The Evaluation Of Diffusion Weighted Imaging And Dynamic Contrast-enhanced MR Imaging In Breast Lesions

Purpose①To investigate the relationship between the menstrual cycle and apparent diffusion coefficient(ADC)values of diffusion weighted imaging.②To investigate the evaluation of diffusion weighted imaging and dynamic contrast-enhanced MR Imaging in distinguishing benign from malignant breast lesions.Materials and Methods 12 healthy, premenopausal female volunteers who had regular menstrual cycles were included in the study. The ages of the volunteers ranged from 22–28 years, with a mean age of 24.4 years. They were scanned with conventional MRI T1WI,T2WI,SPIR and DWI once a week for 4 weeks by Siemens Sonata 1.5T MRI, use a dedicated breast coil, b=1000s/mm2. Each breast at different time points of the ADC values were measured in ADC maps, observed the normal breast ADC value changes in the menstrual cycle.41 lesions from 34 patients proved by surgery or Needle aspiration pathology were examin- ed with conventional MRI, DCE-MRI and DWI. DWI using echo planar imaging technique and frequency selection suppression technology, b=1000 s/mm2. Dynamic contrast-enhanced MRI using fast low angle shot sequence. The data of DWI and dynamic MR imaging were transfer sent Leonardo work station.Results①12 volunteers (24 sets data in bilateral breast) include in this study, mean ADC values in the first, second, third, and fourth week of menstrual cycle are 2.03±0.16×10-3mm2/s, 1.89±0.24×10-3mm2/s, 1.93±0.18×10-3mm2/s, 1.98±0.24×10-3mm2/s. Normal breast ADC values in the second week of the menstrual cycle lower to minimum and then slowly increased, a comparison between the mean was not significant (F=1.197, p> 0.05) .②78.6% malignant breast lesions showed irregular, burr or lobular, unclear border, and strengthen uneven or peripheral enhancement, 53.6%with axillary region lymphadenectasis, 69.2% benign lesions showed regular morphology, smooth margin or lobular ,border clearly, enhanced homogeneous or showed diffuse patchy strengthen, 7.6%with axillary region lymphadenectasisl .③The distribution of the TIC types of benign and malignant lesions has statistical significance difference (χ2 = 18.228, P <0.05), taking typeⅠcurves for the benign,ⅡandⅢfor the malignant, the sensitivity and specificity was 92.9% and 69.2%, accuracy was 85.3%.④The early phase enhancement rates of benign and malignant lesions are 101.1%±53.7% and153.2%±25.7% . T test showed there was a sign- ificant difference between them. (t=3.321,P =0.005). Area under the curve was 0.798 by ROC analysis, and the threshold was 125%. The sensitivity, specificity and accuracy were 89.2% ,76.9% and85.4%.⑤b=1000s/mm2, the ADC values of the normal breast, benign breast lesions and malignant lesions were 1.87±0.22(×10-3mm2/s) , 1.59±0.38 (×10-3mm2/s) and 1.15±0.32(×10-3mm2/s) , a comparison between the mean was significant difference (F=41.05, P<0.05) , Area under the ROC curve for ADC was0.821, the best threshold was 1.22×10-3 mm2/s, The sensitivity, specificity and accuracy were 75% ,84.6% and 78.0%.⑥The combination of The early phase enhancement ratio≥125%,ⅡorⅢtype of TIC, morphological criteria for malignant and ADC values, accord with three of them were considered malignant lesions, the United sensitivity, specificity and accuracy were85.7%, 92.3% and 87.8%. The specificity and accuracy were significantly improved, and the sensitivity is higher than the separate application of ADC value.Conclusion①ADC value was less influenced by the menstrual cycle.②DCE-MRI can provide important value in the differential diagnosis, but has a lower specificity.③The differentiation of benign from malignant breast lesions by DWI and ADC is applicable, but the sensitivity is low.④The specificity and accuracy were improved with the combination of DCE-MRI and DWI.