Apparent diffusion coefficient values as an adjunct to dynamic contrast enhanced MRI for discriminating benign and malignant breast lesions presenting as mass and non-mass like enhancement

Purpose

The purpose of our study was to evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC), measured by diffusion weighted MRI, in discriminating benign and malignant breast lesions presenting as mass and non mass like enhancement (NMLE).

Methods and materials

80 patients with 110 breast lesions identified with dynamic contrast MRI. Diffusion-weighted images were obtained at b values of 0 and 750 S/mm², differences in the apparent diffusion coefficients (ADCs) are included in the study and malignant lesions were compared by lesion type (mass or NMLE), and the analysis was performed to evaluate diagnostic performance based on ADC thresholds. All lesions have pathological results. The study has been done retrospectively 50 patients underwent surgical excision with preoperative localization, while the 30 cases underwent stereotactic biopsies either US or mammographically guided techniques specially if associated with micro calcifications.

Results

The mean ADC value of all benign lesions is 1.41 ± 0.36 × 10⁻³ mm²/s, which is higher than the mean ADC of all malignant lesions (1.05 ± 0.30 × 10⁻³ mm²/s, p < 0.05). In the MASS type, the mean ADC is higher in the benign group (1.34 ± 0.30 × 10⁻³ mm²/s) than in the malignant group (1.02 ± 0.29 × 10⁻³ mm²/s, p < 0.01). In the NMLE type, the mean ADC is also higher in the benign group (1.54 ± 0.45 × 10⁻³ mm²/s) than in the malignant group (1.11 ± 0.32 × 10⁻³ mm²/s, p < 0.01). Therefore, benign lesions have higher ADC values than malignant lesions, regardless of the lesion morphology.

Conclusion

Diffusion-weighted MRI shows adequate help in differentiation of benign and malignant masses and lesions with non-mass like enhancement found at breast MRI.