Role of contrast-enhanced ultrasound in decision support for diagnosis and treatment of hepatic artery thrombosis after liver transplantation

Ultrasound innovations in abdominal radiology: multiparametic imaging in liver transplantation

PURPOSE

Ultrasound plays a central role in liver transplant evaluation. Acute, subacute, and chronic complications can be readily identified using grayscale and color Doppler ultrasound. Contrast-enhanced ultrasound adds a new dimension to liver transplant evaluation, depicting vascular and parenchymal processes with exquisite detail. In addition, emerging evidence suggests that contrast-enhanced ultrasound may allow for localization of biliary leak in select patients. We aimed to assess the use of multiparametric ultrasound-including grayscale, color and spectral Doppler, and contrast-enhanced ultrasound-in the setting of liver transplantation.

METHODS

A literature review was performed using the MEDLINE bibliographic database through the National Library of Medicine. The following terms were searched and relevant citations assessed: "abdominal ultrasound," "contrast-enhanced ultrasound," "liver transplant," and "ultrasound."

RESULTS

Grayscale and color Doppler ultrasound represent the mainstay imaging modalities for postoperative liver transplant evaluation. The addition of contrast enhancement plays a complementary role and can provide valuable information related to the allograft vasculature, parenchyma, and biliary tree. The appropriate implementation of grayscale, color Doppler, and contrast-enhanced ultrasound can optimize sensitivity, specificity, and accuracy for the detection of liver transplantation complications, including hepatic artery stenosis, biliary leakage, and infection.

CONCLUSION

Multimodal sonographic evaluation is essential to identify postoperative complications in liver transplant recipients. Contrast-enhanced ultrasound may be of value in challenging cases, providing excellent anatomic delineation and reducing the risk of false-positive and false-negative diagnoses. A broad familiarity with appropriate applications of both nonenhanced and contrast-enhanced ultrasound may help radiologists optimize allograft assessment and improve patient outcomes.

Prognostic value of ultrasound in early arterial complications post liver transplant

Liver transplantation is the primary therapeutic intervention for end-stage liver disease. However, vascular complications, particularly those involving the hepatic artery, pose significant risks to patients. The clinical manifestations associated with early arterial complications following liver transplantation are often nonspecific. Without timely intervention, these complications can result in graft failure or patient mortality. Therefore, early diagnosis and the formulation of an optimal treatment plan are imperative. Ultrasound examination remains the predominant imaging modality for detecting complications post liver transplantation. This article comprehensively reviews common causes and clinical presentations of early hepatic artery complications in the post-transplantation period and delineates abnormal sonographic findings for accurate diagnosis of these conditions. Overall, ultrasound offers the advantages of convenience, safety, effectiveness, and non-invasiveness. It enables real-time, dynamic, and precise evaluation, making it the preferred diagnostic method for post-liver transplantation assessments.

Diagnostic performance of contrast-enhanced ultrasound in diagnosing hepatic artery occlusion after liver transplantation: A systematic review and meta-analysis

INTRODUCTION

Hepatic artery occlusion (HAO) is a significant complication post-liver transplantation. Doppler ultrasound (DUS) has been widely used as an initial screening test for detecting HAO; however, its performance is often not sufficient. Although other diagnostic tests such as computed tomography angiography (CTA), magnetic resonance angiography (MRA), and angiogram are more accurate, they are invasive and have several limitations. Contrast-enhanced ultrasound (CEUS) is an emerging tool for detecting HAO; however, the results from previous studies were limited due to a small number of patients. Therefore, we aimed to evaluate its performance by performing a meta-analysis.

METHOD

We performed a systemic review and meta-analysis of studies evaluating the performance of CEUS for the detection of HAO in an adult population. A literature search of EMBASE, Scopus, CINAHL, and Medline was conducted through March 2022. Pooled sensitivity, specificity, log diagnostic odd ratio (LDOR), and area under summary receiver operating curve (AUC) were calculated. Publication bias was assessed by Deeks' funnel plot.

RESULT

Eight studies were included, with 434 CEUS performed. Using a combination of CTA, MRA, angiography, clinical follow-up, and surgery as the gold standard, the sensitivity, specificity, and LDOR of CEUS for detection of HAO were .969 (.938, .996), .991 (.981, 1.001), and 5.732 (4.539, 6.926), respectively. AUC was .959. The heterogeneity between studies appeared universally low, and no significant publication bias was found (p = .44).

CONCLUSION

CEUS appeared to have an excellent performance for the detection of HAO and could be considered as an alternative when DUS is non-diagnostic or when CTA, MRA, and angiogram are not feasible.

Secondary sclerosing cholangitis and IgG4-sclerosing cholangitis - A review of cholangiographic and ultrasound imaging

Sclerosing cholangitis (SC) represents a spectrum of chronic progressive cholestatic diseases of the intrahepatic and/or extrahepatic biliary system characterized by patchy inflammation, fibrosis, and stricturing. Primary and secondary SC must be distinguished given the different treatment modalities, risks of malignancy, and progression to portal hypertension, cirrhosis, and hepatic failure. This review focuses on secondary SC and the pathogenic mechanisms, risk factors, clinical presentation, and novel imaging modalities that help to distinguish between these conditions. We explore the detailed use of cholangiography and ultrasound imaging techniques.

Contrast-enhanced ultrasound of transplant organs - liver and kidney - in children

Ultrasound (US) is the first-line imaging tool for evaluating liver and kidney transplants during and after the surgical procedures. In most patients after organ transplantation, gray-scale US coupled with color/power and spectral Doppler techniques is used to evaluate the transplant organs, assess the patency of vascular structures, and identify potential complications. In technically difficult or inconclusive cases, however, contrast-enhanced ultrasound (CEUS) can provide prompt and accurate diagnostic information that is essential for management decisions. CEUS is indicated to evaluate for vascular complications including vascular stenosis or thrombosis, active bleeding, pseudoaneurysms and arteriovenous fistulas. Parenchymal indications for CEUS include evaluation for perfusion defects and focal inflammatory and non-inflammatory lesions. When transplant rejection is suspected, CEUS can assist with prompt intervention by excluding potential underlying causes for organ dysfunction. Intracavitary CEUS applications can evaluate the biliary tract of a liver transplant (e.g., for biliary strictures, bile leak or intraductal stones) or the urinary tract of a renal transplant (e.g., for urinary obstruction, urine leak or vesicoureteral reflux) as well as the position and patency of hepatic, biliary and renal drains and catheters. The aim of this review is to present current experience regarding the use of CEUS to evaluate liver and renal transplants, focusing on the examination technique and interpretation of the main imaging findings, predominantly those related to vascular complications.

Initial experience with contrast-enhanced ultrasound in the first week after liver transplantation in children: a useful adjunct to Doppler ultrasound

BACKGROUND

Doppler US is the primary screening for post-liver transplant vascular complications, but indeterminate findings require further imaging.

OBJECTIVE

To evaluate whether contrast-enhanced US improves diagnostic assessment of vascular complications suspected by Doppler US.

MATERIALS AND METHODS

We retrospectively reviewed Doppler US and contrast-enhanced US studies obtained in the first week following liver transplant. Doppler US was performed twice daily for the first 5 postoperative days, and CEUS in the first postoperative day and when vascular complications were suspected. We correlated Doppler US and CEUS with surgical findings, and clinical and imaging follow-up. We evaluated Doppler US and CEUS quality in demonstrating the main hepatic artery (HA) at the porta hepatis as follows: Grade 0 = not seen, Grade 1 = only segments, Grade 2 = entire main HA, and Grade 3 = entire main HA to the intrahepatic branching. We used a Wilcoxon signed rank test to test the difference between Doppler US and CEUS methods.

RESULTS

Twenty-nine children (15 girls, 14 boys) were identified, with median age 2.2 years (range 0.5-17.6 years). The most common transplant indication was biliary atresia (n=13). There was significantly (P<0.0001) improved main HA visualization with CEUS. In five children, CEUS was performed to evaluate suspected vascular complications; CEUS confirmed normal vascularity in two. CEUS demonstrated portal vein thrombosis (n=2) and main HA thrombosis (n=1), confirmed at surgery. In one child the main HA thrombosis was missed; marked HA narrowing was seen retrospectively on CEUS.

CONCLUSION

Immediately following liver transplantation, CEUS improves main HA visualization and diagnostic assessment of vascular complications.

Contrast-enhanced ultrasound applications in liver transplant imaging

Contrast-enhanced ultrasound (CEUS) is gaining ever-increasing acceptance in the preoperative and postoperative evaluation of liver-transplanted patients. While indications are still a matter of research, CEUS is used in tertiary centers to supplement ultrasound (US) and Color Doppler US examination, with the potential of providing a comprehensive first-line ultrasound-based diagnosis. Alternatively, CEUS is used as a problem-solving tool when previous cross-sectional or US imaging was inconclusive, especially in assessing hepatocellular carcinoma, parenchymal perfusion abnormalities, the vascular status, and even the biliary tree. This review describes the potential use for CEUS in the setting of orthotopic liver transplantation (OLT).

Additional value of superb microvascular imaging for assessing hepatic arterial blood flow after pediatric liver transplantation

BACKGROUND

The aim of this study was to explore the value of SMI compared with conventional ultrasonography for assessing hepatic arterial blood flow after pediatric liver transplantation.

METHODS

From March 2018 to November 2018, a total of 105 pediatric recipients with biliary atresia underwent liver transplantation in our hospital. Ultrasound examinations were performed at the bedside in the intensive care unit to check the patency of the blood flow in the hepatic allograft. CDI, PDI, cSMI, and mSMI were performed to assess the display, orientation, and distribution of the graft hepatic artery. Ultrasound examinations were performed by one radiologist, and the images were judged by two observers.

RESULTS

The median age, weight, and height of the recipients were 6.97 (5.92, 9.58) months, 6.50 (6.00, 7.80) kg, and 64.00 (62.00, 68.00) cm, respectively. The measure of kappa agreement was 0.902, 0.889, 0.882, and 0.882 for CDI, PDI, cSMI, and mSMI, respectively. HAT occurred in 7 pediatric recipients and was confirmed by CTA (computed tomography angiography) and surgery. The diagnostic performance of sensitivity, specificity, PPV (positive predictive value), NPV (negative predictive value), and accuracy were 100%, 92.86%, 50%, 100%, and 93.33% for CDI and 100%, 98.98%, 87.50%, 100%, and 99.05% for SMI.

CONCLUSIONS

As an additional method to CDI, SMI can clearly show the distribution of hepatic arterial blood flow and provide more details, thereby markedly improving the diagnostic performance of postoperative HAT.

Innovations in Vascular Ultrasound

There are several vascular ultrasound technologies that are useful in challenging diagnostic situations. New vascular ultrasound applications include directional power Doppler ultrasound, contrast-enhanced ultrasound, B-flow imaging, microvascular imaging, 3-dimensional vascular ultrasound, intravascular ultrasound, photoacoustic imaging, and vascular elastography. All these techniques are complementary to Doppler ultrasound and provide greater ability to visualize small vessels, have higher sensitivity to detect slow flow, and better assess vascular wall and lumen while overcoming limitations color Doppler. The ultimate goal of these technologies is to make ultrasound competitive with computed tomography and magnetic resonance imaging for vascular imaging.

Hepatic Artery Occlusion after Liver Transplantation in Patients with Doppler Ultrasound Abnormality: Increasing Sensitivity of Contrast-Enhanced Ultrasound Diagnosis

OBJECTIVE

To investigate whether diagnostic performance of contrast-enhanced ultrasound (CEUS) could be improved with modified criteria to diagnose significant hepatic artery occlusion (HAO) and to determine the role of CEUS in patients with a tardus-parvus hepatic artery (HA) pattern on Doppler US.

MATERIALS AND METHODS

Among 2679 adult liver transplantations performed over 7 years, HAO was suspected in 288 recipients, based on Doppler ultrasound. Among them, 130 patients underwent CEUS. After excluding two technical failures, 128 CEUS images were retrospectively reviewed to search for abnormal findings, such as no HA enhancement, abnormal HA enhancement (delayed, faint, and discontinuous enhancement), and perfusion defect in the liver parenchyma. The performance CEUS abnormalities were assessed in the patients overall and in subgroups based on Doppler ultrasound abnormality (group A, no flow; group B, tardus-parvus pattern) and were compared based on the area under the receiver operating characteristic curve (AUC).

RESULTS

HAO were diagnosed in 41 patients by surgery, angiography, or follow-up abnormality. By using the conventional criterion (no HA enhancement) to diagnose HAO in patients overall, the sensitivity, specificity, and AUC were 58.5%, 100%, and 0.793, respectively. Modified criteria for HAO (no HA enhancement, abnormal enhancement, or parenchymal perfusion defect) showed statistically significantly increased sensitivity (97.6%, 40/41) and AUC (0.959) (p < 0.001), although the specificity (95.4%, 83/87) was slightly decreased. The sensitivity and specificity of the modified criteria in Groups A and B were 97.1% (33/34) and 95.7% (22/23), and 100% (7/7) and 95.3% (61/64), respectively.

CONCLUSION

Modified criteria could improve diagnostic performance of CEUS for HAO, particularly by increasing sensitivity. CEUS could be useful for diagnosing HAO even in patients with a tardus-parvus HA pattern on Doppler US, using modified criteria.

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.

Contrast-enhanced ultrasonography - An indispensable tool in the hands of any hepatologist

Vascular complications after liver transplantation may lead to graft dysfunction and liver failure, which in turn results in need for retransplantation and death risk. Therefore, their early diagnosis is critical. Major vascular complications include hepatic artery thrombosis, stenosis and aneurysms; portal vein thrombosis and stenosis; and potential additional complications in hepatic veins and vena cava. Of all these vascular complications hepatic arterial thrombosis, which involves approximately 5% of transplant recipients, is most significant. Portal complications, which are second in significance, are less common (2%).

Contrast-Enhanced Ultrasound for identifying circulatory complications after liver transplants in children

Our main goal with this study was to share our off-label experience with CEUS for identifying circulatory complications after liver transplantation in children. A total of 74 CEUS examinations performed on 34 pediatric patients who underwent a liver transplant were retrospectively included. About 53% of the examinations were performed on children 2 years old or younger. About 82% of the examinations were performed within 30 days from the transplant. About 62% of patients were transplanted due to a cholestatic disease, 11% due to a metabolic disease, 8% were re-transplanted due to graft failure, and 19% was due to other conditions. BA was the most common reason for transplantation and represented 38% of patients. About 38% of the transplantations were performed with whole grafts from DD, 40% with split liver grafts, and 22% with left lateral segments from LD. For diagnosing arterial circulatory complications, the PPV was 80%. For diagnosing portal vein circulatory complications, the PPV was 66.7%. NPV was 100%. In 28% of the examinations, the examiner could not visualize the normal arterial blood flow without CEUS. CEUS is a non-invasive and safe imaging technique that seems valuable in these patients and further efforts are needed to license its use in the post-transplant setting.

Meta-analysis of the diagnostic value of contrast-enhanced ultrasound for the detection of vascular complications after liver transplantation

BACKGROUND

contrast-enhanced ultrasound (CEUS) is increasingly used to identify vascular complications in patients after liver transplantation. The present study aimed to evaluate the diagnostic accuracy of CEUS using all available data.

MATERIALS AND METHODS

relevant studies published before February 2018 were retrieved from PubMed, EMBASE, ScienceDirect and Web of Science. Pooled sensitivity and specificity, diagnostic odds ratio (DOR) and summary receiver operating characteristic curve (SROC) were calculated to estimate the diagnostic performance of CEUS for vascular complications. Sensitivity analysis was performed that stratified studies according to age, study design and sample size in order to determine the influence of these factors on the overall effect. Meta-regression analyses were performed to examine the possible sources of heterogeneity. Quality assessment and publication bias of the included studies were also evaluated.

RESULTS

thirteen studies which consisted of 2,781 CEUS cases were included in the analysis. The pooled weighted estimates of sensitivity and specificity were 0.90 (95% CI, 0.84 to 0.95) and 1.00 (95% CI, 1.00 to 1.00), the diagnostic odds ratio (DOR) was 431.96 (95% CI, 164.60 to 1,133.59) and the area under the curve (AUC) of SROC was 0.9741. According to the sensitivity analysis, age, study design and sample size had an insignificant influence on the diagnostic performance of CEUS. The meta-regression analyses did not reveal a strong correlation between CEUS accuracy and study design, treatment time of patients and experience of the radiologists.

CONCLUSION

the results of our meta-analysis showed a high sensitivity, specificity and accuracy of the CEUS modality for the identification of vascular complications in patients after liver transplantation. Since this is the first meta-analysis investigating in this aspect, more evidence is required to validate the clinical utility of CEUS for the identification of vascular complications in patients with a transplanted liver.

Diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in monitoring vascular complications in patients after liver transplantation - diagnostic performance compared with histopathological results

PURPOSE

To analyse the diagnostic performance of contrast-enhanced ultrasound (CEUS) in patients with vascular complications and transplant rejection compared to histopathological results.

MATERIALS AND METHODS

Our study consisted of 45 retrospectively analysed patients that underwent liver transplantations between January 1993 and December 2015 and developed post-transplant vascular complications with transplant rejection. CEUS examinations took place between September 2006 and December 2015. CEUS findings were correlated with histopathological results.

RESULTS

CEUS showed a sensitivity of 61.5%, a specificity of 100.0%, a positive predictive value (PPV) of 100.0% and a negative predictive value (NPV) of 86,5% in the detection of vascular complications with post-transplant rejection. 5 examinations were reported as normal whereas the histopathological result showed a transplant rejection (false-negative).

CONCLUSION

CEUS might be a useful additional non-invasive technique for the assessment of vascular complications with post-transplant rejection in patients after liver transplantation.

Imaging of liver transplantation

Liver transplantation (LT) is the treatment of choice for end-stage chronic liver disease, fulminant liver failure and early stage hepatocellular carcinoma. As discussed in this review, state-of-the-art imaging modalities including ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) play a pivotal role in the selection of patients and donors, as well as in early detection of those complications at risk of impairing graft function and/or survival. We also illustrate main imaging findings related to the wide spectrum of clinical problems raised by LT.

Evaluation of Liver Ischemia-Reperfusion Injury in Rabbits Using a Nanoscale Ultrasound Contrast Agent Targeting ICAM-1

OBJECTIVE

To assess the feasibility of ultrasound molecular imaging in the early diagnosis of liver ischemia-reperfusion injury (IRI) using a nanoscale contrast agent targeting anti-intracellular adhesion molecule-1 (anti-ICAM-1).

METHODS

The targeted nanobubbles containing anti-ICAM-1 antibody were prepared using the avidin-biotin binding method. Human hepatic sinusoidal endothelial cells (HHSECs) were cultured at the circumstances of hypoxia/reoxygenation (H/R) and low temperature. The rabbit liver IRI model (I/R group) was established using the Pringle's maneuver. The time-intensity curve of the liver contrast ultrasonographic images was plotted and the peak intensity, time to peak, and time of duration were calculated.

RESULTS

The size of the targeted nanobubbles were 148.15 ± 39.75 nm and the concentration was 3.6-7.4 × 109/ml, and bound well with the H/R HHSECs. Animal contrast enhanced ultrasound images showed that the peak intensity and time of duration of the targeted nanobubbles were significantly higher than that of common nanobubbles in the I/R group, and the peak intensity and time of duration of the targeted nanobubbles in the I/R group were also significantly higher than that in the SO group.

CONCLUSION

The targeted nanobubbles have small particle size, stable characteristic, and good targeting ability, which can assess hepatic ischemia-reperfusion injury specifically, noninvasively, and quantitatively at the molecular level.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Application of contrast-enhanced ultrasound after liver transplantation: Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents (UCAs), in combination with contrast-specific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and post-transplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrast-enhanced ultrasound applications in liver transplantation.

Contrast-Enhanced Sonography for Diagnosing Collateral Transformation of the Hepatic Artery After Liver Transplantation

OBJECTIVES

To determine the contrast-enhanced sonographic features of hepatic artery collateral transformation in patients with hepatic artery complications after liver transplantation.

METHODS

Ninety-nine liver transplant recipients who underwent contrast-enhanced sonography were recruited from April 2004 to May 2014. The reference standards were conventional angiography and computed tomographic angiography. The contrast-enhanced sonographic features of the hepatic artery in patients with and without collateral arteries were retrospectively analyzed.

RESULTS

All 15 patients with hepatic artery collateral transformation had hepatic artery thrombosis (10 of 15) or hepatic artery stenosis (5 of 15). The collateral artery detection rate on contrast-enhanced sonography was 100%. The peripheral hepatic artery could not be visualized by contrast-enhanced sonography in most of the patients with hepatic artery collateral transformation (14 of 15). Additionally, many small tortuous collateral arteries in the porta hepatis region were visualized during the arterial and early portal phases, showing reticulated/patchy (15 of 15) and striped (3 of 15) enhancement patterns on contrast-enhanced sonography.

CONCLUSIONS

Collateral transformation of the hepatic artery in patients with hepatic artery complications after liver transplantation appears to have characteristic features on contrast-enhanced sonography, especially a reticulated or patchy enhancement pattern in the porta hepatis region during the arterial and early portal phases combined with the absence of the peripheral hepatic artery. Contrast-enhanced sonography may be a novel method for diagnosing hepatic artery collateral transformation, which may be a highly specific sign of hepatic artery thrombosis or stenosis.

Impact of contrast-enhanced ultrasound in the study of hepatic artery hypoperfusion shortly after liver transplantation: contribution to the diagnosis of artery steal syndrome

OBJECTIVE

To assess the value of contrast-enhanced ultrasound (CEUS) in the absence of hepatic artery signal on Doppler ultrasound (DUS) in the immediate postoperative period after liver transplant.

METHODS

This prospective study included 675 consecutive liver transplants. Patients without hepatic artery signal by DUS within 8 days post-transplant were studied with CEUS. If it remained undetectable, a thrombosis was suspected. In patent hepatic artery, a DUS was performed immediately after CEUS; if low resistance flow was detected, an arteriography was indicated. Patients with high resistance waveform underwent DUS+/CEUS follow-up. Arteriography was indicated when abnormal flow persisted for more than 5 days or liver dysfunction appeared.

RESULTS

Thirty-four patients were studied with CEUS. In 11 patients CEUS correctly diagnosed hepatic artery thrombosis. In two out of 23 non-occluded arteries, a low resistance flow lead to a diagnosis of stenosis/proximal thrombosis. Twenty-one patients had absence of diastolic flow, which normalized in the follow-up in 13 patients. In the remaining eight patients, splenic artery steal syndrome (ASS) was diagnosed.

CONCLUSIONS

CEUS allows us to avoid invasive tests in the diagnostic work-up shortly after liver transplant. It identifies the hepatic artery thrombosis and points to a diagnosis of ASS.

KEY POINTS

• CEUS is useful in the diagnostic work-up shortly after liver transplant • CEUS identifies the hepatic artery thrombosis with reliability • There is little information about DUS and CEUS findings in the ASS • DUS and CEUS offer functional information useful in the diagnosis of ASS.

Minimally invasive endovascular and biliary treatments of children with acute hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis is a major problem after pediatric liver transplantation. Ischemia caused by hepatic artery thrombosis results in severe biliary and parenchymal damage and is associated with high rates of graft loss and mortality. We present a case-based pictorial essay to illustrate the role of minimally invasive treatment in the prompt management of acute hepatic artery thrombosis, and the associated biliary complications.

Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.