Abstract:

Objective

To assess the benefits and application potential of high-frame-rate contrastenhanced ultrasound (HFR-CEUS) in differentiating small benign from malignant breast nodules categorized as BI-RADS 4 nodules (maximum diameter≤20 mm).

Methods

The study involved 75 patients with a total of 82 nodules, treated at the First Affiliated Hospital of Suzhou University from September 2022 to December 2023.Based on pathological diagnosis, the nodules were classified into benign (58 nodules) and malignant groups (24 nodules).Prior to the pathological diagnosis, all patients underwent conventional CEUS (C-CEUS) and HFR-CEUS; characteristics of perfusion patterns for each method were recorded,including enhancement direction, intensity, edge characteristics post-enhancement, enhancement range, and nutrient vessels, alongside time-intensity curve-related parameters (peak intensity, rise time, time to peak,mean transit time, and wash-in area under the curve).These attributes were compared between the groups by χ² test, Fisher test or rank sum test to evaluate their differences.Additionally, the sensitivity, specificity,and accuracy of both ultrasound modalities in distinguishing benign from malignant nodules were analyzed.Receiver operating characteristic (ROC) curves were generated and the area under the curve (AUC) values of both modalities were compared by Delong test.

Results

In HFR-CEUS mode, benign lesions predominantly showed eccentric enhancement direction (37.9%), low enhancement intensity (13.8%), limited expansion of enhancement range (91.4%), and better-defined edges (70.7%) compared to conventional CEUS (17.2%,1.7%, 75.9%, and 46.6%, respectively), with statistically significant differences between the two groups(χ²=6.238, 6.562, 5.098, and 7.663; P=0.044, 0.033, 0.024, and 0.046, respectively).The incidence of radial edge features in the malignant group (45.8%) was significantly higher compared to that of the C-CEUS group (16.7%; χ²=5.807, P=0.047).Furthermore, HFR-CEUS demonstrated higher diagnostic efficacy than C-CEUS in differentiating benign from malignant breast nodules (AUC: 0.937 vs 0.853), with a statistically significant difference (Z=2.488, P=0.013).The diagnostic specificity (91.4%) and accuracy (90.2%) of HFRCEUS were also significantly improved compared to those of C-CEUS (specificity 67.2%, accuracy 74.4%).

Conclusion

HFR-CEUS enhances the visualization of early perfusion processes and edge features in small breast nodules by increasing the frame rate, and improving image contrast and resolution, thereby enhancing the diagnostic performance for benign and malignant small BI-RADS4 breast nodules.

Key words: Breast imaging reporting and data system, Contrast-enhanced ultrasound, High frame rate, Breast cancer