Three-dimensional multislice helical computed tomography with the volume rendering technique in the detection of vascular complications after liver transplantation

Vascular Complications in Pediatric Liver Transplants and Their Management

OBJECTIVES

The blood supply of the liver occurs through the hepatic artery and portal vein. Outflow of blood circulation in the liver is via the hepatic veins. Any disruption in this blood circulation results in deterioration of liver functions. In this study, we evaluated early vascular complications in pediatric liver transplant recipients seen at our center.

MATERIALS AND METHODS

From November 1988 to December 2021, our team has performed 701 liver transplant procedures, which have included 334 pediatric liver transplants. Among these pediatric liver transplant recipients (mean age of 7.34 y), 176 were male patients. Nineteen patients (5.7%) were recipients of deceased donors. Reason for liver failure was mainly biliary atresia (n = 169). Mean weight of recipients was 23.3 kg. Most graft types were left lateral grafts (n = 204).

RESULTS

Three patients had hepatic vein complications. All 3 patients were successfully treated with interventional radiological methods by placing a stent in the anastomosis region. Portal vein complications occurred in 3 patients. One patient had hemostasis performed surgically. The second patient had surgically revision of the anastomosis because of thrombus formation. Because of stenosis of more than 50% in the portal vein anastomosis, the third patient required stent placement in the anastomosis region. Hepatic artery complications occurred in 54 patients: 31 patients had hepatic artery thrombosis, 13 patients had hepatic artery stenosis, 7 patients had bleeding from hepatic artery anastomosis, 2 patients had hepatic artery dissection, and 1 patient had pseudoaneurysm in the hepatic artery. Forty-three of these patients were successfully treated with interventional radiological methods and 11 required surgical treatment.

CONCLUSIONS

Vascular complications after liver transplant can cause deterioration in hepatic functions and acute liver failure. Vascular complications can be successfully treated in experienced organ transplant centers.

Improving the Specificity of CT Angiography for the Diagnosis of Hepatic Artery Occlusion after Liver Transplantation in Suspected Patients with Doppler Ultrasound Abnormalities

OBJECTIVE

To investigate whether the diagnostic performance of CT angiography (CTA) could be improved by modifying the conventional criterion (anastomosis site abnormality) to diagnose hepatic artery occlusion (HAO) after liver transplantation (LT) in suspected patients with Doppler ultrasound (US) abnormalities.

MATERIALS AND METHODS

One hundred thirty-four adult LT recipients (88 males and 46 females; mean age, 52.7 years) with suspected HAO on Doppler US (40 HAO and 94 non-HAO according to the reference standards) were included. We evaluated 1) abnormalities in the HA anastomosis, categorized as a cutoff, ≥ 50% stenosis at the anastomotic site, or diffuse stenosis at both graft and recipient sides around the anastomosis, and 2) abnormalities in the distal run-off, including invisibility or irregular, faint, and discontinuous enhancement. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the conventional (considering anastomosis site abnormalities alone) and modified CTA criteria (abnormalities in both the anastomosis site and distal run-off) for the diagnosis of HAO were calculated and compared using the McNemar test.

RESULTS

By using the conventional criterion to diagnose HAO, the sensitivity, specificity, PPV, NPV, and accuracy were 100% (40/40), 74.5% (70/94), 62.5% (40/64), 100% (70/70), and 82.1% (110/134), respectively. The modified criterion for diagnosing HAO showed significantly increased specificity (93.6%, 88/94) and accuracy (93.3%, 125/134) compared to that with the conventional criterion (p = 0.001 and 0.002, respectively), although the sensitivity (92.5%, 37/40) decreased slightly without statistical significance (p = 0.250).

CONCLUSION

The modified criterion considering abnormalities in both the anastomosis site and distal run-off improved the diagnostic performance of CTA for HAO in suspected patients with Doppler US abnormalities, particularly by increasing the specificity.

Diagnostic accuracy of Doppler ultrasound for detecting hepatic artery stenosis after liver transplantation

AIM

To evaluate the diagnostic accuracy of Doppler ultrasound (DUS) in detecting hepatic artery stenosis (HAS) after liver transplantation using computed tomography angiography (CTA) as the reference standard.

MATERIALS AND METHODS

This study included data from January 2005 to November 2017, where DUS of the hepatic artery of living and deceased donor liver grafts were compared with the reference standard, CTA. DUS parameters, such as intrahepatic artery (IHA) peak systolic velocity (PSV), resistive index (RI), systolic acceleration time (SAT); and extrahepatic artery (EHA) PSV were taken. The optimum cut-off was estimated using area under the receiver operating characteristic curve (AUC). Multivariable logistic regression analysis was developed to predict HAS.

RESULTS

Ninety-nine liver transplant cases were retrieved, 50 met the inclusion criteria where nine patients had significant HAS. HAS patients had a significantly low IHAPSV with a cut-off of 35.1 cm/s (sensitivity 53.8%, specificity 78.4%, AUC 0.701). IHARI had a significantly low RI with a cut-off 0.585 (sensitivity 86.7%, specificity 85.4%, AUC 0.913). The IHASAT cut-off was 0.045 seconds (sensitivity 80%, specificity 91.4%, AUC 0.857). The EHAPSV cut-off was 197.4 cm/s (sensitivity 50%, specificity 99.1%, AUC 0.648). The prediction model using DUS parameters IHARI and IHASAT demonstrated good discrimination with an AUC of 0.930 (95% CI: 0.843, 1.000; sensitivity 93.3%, specificity 88%).

CONCLUSION

A prediction model using the DUS parameters IHARI and IHASAT showed good diagnostic accuracy of 88.6% for monitoring liver transplant patients. If validated externally, this DUS model could be utilised to diagnose HAS in liver transplant recipients.

Management of early hepatic artery thrombosis following living-donor liver transplantation: feasibility, efficacy and potential risks of endovascular therapy in the first 48 hours post-transplant-a retrospective cohort study

This retrospective cohort study aims to review our 18-year experience with early hepatic artery thrombosis (e-HAT) following living-donor liver transplantation (LDLT), as well as to assess the feasibility, efficacy and potential risks of endovascular management of e-HAT in the first 48 hours (hrs) post-LDLT. Medical records of 730 patients who underwent LDLT were retrospectively reviewed. In all cases who had developed e-HAT, treatment modalities employed and their outcomes were evaluated. Thirty-one patients developed e-HAT(4.2%). Definite technical success and 1-year survival rates of surgical revascularization[11/31 cases(35.5%)] were 72.7% & 72.7%, whereas those of endovascular therapy[27/31 cases(87.1%)] were 70.4% & 59.3%, respectively. Endovascular therapy was carried out in the first 48hrs post-transplant in 9/31 cases(29%) [definite technical success:88.9%, 1-year survival:55.6%]. Four procedure-related complications were reported in 3 of those 9 cases(33.3%). In conclusion, post-LDLT e-HAT can be treated by surgical revascularization or endovascular therapy, with comparable results. Endovascular management of e-HAT in the first 48hrs post-LDLT appears to be feasible and effective, but is associated with a relatively higher risk of procedure-related complications, compared to surgical revascularization. Hence, it can be reserved as a second-line therapeutic option in certain situations where surgical revascularization is considered futile, potentially too complex, or potentially more risky.

Complications of liver transplant

Liver transplantation has become a definitive treatment for patients with end-stage liver disease and those meeting Milan criteria for hepatocellular carcinoma. The morbidity and mortality associated with liver transplantation continues to decrease thanks to refinements in surgical technique, immunosuppression, and imaging. In particular, imaging plays a vital role by facilitating early detection of post-operative complications and enabling prompt treatment. Post-operative complications that lead to graft failure and patient morbidity/mortality can be generally categorized as vascular, biliary, parenchymal, and malignant. Vascular complications include stenosis and thrombosis of the hepatic artery, portal vein, and inferior vena cava; hepatic artery pseudoaneurysm; arteriovenous fistula; and celiac stenosis. Biliary abnormalities include strictures, bile leak, obstruction, recurrent disease, and infection. While imaging is not primarily utilized to diagnose allograft rejection, it plays an important role in excluding mechanical causes of graft dysfunction that can mimic rejection. Ultrasound is routinely performed as the first-line imaging evaluation for the detection and follow-up of early and delayed complications. Cholangiography and magnetic resonance cholangiopancreatography are useful in detecting and characterizing biliary complications. Computed tomography is often used to further evaluate abnormal findings on ultrasound or for the characterization of post-operative fluid collections. The aim of this review is to discuss and illustrate the imaging findings of complications associated with liver transplantation and their role in facilitating treatment.

Radiological findings in ischaemic cholangiopathy

Ischaemic cholangiopathy occurs as a consequence of deficient arterial blood flow to the bile duct wall. Bile duct ischaemia can lead to full-thickness necrosis, bile leakage, biloma formation, and sepsis. It is an important cause of graft failure post-orthotopic liver transplantation. In the native liver, the causes of biliary ischaemia are diverse and include vasculitis or a complication of endovascular procedures. The present review describes the pathology and radiological findings of ischaemic cholangiopathy and outlines the role of interventional radiology in its management.

Diagnostic Performance for Hepatic Artery Occlusion After Liver Transplantation: Computed Tomography Angiography Versus Contrast-Enhanced Ultrasound

The purpose of this study was to compare the diagnostic performance of computed tomography angiography (CTA) and contrast-enhanced ultrasound (CEUS) when used to diagnose significant hepatic artery occlusion (HAO) in patients that was suspected on Doppler ultrasound (US). Among 3465 adult liver transplantations (LTs) performed between January 2010 and February 2018, 329 recipients were suspected of having HAO by Doppler US. In these patients, 139 recipients who had undergone both CTA and CEUS as second-line studies were included. CTA and CEUS were retrospectively reviewed using the criteria for HAO used in previous studies (CTA, ≥50% stenosis at the anastomosis; CEUS, no HA enhancement or delayed and discontinuous enhancement). The diagnostic values of CTA and CEUS were compared using the McNemar test. CEUS showed statistically significant better accuracy and specificity than CTA in patients with Doppler US abnormality seen after LT (accuracy, 99.3% versus 89.2%, P < 0.001; specificity, 100% versus 83.1%, P < 0.001). CTA had 15 false-positive diagnoses, and CEUS had 1 false-negative diagnosis. In conclusion, CEUS showed higher specificity and positive predictive value than CTA for the diagnosis of HAO in selected patients with a Doppler US abnormality. However, even if there is no HAO diagnosed on CEUS, continuous monitoring and follow-up imaging are required when HAO is strongly suspected in the clinical setting and on CTA.

The role of multislice computerized tomography angiography in assessing postoperative vascular complications in liver transplant patients

Background/aim

Vascular complications can be detected in liver transplant patients. Digital subtraction angiography has served as the gold standard to make this diagnosis; however, due to its invasive nature, ultrasonography is used for the preliminary evaluation. The purpose of this study was to evaluate the role of multislice computerized tomography angiography (MSCTA) in the detection of vascular complications of symptomatic and asymptomatic liver transplant patients and to compare the results with Doppler ultrasound (Doppler US) findings.

Materials and methods

Fifty-three liver transplant patients (6 symptomatic, 47 asymptomatic) underwent Doppler US examination followed by an MSCTA. The findings in each modality were interpreted in a blinded fashion and then compared.

Results

MSCTA detected 15 abnormalities, none of which were detected by Doppler US. There were hepatic and splenic artery aneurysms (n = 4) and various stenoses (n = 4), infrarenal aortic anastomosis (n = 4), vena cava inferior thrombosis (n = 1), arteriovenous malformation (n = 1), and esophageal varices (n = 1).

Conclusion

MSCTA detected more lesions and we believe that it should be considered as a road map for Doppler US follow-ups as well as a routine screening modality for early detection of vascular complications in symptomatic and asymptomatic liver transplantation patients that may be missed by Doppler US.

Tardus parvus waveforms in Doppler ultrasonography for hepatic artery stenosis after liver transplantation: can a new cut-off value guide the next step?

PURPOSE

Considering the high false-positive diagnosis of the tardus parvus waveform (TPW) in Doppler ultrasonography (DUS) for hepatic artery stenosis (HAS) after liver transplantation (LT), this study aimed to determine clinical features and new cut-off values to help guide treatment.

MATERIALS AND METHODS

This retrospective study was approved by an Institutional Review Board. A total of 171 LT recipients were included and underwent DUS and either computed tomography angiography or digital subtraction angiography with an interval < 4 weeks at least 1 month post-LT. The DUS of 69 patients exhibited TPW [defined as resistive index (RI) < 0.5 and systolic acceleration time (SAT) > 0.08 s]. A multilevel likelihood ratio (LR) analysis was used to explore new cut-off values for DUS. In addition, abnormal liver function was considered additional evidence (defined as any liver enzyme > 3-fold of the upper limit of normal level or 2-fold increased). The results were stratified into three categories, category 1 (subjects with traditional TPW), category 2 (subjects with traditional TPW and abnormal liver function), and category 3 (subjects with traditional TPW and abnormal liver function, or with new cut-off values), and the diagnostic performance of each category was analyzed.

RESULTS

The LR analysis revealed new cut-off values of RI < 0.4 (LR = 10.58) or SAT > 0.12 s (LR = 16.46). The false-positive rates for categories 2 and 3 were significantly lower (7.6% vs. 18.1%, P = 0.038; 1.9% vs. 18.1%, P < 0.001, respectively) than those for category 1, while the sensitivity for category 2 was significantly lower (41.8% vs. 74.6%, P < 0.001; 41.8% vs. 61.2%, P = 0.038, respectively) than that for categories 1 and 3.

CONCLUSION

Using either (1) RI < 0.4 or SAT > 0.12 s, or (2) traditional TPW (RI < 0.5 and SAT > 0.08 s) in the presence of abnormal liver functions as the DUS criteria for HAS will significantly decrease the false-positive rate compared to traditional TPW without a significant increase in the false-negative rate.

Comparison of two- and three-dimensional measurement of the Cobb angle in scoliosis

PURPOSE

The Cobb angle as an objective measure is used to determine the progression of deformity, and is the basis in the planning of conservative and surgical treatment. However, studies have shown that the Cobb angle has two limitations: an inter- and intraobserver variability of the measurement is approximately 3-5 degrees, and high variability regarding the definition of the end vertebra. Scoliosis is a three-dimensional (3D) pathology, and 3D pathologies cannot be completely assessed by two-dimensional (2D) methods, like 2D radiography. The objective of this study was to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using X-rays and 3D computer tomography (CT) reconstructions in scoliotic spines.

METHODS

To assess interoberver variation the Cobb angle and the end vertebra were assessed by five observers in 55 patients using X-rays and 3D CT reconstructions. Definition of end vertebra and measurement of the Cobb angle was repeated two times with a three-week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits were provided for measurement errors.

RESULTS

Intraclass correlation coefficient (ICC) showed excellent reliability for both methods. The measured Cobb angle was on average 9.2 degrees larger in the 3D CT group (72.8°, range 30-144) than on 2D radiography (63.6°, range 24-152).

CONCLUSIONS

In scoliosis treatment it is very essential to determine the curve magnitude, which is larger in a 3D measurement compared to 2D radiography.

Imaging panorama in postoperative complications after liver transplantation

The liver is the second most-often transplanted solid organ after the kidney, so it is clear that liver disease is a common and serious problem around the globe. With the advancements in surgical, oncological and imaging techniques, orthotopic liver transplantation has become the first-line treatment for many patients with end-stage liver disease. Ultrasound, and Doppler are the most economical and cost-effective imaging modalities for evaluating postoperative fluid collections and vascular complications. Computed tomography (CT) is used to confirm the findings of ultrasound and look for pulmonary complications. Magnetic resonance imaging (MRI) is used for the diagnosis of biliary complications, bile leaks and neurological complications. This article illustrates the imaging options for diagnosing the various complications that can be encountered in the postoperative period after liver transplantation.

Radiologic assessment of hepatobiliary surgical complications

The complexity of hepatobiliary procedures continues to evolve at a rapid rate, with an increasing number of living donor liver transplants and extensive cancer resections being performed. The associated complications are a significant cause of morbidity and mortality, and are often complex injuries, involving both vascular and biliary structures. In this paper we describe the complications associated with laparoscopic cholecystectomy, liver transplant surgery, and hepatic resection. Focus is on the classical imaging appearances, imaging modality options, and varying management strategies for these injuries, to show how the radiologist's role is vital in ensuring the correct diagnosis is made and the appropriate treatment is instigated.

Hepatic arterial stenosis assessed with doppler US after liver transplantation: frequent false-positive diagnoses with tardus parvus waveform and value of adding optimal peak systolic velocity cutoff

PURPOSE

To evaluate the utility of the tardus parvus waveform of the hepatic artery at Doppler ultrasonography (US) in the diagnosis of hepatic arterial stenosis in liver transplant (LT) recipients and determine whether the accuracy of such a diagnosis is enhanced by including an optimal peak systolic velocity (PSV) cutoff.

MATERIALS AND METHODS

This retrospective study was institutional review board approved; the requirement for informed consent was waived. The authors identified 361 LT recipients (267 male, 94 female) who underwent Doppler US and either computed tomography (CT) or angiography, with an interval between these examinations of less than 1 week. At Doppler US, tardus parvus pattern was defined as a waveform with a resistive index (RI) of less than 0.5 and a systolic acceleration time longer than 0.08 second. At CT or angiography, patients were assigned to the hepatic arterial stenosis (≥50% vessel narrowing) or nonstenosis group. The capability of the tardus parvus pattern to facilitate the diagnosis of hepatic arterial stenosis was calculated. The difference in PSV between the true- and false-positive tardus parvus patterns was evaluated. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff PSV for diagnosing hepatic arterial stenosis. The capability of the tardus parvus pattern and an optimal PSV cutoff in the diagnosis of hepatic arterial stenosis was determined.

RESULTS

Sixty transplant recipients had the tardus parvus pattern at Doppler US. The sensitivity, specificity, and positive predictive value (PPV) of the tardus parvus pattern were 72% (23 of 32 LT recipients), 88.8% (292 of 329 LT recipients), and 38% (23 of 60 LT recipients), respectively. The false-positive rate was 11.2% (37 of 329 LT recipients). ROC analysis revealed an optimal PSV cutoff of less than or equal to 48 cm/sec for diagnosing hepatic arterial stenosis. The combination of the tardus parvus pattern and a PSV cutoff of less than or equal to 48 cm/sec improved specificity to 99.1% (326 of 329 LT recipients) and the PPV to 88% (22 of 25 LT recipients), thereby reducing the false-positive rate to 1% (three of 329 LT recipients) while slightly decreasing the sensitivity to 69% (22 of 32 LT recipients).

CONCLUSION

Use of the tardus parvus waveform of the hepatic artery resulted in a low PPV and a high false-positive rate. However, the combination of the tardus parvus pattern and an optimal PSV cutoff greatly improved the PPV and reduced the false-positive rate in the diagnosis of hepatic arterial stenosis.

Vascular complications after deceased and living donor liver transplantation: a single-center experience

INTRODUCTION

Vascular complications (VC) after liver transplantation (OLT) are one of the most feared problems that frequently result in graft and patient loss. Herein we have reported our experience with VC after either deceased donor liver transplantation (DDLT) or living donor liver transplantation (LDLT).

PATIENTS AND METHODS

Between April 2001 and September 2009, we performed 224 OLT: 155 DDLT and 69 LDLT. The overall male/female ratio was 136/88 and the adult/pediatric ratio was 208/16. We retrospectively identified and analyzed vascular complications in both groups.

RESULTS

In the DDLT group, 11/155 recipients (7%) suffered vascular complications; hepatic artery thrombosis (HAT; n=5; 3.2%), portal vein thrombosis occurred (n=4; 2.6%); hepatic vein stenosis (n=1; 0.6%), and severe postoperative bleeding due to a slipped splenic artery ligature (n=1, 0.6%). In the DDLT group, 4/11 (36.4%) patients died as a direct result of the vascular complications. In the LDLT group, 9/69 recipients (13%) suffered vascular complications: HAT (n=3; 4.3%), portal vein problems (n=5; 7.2%), and hepatic vein stenosis (n=1; 1.5%). Among LDLT, 3/9 (33.3%) patients died as a direct result of the vascular complications. In both groups vascular complications were associated with poorer patient and graft survival.

CONCLUSIONS

In our experience, the incidence of vascular complications was significantly higher among the LDLT group compared with the DDLT group. Vascular complications were associated with poorer graft and patient survival rates in both groups.

Contrast-enhanced ultrasound for the evaluation of hepatic artery stenosis after liver transplantation: potential role in changing the clinical algorithm

Hepatic artery stenosis (HAS) is a common complication in liver transplant patients. Conventional angiography remains the gold standard for diagnosis. Recently, contrast-enhanced ultrasound (CEUS) has begun providing real-time angiographic-like images of vessels and allowing the accurate diagnosis of arterial diseases such as hepatic artery thrombosis. The purpose of this study was to evaluate the efficacy of CEUS in depicting HAS after liver transplantation. Forty-seven liver transplant recipients underwent CEUS examinations with the intravenous injection of microbubble contrast agents. The reference standard was conventional angiography for 15 patients and computed tomographic angiography for 32 patients. The presence, degree, location, and type of HAS were evaluated. For the detection of HAS by CEUS, the following was found: an accuracy of 91.5% (43/47), a sensitivity of 92.3% (36/39), a specificity of 87.5% (7/8), a positive predictive value of 97.3% (36/37), and a negative predictive value of 70% (7/10). CEUS corrected false-positive findings on color Doppler ultrasound in 7 of 47 cases (14.9%). The accuracy of CEUS in identifying the location and type of HAS was 92.3% (36/39) and 84.6% (33/39), respectively. CEUS is a useful noninvasive technique for the detection of HAS in liver transplant patients because it provides comprehensive information, including the presence, location, degree, and type. A positive CEUS finding suggests angiography as the next step rather than a computed tomography scan and may thereby alter the clinical imaging algorithm.

Endovascular treatment of hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis (HAT) is the most frequent vascular complication following orthotopic liver transplantation. Urgent retransplantation has been considered as the mainstay therapy. Surgical revascularization is an effective alternative in asymptomatic patients. Endovascular therapies including intra-arterial thrombolysis, percutaneous transluminal angioplasty (PTA), and stent placement have shown encouraging results in recent years; however, their use remains controversial because of potential risk of hemorrhage. Until June 2009, 69 cases were published in 16 reports describing therapeutic potential of endovascular modalities. Interventions were performed as early as within 4 h to as late as 120 days in patients ranging from 4 months to 64 years of age. Majority of published reports suggested the use of urokinase. Thrombolysis was successful in 47 out of 69 (68%) patients. Bleeding was the most common complication including fatal intra-abdominal hemorrhage in three patients. Twenty-nine out of 47 (62%) patients underwent further intervention in the form of PTA, stenting, or both. The follow-up patency ranged from 1 month to 26 months. In conclusion, whenever possible, efforts should be made to rescue the liver grafts through urgent revascularization (surgical and/or endovascular) depending on patient's condition and interventional expertise at the transplant center; reserving the option of retransplantation for failure, complications, and cases with severe clinical symptoms or allograft dysfunction.

Diagnosis and treatment of pediatric patients with late-onset portal vein stenosis after living donor liver transplantation

Portal vein stenosis (PVS) after living donor liver transplantation (LDLT) is a serious complication that can lead to graft failure. Few studies of the diagnosis and treatment of late-onset (> or = 3 months after liver transplantation) PVS have been reported. One hundred thirty-three pediatric (median age 7.6 years, range 1.3-26.8 years) LDLT recipients were studied. The patients were followed by Doppler ultrasound (every 3 months) and multidetector helical computed tomography (once a year). Twelve patients were diagnosed with late-onset PVS 0.5-6.9 years after LDLT. All cases were successfully treated with balloon dilatation. Five cases required multiple treatments. Early diagnosis of late-onset PVS and interventional radiology therapy treatment may prevent graft loss.

Interventional radiology in the diagnosis, management, and follow-up of pseudoaneurysms

Arterial wall disruption, as a consequence of inflammation/infection, trauma (penetrating or blunt), or iatrogenic causes, may result in pseudoaneurysm formation. Currently, iatrogenic causes are increasing as a result of the growth of endovascular intervention. The frequency of other causes also seems to be increasing, but this may simply be the result of increased diagnosis by better imaging techniques, such as multidetector contrast-enhanced computed tomography. Clinically, pseudoaneurysms may be silent, may present with local or systemic signs, or can rupture with catastrophic consequences. Open surgical repair, previously the mainstay of treatment, has largely been replaced by image-guided occlusion methods. On the basis of an experience of over 100 pseudoaneurysms, treatments at various anatomical sites, imaging modalities used for accurate diagnosis, current changing therapeutic options for pseudoaneurysm management, approved embolization agents, and clinical follow-up requirements to ensure adequate treatment will be discussed. Image-guided direct percutaneous and endovascular embolization of pseudoaneurysms are established treatment options with favorable success rates and minimal morbidity. The pendulum has now swung from invasive surgical repair of pseudoaneurysms to that of image-guided interventional radiology.

Portal vein complications after adult-to-adult living donor liver transplantation

Successful management of portal vein (PV) complications after liver transplantation is crucial to long-term success. Little information is available, however, regarding the incidence and treatment of PV complications after adult-to-adult living donor liver transplantation (LDLT). Between January 1996 and October 2006, 310 adult LDLTs were performed at our institution. PV thrombus was present in 54 patients at the time of LDLT. The incidence of PV complications, choice of therapeutic intervention, and outcomes were retrospectively analyzed. Among the 310 recipients, PV complications were identified in 28 (9%). Risk factors included smaller graft size, presence of PV thrombus at the time of LDLT, and use of jump or interposition cryo-preserved vein grafts for PV reconstruction. When divided into early (within 3 months, n = 11) and late (after 3 months, n = 17) complications, the use of vein grafts for PV reconstruction predisposed to the occurrence of late, but not early, PV complications. Portal vein thrombosis occurred more frequently in the early period (eight out of 11, 73%), whereas stenosis occurred more frequently in the later period (14 out of 17, 82%). Surgical interventions were favored in the earlier period, whereas interventional radiologic approaches were selected for later events. Overall 3- and 5-year survival rates were 81% and 77%, respectively, in patients with PV complications and 88% and 84%, respectively, in those without PV complications (P = 0.21, log-rank test). PV complications are a significant problem following LDLT with both early and late manifestations. Acceptable long-term results, however, are achievable with periodic ultrasonographic surveillance and timely conventional therapeutic interventions. The use of cryo-preserved vein grafts for reconstructing portal flow should be discouraged.

Multimodality postoperative imaging of liver transplantation

Liver transplantation is the only effective and definitive treatment for patients with end-stage liver disease. The shortage of cadaveric livers has lead to the increasing use of split-liver transplantation and living-donor liver transplantation, but the expansion of the donor pool has increased the risk for postoperative vascular and biliary complications. Early recognition of the imaging appearances of the various postoperative complications of liver transplantation is crucial for both graft and patient survival. This review describes the imaging findings of normal and abnormal transplanted liver parenchyma and of vascular and biliary post-transplantation complications.

Multidetector computed tomography angiography in detection of active bleeding in renal and liver transplant recipients

OBJECTIVES

The aim of this study was to evaluate the effectivity of multidetector computed tomography angiography (MDCT-A) to detect active bleeding in transplant patients.

MATERIALS AND METHODS

Between 1999 and 2006, 532 patients underwent renal or liver transplantation. MDCT-A was performed on recipients who displayed decreased hemoglobin levels or who had a hematoma during abdominal ultrasound imaging. The MDCT-A used a 16-detector CT device (Siemens, Sensation) with slices 0.75 mm thick after injection of nonionic contrast media (4 mL per second). A multiple intensity projection (MIP) technique was used to maintain angiographic images in the axial and coronal planes.

RESULTS

MDCT-A detected active bleeding among 23 posttransplant patients: 10 of arterial origin and 13 venous, as proven either by angiography or during operation. Among 8 of the 11 patients who underwent angiographic imaging the arterial origin was embolized. For three patients the angiographic evaluation was not helpful to find the bleeding point. A cohort of 5 of 12 patients did not undergo angiographic evaluation and were followed by clinical and ultrasonographic findings. Seven patients underwent re-operating.

DISCUSSION

Management of the patients who were suspected to have active bleeding after renal or liver transplantation was benefitted by MDCT-A as an accurate and feasible screening modality.

Computer-assisted operative planning in adult living donor liver transplantation: a new way to resolve the dilemma of the middle hepatic vein

An adequate venous outflow is essential for securing viability of both graft and remnant in adult living donor liver transplantation (ALDLT). Seventy-five potential live liver donors were evaluated for LDLT by means of an "all-in-one" CT, which defined the biliary tree, portal vein, hepatic artery, and hepatic vein anatomy. The acquired data sets were further analysed by means of the software HepaVision (MeVis, Germany). Only a minority (29%) of potential donors were found to have a vascular and biliary anatomy consistent with the classically described "normal" patterns. The vast majority (71%) had "anatomical variations". Thirty-nine (52%) donors underwent ALDLT hepatectomy. The right hepatic vein was dominant in 64 cases, representing 48 +/- 6% of the total liver volume (TLV). The middle hepatic vein was dominant in 11 cases, making up 40 +/- 8% of the TLV. The left hepatic vein was never dominant. The volume contribution of the middle hepatic vein (MHV) was 114-782 ml for the right and 87-419 ml for the left hemiliver. Computer-assisted planning allows for the 3D reconstruction of the vascular and biliary anatomy, automatic calculation of the total and territorial liver volumes, and risk analysis of hepatic vein dominance relationships. This comprehensive data acquisition supports preoperative evaluation and provides a high degree of safety for donors and improved outcomes for recipients.

Multidetector row CT of various hepatic artery complications after living donor liver transplantation

Although it is uncommon, hepatic artery (HA) complications including pseudoaneurysm, dissection, and flow steal phenomenon as well as stenosis and thrombosis may occur after living donor liver transplantation (LDLT). A timely diagnosis is of utmost importance for graft and patient survival, because it may result in serious complications, such as life-threatening hemorrhage, severe graft dysfunction or even failure, bile duct necrosis or stricture. Multidetector row CT (MDCT), with superb spatial- and time-resolution, may facilitate the diagnosis of HA complications in LDLT recipients. However, little attention has been paid to MDCT findings of various HA complications following LDLT. For an early recognition and accurate diagnosis of HA complications, radiologists should be familiar with their MDCT findings. In this essay, we present a comprehensive review of various HA complications after LDLT and illustrate their MDCT findings.

THREE-DIMENSIONAL MULTISLICE HELICAL COMPUTED TOMOGRAPHY TECHNIQUES FOR CANINE EXTRA-HEPATIC PORTOSYSTEMIC SHUNT ASSESSMENT

The purpose of the present study was to investigate the feasibility and usefulness of three-dimensional (3D) multislice computed tomography (CT) angiography with maximum intensity projection (MIP) and volume rendering (VR) in six dogs with clinical and sonographic findings suggestive of portosystemic shunt. Furthermore, we aimed to estimate the diameter of the portal vein and shunt vessels. MIP and VR reconstructions were performed for each patient and the origin and insertion of all shunt vessels were detected. In addition, 3D reconstructions allowed excellent depiction of vascular morphology and topography. All diagnoses and vessel measurements were confirmed by surgery. 3D multidetector CT angiography is a promising, noninvasive, and accurate method of evaluating dogs with suspected portosystemic shunts.

Traumatic arterial injuries of the extremities: initial evaluation with MDCT angiography

OBJECTIVE

The purpose of this study was to retrospectively assess the accuracy of MDCT angiography as the initial diagnostic technique to depict arterial injury in patients with extremity trauma.

MATERIALS AND METHODS

Over 36 months, 87 patients (16 females and 71 males; age range, 16-87 years) with clinically suspected arterial injury after extremity trauma underwent 4-MDCT angiography and 67 ultimately underwent surgery. Eighty patients had blunt injuries, and seven had penetrating injuries. The presence of arterial involvement was investigated prospectively by the radiologist in charge and retrospectively by two independent radiologists. Each detected arterial lesion was then characterized as a spasm, stenosis, occlusion, or rupture. The standard of reference was surgery in 67 patients, angiography in two patients, and clinical and radiologic follow-up findings in 18 patients. MDCT angiography was assessed by means of receiver operating characteristic (ROC) curve analysis for lesion detection and Spearman's rank correlation test for lesion characterization. Image quality, lesion depiction, and artifacts were subjectively assessed.

RESULTS

Sixty-two traumatic arterial lesions were confirmed at surgery in 55 patients. MDCT angiography yielded high accuracy in detection (area under the ROC curve [Az] = 0.96; p < 0.001) and characterization (r = 0.94; p < 0.001) of traumatic arterial injuries and in recognizing an underlying dissection (Az= 0.82; p < 0.001). Prospective sensitivity and specificity were 95% and 87%, respectively, and retrospective sensitivity and specificity were 99% and 87%, respectively. MDCT angiography was considered to be sufficient for a reliable diagnosis in 83 patients (p < 0.001). Image quality and lesion depiction on MDCT angiograms were considered to be good and artifacts were considered mild with substantial interobserver agreement (kappa, 0.62-0.69).

CONCLUSION

MDCT angiography provides significant and reproducible technique for the detection and characterization of arterial injuries to the extremities with high image quality and vascular delineation.

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.

Pseudoaneurysms and the role of minimally invasive techniques in their management

Pseudoaneurysms are common vascular abnormalities that represent a disruption in arterial wall continuity. Some complications associated with pseudoaneurysms develop unpredictably and carry high morbidity and mortality rates. The advent of new radiologic techniques with a greater sensitivity for asymptomatic disease has allowed more frequent diagnosis of pseudoaneurysms. Conventional angiography remains the standard of reference for diagnosis but is an invasive procedure, and noninvasive diagnostic modalities (eg, ultrasonography [US], computed tomographic angiography, magnetic resonance angiography) should be included in the initial work-up if possible. A complete work-up will help in determining the cause, location, morphologic features, rupture risk, and clinical setting of the pseudoaneurysm; identifying any patient comorbidities; and evaluating surrounding structures and relevant vascular anatomy, information that is essential for treatment planning. Therapeutic options have evolved in recent years from the traditional surgical option toward a less invasive approach and include radiologic procedures such as US-guided compression, US-guided percutaneous thrombin injection, and endovascular management (embolization, stent-graft placement). The use of noninvasive treatment has led to a marked decrease in the morbidity and mortality rates for pseudoaneurysms.

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.

Continuous Transcatheter Arterial Thrombolysis for Early Hepatic Artery Thrombosis After Liver Transplantation

Early hepatic artery thrombosis (HAT) after orthotopic liver transplantation remains a significant cause of graft loss and patient death. The most effective treatment approach is still controversial. The purpose of this study was to assess the effect of continuous transcatheter arterial thrombolysis in the treatment of early HAT. Routine posttransplant color Doppler imaging (CDI) was performed to monitor hepatic artery blood flow. HAT was confirmed by arterial angiography in suspected cases. HAT was identified in 8 patients (8/287, 2.8%) which occurred on days 2 to 19 (mean, 5.2 days) after liver transplantation. Patients with HAT were treated with continuous transcatheter arterial thrombolysis using urokinase. Successful revascularization through thrombolysis was obtained in all eight cases. One patient died of a pulmonary infection at 2 months after liver transplantation. Another patient underwent retransplantation because of resistant allograft rejection and recurrence of HAT 6 months after the first operation, but died from multiple system organ failure 2 months later. The other six patients remained in good health during the follow-up period of 3 to 27 months. Our results demonstrate that CDI is an effective method to monitor the occurrence of early HAT after liver transplantation. Furthermore, continuous transcatheter arterial thrombolysis with urokinase could be a rational therapeutic approach to rescue the allograft following early HAT diagnosis confirmed by arterial angiography.

THREE-DIMENSIONAL HELICAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF THE LIVER IN FIVE DOGS

The objective of this study was to develop a simple, safe, minimally invasive protocol to evaluate the hepatic vasculature. Five purpose-bred Beagle dogs underwent noncontrast-enhanced computed tomographic scan of the entire abdomen. A dynamic, nonincremental computed tomography scan at the level of T11 was then performed using a test bolus of contrast medium to determine time to peak opacification and to aid in the calculation of scan delay. The time to peak arterial enhancement ranged from 2.0 to 7.0 s, with a median of 2.0 s. The time to peak portal venous enhancement ranged from 23.0 to 46.0 s, with a median of 32.0 s. Scan delay for arterial opacification ranged from 0 to 5.0 s, with a median of 0 s. Scan delay for the portal phase of opacification ranged from 6.0 to 21.0 s, with a median of 17.0 s. Using this information, two separate computed tomographic studies were used to image the arterial and portal venous phases of circulatory opacification, respectively. The dogs were hyperventilated to prevent breathing motion during the scan, each of which required approximately 20 s. A power injector was used to inject diatrizoate meglumine (128 mg I/kg) through an 18-gauge cephalic vein catheter at a rate of 5 ml/s. Scanning was initiated after the appropriate scan delay to optimize the specific phase of vascular filling. Maximum intensity projections allowed clear delineation of the hepatic arteries and the portal venous system, while eliminating overlying structures that might interfere with image analysis. Time/density curves were generated, and the time needed for each study was recorded. Hepatic arteries and portal veins were clearly visualized in all dogs. Parenchymal opacification was also observed.

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.

Multidetector Row CT of the Liver

CT has always played a major role in the imaging of the liver despite continuous challenge by ultrasound and MR imaging. Introduction of multidetector row CT technology has helped CT to excel in its already established indications and has expanded its capabilities by adding new clinical indications, such as CT angiography or liver perfusion. This article discusses the advantages of multidetector row CT scanners in liver imaging, examines the guidelines to improve image quality by optimizing scanning protocols and contrast administration strategies, and reviews the current and potential clinical applications.

Multi-detector computed tomography angiography of the hepatic artery in liver transplant recipients

PURPOSE

To evaluate the ability of multi-detector row computed tomography angiography (CTA) in detecting hepatic artery complications in the follow-up of liver transplant patients, performing volume-rendering as reconstruction technique.

MATERIAL AND METHODS

The anatomy of hepatic artery was studied in 27 liver transplant recipients with a four-row CT scanner using the following parameters: collimation, 1 mm; slice width, 1 mm; table feed, 6-8 mm/s; spiral reconstruction time, 0.5 s; reconstruction interval, 0.5 mm; mAs, 160; kVp, 120. Before the study, the patients received 1000 ml of water as oral contrast agent to produce negative contrast in the stomach and the small bowel. A non-ionic contrast medium was infused intravenously at a rate of 5 ml/s with a bolus tracking system. Volume-rendering of hepatic artery was performed with the 3D Virtuoso software.

RESULTS

The celiac trunk, the hepatic artery, and the right and left hepatic arteries were successfully displayed in high detail in all patients. Side branches, including small collaterals, and hepatic artery anastomosis could also be readily visualized. Volume-rendered CTA detected six hepatic artery stenoses, two hepatic artery thromboses, and two intrahepatic pseudoaneurysms. In two cases, CT detected hepatic artery stenosis with a diameter reduction of less than 50%, while digital subtraction angiography showed a normal artery.

CONCLUSION

Volume-rendered multi-detector CTA is a promising non-invasive technique, since it allows images of high quality to be generated with excellent anatomical visualization of the hepatic artery and its complications in liver transplant recipients.

Diagnostic Value of Gadolinium-Enhanced 3D Magnetic Resonance Angiography in Patients With Suspected Hepatic Arterial Complications After Liver Transplantation

PURPOSE

To evaluate the accuracy and clinical role of gadolinium-enhanced 3D magnetic resonance angiography (MRA) in patients with suspected hepatic arterial complications after liver transplantation.

MATERIALS AND METHODS

Thirty-six consecutive MRA studies were performed in 33 liver transplant recipients after transplantation. MRA image quality was assessed subjectively. Thirty-two MRA studies were retrospectively reviewed and correlated with surgery (n = 2), conventional angiography (n = 18), or clinical follow-up (n = 12). MRA findings were also correlated with those of Doppler sonography in 30 of the cases. In 20 cases, concordance between MRA and surgery or conventional angiography was evaluated for each grade of hepatic artery stenosis (normal, mild [<50%], moderate [50-75%], severe [>75%], or occluded).

RESULTS

MRA image quality was degraded 13 of 36 cases (36.1%) studies. The sensitivity, specificity, and accuracy of MRA by consensus reading for more than 50% of hepatic artery stenosis or occlusion were 67%, 90%, and 81.3%, respectively. Of the 19 cases in which Doppler sonography was abnormal, MRA correctly characterized hepatic artery stenosis in 16 (84.2%). MRA also correctly identified all 5 occurrences of celiac artery stenosis. However, MRA overestimated the severity of hepatic arterial stenosis in 3 (15%) of 20 cases and underestimated 5 (25%) of 20 cases.

CONCLUSION

MRA complements Doppler ultrasound to exclude significant hepatic artery stenosis. However, a substantial number of MRA studies were technically inadequate, and MRA demonstrated limited efficacy for correctly grading the severity of hepatic artery stenosis.

Hepatic artery pseudoaneurysms in adult living-donor liver transplantation: efficacy of CT and Doppler sonography

OBJECTIVE

The purpose of this study was to evaluate the efficacy of contrast-enhanced CT and Doppler sonography in the diagnosis of hepatic artery pseudoaneurysm after adult living-donor liver transplantation (LDLT).

CONCLUSION

Because patients with hepatic artery pseudoaneurysm after LDLT can have diverse clinical presentations, routine imaging follow-up is important for early detection. Although Doppler sonography is limited in showing the pseudoaneurysm, contrast-enhanced CT, especially MDCT with CT arteriography, is effective in showing it in most patients.

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.

CO2 Splenoportography for Evaluating the Splenic and Portal Veins before or after Liver Transplantation

The authors report their experience with CO(2) splenoportography in a retrospective review of 15 studies performed in 13 patients before or after liver transplantation. The studies were performed by injecting CO(2) through a small caliber needle introduced into the splenic parenchyma with ultrasound guidance and imaging with conventional digital subtraction techniques. The findings were compared with clinical follow-up and other imaging studies when available. Eight of the 15 studies were normal, of which two were confirmed by additional studies. Six of the 15 studies were abnormal, all of which were compared with additional studies. There was one nondiagnostic study and two false positives. There were no reported complications. The authors' experience suggests that CO(2) splenoportography is a minimally invasive method for safely and accurately evaluating the splenic and portal veins.

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.

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.