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objective : To analyze the sensitivity, specificity, accuracy of Dynamic contrast-enhanced imaging、Diffusion-weighted imaging and combination of the two methods for the diagnosis of breast lesion,and to evaluate their diagnostic validity.Methods: Forty patients （mean age, 44 years; age range, 14–61 years） with 40 lesions were referred for positive or dubious findings. All the 40 lesions were proved by pathologic examination. Siemens Magnetom Verio Tim 3.0T MR was used ,with a proprietary phase array breast coil to do both and whole breasts.MR scan included T1-weighted imaging（T1WI）and suppressed T2-weighted imaging（T2WI）. EPI diffusion-weighted imaging （DWI） with fat saturation was performed, and with b values of 50and800s/mm2 .Three dimensional fast low-angle shot （3D-FLASH） with contrast injection was applied.The morphology of contrast-enhancing lesion and the shape of time-signal intensity curve（TIC） were evaluated by two radiologists at workstation.The suspicious malignant aspect of morphology, the type of TIC was given a point.The total number of point for all the criteria was summed ,and the lesions were classified as malignant, suspicious or benign according to the score summed up.We measured the apparent diffusion coefficien（tADC） of lesions using region of interest （ROI）technique with the location of enhanced lesion.Threshold of ADC for diagnosis was acquired by ROC analysis,and lesions were classified as benign and malignant.The difference of ADC between malignant and benigh lesions was evaluated by t-tested, and the validities of dynamic contrast-enhanced imaging,ADC,and combination of the two methods were evaluated.Results:40cases that had been proved by pathology include 22 malignant lesions, infiltrating duct carcinoma（n=19）, ductal carcinoma in situ（n=3）;18 benign lesions, fibroadenoma（n=8）, intraductal papilloma（n=1）, papillomatosis（n=2） ,adenosis of breast （n=5）, ductal ectasia with galactostasis（n=2） .The sensitivity, specificity and accuracy of the morphology of contrast-enhancing were86.4%,50.0%, and 70.0%;according to the type of TIC, the sensitivity, specificity and accuracy were 95.5%,55.6%,and 77.5%respectively;the validities of combing of the two mathods were 90.9%,66.7%,80.0%The ADC value of malignant lesions was markedly lower than that of benign lesions, with significant statistical difference（P<0.05）. the threshold between benign and malignant lesions was 1.25×10-3mm2/s by ROC analysis, and with the sensitivity ,specificity and accuracy as 86.4%,72.2%, and80.0%. combination of the contrast-enhanced imaging and ADC, the sensitivity ,specificity and accuracy were 90.9%,88.9% and 90.0%respectively.Conclusion:1. DCE-MRI is widely used to diagnose the breast cancer, it has high sensitivity and it is the most essential method to determine breast cancer; the irregular, speculated margin and the wash-out curve were valuable to diagnose maligant lesions, but the plateau curve was more overlap for the diagnosis of breast lesions, inducing the low specificity, also need other examination.2. the threshold between benign and malignant lesions was 1.25×10-3mm2/s , the ADC Value has a very high sensitivity and accuracy, and DWI takes short time, doesn’t need contrast agent, the ADC may help to differentiate benign and malignant lesions with good specificity, so DWI can be one of the conventional sequences for breast.3. The combination of dynamic contrast-enhanced MRI and DWl may help to improve the diagnostic validity.
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