Objective To study the effect of heterogeneity in different parts of acute and chronic deep venous thrombus on the ultrasound shear wave elasticity value.Methods Fifteen Japanese rabbits were used to create an inferior vena cava (IVC) thrombus model via IVC ligation.Young's modulus of the thrombus head,body and tail were measured using ultrasonic shear wave elasticity technique on the fifth day (acute phase) and 14th day (chronic phase) of thrombus formation.Pathological sections were obtained from the IVC thrombus in five rabbits at the two points of time mentioned above.Pair t-test and one-way analysis of variance (ANOVA) were used to compare the data between groups.Results On the fifth day,Young's modulus values of the thrombus head,body and tail were (5.73 ±0.47)kPa,(7.82±0.63)kPa and (4.76±0.45)kPa respectively.ANOVA showed significant difference among three parts (F=134.468,P ＜ 0.01).The value of the thrombus body was significantly higher than that of the head and tail (both P ＜ 0.01),and the value of the head was significantly higher than that of the tail (P ＜ 0.01).On the 14th day,Young's modulus values of the thrombus head,body and tail were (12.46 ± 2.59)kPa,(15.08 ±2.71)kPa and (10.03 ± 2.02)kPa,respectively.ANOVA analysis also showed significant difference among three parts (F=10.539,P ＜ 0.01).The value of the thrombus body was significantly higher than that of the tail (P ＜ 0.01),and also higher than that of the head,although the difference was not significant (P ＞ 0.05).There was no significant difference between the head and tail (P ＞ 0.05).Young's modulus values of the thrombus head,body and tail in the chronic phase were significantly higher than those in the acute phase (t=-7.456,-7.989 and-8.159,respectively,all P ＜ 0.01).Pathological results showed that there was significant difference in thrombus structure and composition among different parts of the thrombus and among the thrombi in different individuals at corresponding points of time following thrombus formation.Conclusion There is significant heterogeneity among different parts of the same thrombus and among different thrombi at corresponding points of time after thrombus formation.Continual monitoring of the thrombus with ultrasound elasticity imaging may help to improve the accuracy of thrombosis staging.

Objective:To analyze the trend relevant factors leading to death and their patterns over a 10-year period in inpatients with connective tissue diseases (CTDs).Methods:All clinical data about death in inpatients with CTDs were retrospectively reviewed between 2005 and 2014 at the Department of Rheumatology and Immunology in Xiangya Hospital of Central South University.Results:In the 10-year time period,the overall hospital mortality was 15.689‰.The disease itself accounted for 44.71% of the total causes of death,infection accounted for 42.94%,and comorbidities accounted for 12.35%.The constituent ratio of deaths and the average hospital mortality caused by the disease itself declined gradually year by year,and the constituent ratio of deaths caused by infection and comorbidities increased gradually year by year (P<0.05).In 2013-2014,infection was the leading cause of death,which accounted for 51.06%.The survival time for CTDs inpatients with interstitial lung disease (ILD) was shorter than that of CTDs inpatients without ILD,and even the risk of death was 1.722 times of the latter.The proportion of deaths caused by the disease itself was the highest in systemic sclerosis and systemic lupus erythematosus,that by infection was the highest in idiopathic inflammatory myopathy (IIM),and that by comorbidities was the highest in rheumatoid arthritis.Conclusion:The proportion of deaths and the hospital mortality in CTDs inpatients caused by the disease itself show a declining trend,while the proportion of deaths caused by infection and comorbidities increase.CTDs patients with ILD have shorter survival time and an increase in risk of death.