Detection of the differences in the apparent diffusion coefficient values in different histopathological types of malignant breast lesions and comparison of cellular region/ stroma ratio and histopathological results

Background/aim: This study aimed to compare the apparent diffusion coefficient (ADC) values of malignant breast lesions with different histopathological types on diffusion-weighted imaging (DWI) and the cellular region/stroma (CR/S) ratio and histopathological results. Materials and methods: Breast diffusion-weighted magnetic resonance findings of 59 patients were retrospectively analyzed for malignant breast lesions. The CR/S ratio was calculated using breast wide-excisional biopsy or mastectomy specimens. Results: Receiver operating characteristic analysis was performed for malignant lesions and subtypes. An ADC threshold of 1.260 × 10 ­3 mm 2 /s was set to detect invasive ductal carcinoma with 80.8% sensitivity and 81.4% specificity. An ADC threshold of 1.391 × 10 ­3 mm 2 /s was set to detect invasive lobular carcinoma lesions with 88.2% sensitivity and 79.5% specificity. The ADC value for lesions with low CR/S ratio (n = 21) was 1.135 ± 0.429 × 10 ­3 mm 2 /s and it was 1.155 ± 0.429 × 10 ­3 mm 2 /s in the high CR/S ratio group (n = 18). Conclusion: ADC value calculation does not seem to be used as an alternative for histopathological detection, which is the gold standard for the differentiation of subtypes of malignant breast cancer. In addition, since there is a positive correlation between CR/S ratio and ADC values, it may be a strong marker to evaluate the stromal component of lesions.