu）达到了最高的诊断准确性，AUC高达0.71。阅读器间一致性在Dptu ADC max（CCC 0.42）时最高，在点肿瘤（Ptu）ADC min（CCC =-0.01）时最低。使用Wtu ADC均值时，阅读器内部协议最高（阅读器1、0的CCC = 0.44。对于阅读器2）为41），但这与最高的诊断准确性无关。结论在NME病变中，ADC映射对DWI的诊断准确性受到限制。DWI无法评估在DCE-MRI上显示为NME的病变的31％，因此DCE-MRI仍然是必不可少的。使用Dptu 2D ROI测量和ADC均值可获得最佳结果。