Super-Resolution Ultrasound Imaging for Assessing Response to Neoadjuvant Chemotherapy in Breast Cancer

1. Study Design Overview Study Type: Single-center, prospective, observational, diagnostic study. Primary Objective: To validate whether Super-Resolution Ultrasound Imaging (SRUS) can accurately predict pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer at an early stage (after the first cycle of chemotherapy). Sample Size: A total of 150 patients are planned to be enrolled. Study Period: March 2026 - March 2028. 2. Core Methodology: Cohort Allocation This study employs a classic "Model Development-Validation" cohort design to construct a predictive model and verify its generalizability. Allocation Method: Systematic random allocation. Allocation Ratio: 7:3. Randomization: Patients will be assigned based on the sequence of enrollment using a computer-generated random sequence. Blinding Principle: Allocation information will be concealed (blinded) from patients and the clinical treatment team. Only the research coordinators and statisticians will have access to the grouping data to prevent information leakage. Validation Set (Independent Validation Cohort): Comprising 30% of the sample (45 cases). The data will remain "sealed" until model construction is finalized. It will be used for unbiased, objective performance evaluation of the final model (e.g., calculating AUC, sensitivity). 3. Study Procedures and Visits The study workflow strictly adheres to the chemotherapy timeline, with core data collection points focused on the early phase of treatment: V0 (Screening): Confirmation of eligibility criteria. V1 (Baseline, Pre-chemotherapy): Initial SRUS examination to acquire baseline tumor data. V2 (Early Visit, 48-72 hours after the 1st cycle): The critical data point for the predictive model; the first follow-up examination. V3 (Mid-term Visit, Pre-4th cycle): The second follow-up examination. V4 (Surgery, 3-4 weeks after the last cycle): Radical surgery is performed. V5 (Endpoint Assessment, 2-4 week