Abstract: OcjectiVe The report is to observe the changes of duct diameter and thickness of breast among four ultrasonic patterns of the normal resting stage breasts in adult females by high-resolution ultrasound,and to investigate the correlation of breast ultrasonography with breast cancer. Methods The ultrasonic patterns were classified into four categories:duct type,miXture type,density type and inhomogeneous type according to proportion of glandular duct,fibrous and fatty of breast contents. Breast thickness and duct diameter of bilateral sides were measured and recorded for a statistical analysis. At the same time,the 185 cases of breast cancer were matched to 3 964 screened-negative controls,which analyzed the odds ratio( OR)of breast cancer with different breast ultrasonic patterns. Results The duct diameter of bilateral breast was the largest in duct type. The duct diameter of the density type was the smallest. The difference of duct diameter between miXture type and inhomogeneous type was not statistically significant( p>0 . 05 ). The comparison between the other groups had significant difference ( p<0 . 01 ). The thickness of bilateral breast of inhomogeneous type was the largest and that of density type was the smallest. The difference of thickness between different groups was statistically significant (p<0. 05). In the 185 cases of breast cancer,density pattern and inhomogeneous pattern were grouped into high-risk groups( OR =3 . 181 ,2 . 736 ). Conclusion The breast thickness and duct diameter of density type were the smallest;the thickness of inhomogeneous type was the largest. The density type and inhomogeneous type had the greatest impact on breast cancer risk.

Key words: breast neoplasms, catheters, ultrasonography