Complications of orthotopic liver transplantation: spectrum of findings with helical CT

Imaging of complications of liver transplantation: multidetector computed tomography findings

BACKGROUND

Liver transplantation is the treatment of choice for patients with end-stage liver disease; however, it is associated with a multitude of postoperative complications. Herein we have presented our experience with the application of multidetector computed tomography (MDCT) in the follow-up of liver transplant recipients.

PATIENTS AND METHODS

Twenty-four liver transplantation patients were examined with triphasic hepatic computed tomography. Both symptomatic and asymptomatic patients were included in the study. Examinations were performed using a multidetector scanner.

RESULTS

We documented seven cases of thrombosis, three stenosis, and two hepatic artery (HA) aneurysms. Portal vein (PV) stenosis and PV thrombosis were observed in two cases each. We observed one case of synchronous HA and PV stenosis; one inferior vena cava (IVC) and left renal vein thrombosis, and one IVC thrombosis. In three cases of HA obstruction we observed transplant neovascularization. One HA obstruction and one HA stenosis were accompanied by bilomas. Finally, we discovered three cases of hepatocellular carcinoma.

CONCLUSION

In our experience MDCT as a single noninvasive examination, was a sensitive means to detect and evaluate vascular complications after liver transplantation, offering adequate information concerning the liver parenchyma, the rest of the abdomen, and to a lesser extent the biliary tract.

Portal interventions in liver transplant recipients

Portal vein interventions in liver transplant recipients represent a group of interventions in the management of several disease entities including portal vein stenosis, portal vein thrombosis, and recurrent liver cirrhosis with portal hypertension with and without gastric varices. The procedures performed in these patient populations include portal vein angioplasty with or without stent placement for portal vein stenosis, portal vein thrombolysis with or without stent placement for portal vein thrombosis, transjugular intrahepatic portosystemic shunts or splenic embolization for cirrhosis, and balloon-occluded retrograde transvenous obliteration for gastric varices. This article discusses these disease entities and the minimal invasive procedures used in their management.

Impact of localized ascites after pediatric living donor liver transplantation: report of three cases

Fluid collection is common after living donor liver transplantation (LDLT), and can include hematomas, bilomas, abscesses, and seromas. Although accumulated fluid rarely becomes infected and usually remains localized, localized ascites can sometimes be sufficiently extensive to induce vascular complications. This report presents three such cases in pediatric patients that underwent LDLT. A 33-month-old patient showed an increase in the volume of localized ascites around the hepatic vein anastomoses together with low hepatic vein flow on postoperative day (POD) 47. An 82-month-old patient showed an increase in the volume of localized ascites around the portal vein anastomoses together with low portal vein flow on POD 71. A 63-month-old patient showed an increase in the size of a localized abscess around the hepaticojejunostomy with dilatation of all of the intrahepatic bile ducts on POD 20. These cases illustrate the need for awareness of possible vascular or biliary complications due to compressive localized ascites after LDLT.

Outcome of post-liver transplant ischemic and nonischemic biliary stenoses treated with percutaneous interventions: the Bologna experience

In liver transplantation (LT), biliary strictures (BSs) are among the most common complications. The aim of this study was to evaluate the efficacy of percutaneous treatments in the management of post-LT BSs. Between 1999 and 2007, 48 patients underwent percutaneous treatments for posttransplant BSs. We divided the population into 2 groups according to the cause [ischemic (n = 14) or nonischemic (n = 34)] and into further subgroups according to the site [anastomotic (n = 34) or nonanastomotic (n = 14)]. All patients were treated with bilioplasty; in 9 patients who were refractory to bilioplasty, metallic stents were implanted. A technical success rate of 90% was achieved without differences between the ischemic and nonischemic groups or between the anastomotic and nonanastomotic subgroups (P = 0.10). The major complication rate was 4%. The overall 1- and 3-year primary patency rates were 94% and 45%, respectively, and better results were found for patients with nonischemic stenoses versus patients with ischemic stenoses (P = 0.032). The overall secondary patency rates were 94% and 83% at 1 and 3 years, respectively, and there were no statistical differences between the ischemic and nonischemic groups or between the anastomotic and nonanastomotic groups. In the stent subgroup, the overall primary 1- and 2-year patency rates were 100% and 71%, respectively, and the secondary patency rates were 100% and 100%, respectively. In conclusion, a percutaneous approach is highly effective for the treatment of post-LT BSs, and the best results are obtained for patients with simple, nonischemic BSs (technical success rate = 94%, 3-year primary patency rate = 81%, 3-year secondary patency rate = 75%). For patients with ischemic BSs, closer follow-up and retreatment are more frequently needed to achieve secondary patency rates comparable to (or even better than) those for patients with nonischemic stenoses.

Multimodality imaging of normal hepatic transplant vasculature and graft vascular complications

Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.

Benign biliary strictures: a current comprehensive clinical and imaging review

OBJECTIVE

There is a wide spectrum of nonneoplastic causes of biliary stricture that can pose a significant challenge to clinicians and radiologists. Imaging plays a key role in differentiating benign from malignant strictures, defining the extent, and directing the biopsy. We describe the salient clinical and imaging manifestations of benign biliary strictures that will help radiologists to accurately diagnose these entities.

CONCLUSION

Accurate diagnosis and management are based on correlating imaging findings with epidemiologic, clinical, and laboratory data. Cross-sectional imaging modalities permit precise localization of the site and length of the segment involved, thereby serving as a road map to surgery, and permit exclusion of underlying malignancy.

Postoperative imaging in liver transplantation: what radiologists should know

Liver transplantation is now frequently used in the treatment of end-stage liver disease. Therefore, it is important that radiologists be aware of common anastomotic techniques and expected postoperative imaging findings. Imaging is most useful in evaluating for posttransplantation complications, which are broadly classified into vascular, biliary, and other complications. Hepatic artery thrombosis is the most significant complication and is often associated with graft failure. Radiologists have multiple modalities at their disposal for optimal evaluation. Doppler ultrasonography (US) is the preliminary imaging modality for gross evaluation of the liver parenchyma, biliary tree, and vasculature for abnormalities. When US findings are indeterminate or there is persistent clinical suspicion for an abnormality, computed tomography (CT) is often performed. The major indications for CT are detection of bile leak, hemorrhage, and abscess, but CT is also useful in the assessment of the vasculature. T-tube cholangiography and magnetic resonance cholangiopancreatography are the best noninvasive imaging tools for evaluating for biliary stricture. Some investigators would argue that endoscopic retrograde cholangiopancreatography (ERCP) is a better diagnostic imaging modality; however, ERCP is invasive. Hepatobiliary scintigraphy is optimal for the evaluation of biliary leakage. Early detection of posttransplantation complications will help lower morbidity rates and will likely allow graft salvage in selected cases.

Interventional radiologic procedures in the treatment of complications after liver transplantation

The aim of this study is to report our interventional radiologic procedures (IRP) in liver transplant (LTX) patients. These include procedures for biliary, arterial, venous, and portal complications, as well as the treatment of infected and non-infected fluid collections. This retrospective study covered 583 patients (mean age: 44 +/- 14 yr) in whom a total of 685 LTX were performed from August 1987 to April 2005. Overall, 182 LTX patients underwent a total of 428 IRP, including digital subtraction angiography (n = 152/35.51%), percutaneous transluminal angioplasty (PTA) (n = 4/0.93%) and PTA + stent (n = 7/1.63%) of arterial anastomosis, PTA + stent of the celiac trunk (n = 2/0.46%), transjugular intrahepatic portosystemic shunt (TIPS) (n = 2/0.46%), arterial lysis (n = 4/0.93%), venous lysis (n = 2/0.46%), inferior vena cava stenting (n = 2/0.46%), percutaneous biliary drainage (n = 34/7.94%), percutaneous transluminal dilatation (PTD) of the choledocho-enteric anastomosis (n = 16/3.73%), biliary stent (n = 5/1.16%), intrahepatic biliary flushing treatment, stone and cast biliary extraction (n = 27/6.30%), other interventions (e.g., embolization in other regions, transjugular liver biopsies, lymphangiographies) (n = 9/2.10%), and ultrasound- and computer tomography-guided biopsies and percutaneous drainage (n = 153/35.74%). The overall success rate was 85.7%. Technical improvements in LTX and interventional radiology permit vascular and biliary complications to be treated successfully by interventional radiology.

CT of nonneoplastic hepatic vascular and perfusion disorders

The unique dual blood supply of the liver (75% portal venous, 25% hepatic arterial) makes multiphase helical computed tomography (CT) a highly suitable technique for hepatic evaluation with imaging in two (arterial and portal venous) or more phases. Multiphase helical CT has become an important tool in the detection and characterization of hepatic tumors. In some situations, hemodynamic changes might mimic neoplastic or inflammatory lesions and evoke diagnostic uncertainty. To confidently identify hepatic conditions such as venous outflow obstruction (Budd-Chiari syndrome), arterioportal shunts, hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome), peliosis hepatis, passive congestion, and hepatic infarction, radiologists must be familiar with the disease-specific CT appearances and related clinical manifestations.

Spectrum of normal or near-normal sonographic findings after orthotopic liver transplantation

The initial imaging immediately after orthotopic liver transplantation is generally performed with ultrasound. Although significant posttransplant complications do occur, many abnormal findings including minor vascular waveform abnormalities, anastomotic mismatches, and fluid collections can be seen in asymptomatic patients. It is important to differentiate these benign findings from more serious complications to avoid unnecessary intervention.

Platelets in liver transplantation: friend or foe?

Apart from the well-known role of blood platelets in hemostasis, there is emerging evidence that platelets have various nonhemostatic properties that play a critical role in inflammation, angiogenesis, tissue repair and regeneration, and ischemia/reperfusion (I/R) injury. All these processes may be involved in the (patho)physiological alterations occurring in patients undergoing liver transplantation. Experimental and clinical research points toward a dualistic role of platelets in patients undergoing liver transplantation, resulting in both beneficial and detrimental effects. Although a low platelet count is generally considered a risk factor for perioperative bleeding, recent studies have indicated that platelet function in patients with cirrhosis may not be as abnormal as previously assumed. Platelet transfusions are frequently considered in liver transplant recipients to correct low platelet counts and to prevent bleeding; however, evidence-based transfusion thresholds are lacking, and the other detrimental and nonhemostatic properties of platelets are generally not weighed in this respect. First, platelets have been shown to contribute to I/R injury of the liver graft via induction of sinusoidal endothelial cell apoptosis. Second, platelet transfusion has been identified as an independent risk factor for reduced survival via mechanisms that are not completely understood yet. On the other hand, recent studies indicate that platelets are critically involved in restoration after liver injury and in liver regeneration via serotonin-mediated mechanisms. These findings make platelets both friend and foe in liver transplantation. The scientific challenge will be to further dissect the mechanisms and clinical relevance of these contrasting roles of platelets in liver transplantation.

Routine intraoperative Doppler sonography in the evaluation of complications after living-related donor liver transplantation

PURPOSE

To determine whether quantitative and qualitative analysis of intraoperative Doppler sonography data are predictive of vascular complications after living-related donor liver transplantation.

METHODS

Intraoperative sonograms of 81 transplanted livers (right lobe in 61 patients, left lobe in 20 patients) were analyzed for the presence of blood flow, resistance index, systolic acceleration time (SAT), peak systolic velocity, and morphologic characteristics of spectral waveform of the hepatic artery. Peak velocity and spectral waveforms of portal and hepatic veins were also analyzed. Intraoperative sonography results were compared with information obtained with multidetector-row CT (MDCT) angiography or conventional angiography. The time interval between operation and angiography ranged from 1 to 23 days (mean, 8.5 days).

RESULTS

Hepatic artery stenosis (HAS) was identified in 20 patients via MDCT angiography, conventional angiography, or both. The Doppler parameters found helpful for predicting HAS were tardus-parvus pattern and delayed SAT. The sensitivity, specificity, and negative predictive value (NPV) were 60.0%, 73.7%, and 84.9%, respectively, for tardus-parvus pattern and 40.0%, 83.6%, and 80.9%, respectively, for delayed SAT. Peak velocities of the portal and hepatic veins were not reliable indicators of vascular complication. Loss of triphasity of the hepatic vein had a 98.4% NPV for venous obstruction.

CONCLUSIONS

Delayed SAT of the hepatic artery and loss of triphasity of the hepatic vein had a >80% for specificity for predicting vascular complications. Tardus-parvus pattern, delayed SAT of the hepatic artery, and loss of triphasity of the hepatic vein showed an acceptable NPV for identifying vascular complications.

Complications of liver transplantation: multimodality imaging approach

Liver transplantation is currently an accepted first-line treatment for patients with end-stage acute or chronic liver disease, but postoperative complications may limit the long-term success of transplantation. The most common and most clinically significant complications are arterial and venous thrombosis and stenosis, biliary disorders, fluid collections, neoplasms, and graft rejection. Early diagnosis is crucial to the successful management of all these complications, and imaging plays an important role in the diagnosis of all but graft rejection. A multimodality approach including ultrasonography and cross-sectional imaging studies often is most effective for diagnosis. Each imaging modality has specific strengths and weaknesses, and the diagnostic usefulness of a modality depends mainly on the patient's characteristics, the clinical purpose of the imaging evaluation, and the expertise of imaging professionals.

Contrast-enhanced ultrasound with SonoVue in the evaluation of postoperative complications in pediatric liver transplant recipients

PURPOSE

To evaluate the utility of contrast-enhanced sonography in the study of pediatric liver transplant recipients and its potential impact in reducing the need for invasive diagnostic procedures.

MATERIALS AND METHODS

From October 2002 to December 2003 we performed routine color Doppler ultrasound and contrast-enhanced ultrasound studies on 30 pediatric patients who had undergone liver transplantation. Findings indicative of complications were confirmed with invasive studies (angiography, computed tomography, and PTC).

RESULTS

Contrast-enhanced sonography correctly identified four of the five cases of hepatic artery thrombosis and all those involving the portal (n = 6) and hepatic vein (n = 3) thrombosis. It failed to identify one case of hepatic artery thrombosis characterized by collateral circulation arising from the phrenic artery and the single case of hepatic artery stenosis. The latter was more evident on color Doppler, which revealed a typical tardus parvus waveform. The use of contrast offered no significant advantages in the study of biliary complications although it did provide better visualization of bile leaks.

CONCLUSIONS

Contrast-enhanced sonography improves diagnostic confidence and reduces the need for more invasive imaging studies in the postoperative follow-up of pediatric liver transplant recipients.

Post-transplant hepatic complications: Imaging findings

Transplantation is considered definitive therapy for acute or chronic irreversible pathologies of the liver, and the increased survival rates are mainly due to improved immunosuppressive therapies and surgical techniques. However, early diagnosis of possible graft dysfunction is crucial to liver graft survival. Diagnostic imaging plays an important role in the evaluation of the liver before and after transplant and in the detection of complications such as vascular and biliary diseases, acute and chronic rejection and neoplastic recurrence. Integrated imaging using color-Doppler, CT, MRI and traditional x-ray reach a high level of sensitivity and specificity in the management of transplanted patients.

Favorable resolution of hepatic infarctions in transplanted liver after portal vein thrombosis treated by surgical thrombectomy: a case report

Portal vein thrombosis (PVT) after orthotopic liver transplantation (OLT) is a life-threatening complication associated with a high rate of graft loss and patient death, with reported incidence of 1% to 2% in adults. We report a case of an early PVT after OLT complicated by hepatic infarctions in the liver graft. After surgical thrombectomy and restoration of the portal inflow, hepatic infarctions resolved spontaneously within 6 months, which was confirmed by computed tomography.

Utilizing generalized autocalibrating partial parallel acquisition (GRAPPA) to achieve high-resolution contrast-enhanced MR angiography of hepatic artery: initial experience in orthotopic liver transplantation candidates

OBJECTIVE

To evaluate feasibility of using GRAPPA to acquire high-resolution 3D contrast-enhanced MR angiography (CE-MRA) of hepatic artery and value of GRAPPA for displaying vessels anatomy.

MATERIALS AND METHODS

High-resolution CE-MRA using GRAPPA was performed in 67 orthotopic liver transplantation recipient candidates. Signal intensity (SI) and relative SI, i.e., Cv-ro (vessel-to-liver contrast) of the aorta and the hepatic common artery (HCA), were measured. The SI and the relative SI were compared and analyzed using T-test. For purpose of qualitative evaluation, the vessel visualization quality and the order of depicted hepatic artery branches were evaluated by two radiologists independently and assessed by weighted kappa analysis. The depiction of hepatic arterial anatomy and variations was evaluated, and results were correlated with the findings in surgery.

RESULTS

The mean SI values were 283.29+/-65.07 (mean+/-S.D.) for aorta and 283.16+/-64.07 for HCA, respectively. The mean relative SI values were 0.698+/-0.09 for aorta and 0.696+/-0.09 for HCA, respectively. Homogeneous enhancement between aorta and HCA was confirmed by statistically insignificant differences (p-values were 0.89 for mean SI values and 0.12 for mean relative SI values, respectively). The average score for vessel visualization ranged from good to excellent for different artery segments. Overall interobserver agreement in the visualization of different artery segments was excellent (kappa value>0.80). The distal intrahepatic segmental arteries were well delineated for majority of patients with excellent interobserver agreement. Normal hepatic arterial anatomy was correctly demonstrated in 53 patients, and arterial anomalies were accurately detected on high-resolution MRA image of all 14 patients.

CONCLUSION

High-resolution hepatic artery MRA acquired using GRAPPA in a reproducible manner excellently depicts and delineates small vessels and can be routinely used for evaluating OLT candidates.

Intrahepatic biliary strictures after liver transplantation

Biliary complication has been one of the most common complications after liver transplantation. Nonanastomotic strictures and dilatations involving the intrahepatic biliary tree have been recognized as biliary complications. These lesions were reported to be associated with hepatic artery thrombosis; prolonged preservation time; ABO-incompatible organs; and immunological injury, including injuries to vascular endothelial cells (chronic rejection) and the bile duct (primary sclerosing cholangitis). However, the etiology of these lesions appeared to be mostly related to ischemic injury. Anatomical research on the arterial supply of the bile duct has provided further insights into bile duct blood supply and its surgical implications. The biliary tract is supplied with arterial blood by a vasculature called the peribiliary vascular plexus. Any injury to the peribiliary vascular plexus may contribute to ischemic death of the biliary system mucosa. At many points, the process of liver transplantation exposes the endothelial cells and peribiliary vascular plexus to ischemic injury. The majority of intrahepatic biliary strictures (IHBS) are diffuse or bilateral. A percutaneous or an endoscopic approach has been used as the initial treatment. However, a low threshold for surgical intervention (retransplantation) should be adopted, because these patients demonstrate high mortality. The aim of this article is to review the anatomy, etiology, clinical picture, diagnosis, management, and prognosis of IHBS after liver transplantation.

Biliary complications after deceased-donor orthotopic liver transplantation

A wide range of potential biliary complications can occur after orthotopic liver transplantation (OLT). The most common biliary complications are bile leaks, anastomotic and intrahepatic strictures, stones, and ampullary dyfunction, which may occur in up to 20%-40% of OLT recipients. Leaks predominate in the early posttransplant period; stricture formation typically develops gradually over time. However, with the advent of new techniques, such as split-liver, reduced-size, and living-donor liver transplantation, the spectrum of biliary complications has changed. Risk factors for biliary complications comprise technical failure; T-tube or stent-related complications; hepatic artery thrombosis; bleeding; ischemia/reperfusion injury; and other immunological, nonimmunological, and infectious complications. Noninvasive diagnostic methods have been established and treatment modalities have been modified towards a primarily nonoperative, endoscopy-based strategy. Besides, the management of biliary complications after OLT requires a multidisciplinary approach, in which interventional and endoscopic treatment options have to be weighed up against surgical treatment options. The etiology and spectrum of bile duct complications, their diagnosis, and their treatment will be reviewed in this article.

Imaging and invasive techniques for diagnosis and treatment of surgical infections

BACKGROUND

Advances in imaging techniques have caused a radical change in the radiologic approach to the diagnosis and treatment of surgical infections.

METHOD

Review of the pertinent English-language literature.

RESULTS

Ultrasonography (US) is a useful modality for the initial evaluation of intra-abdominal infection, whereas computed tomography (CT) often represents the modality of choice for definitive identification of the cause and extent of the infection. Both US and CT can be used to guide diagnostic fluid aspiration or drainage catheter placement. Fluoroscopy may be useful for diagnostic and interventional procedures in the biliary and urinary tracts, whereas magnetic resonance imaging plays a leading role in evaluating bone and soft tissue structures and the pancreatobiliary tree.

CONCLUSION

The choice of imaging study must be individualized to the particular circumstances of the clinical situation, particularly whether image-guided therapy may be required in addition to diagnosis. Computed tomography is the most versatile for most clinical circumstances.

Pediatric liver transplantation: a pictorial essay of early and late complications

Orthotopic liver transplantation is currently the treatment of choice in patients with end-stage liver disease for which no other therapy is available. In children, segmental liver transplantation with living donor, reduced-size cadaveric, and split cadaveric allografts has become an important therapeutic option. However, the resulting expansion of the donor pool has increased the risk for postoperative vascular and biliary complications, which affect children more frequently than adults. Early recognition of these complications requires radiologic evaluation because their clinical manifestations are frequently nonspecific and vary widely. Doppler ultrasonography (US) plays the leading role in the postoperative evaluation of pediatric patients. Current magnetic resonance (MR) imaging techniques, including MR angiography and MR cholangiography, may provide a wealth of pertinent information and should be used when findings at US are inconclusive. Computed tomography is a valuable complement to US in the evaluation of complications involving the hepatic parenchyma as well as extrahepatic sites and is commonly used to guide percutaneous aspiration and fluid collection drainage. Familiarity with and early recognition of the imaging appearances of the various postoperative complications of pediatric liver transplantation are crucial for graft and patient survival.

Hypoattenuation in unenhanced CT reflects histological graft dysfunction and predicts 1-year mortality after living donor liver transplantation

Early postoperative graft function assessments are essential after living donor liver transplantation (LDLT) to predict patient and graft outcome. Computed tomography (CT) is usually used to evaluate various complications and parenchymal abnormalities after LDLT. Here, we attempted to determine the prognostic values of CT attenuation changes of grafts for predicting 1-year patient survival. Liver attenuation indices (LAIs), derived from differences between hepatic and splenic attenuations, were calculated on unenhanced CT images obtained 10 days after LDLT in 62 adult LDLT recipients between September 2002 and August 2004. Patients were assigned to 1 of 2 groups according to LAI value on the 10th postoperative day, as follows: group L (LAI < or = 5, n = 14) or group H (LAI > 5, n = 48). Parenchymal dysfunction scores, summed parameters for histological dysfunction including both portal tract and centrilobular features, were also assessed on the 10th postoperative day using liver biopsy specimens. Histological parenchymal dysfunction, especially in the centrilobular area, in terms of cholestasis, centrilobular necroinflammation, central vein fibrosis, steatosis, mononuclear infiltrates, and hepatocyte ballooning, was more prominent in group L than in group H, while that in the portal area was similar between the 2 study groups. Significant negative linear correlations were observed between LAI and parenchymal dysfunction scores (r = 0.486, P < 0.001). Group L patients showed lower 1-year survival (69.7%) than group H patients (95.8%; P = 0.0002). Moreover, group H patients died with a functioning graft (n = 3), whereas group L patients died of graft failure (n = 6). After multivariate analysis, LAI alone remained independently associated with 1-year mortality (P = 0.014; odds ratio = 0.845; 95% confidence interval, 0.739-0.967). The sensitivity and specificity of LAI were 84.6% and 75%, respectively, and LAI outperformed MELD score as a predictor of 1-year mortality after LDLT by receiver operating characteristic curve analysis. In conclusion, LAI, as determined by unenhanced CT 10 days after LDLT, well predicts 1-year patient survival after LDLT.

Localized fluid collections after liver transplantation

BACKGROUND

Liver transplantation is an accepted effective therapy for patients with diseases that lead to hepatic failure. In addition to vascular, rejection-related, biliary, and lymphoproliferative complications, posttransplantation fluid collections, such as hematomas, seromas, bilomas, localized ascites, and abscesses can affect graft survival. In this study, we have presented, ultrasonography and computed tomography images as well as reviewed the literature.

METHODS

Between December 1988 and March 2005, 138 patients (94 men [68.11%], 44 women [31.89%] of mean age, 26.77 years (range, 1 to 64) underwent liver transplantation in our institution from living-related donors in 85 and deceased donors in 53 recipients. This retrospective study analyzed the fluid collections diagnosed after liver transplantation.

RESULTS

Among 138 liver transplants we identified 56 localized intra-abdominal fluid collections, including 46 hematomas, 4 bilomas, and 6 abscesses. Fluid collections were noticed between 0 and 1095 days (mean = 13.50 +/- 152.82 days). Thirty-three collections were identified in living-related, and 23 in deceased donor recipients. The collections showed an average volume of 375 cm3, with a range of 1 to 4368 cm3. Two cases of bilomas were related to hepatic arterial insufficiency, one from a hepatic artery occlusion and the other from a significant stenosis.

CONCLUSIONS

Localized intra-abdominal fluid collections were commonly seen after liver transplantations, diminished in size without treatment, but required aspiration or drainage in some patients.

Transhepatic dilation of anastomotic biliary strictures in liver transplant recipients with use of a combined cutting and conventional balloon protocol: technical safety and efficacy

PURPOSE

To determine the safety and technical efficacy of a transhepatic dilation protocol involving the use of a combined cutting and conventional balloon protocol in the management of anastomotic biliary strictures in adult liver transplant recipients.

MATERIALS AND METHODS

Retrospective review of adult transplant recipients undergoing transhepatic cutting balloon dilation for anastomotic biliary strictures was performed over a period of 8 months. Cutting balloon dilation was followed by conventional balloon dilation with use of a balloon with a diameter at least as large as that of the initial cutting balloon. Technically successful dilation was defined by improvement of the biliary stricture. A technically successful regimen was defined by a residual stenosis less than 30% after a maximum of three sessions. The technical results were stratified according to lesions treated for the first time and those with restenosis. Comparison among institutions in terms of published methods and technical results were made.

RESULTS

Twenty-two patients with liver transplants underwent 49 cutting balloon dilation sessions as part of 27 regimens (1.8 sessions per regimen): 12 cases of primary treatment, 10 cases of restenosis, four for intraprocedural failures of conventional balloon dilation, and one for the latter two indications. Technical success rates of regimens for primary stenoses, restenoses, and all cases were 100%, 90%, and 93%, respectively. These results compare favorably with historic intrainstitutional results, which are 89%, 73%, and 85% for primary stenoses, restenoses, and all cases, respectively. In addition, no biliary ruptures or cases of major hemobilia were encountered. Minor hemobilia was encountered in 10% of cases.

CONCLUSIONS

The use of commercially available cutting balloons augmented subsequently with larger conventional balloons is safe for transhepatic balloon dilation and can increase the technical success rate of percutaneous management of transplant biliary strictures.

Ultrasound of living donor liver transplantation

Liver transplantation is the most effective treatment for various end-stage liver diseases. Living donor liver transplantation (LDLT) was first developed in Asia due to the severe lack of cadaveric graft in this region. The Liver Transplant Service at Queen Mary Hospital (QMH), Hong Kong, has pioneered the application of LDLT to patients using both left lobe and right lobe grafts. The QMH liver transplant programme is the largest of its kind in China and Southeast Asia.

Ultrasound (US) is often employed in the initial work-up of potential donor and recipient of LDLT. It is the imaging technique of choice to assess the early and late complications of LDLT, with colour Doppler ultrasound being the most useful in the evaluation of post-LDLT vascular complications. The use of ultrasound contrast agents improves the visualisation of the hepatic vasculature, possibly delaying or removing the need for more invasive investigations. Intra-operative ultrasound facilitates the determination of the resection plane during donor hepactectomy.

Computed tomography (CT) or magnetic resonance imaging (MRI) can be used as the single imaging modality in the evaluation of LDLT candidates.

Ultrasound is most useful as the initial screening test in detecting hepatic parenchymal abnormalities, while CT or MRI is the modality of choice in the demonstration of vascular and biliary anatomy of the potential liver donor.

Biliary complications are more common in LDLT than in cadaveric liver transplantation. The ductal dilatation, resulting from biliary stricture, is clearly demonstrated by ultrasound. Bilomas can be aspirated under ultrasound guidance to confirm the diagnosis and to promote healing. Perihepatic fluid collections and abscesses are also common after LDLT. Intra-hepatic collections may represent seromas, haematomas or infarction. Ultrasound is a sensitive means of detecting these collections and can be employed to guide drainage in suitable patients.

Transplant-related malignancies include recurrent neoplasia and post-transplant lymphoproliferative disease (PTLD). Ultrasound can be used to screen for recurrent disease and to detect PTLD in the transplanted liver.

Nonvascular complications in pediatric liver recipients: multidetector computed tomography evaluation

In pediatric liver transplantation postoperative diagnosis of complications is crucial for graft salvage. Multidetector computed tomography (MDCT) is a technique to evaluate complications. In this study we present nonvascular abdominal complications encountered in pediatric recipients after liver transplantation. We retrospectively examined 113 MDCT examinations in 43 pediatric patients who underwent liver transplantation between 1997 and 2005. Computed tomography (CT) examinations were made by a 16-detector multislice CT scanner. The pathological findings on CT images were: intraperitoneal free fluid, intrahepatic bile duct dilatation, graft liver infarction, perihepatic and intraperitoneal fluid collections (six biloma), colonic and/or intestinal dilatation, splenic infarction, perihepatic hematoma, right adrenal hemorrhage, perihepatic abscess, incisional hernia, intrahepatic biloma and periportal collar. In one patient intestinal hemorrhage was suspected. Intestinal perforation was suspected in three patients. Among these three patients, one patient died before any surgical intervention. In two patients the diagnosis was confirmed at surgery. In pediatric patients, the short examination time, brief sedation duration, and high-resolution images make MDCT an effective radiological method to evaluate nonvascular transplant complications.

Interventional radiology in liver transplantation

Improvements in surgical technique, advances in the field of immunosuppresion and the early diagnosis and treatment of complications related to liver transplantation have all led to prolonged survival after liver transplantation. In particular, advances in diagnostic and interventional radiology have allowed the Interventional Radiologist, as part of the transplant team, to intervene early in patients presenting with complications related to organ transplant with resultant increase in graft and patient survival. Such interventions are often achieved using minimally invasive percutaneous endovascular techniques. Herein we present an overview of some of these diagnostic and therapeutic approaches in the treatment and management of patients before and after liver transplantation.

Liver and Biliary System: Evaluation by Multidetector CT

CT commonly is indicated for the evaluation of suspected hepatic and biliary pathology. The recent introduction of multidetector CT (MDCT) provides unique capabilities that are valuable especially in hepatic volume acquisitions, combining short scan times, narrow collimation, and the ability to obtain multiphase data. These features result in improved lesion detection and characterization. Concomitant advances in computer software programs have made three-dimensional applications practical for a range of hepatic image analyses and displays. This article discusses the specific areas of hepatic and biliary pathology where MDCT has a significant diagnostic impact.

Transhepatic Balloon Dilation of Anastomotic Biliary Strictures in Liver Transplant Recipients: The Significance of a Patent Hepatic Artery

PURPOSE

To determine the significance of hepatic artery steno-occlusive disease on the patency of anastomotic biliary strictures in liver transplant recipients after transhepatic balloon dilation.

MATERIALS AND METHODS

A retrospective review of records of all patients undergoing transhepatic balloon dilation for anastomotic biliary strictures after orthotopic liver transplantation was performed over an 8-year period. Patency of the anastomosis was based on subsequent cholangiography. The presence of hepatic artery steno-occlusive disease was determined by Doppler ultrasound and/or angiography. The anastomotic biliary stricture patency rates were calculated by the Kaplan-Meier method.

RESULTS

Thirty-eight patients who had undergone liver transplants underwent 53 balloon dilations for anastomotic biliary strictures (nine patients for arterial disease, 26 patients had patent arteries and three patients had arteries of indeterminate patency). Eight of the 53 strictures treated (15%) were refractory to balloon dilation: 10.5% of first comers and 27% of restenotic lesions. Two of the 53 strictures treated (4%) had significant complications: hemobilia requiring blood transfusion and ductal rupture. One-year cumulative primary patency rates for anastomotic biliary strictures for patients with arterial disease, patent hepatic arteries, and all-comers were: 0%, 45% (P = .01), and 36%, respectively. One-year cumulative primary patency rates for choledocho-choledocal and choledocho-jejunal anstomoses in patients with patent arteries were 43% and 48%, respectively (P = .10).

CONCLUSIONS

In the presence of hepatic artery disease there is a lower patency of anastomotic biliary strictures after balloon dilation. Imaging of the hepatic artery should be considered to stratify patients who will have a successful outcome.

Diagnosis of biliary strictures after liver transplantation: Which is the best tool?

AIM: To evaluate the diagnostic value of different indirect methods like biochemical parameters, ultrasound (US) analysis, CT-scan and MRI/MRCP in comparison with endoscopic retrograde cholangiography (ERC), for diagnosis of biliary complications after liver transplantation.

METHODS: In 75 patients after liver transplantation, who received ERC due to suspected biliary complications, the result of the cholangiography was compared to the results of indirect imaging methods performed prior to ERC. The cholangiography showed no biliary stenosis (NoST) in 25 patients, AST in 27 and ITBL in 23 patients.

RESULTS: Biliary congestion as a result of AST was detected with a sensitivity of 68.4% in US analysis (specificity 91%), of 71% in MRI (specificity 25%) and of 40% in CT (specificity 57.1%). In ITBL, biliary congestion was detected with a sensitivity of 58.8% in the US, 88.9% in MRI and of 83.3% in CT. However, as anastomotic or ischemic stenoses were the underlying cause of biliary congestion, the sensitivity of detection was very low. In MRI detected the dominant stenosis at a correct localization in 22% and CT in 10%, while US failed completely. The biochemical parameters, showed no significant difference in bilirubin (median 5.7; 4,1; 2.5 mg/dL), alkaline phosp-hatase (median 360; 339; 527 U/L) or gamma glutamyl transferase (median 277; 220; 239 U/L) levels between NoST, AST and ITBL.

CONCLUSION: Our data confirm that indirect imaging methods to date cannot replace direct cholangiography for diagnosis of post transplant biliary stenoses. However MRI may have the potential to complement or precede imaging by cholangiography. Optimized MRCP-processing might further improve the diagnostic impact of this method.

Diagnosis and treatment of hepatic artery stenosis after orthotopic liver transplantation

PURPOSE

The purpose of this study was to evaluate the accuracy of Multidetector Computed Tomographic Angiography (MDCTA) to detect hepatic artery (HA) stenosis after orthotopic liver transplantation (OLT) and the efficacy of treatment using percutaneous transluminal angioplasty (PTA).

MATERIALS AND METHODS

Twenty-two consecutive patients with OLT underwent MDCTA for evaluation of HA, followed by digital subtraction angiography (DSA) (gold standard). Source images (Ax) were processed, obtaining multiplanar reformations (MPRs), maximum intensity projections (MIPs), and volume renderings (VRs). Images were evaluated to identify the following: (1) arterial depiction (celiac axis, anastomosis, and left [LHA] and right [RHA] HA), (2) detection of stenoses, and (3) grading of stenoses. Indications for PTA were set at MDCTA and DSA, and PTA was performed when appropriate.

RESULTS

MDCTA depicted the celiac axis and anastomoses in all patients; LHA and RHA were visualized in 21 of 22 patients with Ax, MPRs, and MIPs, and in 17 of 22 with VRs. All reconstruction modalities enabled correct diagnosis of celiac (n = 3) and anastomotic stenoses (n = 14). Of 6 LHA and RHA stenoses, 4 (66.7%) were visualized with Ax, MPRs, and VRs, and 5 (83.3%) were visualized with MIPs. Stenosis was overestimated in 9 (39.1%) cases with VRs and in 3 (13%) with the other modalities. PTA was performed in 8 cases, with 1 case of arterial dissection requiring re-OLT. At a median follow-up of 28 months, the primary and secondary patency rates were 71.4% (5 of 7) and 85.7% (6 of 7), respectively.

CONCLUSIONS

MDCTA and accurate postprocessing enable confident depiction of the arterial anatomy and detection of stenosis after OLT. PTA is safe and allows allograft saving, at least until another suitable donor becomes available.

Complications of orthotopic liver transplantation: imaging findings

Orthotopic liver transplantation has become the major treatment for end-stage chronic liver disease and for severe acute liver failure. Despite the improvement in survival due to advances in organ preservation, improved immunosuppressive therapy agents, and refinement of surgical techniques, there are significant complications after liver transplantation. These complications mainly include biliary strictures, stones, and leakage; arterial and venous stenoses and thromboses; lymphoproliferative disorders; recurrent tumors; hepatitis virus C infection; liver abscesses; right adrenal gland hemorrhage; fluid collections; and hematomas. The diagnosis of acute rejection, one of the most serious complications after liver transplantation, is established with graft biopsy and histologic study. The role of imaging methods consists of excluding the other complications, which can have clinical signs and symptoms similar to those of acute rejection. This pictorial essay describes imaging findings of the various complications after liver transplantation and focuses on their radiologic diagnosis. Knowledge and early recognition of these complications with the most suitable imaging modality are crucial for graft and patient survival.

3DCT angiography for detection of vascular complications in pediatric liver transplantation

Catheter angiography for early diagnosis of vascular complications in pediatric liver transplant yields excellent results but remains an extremely invasive examination for younger children, precluding its routine use. We assessed the efficacy of three-dimensional multislice computed tomographic angiography (3DCTA) as an alternative option in these patients.

METHODS

Twenty children suspected of vascular complications on clinical grounds, laboratory findings, or Doppler ultrasound underwent 3DCTA between April 2000 and April 2003. Interventional procedures via conventional angiography were subsequently performed in 5 cases, thrombolytic therapy in 4, surgical in 1, and conservative treatment in 10.

RESULTS

Two hepatic artery stenosis,1 hepatic artery thrombosis, 5 hepatic vein stenosis, 4 portal vein occlusion, 1 portal vein stenosis, and 7 non-vascular lesions were detected, all of which paralleled the findings of catheter angiography, Doppler ultrasound, and operations. The diagnostic accuracy for vascular complication was 90%. The sensitivity and specificity were 86.7% and 100%, respectively. The positive and negative predictive values were 100% and 71.4%, respectively. To date 19 patients are alive, with a median follow-up period of 24.8 months. In conclusion, 3DCTA is accurate and efficient in the identification of pathological vascular insults and offers essential information for major decision on further management of the vascular complications in pediatric recipients of liver transplant.

Incidence and treatment of hepatic artery complications after orthotopic liver transplantation

AIM: To investigate the incidence and treatment of hepatic artery complications after orthotopic liver transplantation.

METHODS: From February 1999 to May 2002, orthotopic liver transplantations (OLT) were performed in 72 patients with end-stage liver diseases with an average age of 40.2 ± 13.6 years (ranged from 11 to 68 years), 56 were males and 16 females. The preoperative evaluation for the 72 patients was performed using duplexsonography, abdominal CT scan, and angiography of the hepatic artery. All donor grafts were perfused and preserved in University of Wisconsin solution at 4 °C. OLT was performed with standard techniques with or without a veno-venous bypass. Reconstructions of hepatic artery were performed between the branch patches of gastroduodenal/hepatic or splenic/common hepatic artery confluence of the donors and recipients, and an end-to-end anastomosis between other arterial vessels of the donors and recipients was done. Arterial anastomosis was performed with interrupted 7-0/8-0 monofilament polypropylene suture under 3.5 x loupe magnification. Diagnosis of the complications of hepatic artery after OLT was based on the clinical presentations, ultrasound findings and arterial angiography. All patients were followed up regularly for duplex ultrasound scan after discharge.

RESULTS: The overall incidence of arterial complications in 72 patients after OLTs was 1.4% (1/72). One 3 cm pseudoaneurysm at the side of anastomotic site of hepatic artery was found by urgent arteriogram due to hemoperitoneum secondary to bile leakage after OLT. Subsequently the pseudoaneurysm was successfully embolized and the blood flow toward the donor liver in hepatic artery remained. The overall postoperative 30-day mortality rate was 8.33%. The one-year survival rate was 83.72% in 50 patients with benign diseases and was 71.43% in 22 patients with malignant diseases following OLT. No death associated with complications of hepatic artery occurred.

CONCLUSION: Careful preoperative evaluations and intraoperative microsurgical technique for hepatic artery reconstructions are the keys in prevention of hepatic artery complications after OLT.

Complications of liver transplantation:

The radiologist can play a key role in diagnosis and management of many of the infectious, inflammatory, and neoplastic processes that affect patients after liver transplantation. Familiarity and skill with the full range of diagnostic and interventional tools are essential for radiologists dealing with transplant patients, even outside the medical centers where the transplantation takes place.

Doppler evaluation of arterial complications of adult orthotopic liver transplantation

PURPOSE

The aim of this study was to analyze the role of the resistance index (RI), systolic acceleration time (SAT), and spectral waveform's morphologic characteristics in the sonographic evaluation of the hepatic artery for early detection of stenosis or thrombosis after orthotopic liver transplantation.

METHODS

Arterial Doppler sonograms of 174 transplanted livers in 150 patients were analyzed for presence or absence of blood flow, RI, SAT, and peak systolic velocity. A qualitative evaluation of the spectral waveform morphologic characteristics was also made. In patients who had had abnormal findings on sonography, we compared those results with results obtained on multislice helical CT or angiography.

RESULTS

At least 1 of the Doppler criteria for hepatic artery stenosis or thrombosis was identified in 25 of the transplants. The findings on multislice helical CT, angiography, or both confirmed the diagnosis of stenosis or thrombosis in 20 of the 25 cases: in 9 of 10 cases of absent hepatic arterial blood flow, 5 of 9 with an RI lower than 0.5, 6 of 7 cases with an SAT longer than 0.08 second, 10 of 11 cases of changes to a tardus-parvus-like spectral waveform, and in the 1 case of a peak systolic velocity greater than 2 m/second.

CONCLUSIONS

The most accurate indicator of hepatic arterial stenosis or thrombosis was a change in the spectral waveform to a tardus-parvus pattern, with 91% sensitivity and 99.1% specificity. Among the other parameters, an increase of the SAT value (> 0.08 second), when associated with the morphologic modification of the systolic peak, is a more reliable parameter than the RI for early detection of artery stenosis, especially when the type of anastomosis is unknown.

Endovascular treatment of a recipient celiac trunk stenosis after orthotopic liver transplantation

PURPOSE

To present the successful endovascular treatment of a severe recipient celiac trunk stenosis that led to allograft ischemia following liver transplantation.

CASE REPORT

A 56-year-old woman underwent orthotopic liver transplantation because of hepatitis C-induced cirrhosis. After the operation, routine hepatic Doppler ultrasonography showed a tardus parvus flow pattern in the hepatic artery, suggesting an impending hepatic artery thrombosis. Digital subtraction angiography (DSA), however, showed severe stenosis of the recipient celiac trunk and moderate splenic artery steal. The stenosis was dilated and stented in the same session. The postprocedural DSA showed good dilation of the lesion with immediate improvement of hepatic opacification. Follow-up Doppler ultrasound scans showed normal flow patterns in the hepatic artery at 3 and 6 months.

CONCLUSIONS

In the presence of a tardus parvus flow pattern on Doppler ultrasound after liver transplantation, the possibility of an undetected recipient celiac stenosis should be considered in the differential diagnosis. Such lesions can successfully be treated with angioplasty and stenting.

Noninvasive assessment of portomesenteric venous thrombosis: current concepts and imaging strategies

Rapid, noninvasive imaging strategies, especially multidetector spiral CT and CT angiography (CTA) as well as gadolinium-enhanced MR angiography (MRA), have facilitated early diagnosis of splanchnic venous thrombosis, a potentially lethal cause of intestinal ischemia. Single breath-hold volumetric acquisitions permit superior temporal and contrast resolution while eliminating motion artifact and suppressing respiratory misregistration. Increased spatial resolution is aided by thinner slice collimation. These cross-sectional imaging techniques are becoming a preferred noninvasive alternative to conventional selective mesenteric angiography with delayed imaging for venous evaluation and should be considered the primary diagnostic modalities for evaluating patients with high clinical suspicion of nonsurgical mesenteric ischemia.