Differentiation of BIRADS-4 small breast lesions via Multimodal Ultrasound Tomography.

PURPOSE: To demonstrate the use of a new 3D diagnostic imaging technology, termed Multimodal Ultrasonic Tomography (MUT), for the detection of solid breast lesions < 15 mm in maximum dimension. METHODS AND MATERIALS: 3D MUT imaging was performed on 71 volunteers presenting BIRADS-4 nodules, asymmetrical densities, and architectural distortions in X-ray mammograms, who subsequently underwent biopsy. MUT involved D tomographic imaging of the pendulant breast in a water bath using transmission ultrasound and constructed multimodal images corresponding to refractivity and frequency-dependent attenuation (calibrated relative to water). The multimodal images were fused into composite images and a composite index (CI) was calculated and used for diagnostic purposes. The composite images were evaluated against results of histopathology on biopsy specimens.
RESULTS: Histopathology revealed 22 malignant and 49 benign lesions. The pixels of 22 malignant lesions exhibited high values in both refractivity and attenuation, resulting in CI values > 1. In contrast, 99.9% of benign lesions and normal tissue pixels exhibited lower values of at least one of the attributes measured, corresponding to CI values < 1.
CONCLUSIONS: MUT imaging appears to differentiate small malignant solid breast lesions as exhibiting CI values >1, while benign lesions or normal breast tissues exhibit CI values <1. KEY POINTS: • MUT was able to detect all 22 biopsy-confirmed malignant lesions. • MUT was able to differentiate the malignant from the benign lesions. • Additional MUT detections outside the biopsy area must be evaluated prospectively.