The Value Of MRI In Differential Diagnosis Of Breast Lesions With Ductal Dilatation Or Mucinous Carcinoma

Objective: To study the features of breast lesions with ductal dilatation on MRI and to make differential diagnosis between the benignity and malignancy for this kind of breast lesions.Materials and methods: One hundred and fourteen cases of breast lesions with ductal dilatation on MRI were enrolled and confirmed by surgical pathology. The number and distribution of dilated ducts, morphological and contrast-enhanced MRI characteristics and the relationship(type I-V) between the ducts and the lesions were retrospectively reviewed with Breast Imaging Reporting and Data System(BI-RADS). Benign and malignant groups were examined with t test, χ2test and Fisher exact probability test by SPSS 19.0.Results: The 120 breast lesions were found in 114 patients, including 79 benign lesions and 41 malignant lesions. The age of malignant group was older than that of benign,and there was a statistically significant difference between them(P<0.01). The sensitivity, specificity, positive predictive value(PPV), negative predictive value(NPV)of MRI to diagnose lesions with ductal dilatation were 97.6%, 82.3%, 74.1%, 98.5%respectively.(1) At pre-contrast MRI, linear distribution of the dilated ducts can be seen in 50.6% of benign lesions and 22.0% of malignant lesions. Segmental distribution of the dilated ducts can be seen in 49.4% of benign lesions and 78.0% of malignant lesions. There was a statistically significant difference on the distribution of the dilated ducts(P=0.002) between the benign and malignant lesions.(2) At post-contrast MRI,no enhancement(22.8%), ductal enhancement(32.9%), mass enhancement(16.5%),and non-mass enhancement(27.8%) were found in benign lesions, while mass enhancement(58.5%) and non-mass enhancement(41.5%) were found in malignant lesions. There was a statistically significant difference on the enhancement patterns(P<0.01) between the benign and malignant lesions.(3) For non-mass enhancement,benign lesions showed linear enhancement(50.0%), scattered nodular enhancement (45.5%) and type I(40.9%) and III(31.8%) pattern more frequently, whereas segmental enhancement(52.9%), clustered ring enhancement(41.2%) and type IV pattern(70.6%)were more common in malignant lesions.Conclusion: Breast lesions with ductal dilatation on MRI have some characteristics,and accurate analysis of MRI features is helpful in differential diagnosis of this kind of breast diseases.Objective: To investigate the value of contrast-enhanced MR imaging in differential diagnosis of breast mucinous carcinomas and fibroadenomas with high signal intensity on T2 weighted images.Materials and methods: MR imaging findings in pathologically confirmed 16 cases(8pure and 8 mixed type) of mucinous carcinomas and 43 cases(age≥40years) of fibroadenomas with high signal intensity on T2 WI were retrospectively reviewed with Breast Imaging Reporting and Data System(BI-RADS). T test, χ2test and Fisher exact probability test were used to differentiate benign and malignant lesions. All of these patients had pre-operative MRI and the data analysis was performed by SPSS 19.0.Results:(1) Shape: Mucinous carcinomas showed lobulated(56.25%) and irregular(37.5%) shape more frequently, whereas round, oval(53.5%) and lobulated shape(41.9%) were more common in fibroadenomas(P<0.01). The diameter of mucinous carcinomas(30.0±11.9mm) was longer than that of fibroadenomas(17.3±7.6mm)(P<0.01). The margin of mucinous carcinomas could be circumscribed(43.75%),irregular(43.75%) or spiculated(12.5%), whereas circumscribed margin(86.0%) were more common in fibroadenomas(P<0.01).(2) Low signal septations were found in 3cases of mucinous carcinomas and 4 cases of fibroadenomas. The septations in mucinous carcinomas showed delayed enhancement.(3)Enhancement pattern and TIC:In the initial phase, 53.3% of mucinous carcinomas showed rim enhancement, while26.7% of them showed rim enhancement and 26.7% of them showed gradually central part enhancement in the delayed phase. The internal enhancement of breast fibroadenomas was more commonly heterogeneous(53.5%) and homogeneous(44.2%).There was a statistically significant difference between the two groups(P<0.01).Mucinous carcinomas had TIC II more frequently(60.0%), whereas TIC I(81.4%)were more common in fibroadenomas(P<0.01).(4) The ADC of mucinous carcinomas(1.80±0.51×10-3mm2/s) was higher than that of fibroadenomas(1.78±0.34×10-3mm2/s);however, no significant difference was found(P>0.05).Conclusion: Both mucinous carcinomas and fibroadenomas presenting high signal intensity on T2 WI had a high ADC value. And there were overlapping MRI findings between them on morphology. But internal enhancement pattern and TIC in the delayed phase are helpful for differential diagnosis between them.