Clinical evaluation of combining dynamic contrast-enhanced MR imaging and diffusion-weighted MR imaging for diagnosis of breast lesion

Objective To evaluate the clinical value of combining dynamic contrast-enhanced MRI and diffusion weighted MR imaging (DWI) for the diagnosis of breast lesion. Methods Forty-one lesions from 35 patients were acquired with histopathological demonstration, of which 28 were malignant and 13 were benign. All lesions were examined with dynamic contrast-enhanced MRI and DWI. The sequences used were 3D fast spoiled gradient echo (FSPGR) and single-shot echo planar imaging (SS-EPI), b=1000 s/mm2. The images were reviewed by two radiologists at ADW 4.2 workstation and made consensus on the shape, contour and the type of time-signal intensity curve (TIC). The suspicious malignant aspect of morphology and types of TIC was given a point. The lesions were classified as malignant, suspicious or benign according the score summed up. Apparent diffusion coefficient (ADC) of the lesion was acquired using region of interest (ROI) technique correlated with the location of enhanced lesion by Functool Ⅱ software on the workstation. Threshold of ADC for diagnosis was acquired by ROC analysis, and lesions were classified as benign and malignant. The validities of dynamic contrast-enhanced imaging, ADC, and combination of the two methods were evaluated. Results The sensitivity, specificity and accuracy of dynamic contrast-enhanced imaging were 96.4% (26/27), 61.5% (8/13) and 85.4% (35/41). Area under the curve for ADC was 0.690 by ROC analysis, and the threshold was 1.42×10-3 mm2/s. The sensitivity, specificity and accuracy of ADC were 89.3% (25/28), 61.5% (8/13) and 80.5% (33/41). The combination of dynamic contrast-enhanced MRI and DWI-ADC of breast lesions had a sensitivity, specificity and accuracy of 89.3% (25/28), 76.9% (10/13) and 85.4% (35/41). In half of malignant lesions which manifest atypically on dynamic contrast-enhanced MRI, definite diagnosis for malignance make instead of suspicious diagnosis due to combination with ADC. In two benign lesions, the suspicious malignant diagnosis was changed to be benign according to combination of dynamic MRI and ADC. Conclusion The combination of dynamic contrast-enhanced MRI and DWI is useful to increase specificity, and provide valuable information for the diagnosis of those lesions suspicious in dynamic contrast-enhanced MRI.