Multiparametric MRI in Idiopathic Granulomatous Mastitis: Correlation with clinical classification and its potential role in diagnosis and management—A retrospective observational study

Background Idiopathic Granulomatous Mastitis (IGM) is a rare, benign inflammatory breast disease with a variable clinical course. While recent clinical classifications provide guidance for management based on disease severity, objective imaging correlates remain limited. Purpose To assess the correlation between multiparametric breast MRI parameters and consensus based clinical types of IGM at presentation. Materials and methods This retrospective observational study included 40 patients with biopsy-proven IGM (age 18–45) who underwent multiparametric breast MRI. Apparent diffusion coefficient (ADC) values, STIR (Short Tau Inversion Recovery) signal intensities, and enhancement patterns were analyzed according to clinical classification. In abscess-forming lesions, separate ADC measurements were obtained from necrotic cores and peripheral walls. Proton MR spectroscopy was performed in 22 patients with indeterminate findings. Statistical analyses included ANOVA with post hoc tests, chi-square, Spearman correlation, and inter-observer agreement using ICC and Cohen’s Kappa. Results STIR signal intensity and ADC values increased significantly from Type 1 to Type 4 disease (p < 0.001). The necrosis-to-wall ADC ratio showed a modest correlation with the consensus-based clinical types (r = 0.35, p = 0.036). MR spectroscopy revealed no significant metabolite differences, although borderline lactate elevation was observed in later clinical types (Types 3–4). Specifically, mean ADC values rose from 1.04 to 1.66 × 10⁻3 mm2/s, while mean STIR signal intensity increased from 154 to 300 a.u. across the clinical types (p < 0.001). Conclusion Clinical classification systems based on disease severity are increasingly emphasized to standardize the diagnosis and management of IGM. Multiparametric breast MRI provides noninvasive imaging correlates of the consensus-based clinical types (Types 1–4) at presentation. ADC values and STIR signal intensity appear to be promising quantitative imaging correlates of consensus-based clinical types at presentation, whereas enhancement patterns should be interpreted mainly as descriptive baseline findings. These findings support the use of multiparametric MRI as an adjunct for baseline characterization of IGM. Copyright © 2026. Published by Elsevier B.V.