The goal of this study was to investigate the strain elastography imaging characteristics of idiopathic granulomatous mastitis (IGM) and compare strain ratio values of IGM with those of breast cancer.

Twenty-three consecutive women with IGM (mean age, 37.9±6.6 [SD] years; range: 26–52 years) and 45 women with malignant breast tumor (mean age, 52.8±12.0 [SD], range, 32–77 years) who had been scheduled for ultrasound-guided core biopsy were recruited to the study. All had ultrasonography with elastography before biopsy. The strain ratios of lesions were calculated using surrounding normal breast tissue as the reference in both groups and compared between the two groups. Receiver-operating-characteristics (ROC) curves were formed. Sensitivity, specificity, cut-off, and area under curve (AUC) values were calculated.

The mean strain ratio on sonoelastography was 1.5±0.8 (SD) (range: 0.2–4.0) for IGM and 5.3±5.2 (SD) (range: 1.4–33) for malignant lesions. Strain ratio values in IGM lesions were significantly lower than in malignant lesions (P˂0.05). ROC test yielded an AUC value of 0.939 (95% confidence interval, 0.882–0.995; P<0.0001). Optimal cut-off value for strain ratio value was 2.5 yielding 87% sensitivity and 96% specificity for the diagnosis of IGM.

Sonoelastographic strain ratio contributes to differentiate IGM from malignant breast lesions, thus has potential to influence clinical decision making for further biopsies.