Endoscopic ultrasound versus magnetic resonance cholangiopancreatography for common bile duct stones

Role of endoscopic ultrasound in idiopathic pancreatitis

Recurrent acute pancreatitis (RAP) is defined based on the occurrence of two or more episodes of acute pancreatitis. The initial evaluation fails to detect the cause of RAP in 10%-30% of patients, whose condition is classified as idiopathic RAP (IRAP). Idiopathic acute pancreatitis (IAP) is a diagnostic challenge for gastroenterologists. In view of associated morbidity and mortality, it is important to determine the aetiology of pancreatitis to provide early treatment and prevent recurrence. Endoscopic ultrasound (EUS) is an investigation of choice for imaging of pancreas and biliary tract. In view of high diagnostic accuracy and safety of EUS, a EUS based management strategy appears to be a reasonable approach for evaluation of patients with a single/recurrent idiopathic pancreatitis. The most common diagnoses by EUS in IAP is biliary tract disease. The present review aims to discuss the role of EUS in the clinical management and diagnosis of patients with IAP. It elaborates the diagnostic approach to IAP in relation to EUS and other different modalities. Controversial issues in IAP like when to perform EUS, whether to perform after first episode or recurrent episodes, comparison among different investigations and the latest evidence significance are detailed.

Sensitivity and Specificity of Magnetic Resonance Cholangiopancreatography versus Endoscopic Ultrasonography against Endoscopic Retrograde Cholangiopancreatography in Diagnosing Choledocholithiasis: The Indonesian Experience

BACKGROUND/AIMS

Biliary stone disease is one of the most common conditions leading to hospitalization. In addition to endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) are required in diagnosing choledocholithiasis. This study aimed to compare the sensitivity and specificity of EUS and MRCP against ERCP in diagnosing choledocholithiasis.

METHODS

This retrospective study was conducted after prospective collection of data involving 62 suspected choledocholithiasis patients who underwent ERCP from June 2013 to August 2014. Patients were divided into two groups. The first group (31 patients) underwent EUS and the second group (31 patients) underwent MRCP. Then, ERCP was performed in both groups. Sensitivity, specificity, and diagnostic accuracy of EUS and MRCP were determined by comparing them to ERCP, which is the gold standard.

RESULTS

The male to female ratio was 3:2. The mean ages were 47.25 years in the first group and 52.9 years in the second group. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for EUS were 96%, 57%, 87%, 88%, and 80% respectively, and for MRCP were 81%, 40%, 68%, 74%, and 50%, respectively.

CONCLUSIONS

EUS is a better diagnostic tool than MRCP for diagnosing choledocholithiasis.

Routine Cysticotomy and Flushing of the Cystic Duct in Patients with Low Risk of Common Duct Stones: Can It Be Beneficial?

Background

Gallstone disease affects 15–20% of the general population and up to 20% of these patients present common bile duct stones.

Aim

This observational study reports our experience on routine cysticotomy and flushing of the cystic duct in patients with low risk of common duct stones.

Materials and Methods

We analyzed 731 patients who underwent laparoscopic cholecystectomy between September 2013 and September 2015.

Results

Patients were preoperatively stratified on the clinical risk; those presenting with low preoperative risk of common bile duct stones were referred to undergo laparoscopic cholecystectomy and routine cysticotomy with bile duct flushing. Patients presenting thick bile sludge, solid debrides, and/or increased tension of bile outflow underwent unplanned cholangiography. No intraoperative complications or conversion to open technique occurred. Average follow-up time was 22,8 months (range 12 to 37). Rate of retained ductal stones accounted for 0,3%.

Conclusions

Routine cysticotomy and bile flushing in our experience is a valid, simple, and not time consuming manoeuvre that can help decompressing and flushing CBD. Moreover, it is a valid tool for extending selective IOC approach in a focused manner. Further evaluations have to be conducted to evaluate risks and effectiveness of this manoeuvre.

Comparative performance of non-contrast MRI with HASTE vs. contrast-enhanced MRI/3D-MRCP for possible choledocholithiasis in hospitalized patients

PURPOSE

To compare the performance of non-contrast MRI with half-Fourier acquisition single-shot turbo spin echo (HASTE) vs. contrast-enhanced MRI/3D-MRCP for assessment of suspected choledocholithiasis in hospitalized patients.

METHODS AND MATERIALS

123 contrast-enhanced abdominal MRI/MRCP scans in the hospital setting for possible choledocholithiasis were retrospectively evaluated. Endoscopic retrograde cholangiopancreatography, intraoperative cholangiogram or documented clinical resolution served as the reference standard. Readers first evaluated the biliary tree using coronal and axial HASTE and other non-contrast sequences, and later reviewed the entire exam with post-contrast sequences and 3D-MRCP. Test performance for the image sets was compared for choledocholithiasis, acute hepatitis, cholangitis, and acute cholecystitis. Reader agreement, MRCP image quality, and confidence levels were also assessed. Clinical predictors of age and fever were tested for association with perceived need for contrast in biliary assessment.

RESULTS

There were 27 cases of choledocholithiasis, 31 cases of acute hepatitis, 37 cases of acute cholecystitis, and 3 clinically diagnosed cases of acute cholangitis. Both the abbreviated and full contrast-enhanced/MRCP image sets resulted in high accuracy for choledocholithiasis (91.1-94.3% vs. 91.9-92.7%). There was no difference in sensitivity or specificity for either reader for any diagnosis between image sets (p > 0.40). 1 reader showed improved confidence (p < 0.001) with inclusion of MRCP and contrast-enhanced images, but neither confidence nor MRCP quality scores were associated with diagnostic accuracy. Patient age and fever did not predict the need for contrast-enhanced images.

CONCLUSION

In hospitalized patients with suspected choledocholithiasis, performance of non-contrast abdominal MRI with HASTE is similar to contrast-enhanced MRI with 3D-MRCP, offering potential for decreased scanning time and improved patient tolerability.

Acute calculous cholecystitis: Review of current best practices

Acute calculous cholecystitis (ACC) is the most frequent complication of cholelithiasis and represents one-third of all surgical emergency hospital admissions, many aspects of the disease are still a matter of debate. Knowledge of the current evidence may allow the surgical team to develop practical bedside decision-making strategies, aiming at a less demanding procedure and lower frequency of complications. In this regard, recommendations on the diagnosis supported by specific criteria and severity scores are being implemented, to prioritize patients eligible for urgency surgery. Laparoscopic cholecystectomy is the best treatment for ACC and the procedure should ideally be performed within 72 h. Early surgery is associated with better results in comparison to delayed surgery. In addition, when to suspect associated common bile duct stones and how to treat them when found are still debated. The antimicrobial agents are indicated for high-risk patients and especially in the presence of gallbladder necrosis. The use of broad-spectrum antibiotics and in some cases with antifungal agents is related to better prognosis. Moreover, an emerging strategy of not converting to open, a difficult laparoscopic cholecystectomy and performing a subtotal cholecystectomy is recommended by adept surgical teams. Some authors support the use of percutaneous cholecystostomy as an alternative emergency treatment for acute Cholecystitis for patients with severe comorbidities.

Inpatient magnetic resonance cholangiopancreatography: does it increase the efficiency in emergency hepatopancreaticobiliary surgery services?

INTRODUCTION Magnetic resonance cholangiopancreatography (MRCP) is commonly used to evaluate the biliary tree, although indications for patients who require inpatient imaging are not fully defined. The aim of this study was to evaluate inpatient MRCP performed on surgical patients and to devise a treatment pathway for these patients. MATERIAL AND METHODS All adult inpatient MRCP examinations between January 2012 and December 2013 were reviewed. Demographic, clinical and radiological data were collated. RESULTS During the study period, 271 inpatient MRCP were requested, of which 234 examinations were included. The majority of patients were female (n=140) and the median age was 63 years (range 16-93 years). Surgical admissions accounted for 171 (73%) of cases. Indications for inpatient MRCP include gallstone-related complications (n=173; 74%), malignant process (n=17; 7%) and other indications (n=44; 19%). Overall, inpatient MRCP led to further inpatient interventions in 22% (gallstone group, n=32, 18%; patients with malignancy, n=8, 47%; other indications, n=12, 27%). The median duration of inpatient MRCP from request to examination was 2 days (range 0-15 days) and median reporting after examination was 1 day (range 0-14 days). DISCUSSION AND CONCLUSION Improved access and timely reporting of iMRCP may reduce length of hospital stay. Inpatient MRCP also led to further inpatient interventions, in particular, in patients with malignancy.

Imaging of autoimmune biliary disease

Autoimmune biliary diseases are poorly understood but important to recognize. Initially, autoimmune biliary diseases are asymptomatic but may lead to progressive cholestasis with associated ductopenia, portal hypertension, cirrhosis, and eventually liver failure. The three main forms of autoimmune biliary disease are primary biliary cirrhosis, primary sclerosing cholangitis, and IgG4-associated cholangitis. Although some overlap may occur between the three main autoimmune diseases of the bile ducts, each disease typically affects a distinct demographic group and requires a disease-specific diagnostic workup. For all the autoimmune biliary diseases, imaging provides a means to monitor disease progression, assess for complications, and screen for the development of hepatobiliary malignancies that are known to affect patients with these diseases. Imaging is also useful to suggest or corroborate the diagnosis of primary sclerosing cholangitis and IgG4-associated cholangitis. We review the current literature and emphasize radiological findings and considerations for these autoimmune diseases of the bile ducts.

Choledocholithiasis: Evaluation, Treatment, and Outcomes

Choledocholithiasis occurs in up to approximately 20% of patients with cholelithiasis. A majority of stones form in the gallbladder and then pass into the common bile duct, where they generate symptoms, due to biliary obstruction. Confirmatory diagnosis of choledocholithiasis is made with advanced imaging, including magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP). Treatment varies locally; however, ERCP with sphincterotomy is most commonly employed with a high degree of success. Difficult anatomy and difficult stone burden require advanced surgical, endoscopic, and percutaneous techniques to extract or expel biliary stones. Knowledge of these treatment strategies will optimize outcomes.

Prospective Endoscopic Ultrasound-Based Approach to the Evaluation of Idiopathic Pancreatitis: Causes, Response to Therapy, and Long-term Outcome

OBJECTIVES

Although idiopathic pancreatitis is common, the natural history is not well studied, and the best diagnostic approach to both single and multiple attacks remains undefined.

METHODS

We prospectively evaluated patients with idiopathic pancreatitis over a 10-year period, and clinical information for each episode was reviewed. Endoscopic ultrasound (EUS) was performed in all patients. Patients with microlithiasis or bile duct stones were referred for cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP), respectively. For those with a single attack, if EUS was normal or chronic pancreatitis or pancreas divisum was diagnosed, the patient was followed up for recurrence. For those with multiple attacks and a negative EUS, ERCP and sphincter of Oddi manometry with endoscopic therapy as appropriate were recommended. All patients were followed up in the long term to evaluate for recurrent pancreatitis, the primary study end point.

RESULTS

Over the study period, 201 patients were identified (80 single attack, 121 multiple attacks; mean age 53 years, range 17-95 years, s.d. 16.3 years; and 53% female). After EUS, 54% of patients with a single attack were categorized as idiopathic, and for multiple attacks sphincter of Oddi dysfunction (SOD) was the most common diagnosis (41%). Long-term follow-up (median 37 months; interquartile range 19-70 months) documented recurrence of pancreatitis in 15 (24%; 95% confidence interval (CI), 15-38%) patients with a single attack and in 48 (49%; 95% CI, 38-62%) patients with multiple attacks. Despite endoscopic therapy, patients with pancreas divisum and SOD had relapse rates of 50% (95% CI, 35 to 68%) and 55% (95% CI, 31 to 82%), respectively.

CONCLUSIONS

Following a single idiopathic attack of pancreatitis and a negative EUS examination, relapse was infrequent. Despite endoscopic therapy, patients with multiple attacks, especially those attributed to pancreas divisum and SOD, had high rates of recurrence. EUS may be a useful, minimally invasive tool for the diagnostic evaluation of idiopathic pancreatitis. The study was listed in Clinicaltrials.gov NCT00609726.

2016 WSES guidelines on acute calculous cholecystitis

Acute calculus cholecystitis is a very common disease with several area of uncertainty. The World Society of Emergency Surgery developed extensive guidelines in order to cover grey areas. The diagnostic criteria, the antimicrobial therapy, the evaluation of associated common bile duct stones, the identification of “high risk” patients, the surgical timing, the type of surgery, and the alternatives to surgery are discussed. Moreover the algorithm is proposed: as soon as diagnosis is made and after the evaluation of choledocholitiasis risk, laparoscopic cholecystectomy should be offered to all patients exception of those with high risk of morbidity or mortality. These Guidelines must be considered as an adjunctive tool for decision but they are not substitute of the clinical judgement for the individual patient.

Accuracy of ASGE criteria for the prediction of choledocholithiasis

BACKGROUND/AIMS

Few studies have validated the performance of guidelines for the prediction of choledocholithiasis (CL). Our objective was to prospectively assess the accuracy of the American Society for Gastrointestinal Endoscopy (ASGE) guidelines for the identification of CL.

METHODS

A two-year prospective evaluation of patients with suspected CL was performed. We evaluated the ASGE guidelines and its component variables in predicting CL.

RESULTS

A total of 256 patients with suspected CL were analyzed. Of the 208 patients with high-probability criteria for CL, 124 (59.6%) were found to have a stone/sludge at endoscopic retrograde cholangiopancreatography (ERCP). Among 48 patients with intermediate-probability criteria, 21 (43.8%) had a stone/sludge. The performance of ASGE high- and intermediate-probability criteria in our population had an accuracy of 59.0% (85.5% sensitivity, 24.3% specificity) and 41.0% (14.4% sensitivity, 75.6% specificity), respectively. The mean ERCP delay time was 6.1 days in the CL group and 6.4 days in the group without CL, p = 0.638. The presence of a common bile duct (CBD) > 6 mm (OR 2.21; 95% CI, 1.20-4.10), ascending cholangitis (OR 2.37; 95% CI, 1.01-5.55) and a CBD stone visualized on transabdominal US (OR 3.33; 95% CI, 1.48-7.52) were stronger predictors of CL. The occurrence of biliary pancreatitis was a strong protective factor for the presence of a retained CBD stone (OR 0.30; 95% CI, 0.17-0.55).

CONCLUSIONS

Irrespective of a patient's ASGE probability for CL, the application of current guidelines in our population led to unnecessary performance of ERCPs in nearly half of cases.

Early biliary decompression versus conservative treatment in acute biliary pancreatitis (APEC trial): study protocol for a randomized controlled trial

Background

Acute pancreatitis is mostly caused by gallstones or sludge. Early decompression of the biliary tree by endoscopic retrograde cholangiography (ERC) with sphincterotomy may improve outcome in these patients. Whereas current guidelines recommend early ERC in patients with concomitant cholangitis, early ERC is not recommended in patients with mild biliary pancreatitis. Evidence on the role of routine early ERC with endoscopic sphincterotomy in patients without cholangitis but with biliary pancreatitis at high risk for complications is lacking. We hypothesize that early ERC with sphincterotomy improves outcome in these patients.

Methods/Design

The APEC trial is a randomized controlled, parallel group, superiority multicenter trial. Within 24 hours after presentation to the emergency department, patients with biliary pancreatitis without cholangitis and at high risk for complications, based on an Acute Physiology and Chronic Health Evaluation (APACHE-II) score of 8 or greater, Modified Glasgow score of 3 or greater, or serum C-reactive protein above 150 mg/L, will be randomized. In 27 hospitals of the Dutch Pancreatitis Study Group, 232 patients will be allocated to early ERC with sphincterotomy or to conservative treatment. The primary endpoint is a composite of major complications (that is, organ failure, pancreatic necrosis, pneumonia, bacteremia, cholangitis, pancreatic endocrine, or exocrine insufficiency) or death within 180 days after randomization. Secondary endpoints include ERC-related complications, infected necrotizing pancreatitis, length of hospital stay and an economical evaluation.

Discussion

The APEC trial investigates whether an early ERC with sphincterotomy reduces the composite endpoint of major complications or death compared with conservative treatment in patients with biliary pancreatitis at high risk of complications.

Trial registration

Current Controlled Trials ISRCTN97372133 (date registration: 17-12-2012)

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1132-0) contains supplementary material, which is available to authorized users.

Cost-effectiveness analysis of endoscopic ultrasound versus magnetic resonance cholangiopancreatography in patients with suspected common bile duct stones

BACKGROUND

Patients with suspected common bile duct (CBD) stones are often diagnosed using endoscopic retrograde cholangiopancreatography (ERCP), an invasive procedure with risk of significant complications. Using endoscopic ultrasound (EUS) or Magnetic Resonance CholangioPancreatography (MRCP) first to detect CBD stones can reduce the risk of unnecessary procedures, cut complications and may save costs.

AIM

This study sought to compare the cost-effectiveness of initial EUS or MRCP in patients with suspected CBD stones.

METHODS

This study is a model based cost-utility analysis estimating mean costs and quality-adjusted life years (QALYs) per patient from the perspective of the UK National Health Service (NHS) over a 1 year time horizon. A decision tree model was constructed and populated with probabilities, outcomes and cost data from published sources, including one-way and probabilistic sensitivity analyses.

RESULTS

Using MRCP to select patients for ERCP was less costly than using EUS to select patients or proceeding directly to ERCP ($1299 versus $1753 and $1781, respectively), with similar QALYs accruing to each option (0.998, 0.998 and 0.997 for EUS, MRCP and direct ERCP, respectively). Initial MRCP was the most cost-effective option with the highest monetary net benefit, and this result was not sensitive to model parameters. MRCP had a 61% probability of being cost-effective at $29,000, the maximum willingness to pay for a QALY commonly used in the UK.

CONCLUSION

From the perspective of the UK NHS, MRCP was the most cost-effective test in the diagnosis of CBD stones.

Ultrasound versus liver function tests for diagnosis of common bile duct stones

BACKGROUND

Ultrasound and liver function tests (serum bilirubin and serum alkaline phosphatase) are used as screening tests for the diagnosis of common bile duct stones in people suspected of having common bile duct stones. There has been no systematic review of the diagnostic accuracy of ultrasound and liver function tests.

OBJECTIVES

To determine and compare the accuracy of ultrasound versus liver function tests for the diagnosis of common bile duct stones.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded, BIOSIS, and Clinicaltrials.gov to September 2012. We searched the references of included studies to identify further studies and systematic reviews identified from various databases (Database of Abstracts of Reviews of Effects, Health Technology Assessment, Medion, and ARIF (Aggressive Research Intelligence Facility)). We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included studies that provided the number of true positives, false positives, false negatives, and true negatives for ultrasound, serum bilirubin, or serum alkaline phosphatase. We only accepted studies that confirmed the presence of common bile duct stones by extraction of the stones (irrespective of whether this was done by surgical or endoscopic methods) for a positive test result, and absence of common bile duct stones by surgical or endoscopic negative exploration of the common bile duct, or symptom-free follow-up for at least six months for a negative test result as the reference standard in people suspected of having common bile duct stones. We included participants with or without prior diagnosis of cholelithiasis; with or without symptoms and complications of common bile duct stones, with or without prior treatment for common bile duct stones; and before or after cholecystectomy. At least two authors screened abstracts and selected studies for inclusion independently.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data from each study. Where meta-analysis was possible, we used the bivariate model to summarise sensitivity and specificity.

MAIN RESULTS

Five studies including 523 participants reported the diagnostic accuracy of ultrasound. One studies (262 participants) compared the accuracy of ultrasound, serum bilirubin and serum alkaline phosphatase in the same participants. All the studies included people with symptoms. One study included only participants without previous cholecystectomy but this information was not available from the remaining studies. All the studies were of poor methodological quality. The sensitivities for ultrasound ranged from 0.32 to 1.00, and the specificities ranged from 0.77 to 0.97. The summary sensitivity was 0.73 (95% CI 0.44 to 0.90) and the specificity was 0.91 (95% CI 0.84 to 0.95). At the median pre-test probability of common bile duct stones of 0.408, the post-test probability (95% CI) associated with positive ultrasound tests was 0.85 (95% CI 0.75 to 0.91), and negative ultrasound tests was 0.17 (95% CI 0.08 to 0.33).The single study of liver function tests reported diagnostic accuracy at two cut-offs for bilirubin (greater than 22.23 μmol/L and greater than twice the normal limit) and two cut-offs for alkaline phosphatase (greater than 125 IU/L and greater than twice the normal limit). This study also assessed ultrasound and reported higher sensitivities for bilirubin and alkaline phosphatase at both cut-offs but the specificities of the markers were higher at only the greater than twice the normal limit cut-off. The sensitivity for ultrasound was 0.32 (95% CI 0.15 to 0.54), bilirubin (cut-off greater than 22.23 μmol/L) was 0.84 (95% CI 0.64 to 0.95), and alkaline phosphatase (cut-off greater than 125 IU/L) was 0.92 (95% CI 0.74 to 0.99). The specificity for ultrasound was 0.95 (95% CI 0.91 to 0.97), bilirubin (cut-off greater than 22.23 μmol/L) was 0.91 (95% CI 0.86 to 0.94), and alkaline phosphatase (cut-off greater than 125 IU/L) was 0.79 (95% CI 0.74 to 0.84). No study reported the diagnostic accuracy of a combination of bilirubin and alkaline phosphatase, or combinations with ultrasound.

AUTHORS' CONCLUSIONS

Many people may have common bile duct stones in spite of having a negative ultrasound or liver function test. Such people may have to be re-tested with other modalities if the clinical suspicion of common bile duct stones is very high because of their symptoms. False-positive results are also possible and further non-invasive testing is recommended to confirm common bile duct stones to avoid the risks of invasive testing.It should be noted that these results were based on few studies of poor methodological quality and the results for ultrasound varied considerably between studies. Therefore, the results should be interpreted with caution. Further studies of high methodological quality are necessary to determine the diagnostic accuracy of ultrasound and liver function tests.

Endoscopic retrograde cholangiopancreatography versus intraoperative cholangiography for diagnosis of common bile duct stones

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) and intraoperative cholangiography (IOC) are tests used in the diagnosis of common bile duct stones in people suspected of having common bile duct stones. There has been no systematic review of the diagnostic accuracy of ERCP and IOC.

OBJECTIVES

To determine and compare the accuracy of ERCP and IOC for the diagnosis of common bile duct stones.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded, BIOSIS, and Clinicaltrials.gov to September 2012. To identify additional studies, we searched the references of included studies and systematic reviews identified from various databases (Database of Abstracts of Reviews of Effects (DARE)), Health Technology Assessment (HTA), Medion, and ARIF (Aggressive Research Intelligence Facility)). We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included studies that provided the number of true positives, false positives, false negatives, and true negatives for ERCP or IOC. We only accepted studies that confirmed the presence of common bile duct stones by extraction of the stones (irrespective of whether this was done by surgical or endoscopic methods) for a positive test, and absence of common bile duct stones by surgical or endoscopic negative exploration of the common bile duct, or symptom-free follow-up for at least six months for a negative test as the reference standard in people suspected of having common bile duct stones. We included participants with or without prior diagnosis of cholelithiasis; with or without symptoms and complications of common bile duct stones; with or without prior treatment for common bile duct stones; and before or after cholecystectomy. At least two authors screened abstracts and selected studies for inclusion independently.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data from each study. We used the bivariate model to summarise the sensitivity and specificity of the tests.

MAIN RESULTS

We identified five studies including 318 participants (180 participants with and 138 participants without common bile duct stones) that reported the diagnostic accuracy of ERCP and five studies including 654 participants (125 participants with and 529 participants without common bile duct stones) that reported the diagnostic accuracy of IOC. Most studies included people with symptoms (participants with jaundice or pancreatitis) suspected of having common bile duct stones based on blood tests, ultrasound, or both, prior to the performance of ERCP or IOC. Most studies included participants who had not previously undergone removal of the gallbladder (cholecystectomy). None of the included studies was of high methodological quality as evaluated by the QUADAS-2 tool (quality assessment tool for diagnostic accuracy studies). The sensitivities of ERCP ranged between 0.67 and 0.94 and the specificities ranged between 0.92 and 1.00. For ERCP, the summary sensitivity was 0.83 (95% confidence interval (CI) 0.72 to 0.90) and specificity was 0.99 (95% CI 0.94 to 1.00). The sensitivities of IOC ranged between 0.75 and 1.00 and the specificities ranged between 0.96 and 1.00. For IOC, the summary sensitivity was 0.99 (95% CI 0.83 to 1.00) and specificity was 0.99 (95% CI 0.95 to 1.00). For ERCP, at the median pre-test probability of common bile duct stones of 0.35 estimated from the included studies (i.e., 35% of people suspected of having common bile duct stones were confirmed to have gallstones by the reference standard), the post-test probabilities associated with positive test results was 0.97 (95% CI 0.88 to 0.99) and negative test results was 0.09 (95% CI 0.05 to 0.14). For IOC, at the median pre-test probability of common bile duct stones of 0.35, the post-test probabilities associated with positive test results was 0.98 (95% CI 0.85 to 1.00) and negative test results was 0.01 (95% CI 0.00 to 0.10). There was weak evidence of a difference in sensitivity (P value = 0.05) with IOC showing higher sensitivity than ERCP. There was no evidence of a difference in specificity (P value = 0.7) with both tests having similar specificity.

AUTHORS' CONCLUSIONS

Although the sensitivity of IOC appeared to be better than that of ERCP, this finding may be unreliable because none of the studies compared both tests in the same study populations and most of the studies were methodologically flawed. It appears that both tests were fairly accurate in guiding further invasive treatment as most people diagnosed with common bile duct stones by these tests had common bile duct stones. Some people may have common bile duct stones in spite of having a negative ERCP or IOC result. Such people may have to be re-tested if the clinical suspicion of common bile duct stones is very high because of their symptoms or persistently abnormal liver function tests. However, the results should be interpreted with caution given the limited quantity and quality of the evidence.