Portable Electrical Impedance Prescreening for Breast tissue suspicious for malignancy: Model Optimization and Clinical Performance of the Julieta Device in a Multicenter Cross-Sectional Study in Colombia

Introduction Breast cancer remains a leading cause of cancer mortality despite being potentially curable when detected early, particularly in low- and middle-income countries where access to screening is limited. This is largely driven by operational gaps, including limited access to screening and delays in diagnosis and treatment. JULIETA is a portable bioimpedance spectroscopy device designed to identify electrical tissue patterns associated with potentially malignant findings and to prioritize women for further diagnostic evaluation. This study assessed the performance of a hierarchical algorithm integrated into JULIETA to distinguish findings without malignant potential (BI-RADS 1-2) from those with malignant potential (BI-RADS ≥3), using mammography as the reference standard.

Methods A cross-sectional observational study with prospective data collection was conducted between May and July 2024 in four Colombian cities. Adult women undergoing screening or follow-up mammography were evaluated with JULIETA prior to imaging. Impedance-derived features, breast density estimates, and individual risk scores were used to retrain a hierarchical classifier combining Random Forest and SVM-RBF models, using an 80/20 stratified split and cross-validation.

Results A total of 1350 women were recruited (mean age 56.5 ± 8.0 years); 67% were BI-RADS 1-2 and 21% BI-RADS 4. After data cleaning, 673 breasts (469 women) were included. The model achieved 73% sensitivity, 76% specificity, 65.5% positive predictive value, and 82.1% negative predictive value.

Conclusion JULIETA is a feasible, safe, and reproducible noninvasive bioimpedance pre-screening tool that may enable scalable triage and support earlier detection and improved equity when integrated into public health pathways.