Objective To explore the relationship between the types of female breast density and age and breast cancer .Methods By accepting the digital mammography X -ray examination for 5 006 women cases and according to the ACR BI -RADS standard in the fourth edition ,the breast density assessment was quantified . We analysed the relationship between the breast density and age and breast cancer .Results In 5 006 cases,the average female age was between 44.22 ±8.09 years old,median age was 43 years old.The components of the breast density were fat type , small amount type , large amount type and compact type each count were 256 (5.11%),726(14.51%),3 719(74.29%),305(6.09%)respectively.By dividing into different age -group to analyze the breast density,there was significant statistical differences of the breast density among age -groups(P<0.001).Among them the breast cancer were 184 cases.Age was between 51.26 ±10.15 years old.Breast cancer in each breast density were fat type 10.16%(26/256),small amount type 9.09%(66/726),large a-mount type 2.45%(91/3719)and compact type 0.33%(1/305).There were statistical differences among age -groups and breast densities and breast (P<0.001).Conclusion Age plays a very important effects on the fe-male breast density .The lower breast density is a high risk factor to breast cancer occurrence .

Objective To compare the diagnostic value of X-ray film and MRI in the posterior ankle impingement syndrome (PAIS).Methods X-ray film and MRI data of 72 cases with posterior ankle pain were analyzed retrospectively.Passive plantar flexion test and diagnostic blocking were used as the diagnostic criteria.72 patients with posterior ankle pain were divided into PAIS group and non PAIS group.X-ray film and MRI findings in the PAIS group and non PAIS group were compared,and features which had differential diagnostic value were selected for calculating and comparing the efficacy of X-ray film and MRI in diagnosing or excluding PAIS.Results There was no significant difference for X-ray film findings such as os trigonum osteosclerosis(χ2 =2.947,P =0.086),os trigonum cystic changes(χ2 = 3.031,P =0.082)and posterior ankle soft tissue swelling(χ2 = 1.610,P =0.205 )between the PAIS group and the non PAIS group.There was significant difference for MRI features such as os trigonum or posterior talus bone marrow edema(χ2 =38.868,P =0.000 ),edema around os trigonum(χ2 =39.919,P =0.000 )and tenosynovitis of the flexor hallucis longus (χ2 =8.854,P =0.003)between the PAIS group and the non PAIS group.There was no significant difference for MRI features such as posterior ankle synovitis(χ2 =2.534,P =0.119)and posterior ankle ligament thickening(χ2 =1.515,P =0.218)between the PAIS group and the non PAIS group.Conclusion Using passive plantar flexion test and diagnostic blocking as the gold standard,the diagnostic efficacy of MRI on PAIS is obviously higher than that of X-ray film.MRI can significantly improve the diagnostic accuracy of PAIS,and avoid unnecessary diagnostic blocking.