Ductal Carcinoma In Situ:Characteristics Of MRI And Correlation With Nuclear Grade

Objective:To characterize the MRI features of breast ductal carcinoma in situ (DCIS), and to assess diagnostic accuracy of MRI for DCIS compared with that of mammography and ultrasonography. To analyze the correlation between the DCE-MRI characteristicts of DCIS and the nuclear grade in histopathology.Materials and Methods:Results of MRI from50consecutive women with histopathological diagnosis of breast DCIS were reviewed. Among which,23cases had histopathological grade diagnosis,37cases had the examination of mammography, and40cases had the rxamination of ultrasonograhy. MR examination was performed on1.5Tesla scanner (Signa Infinity, GE) and MR examinations included:3D dynamic contrast enhancement MRI (DCE-MRI), T1-Weighted imaging, fat-suppressed T2-Weighted imaging, and diffusion-weighted imaging (DWI) with the b value of1000s/mm. The23cases, which had histopathological grade diagnosis, was classified into non-high-grade group and high-grade group to analyze the correation between groups. Mammography examination was performed on HOLOGIC SELENIA DR equipment. Ultrasonography examination was performed on GE VOLUSON730or GE LOGIQ E9equipment. Diagnoses for MRI, mammography, and ultrasonography were made according to the lexicon of Breast Imaging Reporting and Data System (BI-RADS) designed by American College of Radiology, with BI-RADS4,5lesions considered as positive diagnoses, and then compared the imaging diagnostic result with histopathological result to analyze the diagnostic accuracy of MRI, mammography, and ultrasonography for DCIS, respectively.Results:Among the50lesions on MRI,49cases were diagnosed as BI-RADS4,5lesions and1case as BI-RADS1. In the49BI-RADS4,5lesions:10cases were mass-like lesions,39cases were non-mass-like lesions. Type Ⅰ, Type Ⅱ, and TypeⅢ TIC were demonstrated in14,15and20cases. In the10mass-like lesions:2cases showed smooth margin,2cases showed lobulated manrgin,3cases showed speculated margin, and3cases showed lobulated and speculated manrgin.1case showed central enhancement,3cases showed enhancing internal septatins,3cases showed rim enhancement, and3cases showed heterogeneous enhancement. Type II and TypeⅢ TIC were demonstrated in2and8cases. In39non-mass-like lesions:9cases showed focal distribution,6cases showed ductal distribution,23cases showed segmental distribution, and1case showed regional distribution.5cases showed homogeneous enhancement,10cases showed heterogeneous enhancement, and24cases showed clustered-ring enhancement. Type Ⅰ, Type Ⅱ, and TypeⅢ TIC were demonstrated in14cases,13, cases and12cases.Among, the23lesions, which had histopathologic grade diagnosis,15cases belonged to non-high-grade group,8cases belonged to high-grade group. There were not significant differences for distribution pattern, internal enhancement, and early enhancement ratio between non-high-grade group and high-grade group (P=0.746,0.274, and0.060, respectively). There were significant differences for TIC type between non-high-grade group and high-grade group GP=0.002).37patients with37lesions had the b=1000s/mm2DWI examination, among which,8cases showed isointense signal on DWI,29cases showed high signal on DWI, respectively. In the29high-signal-DWI cases, the ADC values for lesions and normal breast were (1.27±0.20)×10-3mm2/s and (1.65±0.23)×10-3mm2/s, respectively, there were significant differences for the ADC values between lesions and normal breast (t=6.682, P=0.000). In the29high-signal-DWI cases, ADC values for mass-like lesions and non-mass-like lesions were (1.15±0.16)×10-3mm2/s and (1.32±0.20)×10-3mm2/s, respectively, there were significant differences for the ADC values between mass-like lesions and non-mass-like lesions(t=2.28, P=0.040).The diagnostic accuracy of MRI, mammography, and ultrasonography for DCIS was98%(49/50),94.6%(35/37), and70%(30/40), respectively.Conclusion:Non-mass-like enhancement, especially segmental clustered-ring enhancement, is the most common morphological characteristic of DCIS, and for which, Type Ⅰ and Type Ⅱ TIC are the most common types. TIC for DCIS has correlation with the nuclear grade of DCIS:non-high-grade DCIS is likely to demonstrate Type I TIC and high-grade DCIS is likely to demonstrate TypeⅢ TIC. DWI and ADC can make some contributions to the detection for DCIS, while, ADC for mass-like DCIS lesions is different from that for non-mass-like DCIS lesions. The combination of MRI and mammography could improve diagnostic accuracy.