Objective To study the changes of Young's modulus value of the renal cortex,vertebral body and sinus when there was a different degree of acute renal artery stenosis.Methods 10 Japanese white rabbits were used for this study.The left renal artery was dissected.An ultrasound probe was placed on the left kidney,Young's modulus of the renal cortex,vertebral body and sinus were recorded using shear wave ultrasound elastic imaging technique during three stages:when the renal artery was intact (0％ stenosis),tied with a suture (＞ 50％ stenosis),and ligated (100％ stenosis).Renal tissue elasticity with different degrees of renal artery stenosis were compared.Pathological study was carried out in the kidneys,each with either 0％,＞ 50％ or 100％ renal artery stenosis.Results The mean values of Young's modulus from the renal cortex,vertebral body and sinus with different degrees of renal artery stenosis were as follows:0％ stenosis,(16.31 ±1.70) kPa,(13.38± 1.63) kPa,and (12.75±2.26) kPa;＞ 50％ stenosis,(14.16±2.34) kPa,(11.49±2.70) kPa,and (10.72±2.56) kPa;100％ stenosis,(11.35 ± 1.48) kPa,(8.39± 1.29) kPa,and (7.08 ± 1.52) kPa.The mean value of Young's modulus from the renal cortex was significantly higher than those from the renal vertebral body and sinus (P ＜ 0.05).The mean values of Young's modulus from different parts of the kidney decreased progressively with an increase in renal artery stenosis (P ＜ 0.05).The pathological study demonstrated that with the increase in the severity of renal artery stenosis,glomerular volume,renal interstitial capillary diameter and red blood cells decreased.When renal artery stenosis reached 100％,there was patch degeneration and inflammatory cell infiltration within the renal interstitium,and mild degeneration of tubular epithelial cells with obscure cell borders.Conclusions The value of Young's modulus from the renal cortex was higher than those from the renal pyramid and sinus in rabbits.The values of Young's modulus from the renal cortex,pyramid and sinus decreased with an increase in the severity of renal artery stenosis,which suggest that,in the study of the elasticity of the kidney,the renal artery blood flow dynamic state can obviously affect the value of the elasticity of the kidney.

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 observe the value of micro flow imaging(MFI)for diagnosing closed liver trauma in pigs.Methods A self-made impactor was used to impact the liver of 15 healthy pigs under general anesthesia and establish pig models of closed liver trauma.Conventional ultrasound,MFI and contrast-enhanced ultrasound(CEUS)were used to observe the location,extent and degree of liver trauma.Afterwards,the pigs were executed and the livers were removed,and the liver lesions were observed.According gross pathological findings,the diagnostic efficacy of MFI was analyzed.Results Gross pathology showed a total of 29 liver traumas in 15 pigs.The accuracy rate of conventional ultrasound,MFI and CEUS for diagnosing liver trauma in pigs was 37.93％(11/29),82.76％(24/29)and 96.55％(28/29),respectively.Significant difference was found between conventional ultrasound and MFI,also between conventional ultrasound and CEUS(both P＜0.05),but not between MFI and CEUS(P＞0.05).MFI showed no obvious blood flow signal in more than half pig liver trauma sites,while showed"spring like"in 1 pig and scattered blood flow signals in 5 pigs.On CEUS,liver trauma sites in pigs present as low or no perfusion,while"jet like"contrast agent overflow from the liver was noticed in 1 pig and"spring like"contrast agent overflow in 5 pigs,forming liquid dark areas around the liver or in abdominal cavity.Conclusion MFI had certain value for diagnosing closed liver trauma in pigs,hence being comparable to CEUS.