Introduction: Breast density is a well-recognized factor in breast cancer risk assessment, with higher density linked to increased malignancy risk and reduced sensitivity of conventional mammography. Background parenchymal enhancement (BPE), observed in contrast-enhanced imaging, reflects physiological contrast uptake in non-pathologic breast tissue. While extensively characterized in breast MRI, the role of BPE in contrast-enhanced mammography (CEM) remains uncertain due to inconsistent findings regarding its correlation with breast density and cancer risk. Unlike breast density—standardized through the ACR BI-RADS lexicon—BPE lacks a uniform classification system in CEM, leading to variability in clinical interpretation and research outcomes. To address this gap, we introduce the BPE-CEM Standard Scale (BCSS), a structured four-tiered classification system specifically tailored to the two-dimensional characteristics of CEM, aiming to improve consistency and diagnostic alignment in BPE evaluation.Materials and Methods:In this retrospective single-center study, 213 patients who underwent mammography (MG), ultrasound (US), and contrast-enhanced mammography (CEM) between May 2022 and June 2023 at the “A. Perrino” Hospital in Brindisi were included. Breast density was classified according to ACR BI-RADS (categories A–D). BPE was categorized into four levels: Minimal (< 10% enhancement), Light (10–25%), Moderate (25–50%), and Marked (> 50%). Three radiologists independently assessed BPE in a subset of 50 randomly selected cases to evaluate inter-observer agreement using Cohen’s kappa. Correlations between BPE, breast density, and age were examined through regression analysis.Results:BPE was Minimal in 57% of patients, Light in 31%, Moderate in 10%, and Marked in 2%. A significant positive association was found between higher breast density (BI-RADS C–D) and increased BPE (p< 0.05), whereas lower-density breasts (A–B) were predominantly associated with minimal or light BPE. Regression analysis confirmed a modest but statistically significant association between breast density and BPE (R2= 0.144), while age showed no significant effect. Inter-observer agreement for BPE categorization using the BCSS was excellent (κ = 0.85; 95% CI: 0.78–0.92), supporting its reproducibility.Conclusions:Our findings indicate that breast density is a key determinant of BPE in CEM. The proposed BCSS offers a reproducible, four-level framework for standardized BPE assessment tailored to the imaging characteristics of CEM. By reducing variability in interpretation, the BCSS has the potential to improve diagnostic consistency and facilitate integration of BPE into personalized breast cancer risk models. Further prospective multicenter studies are needed to validate this classification and assess its clinical impact.
引言：乳腺密度是乳腺癌风险评估中公认的重要因素，较高密度与恶性肿瘤风险增加及传统乳腺X线摄影敏感性降低相关。背景实质强化（BPE）在对比增强影像中可见，反映了非病理性乳腺组织的生理性对比剂摄取。尽管在乳腺MRI中已得到广泛表征，但BPE在对比增强乳腺X线摄影（CEM）中的作用仍不明确，因其与乳腺密度及癌症风险的相关性研究结果存在不一致性。与通过ACR BI-RADS词典标准化的乳腺密度不同，BPE在CEM中缺乏统一的分类系统，导致临床解读和研究结果存在差异。为填补这一空白，我们提出BPE-CEM标准分级量表（BCSS），这是一个专门针对CEM二维成像特征构建的四级分类系统，旨在提高BPE评估的一致性和诊断协调性。 材料与方法：本回顾性单中心研究纳入了2022年5月至2023年6月期间在布林迪西"A. Perrino"医院接受乳腺X线摄影（MG）、超声（US）和对比增强乳腺X线摄影（CEM）的213例患者。乳腺密度根据ACR BI-RADS标准（A-D类）进行分类。BPE分为四级：极少强化（<10%）、轻度强化（10-25%）、中度强化（25-50%）和显著强化（>50%）。三位放射科医师独立评估随机选取的50例病例的BPE，采用Cohen's kappa系数评估观察者间一致性。通过回归分析检验BPE、乳腺密度和年龄之间的相关性。 结果：57%的患者BPE为极少强化，31%为轻度强化，10%为中度强化，2%为显著强化。研究发现较高乳腺密度（BI-RADS C-D类）与增强的BPE之间存在显著正相关（p<0.05），而较低密度乳腺（A-B类）主要与极少或轻度BPE相关。回归分析证实乳腺密度与BPE之间存在适度但具有统计学意义的关联（R²=0.144），而年龄则无显著影响。使用BCSS进行BPE分类的观察者间一致性极佳（κ=0.85；95% CI：0.78-0.92），支持了该系统的可重复性。 结论：我们的研究结果表明，乳腺密度是CEM中BPE的关键决定因素。提出的BCSS为CEM的影像学特征量身定制了一个可重复的四级标准化BPE评估框架。通过减少解读的差异性，BCSS有望提高诊断一致性，并促进BPE整合到个性化乳腺癌风险模型中。需要进一步的前瞻性多中心研究来验证该分类系统并评估其临床影响。
肿瘤(癌症)患者之家