The role of ultrasound and magnetic resonance cholangiopancreatography for the diagnosis of biliary stricture after liver transplantation

Coronavirus Disease in the Abdomen

Numerous abdominal manifestations have been reported in patients with coronavirus disease 2019 (COVID-19), including involvement of the luminal gastrointestinal (GI) tract, hepatobiliary system, pancreas, kidneys, spleen, and blood vessels. Although most of the associated radiological abnormalities are nonspecific without distinguishing imaging features to suggest COVID-19, unique presentations such as findings of bowel ischemia preceding gross findings of bowel necrosis have been reported. Awareness of the spectrum of abdominal manifestations of COVID-19 allows radiologists to optimize their search pattern and to raise the possibility of this etiology when appropriate. Awareness of the possible abdominal manifestations of COVID-19 should enhance detection by radiologists and improve patient care. This review provides a comprehensive overview with illustrative imaging examples of COVID-19 in the abdomen.

Endoscopic retrograde cholangiopancreatography and liver biopsy in the evaluation of elevated liver function tests after liver transplantation

BACKGROUND

Abnormal liver function tests (LFTs) in post-liver transplant (LT) patients pose a challenge in the timing and selection of diagnostic modalities. There are little data regarding the accuracy of endoscopic retrograde cholangiopancreatography (ERCP) and liver biopsy (LB) in diagnosing post-transplant complications.

AIM

To evaluate the diagnostic performance of ERCP and LB in patients with non-vascular post-LT complications.

METHODS

This single-center retrospective study evaluated patients undergoing both ERCP and LB for evaluation of elevated LFTs within 6 mo of LT from 2000 to 2017. Diagnostic operating characteristics including accuracy, sensitivity and specificity for various diagnoses were calculated for ERCP and LB. The R factor (ratio of alkaline phosphatase to alanine aminotransferase) was also calculated for each patient.

RESULTS

Of the 1284 patients who underwent LT, 91 patients (74.7% males, mean age of 51) were analyzed. Anastomotic strictures (AS, 24.2%), acute cellular rejection (ACR, 11%) and concurrent AS/ACR (14.3%) were the most common diagnoses. ERCP carried an accuracy of 79.1% (95%CI: 69.3-86.9), LB had an accuracy of 93.4% (95%CI: 86.2-97.5), and the combination of the two had an accuracy of 100% (95%CI: 96-100). There was no difference between patients with AS and ACR in mean R factor (AS: 1.9 vs ACR: 1.1, P = 0.24). Adverse events did not differ between the two tests (ERCP: 3.1% vs LB: 1.1%, P = 0.31).

CONCLUSION

In patients with abnormal LFTs after LT without vascular complications, the combination of LB and ERCP carries low risk and improves diagnostic accuracy over either test alone.

Subclinical biliary strictures as a cause of long-term allograft dysfunction in children who underwent liver transplantation

We aimed to evaluate the role of liver biopsy to predict subclinical biliary strictures (BS) and assess the impact of BS on long-term allograft dysfunction following liver transplantation in children (LT). We reviewed all liver biopsies performed from 2012-2018. Percutaneous transhepatic cholangiography (PTC) was performed in patients presenting cholangiolar proliferation on cytokeratin-7 stained sections. We performed 271 biopsies in 161 children (86% with a left lateral segment); 44/161 (27%) presented with diffuse or multifocal cholangiolar proliferation. Among them, a tight BS was confirmed in 38/44 (86%, 24% of total) and it was managed by balloon dilatation. Cholangiolar proliferation showed a positive predictive value (PPV) for BS of 86.4%. Levels of alkaline phosphatase >325 IU/L predicted BS (P = .007). Dilatation of intrahepatic bile ducts on ultrasound was found only in 44% of patients with BS. Following a median follow-up of 9.2 years, only 15/38 (39%) patients resolved the BS. In conclusion subclinical BS is very common and probably underdiagnosed in these patients. Histological evidence of cholangiolar proliferation detectable by cytokeratin-7 immunostain should be preferred to liver function tests and ultrasound to suspect BS. BS in this setting should be regarded as a main cause of long-term allograft dysfunction.

Can ultrasonography differentiate anastomotic and non-anastomotic biliary strictures after orthotopic liver transplantation- a single-center experience

PURPOSE

To evaluate the role of ultrasonography (US) in differentiating anastomotic biliary strictures (AS) and non-anastomotic biliary strictures (NAS) after orthotopic liver transplantation (OLT).

METHOD

This retrospective study included 1259 OLT recipients between 2005-2018. Seventy-six with anastomotic strictures (AS) and 103 with non-anastomotic strictures (NAS) were analyzed. The reference standard was cholangiography. The sensitivity, specificity, accuracy of US was evaluated.

RESULTS

There were significant differences between AS and NAS groups (p < 0.001) for skipped and irregular dilatation of intrahepatic bile duct and visualization of hilar biliary lumen. The better US imaging feature for NAS was poorly visualized and non- visible hilar bile duct luminal contour. The sensitivity, specificity and accuracy were 94.2 %, 84.2 % and 88.9 % respectively. Combined two predictors greatly increased the specificity to 93.4 % while diminished its sensitivity and accuracy.

CONCLUSION

US is useful and efficient to differentiate AS and NAS after OLT.

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.

Role of MRCP in Diagnosing Biliary Anastomotic Strictures After Liver Transplantation: A Single Tertiary Care Center Experience

BACKGROUND

Biliary strictures (BS) are common complication after liver transplantation. We aimed to determine the accuracy of magnetic resonance cholagiopancreatography (MRCP) in diagnosing BS in liver transplant recipients (LTRs) when compared to direct cholangiographic methods (endoscopic resonance cholagiopancreatography [ERCP] and/or percutaneous transhepatic cholangiography [PTC]).

METHODS

Retrospective chart review of 910 LTRs (July 2008 to April 2015) was performed, and a total of 39 patients with duct-to-duct anastomosis (22 males; 56.4%; mean age, 52.8 ± 8.3 years) were included who had an MRCP followed by either ERCP and/or PTC within 4 weeks. A cholangiographic narrowing (on ERCP and/or PTC) that required balloon dilation and/or stent placement was considered a BS and was considered clinically significant if the intervention resulted in at least 30% improvement of bilirubin within 2 weeks. Sensitivity, specificity, accuracy, positive predictive values and negative predictive values of MRCP in diagnosing BS were calculated.

RESULTS

Magnetic resonance cholagiopancreatography showed anastomotic BS in 17 of 39 patients, and subsequent ERCP and/or PTC revealed a total of 25 BS (positive predictive value of 0.94). Nine BS on cholangiography (ERCP, 8; PTC, 1) were not detected on earlier MRCP (sensitivity, 0.64; 95% CI, 0.45-0.82); 2 were clinically significant BS and 6 of the remaining 7 had no improvement in their liver function test with biliary intervention. Thirteen LTRs had no BS on either modality (specificity, 0.93; 95% CI, 0.66-0.99). The negative predictive value of MRCP was 0.59 for cholangiographic BS. The overall accuracy of MRCP is 0.74 (exact 95% CI, 0.58-0.87). Inclusion of age, race, and alanine aminotransferase level improved the predictive value of MRCP (area under the curve = 0.94, 95% CI: 0.86-1.00).

CONCLUSIONS

Magnetic resonance cholagiopancreatography has high specificity but low sensitivity in diagnosing cholangiographic BS in LTRs, although the predictive value further improved with inclusion of age, race, and alanine aminotransferase. Clinical significance of BS in LTRs not identified on MRCP is questionable because ERCP with intervention did not improve their liver function tests in the vast majority.

Benign Biliary Strictures

Differentiating benign and malignant biliary strictures is a challenging and important clinical scenario. The typical presentation is indolent and involves elevation of liver enzymes, constitutional symptoms, and obstructive jaundice with or without superimposed or recurrent cholangitis. While overall the most common causes of biliary strictures are malignant, including cholangiocarcinoma and pancreatic adenocarcinoma, benign strictures encompass a wide spectrum of etiologies including iatrogenic, autoimmune, infectious, inflammatory, and congenital. Imaging plays a crucial role in evaluating strictures, characterizing their extent, and providing clues to the ultimate source of biliary obstruction. While ultrasound is a good screening tool for biliary ductal dilatation, it is limited by a poor negative predictive value. Magnetic resonance cholangiopancreatography is more than 95% sensitive and specific for detecting biliary strictures with the benefit of precise anatomic localization. Other commonly employed imaging modalities include endoscopic retrograde cholangiopancreatography with endoscopic ultrasound, contrast-enhanced CT, and cholangiography. First-line treatment of benign biliary strictures is endoscopic dilation and stenting. In patients with anatomy that precludes endoscopic cannulation, percutaneous biliary drain insertion and balloon dilation is preferred.

Accuracy of Hepatobiliary Scintigraphy after Liver Transplantation and Liver Resection

Background and Aims. Biliary complications are the most frequent complications after common liver surgeries. In this study, accuracy of hepatobiliary scintigraphy (HBS) and impact of hyperbilirubinemia were evaluated. Methods. Between November 2007 and February 2016, 131 patients underwent hepatobiliary scintigraphy after having liver surgery. 39 patients with 42 scans after LTX (n = 13) or hepatic resection (n = 26) were evaluated in the study; 27 were male, with mean age 60 years. The subjects underwent hepatobiliary scintigraphy with Tc-99m labeled Mebrofenin. The results were compared to ERCP as gold standard performed within one month after HBS. We calculated sensitivity, specificity, PPV, and NPV. We compared LTX patients to patients with other liver surgeries. Furthermore the influence of hyperbilirubinemia on HBS scans was evaluated. Results. HBS always provided the correct diagnosis in cases of bile leak in the liver-resected group (14/14). Overall diagnostic accuracy was 76% (19/25) in this group and 54% (7/13) in the LTX group. False negative (FN) diagnoses occurred more often among LTX patients (p = 0.011). Hyperbilirubinemia (>5 mg/dL) significantly influenced the excretion function of the liver, prolonging HBS's time-activity-curve (p = 0.001). Conclusions. Hepatobiliary scintigraphy is a reliable tool to detect biliary complications, but reduced accuracy must be considered after LTX.

Nonvascular post-liver transplantation complications: from US screening to cross-sectional and interventional imaging

Orthotopic liver transplantation is becoming an increasingly routine procedure for a variety of benign and malignant diseases of the liver and biliary system. Continued improvements in surgical techniques and post-transplantation immunosuppression regimens have resulted in better graft and patient survival. A number of potentially treatable nonvascular complications of liver transplantation are visible at imaging, and accurate diagnosis of these complications allows patients to benefit from potential treatment options. Biliary complications include stricture (anastomotic and nonanastomotic), leak, biloma formation, and development of intraductal stones. Pathologic conditions, including hepatitis C infection, hepatocellular carcinoma, hepatic steatosis, and primary sclerosing cholangitis, may recur after liver transplantation. Transplant patients are at increased risk for developing de novo malignancy, including post-transplantation lymphoproliferative disorder, which results from immunosuppression. Patients are also at increased risk for systemic infection from immunosuppression, and patients with hepatic artery and biliary complications are at increased risk for liver abscess. Transplant recipients are typically followed with serial liver function testing; abnormal serum liver function test results may be the first indication that there is a problem with the transplanted liver. Ultrasonography is typically the first imaging test performed to try to identify the cause of abnormal liver function test results. Computed tomography, magnetic resonance imaging, angiography, and/or cholangiography may be necessary for further evaluation. Accurately diagnosing nonvascular complications of liver transplantation that are visible at imaging is critically important for patients to benefit from appropriate treatment.

Endoscopic management of post-liver transplant biliary complications

Biliary complications are being increasingly encountered in post liver transplant patients because of increased volume of transplants and longer survival of these recipients. Overall management of these complications may be challenging, but with advances in endoscopic techniques, majority of such patients are being dealt with by endoscopists rather than the surgeons. Our review article discusses the recent advances in endoscopic tools and techniques that have proved endoscopic retrograde cholangiography with various interventions, like sphincterotomy, bile duct dilatation, and stent placement, to be the mainstay for management of most of these complications. We also discuss the management dilemmas in patients with surgically altered anatomy, where accessing the bile duct is challenging, and the recent strides towards making this prospect a reality.

Endoscopic ultrasound: valuable tool for diagnosis of biliary complications in liver transplant recipients?

BACKGROUND

Biliary complications after liver transplantation (LT) are still common and are an important cause of mortality and morbidity. Until now, endoscopic retrograde cholangiopancreatography (ERCP) has been considered the gold standard for diagnosing such complications. The aim of this study was to evaluate the diagnostic yield and therapeutic impact of endoscopic ultrasound (EUS) in the management of biliary complications after LT.

METHODS

Thirty-seven liver transplant patients who presented with clinical, biochemical, sonographic, and/or histological evidence of biliary complications, and who first received EUS followed by ERCP, were enrolled into this prospective observational study. Subsequently, we evaluated the value of EUS in detecting and classifying biliary complications after LT.

RESULTS

Thirty-seven biliary complications were detected in 32 patients. Endoscopic ultrasound showed an overall sensitivity and accuracy of 94.6 % each. In cases of biliary cast and ischemic cholangiopathy, EUS was found to be diagnostically superior to ERCP and has had, in these cases, a significant impact on clinical decision-making. However, EUS was less reliable when diagnosing anastomotic strictures.

CONCLUSION

EUS can complement ERCP to improve diagnosis of biliary complications after LT and help guide treatment strategies to address these complications.

Diagnosis and management of biliary complications in pediatric living donor liver transplant recipients

The incidence of biliary complications (BCs) after living donor liver transplantation (LDLT) can reach 40%. Published data on the pediatric population are limited, and treatment protocols vary. Our aim was to describe the clinical scenario for BCs and treatment approaches after LDLT. Between October 1995 and December 2012, 489 pediatric LDLT procedures were performed. BCs developed in 71 patients (14.5%). Biliary strictures (BSs) developed in 45 (9.2%) patients, and bile leaks (BLs) developed in 33 patients (6.7%). The BL diagnosis was clinical in all cases, and 69.7% of the patients underwent surgery. Nearly half of the BS cases had clinical features or suggestive ultrasound findings. Liver biopsy findings suggested BSs in 51.7%. Percutaneous transhepatic cholangiography was performed in 95.6% of the BS patients. The success rate was 77% [mean number of percutaneous biliary interventions (PBIs) = 3.9 ± 1.98, median drainage time = 8 months]. In conclusion, BL patients can be managed with conservative therapy, even though most of these patients will ultimately be treated with surgery. Diagnosing a BS requires a high degree of clinical suspicion because the available resources for its identification can fail in up to 50% of cases. A higher number of PBIs and the use of a drainage catheter for a longer time may be required to achieve better results with this technique.