Contrast-Enhanced Ultrasound in the Evaluation of Complex Cystic and Solid Breast Masses-A Feasibility Study.

Objective: Complex cystic and solid breast mass (CCSBM) is a radiological diagnosis based on grayscale B-mode sonographic features. Because of potential for malignancy, biopsy is typically recommended. We examined the feasibility of contrast-enhanced US (CEUS) as a tool to identify benign CCSBMs.

Methods: This Institutional Review Board-approved prospective observational study performed targeted CEUS of 14 CCSBMs that were subsequently biopsied. CEUS images were independently reviewed by two readers blinded to other sonographic features, noting presence or absence of enhancement and time to perceived optimal enhancement. Interobserver agreement for presence or absence of enhancement was analyzed using Cohen's kappa coefficient. From retrospective review of initial diagnostic US examinations, descriptive CCSBM sizes, subtypes, and Doppler information were recorded. Histopathologies were categorized as benign, benign with upgrade potential (BWUP), and malignant. Measures of diagnostic accuracy and 95% CIs were calculated for CEUS enhancement.

Results: Of 14 CCSBMs, 12 were nonmalignant (9 benign, 3 BWUP) and 2 were malignant. There was perfect interobserver agreement (Cohen's kappa 1.00) between the 2 readers for CEUS enhancement. CEUS was 100% sensitive, 25% specific, with an area under the receiver operating characteristic curve (AUROC) of 0.625 (95% CI, 0.50-0.75) in differentiating nonmalignant from malignant lesions. It was 100% sensitive, 33.3% specific, with an AUROC of 0.667 (95% CI, 0.50-0.85) in differentiating benign from surgically significant (BWUP and malignant) CCSBMs.

Conclusion: This small feasibility study highlighted the potential of CEUS as a safe noninvasive tool to identify the proportion of CCSBMs that are benign and can avoid tissue biopsy.