The role of apperent coefficent values in the differential diagnosis of breast lessions in diffusion-wei̇ghted MRI

Diffusion-weighted imaging (DWI) is one of the studies that have higher specificity in detection of breast lesions in magnetic resonanse imaging (MRI). In this study, our goal was to evaluate the diagnostic efficacy of DWI in thedifferentiation of the malignant and benign breast lesions. Out of 145 patients who had dynamic breast MRI, 107 patients with 110 lesions were included in our study. The patients were between 17-75 years old (mean= 40,6). The patients were evaluated with a 1.5 Tesla MRG scanner using breast coils. DWI images were obtained by EPI (echo planar imaging) sequence and "b" values were selected as 50, 400 and 800 s/mm2. ADC values were calculated both for breast lesions and the normal fibroglandular tissue of the contralateral breast. ADC values were statistically compared by using Student's t test, Kruskal Wallis H test, Mann-Whitney U test and the Receiver Operating Curve. Of 110 lesions, 27 were malignant and 83 were benign. Average ADC values of the lesions were determined for each "b" value. In malignant lesions, the mean ADC values were 1.014±0.03710-3 mm2/sn for b=400, 0.959±0.03910-3mm2/sn for b=800 and 0.939±0.03610-3 mm²/sn for average b values. In benign lesions, the mean ADC values were 1.472±0.02710-3mm2/sn for b=400, 1.433±0.02610-3 mm²/sn for b=800, 1.420±0.02710-3 mm²/sn for average b values. The success of ADC values in classification of malignant and benign lesions was statistically significant (p=0.0001). The threshold values were determined to be 1.289 10-3 mm²/sn for b=400, 1.314 10-3 mm²/sn for b=600 and 1.30310-3 mm²/sn for average b values (p<0.05). We concluded that DWI can be an effective radiological method in the differentiation of malignant and benign breast lesions. Keywords: ADC, benign/malignant differentiation, DWI, MRI