Malignant breast tumours: Correlation of apparent diffusion coefficient values using diffusion-weighted images and dynamic contrast-enhancement ratio with histologic grading

PurposeTo evaluate the correlation of the apparent diffusion coefficient (ADC) using diffusion weighted imaging (DWI) and early/delayed enhancement (E/D) ratio using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) with histological grading in malignant breast lesions.Material and methodsThirty-one women with 34 histopathologically proved malignant breast lesions underwent MRI within 2 weeks prior to surgery. MRI examination included T1 and T2 W sequences, DWI and DCE-MRI. ADC values and E/D ratios are correlated with the histological grades.ResultsThe mean ADC of the malignant lesions was 0.85 ± 0.12 × 10−3 mm2/s. The mean ADC values of grade I, II and III were 0.96 ± 0.12 × 10−3 mm2/s, 0.87 ± 0.07 × 10−3 mm2/s and 0.75 ± 0.12 × 10−3 mm2/s, respectively. Tumours with higher grade showed significantly lower ADC value (p = 0.0001) compared with lower grade and there is an inverse correlation between ADC value and histological grade (r = −0.62, p-value = 0.0001). The mean E/D ratio for grade I, II and III tumours were 0.98 ± 0.04, 1.01 ± 0.05 and 1.07 ± 0.08, respectively. Tumours with higher grade showed significantly higher E/D ratio (p = 0.005) compared with lower grade and there was a direct correlation between E/D ratio and histological grade (r = 0.44, p = 0.008).ConclusionDWI is a useful diagnostic parameter with significantly higher correlation with the histological grade of breast cancer than DCE MRI, which is an important factor for proper treatment selection.