Influence of virtual dynamic contrast enhanced breast MRI on lesion size, BI-RADS scores and reader confidence.

backgroundBreast MRI routinely uses gadolinium-based contrast agents (GBCAs) for dynamic contrast-enhanced (DCE) imaging. However, GBCA administration entails periprocedural effort and environmental impact, prompting exploration of contrast-agent-free approaches. Deep learning-based virtual DCE (vDCE) offers a potential solution. This study evaluated vDCE against multiparametric DCE protocols, focusing on BI-RADS, background parenchymal enhancement (BPE), and lesion size. MATERIALS AND

methodsThis IRB-approved retrospective study included 592 3 T examinations divided into training, validation, and test sets. A 2D U-Net generated vDCE series from unenhanced T1-weighted, T2-weighted, and diffusion-weighted acquisitions. Two board-certified radiologists evaluated vDCE and DCE examinations using a BI-RADS-adapted reading protocol. Diagnostic and ordinal outcomes were compared using McNemar and Wilcoxon signed-rank tests with Bonferroni correction.

resultsMean BI-RADS-based diagnostic accuracy was 76% for vDCE and 77% for DCE. Mean sensitivity was 92% vs 96%, and mean specificity was 65% vs 64%, respectively, without significant differences (both readers, p = 1.0). The mean paired lesion-size difference (DCE minus vDCE) was -2.2 mm in the holdout test set and 0.5 mm in the secondary test set. BPE (R1 p = 1.0; R2 p = 1.0) and artefact ratings (R1 p = 1.0; R2 p = 1.0) did not differ significantly. Reader confidence was high for both protocols, although lower for vDCE for one reader (p = 0.072).

conclusionvDCE showed four-percentage-point lower mean sensitivity and small, cohort-dependent lesion-size biases relative to GBCA-enhanced imaging. Further research is warranted to determine its potential role as a contrast-agent-free approach for selected breast imaging indications. KEY POINTS: Question Breast MRI relies on GBCAs, creating procedural and environmental burdens, while clinically validated contrast-agent-free approaches for BI-RADS-based assessment remain unavailable. Findings Virtual DCE MRI showed lower sensitivity than standard DCE, no significant difference in BPE, but more variable reader confidence and lesion size presentation. Clinical relevance Virtual DCE breast MRI currently demonstrates limited diagnostic performance and requires further optimisation, while additional clinical validation studies are needed to determine its potential as a non-contrast alternative.