| Background and purpose：Liver transplantation is an effective therapy for most of the terminal stage liverdiseases.With the development of technique of hepatic transplantation surgery in the world,the utilization of immunodepressant and the accumulation of the clinical experience, theperioperative complications and mortality of liver transplantation have been decreasedobviously, and the survival rate and survival time have been improved notablely.At present in China, the ratio between the acceptor and the donor is150:1. So it’s ofgreat significance to increase the survival rate of liver transplantation.The complications of liver transplantation include vascular complications, biliarycomplications, acute rejection, nonfunction of liver transplantation, infection and otherlong-term complications.Among all the complications after liver transplantation, some can be accuratelydiagnosed by two-dimensional ultrosund and color Dopper flow imaging (CDFI) at the earlystage. However, many complications such as splenic artery steal syndrome (SASS), aredifficult to diagnose by routine ultrasound. SASS, a rare vascular complication with severconsequence, is diagnosed mainly by celiac trunk angiography at present, which is the goldsta-ndard.Contrast enhanced ultrasound (CEUS) is the third revolution of ultrasonography, whichis displaying a great potency in clinical, providing great support for wider application andhigher accuracy of ultrasonic diagnosis.This study tried to expand the utilization of CEUS in liver transplantation. A. to observethe perfusion of normal transplantated liver and the correlation between the microperfusioncontrast enhancement of liver parenchyma and hepatic function. B. to evaluate its ability todetect SASS after liver transplantation that can not be diagnosed by traditional ultrasound,and estimate its potential to be a new method for diagnose of SASS. Materials and methods：1. At the days1,3,5,7,14after liver transplantation, the shape, internal echo, hemod-ynamics of hepatic artery and portal vein of the transplantated liver were examined by routineultrasound with a Siemens Sequoia512color Doppler ultrasonic diagnostic apparatus, andthen CEUS was performed. The rate of display of hepatic artery was detected. A SIEMENSSyngo analysis Software was used to measure the maximum enhancement intensety of hepaticartery, portal vein and edge part of transplanted liver. At the same time, the biochemicalindicator of peripheral blood was detected.2. CEUS was performed in9cases of SASS at different time points after the operationwhen CDFI signals in hepatic artery was slim or undetectable. Celiac angiography wasperformed as SASS was suspected by CEUS. The results between CEUS and celiacangiography were compared. When the interventional procedure was completed, CEUS wasperformed again to evaluate the effectiveness of the interventional treatment.Results:1、The echo of the liver parenchyma was slightly enhanced at the early stage of CEUS.Multiple focal hypoechoic regions were observed at the surface of some transplanted livers.The display rate of hepatic artery by two dimensional ultrasonography and CDFI is53%and73%, respectively. The display mode of transplantated hepatic artery is various. The velocityand resistance index of hepatic artery rose at the early stage and decreased gradually severaldays later. In the first to second week, the blood velocity of the hepatic artery was risen againand stabilized, and the resistance index was maintained at0.7.Distortion of hepatic artery was showed by CEUS in some cases. Enhancing of hepaticartery showed a shape of arborization according to the sequence of proper hepatic artery,left/right hepatic artery, and the first and second classes of arteries, with the edge of liverparenchyma highly enhanced. The display rate of transplantated hepatic artery by CEUS was100%. There was no difference in the maximum enhancement intensity of hepatic artery, aswell as that of the edge of liver parenchyma, among different time points.Main portal vein is easy to show by CEUS. Its flow volume rose at the early stage andreturned gradually. Its display time was4.5s behind that of hepatic artery. And there was nodifference in maximum enhancement intensity of the main portal vein among various timepoints. Hepatic function and biliary tract enzymogram index put back normal gradually afterliver transplantation.2、Nine cases of SASS were diagnosed at different time points from1stday to7thmonthpost liver transplantation. Traditional ultrasonography showed normal in shape of thetransplantated liver and its internal vessels. Multiple hypoechoic nodules with various sizes inliver were found in1case at3rdmonth post transplantation. In the other8patients, CDFIshowed slim or undetectable blood signals and CEUS showed delayed and weakcontrast-enhanced signals in hepatic artery at various time points after operation. In the above9patients, portal vein was clearly presented and a rapid intense enhancement in it wasobserved during CEUS. Spleen was enlarged in different degrees. The internal diameter of thesplenic artery was also enlarged. SASS occured at the rate of approximately2.8%.Celiac trunk angiography showed delayed and low perfusion of hepatic arteries withearly and rapid filling of enlarged splenic arteries. This suggested that the diminished hepaticartery blood flow was due to the shift of hepatic blood flow to the splenic artery.Consequently, the initial diagnosis of SASS by CEUS was confirmed by celiac trunkangiography. After splenic artery embolization, the repeated angiography demonstrated anincreased diameter in hepatic arteries, significantly increased perfusion of the hepatic bloodflow, and a resultant decrease in the portal blood flow in comparison with thepreinterventional values. Splenic artery embolization resulted in a marked increase in thehepatic artery diameter and significant reductions in the velocity and volume of the portalvein, proved by CDFI. Postinterventional CEUS also showed a rapid contrast wash-inenhancement followed by a concrete contrast peak enhancement as well as a blood flow beamthat was significantly wider after the intervention in the arterial phase and a slight reduction inthe contrast-enhanced blood flow signal of the portal vein system in the portal vein phase.Conclusion1、The flow velocity of hepatic artery is high at first after liver transplantation, followedby a decrease to lower than normal, and then turns normal gradually, while that of the portalvein rises greatly and turns back to normal gradually. Hepatic function and biliary tractenzymogram undergo a process of gradual restoring. CEUS can improve visualization of thehepatic artery after liver transplantation and reflect the microperfusion of liver parenchymawhile not reflect the change of hepatic function and biliary tract enzymogram index, which may be possibly related to the surgery operation and the ischemia time of donor liver.2、CEUS is necessary for the hepatic cirrhosis patients undergoes liver transplantationwhen the hepatic function is abnormal or the hepatic artery blood flow signal is weak afteroperation. CEUS has a high value to detect the complication of SASS after OLT. CEUS issuperior to traditional CDFI in distinguishing hepatic artery stenosis from thrombosis in livertransplant recipients. CEUS is an exciting imaging strategy for the evaluation of clinicalefficacy of splenic artery embolization in SASS patients. |
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