Role of magnetic resonance cholangiopancreatography in patients with suspected choledocholithiasis

Cost effectiveness of intraoperative laparoscopic ultrasound for suspected choledocholithiasis; outcomes from a specialist benign upper gastrointestinal unit

INTRODUCTION

Common bile duct stones are present in 10% of patients with symptomatic gallstones. One-third of UK patients undergoing cholecystectomy will have preoperative ductal imaging, commonly with magnetic resonance cholangiopancreatography. Intraoperative laparoscopic ultrasound is a valid alternative but is not widely used. The primary aim of this study was to assess cost effectiveness of laparoscopic ultrasound compared with magnetic resonance cholangiopancreatography.

MATERIALS AND METHODS

A prospective database of all patients undergoing laparoscopic cholecystectomy between 2015 and 2018 at a district general hospital was assessed. Inclusion criteria were all patients, emergency and elective, with symptomatic gallstones and suspicion of common bile duct stones (derangement of liver function tests with or without dilated common bile duct on preoperative ultrasound, or history of pancreatitis). Patients with known common bile duct stones (magnetic resonance cholangiopancreatography or failed endoscopic retrograde cholangiogram) were excluded. Ninety-day morbidity data were also collected.

RESULTS

A total of 420 (334 elective and 86 emergency) patients were suspected to have common bile duct stones and were included in the study. The cost of a laparoscopic ultrasound was £183 per use. The cost of using the magnetic resonance cholangiopancreatography unit was £365 per use. Ten postoperative magnetic resonance cholangiopancreatographies were performed for inconclusive intraoperative imaging. The estimated cost saving was £74,650. Some 128 patients had common bile duct stones detected intraoperatively and treated. There was a false positive rate of 4.7%, and the false negative rate at 90 days was 0.7%. laparoscopic ultrasound use saved 129 bed days for emergency patients and 240 magnetic resonance cholangiopancreatography hours of magnetic resonance imaging.

CONCLUSION

The use of laparoscopic ultrasound during laparoscopic cholecystectomy for the detection of common bile duct stone is safe, accurate and cost effective. Equipment and maintenance costs are quickly offset and hospital bed days can be saved with its use.

Similarities and differences between biliary sludge and microlithiasis: Their clinical and pathophysiological significances

The terms biliary sludge and cholesterol microlithiasis (hereafter referred to as microlithiasis) were originated from different diagnostic techniques and may represent different stages of cholesterol gallstone disease. Although the pathogenesis of biliary sludge and microlithiasis may be similar, microlithiasis could be preceded by biliary sludge, followed by persistent precipitation and aggregation of solid cholesterol crystals, and eventually, gallstone formation. Many clinical conditions are clearly associated with the formation of biliary sludge and microlithiasis, including total parenteral nutrition, rapid weight loss, pregnancy, organ transplantation, administration of certain medications, and a variety of acute and chronic illnesses. Numerous studies have demonstrated complete resolution of biliary sludge in approximately 40% of patients, a cyclic pattern of disappearing and reappearing in about 40%, and progression to gallstones in nearly 20%. Although only a minority of patients with ultrasonographic demonstration of biliary sludge develop gallstones, it is still a matter of controversy whether microlithiasis could eventually evolve to cholesterol gallstones. Biliary sludge and microlithiasis are asymptomatic in the vast majority of patients; however, they can cause biliary colic, acute cholecystitis, and acute pancreatitis. Biliary sludge and microlithiasis are most often diagnosed ultrasonographically and bile microscopy is considered the gold standard for their diagnosis. Specific measures to prevent the development of biliary sludge are not practical or cost-effective in the general population. Laparoscopic cholecystectomy offers the most definitive therapy on biliary sludge. Endoscopic sphincterotomy or surgical intervention is effective for microlithiasis-induced pancreatitis. Ursodeoxycholic acid can effectively prevent the recurrence of solid cholesterol crystals and significantly reduce the risk of recurrent pancreatitis.

Factors and Outcomes Associated with MRCP Use prior to ERCP in Patients at High Risk for Choledocholithiasis

Background. Consensus guidelines recommend that patients at high risk for choledocholithiasis undergo endoscopic retrograde cholangiopancreatography (ERCP) without additional imaging. This study evaluates factors and outcomes associated with performing magnetic resonance cholangiopancreatography (MRCP) prior to ERCP among patients at high risk for choledocholithiasis. Methods. An institutional administrative database was searched using diagnosis codes for choledocholithiasis, cholangitis, and acute pancreatitis and procedure codes for MRCP and ERCP. Patients categorized as high risk for choledocholithiasis were evaluated. Results. 224 patients classified as high risk, of whom 176 (79%) underwent ERCP only, while 48 (21%) underwent MRCP prior to ERCP. Patients undergoing MRCP experienced longer time to ERCP (72 hours versus 35 hours, p < 0.0001), longer length of stay (8 days versus 6 days, p = 0.02), higher hospital charges ($23,488 versus $19,260, p = 0.08), and higher radiology charges ($3,385 versus $1,711, p < 0.0001). The presence of common bile duct stone(s) on ultrasound was the only independent factor associated with less use of MRCP (OR 0.09, p < 0.0001). Conclusions. MRCP use prior to ERCP in patients at high risk for choledocholithiasis is common and associated with greater length of hospital stay, higher radiology charges, and a trend towards higher hospital charges.

Endoscopic ultrasound versus magnetic resonance cholangiopancreatography for common bile duct stones

BACKGROUND

Endoscopic ultrasound (EUS) and magnetic resonance cholangiopancreatography (MRCP) are tests used in the diagnosis of common bile duct stones in patients suspected of having common bile duct stones prior to undergoing invasive treatment. There has been no systematic review of the accuracy of EUS and MRCP in the diagnosis of common bile duct stones using appropriate reference standards.

OBJECTIVES

To determine and compare the accuracy of EUS and MRCP for the diagnosis of common bile duct stones.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded, BIOSIS, and Clinicaltrials.gov until September 2012. We searched the references of included studies to identify further studies and of 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 EUS or MRCP. 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 independently screened abstracts and selected studies for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently collected the data from each study. We used the bivariate model to obtain pooled estimates of sensitivity and specificity.

MAIN RESULTS

We included a total of 18 studies involving 2366 participants (976 participants with common bile duct stones and 1390 participants without common bile duct stones). Eleven studies evaluated EUS alone, and five studies evaluated MRCP alone. Two studies evaluated both tests. Most studies included patients who were suspected of having common bile duct stones based on abnormal liver function tests; abnormal transabdominal ultrasound; symptoms such as obstructive jaundice, cholangitis, or pancreatitis; or a combination of the above. The proportion of participants who had undergone cholecystectomy varied across studies. Not one of the studies was of high methodological quality. For EUS, the sensitivities ranged between 0.75 and 1.00 and the specificities ranged between 0.85 and 1.00. The summary sensitivity (95% confidence interval (CI)) and specificity (95% CI) of the 13 studies that evaluated EUS (1537 participants; 686 cases and 851 participants without common bile duct stones) were 0.95 (95% CI 0.91 to 0.97) and 0.97 (95% CI 0.94 to 0.99). For MRCP, the sensitivities ranged between 0.77 and 1.00 and the specificities ranged between 0.73 and 0.99. The summary sensitivity and specificity of the seven studies that evaluated MRCP (996 participants; 361 cases and 635 participants without common bile duct stones) were 0.93 (95% CI 0.87 to 0.96) and 0.96 (95% CI 0.90 to 0.98). There was no evidence of a difference in sensitivity or specificity between EUS and MRCP (P value = 0.5). From the included studies, at the median pre-test probability of common bile duct stones of 41% the post-test probabilities (with 95% CI) associated with positive and negative EUS test results were 0.96 (95% CI 0.92 to 0.98) and 0.03 (95% CI 0.02 to 0.06). At the same pre-test probability, the post-test probabilities associated with positive and negative MRCP test results were 0.94 (95% CI 0.87 to 0.97) and 0.05 (95% CI 0.03 to 0.09).

AUTHORS' CONCLUSIONS

Both EUS and MRCP have high diagnostic accuracy for detection of common bile duct stones. People with positive EUS or MRCP should undergo endoscopic or surgical extraction of common bile duct stones and those with negative EUS or MRCP do not need further invasive tests. However, if the symptoms persist, further investigations will be indicated. The two tests are similar in terms of diagnostic accuracy and the choice of which test to use will be informed by availability and contra-indications to each test. However, it should be noted that the results are based on studies of poor methodological quality and so the results should be interpreted with caution. Further studies that are of high methodological quality are necessary to determine the diagnostic accuracy of EUS and MRCP for the diagnosis of common bile duct stones.

Diagnostic Accuracy of MRCP as Compared to Ultrasound/CT in Patients with Obstructive Jaundice

BACKGROUND

The expanding spectrum of therapeutic options for patients with surgical jaundice makes it necessary for the radiologist to precisely assess the etiology, location, level and extent of disease.

AIM

To compare the diagnostic accuracy of Magnetic Resonance Cholangiopancreatography (MRCP) with Ultrasound and Computed Tomography (CT) in evaluation of patients with obstructive jaundice taking direct cholangiographies (ERCP and PTC), hystologic tests and anatomo-pathological findings after surgical intervention as gold standard.

SETTINGS AND DESIGN

This prospective study included 50 patients who were referred to the radiology department with clinical features of biliary obstructive disease.

MATERIALS AND METHODS

Initial ultrasonography (USG) evaluation was followed by Computed tomography (CT) and Magnetic Resonance Cholangiopancreatography (MRCP);however in cases of benign pathologies where USG findings were unequivocal Computed tomography (CT )was not done to avoid unnecessary radiation exposure. The results were read by radiologists blinded to other imaging findings. The characteristic Endoscopic Retrograde Cholangiopancreatography (ERCP) features/ histopathological diagnosis / surgical findings (as applicable) were considered as final.

RESULTS

Diagnostic accuracy of MRCP (98%) in the diagnosis of benign and malignant diseases was relatively high (98% and 98%) as compared to CT (82.86% and 91.43% in benign and malignant respectively) and USG (88% and 88%). In the diagnosis of benign diseases MRCP was 100% sensitive compared to ultrasound (80.77%), which was more sensitive than CT scan (54.55%).In the diagnosis of malignant diseases, MRCP was more sensitive (95.83%) as compared to CT scan (91.67%), which was more sensitive than ultrasonography (79.17%).

CONCLUSION

Ultrasound as a screening modality is useful to confirm or exclude biliary dilatation and to choose patients for MRCP examination. MRCP is an important non invasive imaging investigation in the pre operative evaluation of patients with obstructive jaundice.

Role of intraoperative cholangiography in patients whose biliary tree was evaluated preoperatively by magnetic resonance cholangiopancreatography

BACKGROUND

Routine performance of intraoperative cholangiography (IOC) during cholecystectomy is controversial. The aim of this study was to evaluate the role of IOC during cholecystectomy in addition to preoperative magnetic resonance cholangiopancreatography (MRCP) in our institution over a 12-year period.

METHODS

A total of 425 consecutive patients who underwent IOC during cholecystectomy were included in this study. MRCP was performed preoperatively for bile duct evaluation in all patients. When common bile duct (CBD) stones were detected, they were removed endoscopically before the operation. We estimated the results of IOC in terms of the success rate, the detection rate of anatomic abnormality of the biliary system, and the incidence of residual CBD stones.

RESULTS

MRCP preoperatively identified 6 (1.4 %) patients with abnormal biliary systems and 56 with CBD stones, which were endoscopically removed. The success rate of IOC was 93.8 % (399/425). Abnormalities of the biliary system were detected in 12 patients (12/399, 3.0 %) and CBD stones in 8 (8/399, 2.0 %). Of the eight patients with stones, seven had been examined by endoscopy preoperatively and found to have CBD stones. The detection rate of bile duct stones in patients with preoperative endoscopic removal of CBD stones (7/56, 12.5 %) was significantly higher than those with CBD stones first detected during IOC (1/365, 0.3 %) (p < 0.01). Moreover, no residual CBD stones were detected in patients who were operated on within fewer than 12 days from endoscopic treatment to the operation.

CONCLUSIONS

IOC is indicated even after preoperative sphincterotomy for CBD stones. In our study, it resulted in a 12.5 % incidence of persistent stones after sphincterotomy. IOC plays an additional role in detecting CBD stones and in revealing abnormalities of the biliary tree in patients whose biliary tree was preoperatively evaluated by MRCP.

MRCP compared to diagnostic ERCP for diagnosis when biliary obstruction is suspected: a systematic review

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) is an alternative to diagnostic endoscopic retrograde cholangiopancreatography (ERCP) for investigating biliary obstruction. The use of MRCP, a non-invasive procedure, may prevent the use of unnecessary invasive procedures. The aim of the study was to compare the findings of MRCP with those of ERCP by the computation of accuracy statistics.

METHODS

Thirteen electronic bibliographic databases, covering biomedical, science, health economics and grey literature were searched. A systematic review of studies comparing MRCP to diagnostic ERCP in patients with suspected biliary obstruction was conducted. Sensitivity, specificity, likelihood ratios, acceptability and adverse events were reported.

RESULTS

25 studies were identified reporting several conditions including choledocholithiasis (18 studies), malignancy (four studies), obstruction (three studies), stricture (two studies) and dilatation (five studies). Three of the 18 studies reporting choledocholithiasis were excluded from the analysis due to lack of data, or differences in study design. The sensitivity for the 15 studies of choledocholithiasis ranged from 0.50 to 1.00 while specificity ranged from 0.83 to 1.00. The positive likelihood ratio ranged: from 5.44-47.72 and the negative likelihood ratio for the 15 studies ranged from 0.00-0.51. Significant heterogeneity was found across the 15 studies so the sensitivities and specificities were summarised by a Receiver Operating Characteristic (ROC) curve. For malignancy, sensitivity ranged from 0.81 to 0.94 and specificity from 0.92 to 1.00. Positive likelihood ratios ranged from 10.12 to 43 and negative likelihood ratios ranged from 0.15 to 0.21, although these estimates were less reliable.

CONCLUSION

MRCP is a comparable diagnostic investigation in comparison to ERCP for diagnosing biliary obstruction.

Limitations of fluoroscopic intraoperative cholangiography in cases suggestive of choledocholithiasis

BACKGROUND

Fluoroscopic intraoperative cholangiography (IOC) has been proposed as a safe and accurate screening method for choledocholithiasis, with a sensitivity and specificity of nearly 100% in selected cases. In the present study we retrospectively reviewed the diagnostic accuracy of IOC in cases highly suggestive of choledocholithiasis.

MATERIALS AND METHODS

Between January 1999 and December 2002, 103 patients underwent IOC as an imaging method for common bile duct (CBD) stone detection. We did not routinely perform IOC in all patients who were submitted to laparoscopic cholecystectomy, reserving the method for patients with a high probability of choledocholithiasis, namely patients with a history or the presence of painful obstructive jaundice at the time of referral, patients with a history of mild acute pancreatitis of biliary origin, and patients with abnormalities in their liver biochemistry profile as measured by liver function tests (LFT).

RESULTS

The mean rates of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for IOC were 98%, 94%, 94.5%, and 98% for the whole series, respectively. The diagnostic accuracy was 100% in patients with a history of obstructive jaundice or liver biochemical derangement, but was less in patients with a history of biliary pancreatitis. There were 3 false positive cases and 1 case of false negative results, all of which occurred in the subgroup of patients with a history of pancreatitis.

CONCLUSION

Selective fluoroscopic IOC is generally feasible and safe, as well as highly accurate (100%) for CBD stone detection in patients with obstructive jaundice or abnormal LFT. The PPV of the method decreases in patients with a history of pancreatitis (75%), while a negative result is highly suggestive of the absence of CBD stones (NPV = 98%). The present study concluded in a higher incidence of false results in patients with a normal size CBD, suggesting that the diagnostic accuracy of IOC is probably related to the size of the CBD rather than the indication for its performance.