Background Breast nonmass lesions (NMLs) are observed at screening and diagnostic US. However, knowledge is limited on imaging features of NMLs at screening US. Purpose To identify features of NMLs at screening US that are suspicious for malignancy based on mammographic findings. Materials and Methods This retrospective, multicenter study included asymptomatic women who underwent screening US between January 2012 and December 2019. Eligible women had NMLs at US, concurrent screening mammography, and record of a final diagnosis. Logistic regression analyses were used to identify factors associated with malignancy. The diagnostic performance of each sonographic feature according to mammographic findings was calculated. A reader study was performed to assess interreader agreement for sonographic features. Results Among 993 NMLs in 993 patients (mean age, 50 years ± 9 [SD]), 914 (92.0%) were benign and 79 (8.0%) were malignant. Mean size was larger for malignant NMLs than for benign NMLs (2.6 cm ± 1.1 vs 1.9 cm ± 0.8; P < .001). In multivariable analysis, associated calcifications (odds ratio [OR], 21.6 [95% CI: 8.0, 58.2]; P < .001), posterior shadowing (OR, 6.9 [95% CI: 2.6, 18.4]; P < .001), segmental distribution (OR, 6.2 [95% CI: 2.7, 14.4]; P < .001), mixed echogenicity (OR, 5.0 [95% CI: 1.8, 14.0]; P < .001), and size (OR, 1.5 [95% CI: 1.1, 2.1]; P = .01) at US were associated with malignancy. Associated calcifications, posterior shadowing, segmental distribution, and mixed echogenicity showed positive predictive values (PPVs) of 44%, 22%, 22.9%, and 16.6%, respectively. Having a negative mammogram was associated with a lower malignancy rate (2.8% vs 28.8%) and lower PPVs for sonographic features (0.7%-10.4% vs 24%-55%) than having a positive mammogram. Interreader agreement for sonographic features was good to excellent (Fleiss κ 95% CI lower bound range, 0.63-0.81). Conclusion Calcifications, posterior shadowing, segmental distribution, and mixed echogenicity associated with NMLs can be considered suspicious features for malignancy at screening US. As malignancy rates and PPVs differ according to mammographic abnormalities, combined assessment is mandatory. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Grimm in this issue.

中文翻译：

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根据乳房 X 光检查结果评估筛查乳腺 US 检测到的非占位性病变。


背景 在筛查和诊断 US 时观察到乳腺非肿块病变 （NML）。然而，在筛选 US 时对 NML 的成像特征的了解有限。目的 根据乳腺 X 线摄影结果确定筛查 US 时怀疑恶性肿瘤的 NML 特征。材料和方法 这项回顾性、多中心研究包括 2012 年 1 月至 2019 年 12 月期间接受 US 筛查的无症状女性。符合条件的女性在 US 进行了 NML，同时进行了乳房 X 线检查筛查，并有最终诊断记录。采用 Logistic 回归分析确定与恶性肿瘤相关的因素。根据乳腺 X 线摄影结果计算每个超声特征的诊断性能。进行了一项读者研究，以评估读者对超声特征的一致性。结果 在 993 例患者 （平均年龄 50 岁 ± 9 [SD]）的 993 例 NML 中，914 例 （92.0%） 为良性，79 例 （8.0%） 为恶性。恶性 NML 的平均大小大于良性 NML （2.6 cm ± 1.1 vs 1.9 cm ± 0.8;P < .001）.在多变量分析中，相关的钙化（比值比 [OR]，21.6 [95% CI： 8.0,58.2];P < .001）、后阴影 （OR， 6.9 [95% CI： 2.6， 18.4];P < .001）、节段分布 （OR， 6.2 [95% CI： 2.7， 14.4];P < .001）、混合回声 （OR， 5.0 [95% CI： 1.8， 14.0];P < .001） 和大小 （OR， 1.5 [95% CI： 1.1， 2.1];P = .01） 与恶性肿瘤相关。相关钙化、后阴影、节段分布和混合回声显示阳性预测值 （PPV） 分别为 44% 、 22% 、 22.9% 和 16.6%。与乳腺 X 线照片阳性相比，乳腺 X 线照片阴性与较低的恶性肿瘤发生率 （2.8% vs 28.8%） 和超声特征的 PPV 较低 （0.7%-10.4% vs 24%-55%） 相关。 超声特征的读者间一致性为良好至极好 （Fleiss κ 95% CI 下限范围，0.63-0.81）。结论 与 NMLs 相关的钙化、后阴影、节段分布和混合回声可被视为筛查 US 时的恶性肿瘤可疑特征。由于恶性肿瘤发生率和 PPV 因乳腺 X 线摄影异常而异，因此必须进行联合评估。© RSNA，2024 年本文提供补充材料。另请参见本期格林的社论。