Value of contrast-enhanced ultrasound in differentiating granulomatous mastitis from invasive ductal carcinoma

Abstract Objective This study aims to analyse the imaging manifestations of granulomatous mastitis (GM) and invasive ductal carcinoma (IDC) using conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS). The objective is to investigate the clinical value of CEUS in differentiating between GM and IDC. Methods We retrospectively enrolled 39 GM patients and 64 IDC patients between January 2020 and June 2023. All diagnoses were confirmed via core needle biopsy or surgical pathology. The characteristics of both conventional US and CEUS in these patients were analysed to distinguish GM from IDC. Results Based on CEUS features, GM lesions most commonly presented as hypoechoic areas (43.6%), followed by pseudocysts (28.2%), hypoechoic nodules (15.4%), and honeycomb cysts (12.8%). The diffuse enhancement pattern was an independent characteristic for distinguishing GM from IDC, with the ROC analysis revealing an area under the curve (AUC) value of 0.794. Conclusion US is the preferred initial examination for GM, and both its conventional and CEUS features can enhance diagnostic accuracy and guide clinical treatment. CEUS demonstrates high differential diagnostic value in distinguishing GM from IDC. Advances in knowledge This study categorizes GM manifestations on CEUS into four types, each corresponding to different pathological stages of GM. We identified that the diffuse enhancement pattern on CEUS is a distinctive characteristic associated with GM, aiding in its differentiation from IDC.