The decision-making value of magnetic resonance cholangiopancreatography in patients seen in a referral center for suspected biliary and pancreatic disease

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.

Giant choledochal calculosis: surgical treatment

Context:

Gallstone disease is one of the most common surgical pathologies. Choledocholithiasis may occur in some of these cases and require surgical intervention. Although there are relatively non-invasive procedures such as endoscopic retrograde cholangiopancreatography (ERCP), this technique is usually unsuccessful in patients with stones larger than 10 mm. In our case, we aimed to report a giant choledochal stone (15 cm × 4.5 cm), which is rare in surgical practice and our treatment with open surgery.

Case Report:

The patient was a 59-year-old woman. Magnetic resonance cholangiopancreatography (MRCP) had showed a hydropic gallbladder with an excessively dilated CBD and a 110 mm × 41 mm stone. In the operation, an excessively dilated CBD was seen and after choledochotomy and a very large calculus that filled CBD completely. Choledochotomy incision was carried forward and a T-tube choledochostomy with choledochoduodenostomy (CD) was performed. The patient was discharged without any complications on postoperative 8^th day.

Conclusion:

Benign gallstone disease is a multifactorial process, with risk factors such as obesity, hemolytic diseases, diabetes mellitus, and pregnancy. Risk factors for choledocholithiasis are similar to those for gallstone disease. MRCP is a non-invasive technique in detecting choledocholithiasis. The gold standard intervention for CBD stones is ERCP. Stones in CBD may reach very considerable dimensions without causing serious symptoms. The most common symptom is jaundice. During preoperative radiological examination, giant stones may be interfered with malignancies. Surgeons should obey conventional algorithms in diagnosis and open surgery must be kept in mind in earlier stages without being too insistent on endoscopic interventions.

MRCP in patient care: a prospective survey of gastroenterologists

OBJECTIVE

MRCP is increasingly used to evaluate pancreaticobiliary disease, yet its effect on patient care is unknown. The purpose of this study was to measure the effect of MRCP on referring physicians' initial diagnoses, the physicians' confidence in their diagnoses, and the influence of MRCP results on clinical management.

SUBJECTS AND METHODS

We prospectively surveyed gastroenterologists who referred patients for nonurgent MRCP for pancreaticobiliary evaluation. Before MRCP, gastroenterologists reported the working diagnosis, confidence level (high, moderate, low), and next step in clinical management if MRCP was unavailable. MRCP was performed with standard protocols, including secretin enhancement. After reviewing MRCP findings and without referring to their previous assessment, gastroenterologists reported a revised diagnosis, confidence level, and next step in clinical management. They then compared pre- and post-MRCP management plans and rated the influence of MRCP on changing management from 1 (none) to 5 (major). Diagnostic confidence and frequency of common diagnoses and recommendation for an invasive next-step procedure (e.g., ERCP) or endoscopic ultrasound were compared between pre- and post-MRCP assessments.

RESULTS

Survey data were analyzed on 171 patients (123 women, 48 men; mean age, 50 [SD, 17] years; range, 19-88 years) undergoing MRCP for unexplained abdominal pain (42.9%), suspected pancreaticobiliary neoplasm (20%), recent acute (17.1%) or suspected chronic (14.9%) pancreatitis, and other indications (5.1%). Recommendations of ERCP and endoscopic ultrasound decreased after MRCP (from 49.1% to 35.1%, p=0.03, and from 26.9% to 13.5%, p≤0.01). After MRCP, high confidence in diagnosis increased (from 72/171 to 100/171, p<0.01), as did recommendations for noninvasive therapy (from 18/171 to 56/171, p<0.01). A major or substantial change in clinical management was made in the care of 67 of 171 patients (39.2%).

CONCLUSION

Use of MRCP significantly changes gastroenterologists' treatment of patients with suspected pancreaticobiliary disease by increasing diagnostic confidence and reducing the frequency of invasive follow-up procedures.

Pre-ERCP imaging of the bile duct and gallbladder

Advances in biliary imaging have improved making accurate diagnoses of the presence and causes of biliary obstruction. Abdominal ultrasound is a useful screening tool because it is highly specific for choledocholithiasis. New developments in CT and MRI have also been useful in the diagnosis of biliary disease. Although diagnosis of biliary disease can be achieved in a noninvasive manner, there are limitations to modern MRI and CT cholangiographic techniques; their use may not be necessary or cost effective. MRI and CT imaging of the biliary tract provides opportunities for less-invasive diagnostic techniques but should be used judiciously before interventional endoscopy.

Preoperative MRCP to detect choledocholithiasis in acute calculous cholecystitis

PURPOSE

There are risks of common bile duct (CBD) stones in acute cholecystitis, and there is a move among surgeons to identify choledocholithiasis before surgery. Magnetic resonance cholangiopancreaticography (MRCP) has the potential to accurately detect choledocholithiasis in patients with acute cholecystitis. The aim of this study was to evaluate the predictive values of MRCP and elevated biochemical predictors for choledocholithiasis in patients with acute cholecystitis.

METHODS

Between September 2006 and August 2008, of 84 patients with acute cholecystitis based on the diagnosis criteria of the Tokyo guidelines, 57 had MRCP preoperatively. The predictive values of six biochemical predictors for choledocholithiasis were also evaluated.

RESULTS

Of the 57 patients, seven (12.28%) had choledocholithiasis, of whom three had CBD stones in nondilated ducts. The smallest stone detected in a dilated CBD and nondilated duct was 3.19 and 4.55 mm in diameter, respectively. None of our patients whose MRCP showed a clear CBD returned with symptomatic choledocholithiasis during the follow-up period. All biochemical predictors and CBD diameter had limited positive predictive values.

CONCLUSIONS

Magnetic resonance cholangiopancreaticography is a reliable evaluation technique for the detection of choledocholithiasis. It reduces the misdiagnosis of retained choledocholithiasis with normal biochemical predictors and prevents the risk of overlooking choledocholithiasis. No single predictor or combined markers have been found to be reliable for including/excluding the presence of choledocholithiasis.

Impact of magnetic resonance cholangiography in managing liver-transplanted patients: preliminary results of a clinical decision-making study

PURPOSE

This study was performed to assess the role of magnetic resonance cholangiography (MRC) in the clinical decision-making process of referring physicians when managing liver-transplanted patients.

MATERIALS AND METHODS

Over a 6-month period, 21 liver-transplanted patients with a suspected biliary complication were referred for MRC. Referring physicians were asked to prospectively state, before and after MRC, the leading diagnosis; the level of confidence (on a 0-100% scale); the most appropriate diagnostic/therapeutic plan. Data analysis assessed was the diagnostic yield of MRC; the proportion of change in the leading diagnosis; the therapeutic efficacy (i.e. proportion of change in the initial diagnostic/therapeutic plan); the diagnostic thinking efficacy (i.e., gain in diagnostic confidence). Statistical significance was assessed with the Mann-Whitney U test. MRC accuracy was also calculated.

RESULTS

Data analysis showed a diagnostic yield of 85.7%; a proportion of change in leading diagnosis of 19.0%; a therapeutic efficacy of 42.8%; a diagnostic thinking efficacy for concordant and discordant leading diagnoses of 18.8% and 78.7%, respectively (p<0.01). MRC accuracy was 92.3%.

CONCLUSIONS

MRC significantly increased the diagnostic confidence, irrespective of the concordance between pre- and posttest diagnoses. Moreover, MRC determined a change in patient management in a significant proportion of cases, leading to clinical benefits.

EUS accurately predicts the need for therapeutic ERCP in patients with a low probability of biliary obstruction

BACKGROUND

Because of its inherent risks, ERCP should only be performed for purposes of treatment. EUS and MRCP have emerged as diagnostic alternatives before therapeutic ERCP.

OBJECTIVE

Our purpose was to test the accuracy of EUS in predicting the need for therapeutic ERCP in low-risk patients.

DESIGN

Prospective, unblinded, single-center study.

SETTING

Academic center of the University of Witten/Herdecke.

PATIENTS

Fifty patients with clinical, laboratory, or transabdominal US findings suggestive of biliary obstruction were included.

INTERVENTIONS

After clinical assessment and US, all patients underwent EUS. If EUS was conclusive, either ERCP with sphincterotomy (EST) was performed or the patients were followed up for 1 year. If EUS was inconclusive, MRCP was performed, followed by ERCP or a 1-year follow-up. After each diagnostic step, the examiner decided whether any biliary conditon was present and whether therapeutic ERCP was necessary. The decicions were compared with the results of ERCP with EST or the outcome after the 1-year follow-up.

MAIN OUTCOME MEASUREMENTS

Accuracy of EUS in predicting the need for therapeutic ERCP.

RESULTS

Nine patients had ERCP with EST. The final assessment classified 2 of these interventions as having been unnecessary. EUS was conclusive in 49 cases. After EUS, the accuracy of the decision on the presence of a biliary condition increased from 82% to 96% and on the need for therapeutic ERCP from 86% to 96%.

LIMITATION

Single-center experience.

CONCLUSION

EUS accurately predicts the need for therapeutic ERCP in patients at low risk for biliary obstruction.

MRCP-secretin test-guided management of idiopathic recurrent pancreatitis: long-term outcomes

BACKGROUND

In patients with recurrent pancreatitis of unknown etiology and nondilated ducts, accurate morphofunctional evaluation of the pancreaticobiliary ductal system and sphincter of Oddi function is important in the diagnostic workup. However, ERCP and sphincter of Oddi manometry may be nondiagnostic and postprocedure complications may be frequent.

OBJECTIVE

Our purpose was to assess the diagnostic accuracy of the magnetic resonance cholangiopancreatography with secretin test (MRCP-S) in patients with recurrent acute pancreatitis of unknown etiology. Accuracy was established on the basis of ERCP findings and a minimum of 24 months' clinical follow-up.

DESIGN

Thirty-seven consecutive patients with intact gallbladder and a nondilated pancreaticobiliary ductal system with nonpathologic EUS findings entered a prospective MRCP-S-guided and ERCP-guided diagnostic and therapeutic study protocol.

RESULTS

Patients were followed up for a mean of 31.3 months (range 26-38 months). MRCP-S identified some pancreatic outflow impairment, suggesting morphofunctional dysfunction of either the major or minor papilla, in 12 of 37 patients (32.4%). The addition of ERCP to MRCP-S did not substantially improve the diagnostic yield for the etiology of recurrent pancreatitis, and 13.6% of cases had mild postprocedure pancreatitis. The S-test was abnormal in 12 of 20 cases (60%) in whom some dysfunction of the sphincter of Oddi or minor papilla was assumed on the basis of follow-up findings. The outcome was successful after biliary or pancreatic sphincterotomy in all patients with an abnormal S-test result. Sensitivity, specificity, and positive and negative predictive values of the S-test for the diagnosis of pancreatic outflow impairment at the major or minor papilla were, respectively, 57.1%, 100%, 100%, and 64%. When the test showed an abnormal result, we were unable to distinguish between biliary and pancreatic segment dysfunction of the sphincter of Oddi.

CONCLUSIONS

In idiopathic recurrent pancreatitis with nondilated ducts, the MRCP-S-guided approach gave diagnostic accuracy comparable to ERCP with regard to morphologic lesions, and it can be used as an alternative, avoiding ERCP-related complications in the diagnostic phase. An abnormal S-test result showed an excellent positive predictive value and somewhat disappointing negative predictive value for sphincter of Oddi or minor papilla dysfunction and for clinical success of therapeutic endoscopic approach.

Comparison of EUS and ERCP in the investigation with suspected biliary obstruction caused by choledocholithiasis: a randomized study

BACKGROUND

EUS may be used to reduce the need of diagnostic ERCP.

OBJECTIVE

Our purpose was to investigate the benefits and safety of an EUS-guided versus an ERCP-guided approach in the management of suspected biliary obstructive diseases caused by choledocholithiasis, in whom a US study is not diagnostic.

DESIGN

A randomized study.

SETTING

A university medical unit.

PATIENTS

Patients with clinical, biochemical, or radiologic suspicion of biliary obstruction.

INTERVENTIONS

In the EUS group, therapeutic ERCP was performed at the same EUS session if a lesion was found. In the ERCP group, therapeutic treatment was carried out at the discretion of the endoscopist.

MAIN OUTCOME MEASUREMENTS

The number of ERCPs avoided, procedure-related complications, and recurrent biliary symptoms on follow-up at 1 year.

RESULTS

Thirty-three patients were randomized to EUS and 32 to ERCP. Three patients (9.4%) had failed ERCPs, whereas all EUS procedures were successful. Nine (27.3%) patients in the EUS group were found to have biliary lesions that were all treated by ERCP. In the ERCP group, 7 (22%) patients had biliary lesions detected that were treated in the same session. More patients had serious complications (bleeding, acute pancreatitis, and umbilical abscess) in the ERCP group. One patient in each group had recurrent biliary symptoms during follow-up. With EUS used as a triage tool, diagnostic ERCP and its related complications could be spared in 49 (75.4%) patients.

CONCLUSIONS

In patients suspected to have biliary obstructive disease, EUS is a safe and accurate test to select patients for therapeutic ERCP.

Relationship among hospital ERCP volume, length of stay, and technical outcomes

BACKGROUND

The relationship between hospital procedure volume and outcome has been recognized for various specialties and procedures. Although increasingly used and in existence for 40 years, to date, data on the relationship between hospital volume and outcome of ERCP are scant.

OBJECTIVE

We sought to examine health-related outcomes after ERCP in relation to hospital procedure volume.

DESIGN

Secondary analysis of a national administrative database. We used the National Inpatient Sample (NIS) database to evaluate health-related outcomes among patients who underwent ERCP from 1998 to 2001.

MAIN OUTCOME MEASUREMENTS

Logistic and multiple regression models were used to estimate the association of hospital ERCP volume with length of stay (LOS), rates of procedural failure, and mortality. Fixed effect models were used to adjust for all time invariant hospital characteristics for each hospital within the dataset.

RESULTS

Data from 2629 hospitals that performed 199,625 ERCPs were evaluated. The median number of ERCPs performed in participating hospitals was 49 per year (range, 1-1004), with 25% of hospitals performing > or =100 ERCPs per year and 5% performing > or =200 per year. Significant trends in the relationship between volume and outcome were observed with respect to LOS and procedural failure: the median LOS was lower in high-volume (> or =200 ERCP/y) than low-volume (< or =100 ERCP/y) hospitals (6.9 vs 7.8 days, p < 0.0001) and the mean difference in expected LOS was 1.08 days (p < 0.0001). Multivariate regressions with hospital level fixed effects found significant negative relationships between procedure volume and procedure failure rates, but no significant effect on inpatient mortality rates was detected.

LIMITATIONS

NIS database permits analyses of only inpatient ERCPs. It precludes analysis of procedural complications, reinterventions, and influence of individual provider volume on outcomes.

CONCLUSIONS

Inpatients who undergo ERCP at high-volume hospitals have shorter LOS and lower procedural failure rates than those undergoing ERCP at low-volume hospitals. These findings have important implications for health care policy decision making and resource utilization.

EUS vs MRCP for detection of choledocholithiasis

BACKGROUND

Numerous published studies have shown the high diagnostic performance of both EUS and MRCP compared with ERCP for the detection of choledocholithiasis.

DESIGN

We undertook a systematic review of all published randomized, prospective trials that compared EUS with MRCP with the primary aim being to compare the overall diagnostic accuracy for the detection of choledocholithiasis in patients with suspected biliary disease.

METHODS

A MEDLINE review was performed. We identified 5 randomized, prospective, blinded trials comparing MRCP and EUS for the detection of choledocholithiasis, with subsequent ERCP or intraoperative cholangiography as a criterion standard. The study-specific variables for EUS and MRCP for choledocholithiasis were calculated from the data, and analyses were performed by using aggregated variables (sensitivity, specificity, positive and negative predictive values, and likelihood ratios).

RESULTS

The pooled data set consisted of 301 patients. The aggregated sensitivities of EUS and MRCP for the detection of choledocholithiasis were 0.93 and 0.85, respectively, whereas their specificities were 0.96 and 0.93, respectively. The aggregated positive predictive values for EUS and MRCP were 0.93 and 0.87, respectively, with the corresponding negative predictive values of 0.96 and 0.92, respectively. Positive likelihood ratios were >10 for both tests, and corresponding negative likelihood ratios approached 0.10 for both tests. No statistically significant differences between EUS and MRCP were found in our analysis.

CONCLUSIONS

EUS and MRCP have high diagnostic performance overall. Our analysis showed no statistically significant difference between the modalities. We recommend taking into consideration other factors, such as resource availability, experience, and cost considerations in deciding between these 2 tests.

Diagnostic role of secretin-enhanced MRCP in patients with unsuccessful ERCP

AIM: To evaluate the value of MR cholangiopancreatography (MRCP) in patients in whom endoscopic retrograde cholangiopancreatography (ERCP) was unsuccessfully performed by experts in a tertiary center.

METHODS: From January 2000 to June 2003, 22 patients fulfilled the inclusion criteria. The indications for ERCP were obstructive jaundice (n = 9), abnormal liver enzymes (n = 8), suspected chronic pancreatitis (n = 2), recurrent acute pancreatitis (n = 2), or suspected pancreatic cancer (n = 1). The reasons for the ERCP failure were the postsurgical anatomy (n = 7), duodenal stenosis (n = 3), duodenal diverticulum (n = 2), and technical failure (n = 10). MRCP images were evaluated before and 5 and 10 min after i.v. administration of 0.5 IU/kg secretin.

RESULTS: The MRCP images were diagnosed in all 21 patients. Five patients gave normal MR findings and required no further intervention. MRCP revealed abnormalities (primary sclerosing cholangitis, chronic pancreatitis, cholangitis, cholecystolithiasis or common bile duct dilation) in 10 patients, who were followed up clinically. Four patients subsequently underwent laparotomy (hepaticojejunostomy in consequence of common bile duct stenosis caused by unresectable pancreatic cancer; hepaticotomy + Kehr drainage because of insufficient biliary-enteric anastomosis; choledochoj-ejunostomy, gastrojejunostomy and cysto-Wirsungo gastrostomy because of chronic pancreatitis, or choledochojejunostomy because of common bile duct stenosis caused by chronic pancreatitis). Three patients participated in therapeutic percutaneous transhepatic drainage. The indications were choledocholithiasis with choledochojejunostomy, insufficient biliary-enteric anastomosis, or cholangiocarcinoma.

CONCLUSION: MRCP can assist the diagnosis and management of patients in whom ERCP is not possible.

Endoscopic retrograde cholangiopancreatography, intraductal ultrasonography, and magnetic resonance cholangiopancreatography in bile duct strictures: a prospective comparison of imaging diagnostics with histopathological correlation

OBJECTIVES

A variety of imaging techniques are available to diagnose bile duct strictures; the most effective imaging technique, however, has not been established yet. In the present study, we compared the impact of endoscopic retrograde cholangiopancreatography (ERCP), intraductal ultrasonography (IDUS), and magnetic resonance cholangiopancreatography (MRCP) with regard to diagnosing bile duct strictures.

METHODS

We prospectively examined 33 patients with jaundice due to bile duct strictures by ERCP plus IDUS and MRCP. The objectives were to assess diagnostic quality of imaging, complete presentation of the bile duct, and differentiation of malignant from benign lesions. Surgical and histopathological correlations, which were used as the gold standard, were available in all cases since all included patients underwent laparotomy.

RESULTS

Diagnostic image quality for ERCP was 88% and 76% for MRCP (p > 0.05). Comparing ERCP and MRCP, complete presentation of the biliary tract was achieved in 94% and 82%, respectively (p > 0.05). ERCP and MRCP allowed correct differentiation of malignant from benign lesions in 76% and 58% (p= 0.057), respectively. By supplementing ERCP with IDUS, the accuracy of correct differentiation of malignant from benign lesions increased significantly to 88% (p= 0.0047).

CONCLUSIONS

Comparing ERCP with MRCP, we found adequate presentation of bile duct strictures in high imaging quality for both techniques. ERCP supplemented by IDUS gives more reliable and precise information about differentiation of malignant and benign lesions than MRCP alone without additional imaging sequences.

Cost-minimization analysis of MRC versus ERCP for the diagnosis of primary sclerosing cholangitis

Investigations examining the use of magnetic resonance cholangiography (MRC) for the diagnosis of primary sclerosing cholangitis (PSC) have described comparable accuracy when compared to endoscopic retrograde cholangiopancreatography (ERCP). The effectiveness of MRC based on overall cost, however, remains unknown. Our aim was to determine the average cost per correct diagnosis using MRC or ERCP as the initial testing strategy for the diagnosis of PSC. A decision analysis model was constructed employing diagnostic test parameters prospectively determined among 73 patients with clinically suspected biliary disease. ERCP was performed within 24 hours after MRC. Cost data were derived from average Medicare reimbursement fee schedules. The prevalence of PSC in the study cohort was 32%. The sensitivity and specificity of MRC for the diagnosis of PSC were 82% and 98%, respectively. The average cost per correct diagnosis of PSC was 724.00 US dollars for initial MRC (including the cost of ERCP following a negative MRC examination) versus 793.17 US dollars for initial ERCP. In the absence of biliary obstruction, the average cost per correct diagnosis of PSC was 549.64 US dollars with MRC versus 623.25 US dollars or ERCP. The average cost of managing post-ERCP-related complications among patients with PSC was 2902.20 US dollars (range, 1915.40-5031.54 US dollars). For ERCP to be the optimal initial test strategy, a prevalence rate of PSC greater than 45%, MRC specificity less than 85%, or reduction in the average cost per diagnosis to 538.30 US dollars would be required. In conclusion, MRC has comparable accuracy to ERCP and results in cost savings when used as the initial test strategy for diagnosing PSC.

Cost-effectiveness of endoscopic ultrasonography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography in patients suspected of pancreaticobiliary disease

BACKGROUND

It is not known whether initial endoscopic ultrasonography (EUS) or magnetic resonance cholangiopancreatography (MRCP) is more cost effective than endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

A cost-effectiveness analysis of EUS, MRCP and ERCP was performed on 163 patients. The effectiveness of an investigation was defined as the percentage of patients with no need for further evaluation after the investigation in question had been performed. Costs were assumed from the budget-holder's point of view.

RESULTS

MRCP, EUS and ERCP had a total accuracy of 0.91, 0.93 and 0.92, respectively. Eighty-four (52%) patients needed endoscopic therapy in combination with ERCP, giving an effectiveness of MRCP, EUS, and ERCP of 0.44, 0.45 and 0.92, respectively. The cost-effectiveness of MRCP, EUS, and ERCP was 6622, 7353 and 4246 Danish Kroner (DKK) per fully investigated and treated patient (1 DKK=0.14 EUR).

CONCLUSION

Within a patient population with a probability of therapeutic ERCP in 50% of the patients, ERCP was the most cost-effective strategy.

Magnetic resonance cholangiography: applications in patients with calculus disease of the biliary tract

Magnetic resonance cholangiography (MRC) is a non-invasive imaging modality that has become widely available. In the short time since its introduction, MRC has been shown to possess excellent accuracy for the diagnosis of various biliary pathologies, including choledocholithiasis. Investigations of the clinical applications of MRC are ongoing. This review summarizes the diagnostic capabilities of MRC and discusses its application in the management of patients with gallstone diseases.

Is the 'Trondsen Discriminant Function' useful in patients referred for endoscopic retrograde cholangiopancreatography?

BACKGROUND

Ideally, patients should only be referred to endoscopic retrograde cholangiopancreatography (ERCP) if therapy is indicated. The aim of this study was to evaluate whether or not the 'Trondsen Discriminant Function' (DF) could be used for selecting patients directly for ERCP.

METHODS

The DF was calculated in 163 patients referred for ERCP with the DF value being unknown to the endoscopist. Compared to the final diagnoses of the patients, the sensitivity and specificity of a positive DF value for predicting biliary obstruction and need of endoscopic therapy were calculated.

RESULTS

Ninety-three (57%) patients had obstruction of the bile duct and 84 (52%) needed endoscopic therapy. A positive DF value had a sensitivity, specificity, positive predictive value and negative predictive value for predicting biliary obstruction of 81%, 72%, 79% and 73%, respectively. If only patients with a positive DF value had been examined by ERCP, 50 (31%) patients would have been saved from this investigation. Had a negative DF value stopped the patients from further diagnostic evaluation, 18 (11%) would have had undiagnosed pathological conditions.

CONCLUSION

A positive DF value is useful for selecting which patients should be referred directly for ERCP because of a high probability that they will need endoscopic therapy. A negative DF value cannot be used to stop the patient from further diagnostic evaluation.

Making cost-effectiveness analyses clinically relevant: the effect of provider expertise and biliary disease prevalence on the economic comparison of alternative diagnostic strategies

RATIONALE AND OBJECTIVES

This study was performed to assess the incremental cost-effectiveness of initial magnetic resonance cholangiopancreatography (MRCP) and initial endoscopic ultrasonography (EUS) compared with initial endoscopic retrograde cholangiopancreatography (ERCP) and to evaluate the effect of MRCP provider expertise on the relative cost-effectiveness of the three methods.

MATERIALS AND METHODS

Thirty patients with suspected biliary disease and referred for ERCP were prospectively evaluated with EUS, MRCP, or ERCP within 24 hours of referral, according to institutional review board-approved protocol. Performance characteristics were measured for EUS and MRCP, with ERCP as the reference standard. A decision analysis compared the clinical and economic effects of three diagnostic strategies (ERCP, EUS followed by ERCP [EUS-ERCP], and MRCP followed by ERCP [MRCP-ERCP]) using prospective EUS and MRCP test characteristics and Medicare reimbursements. The added costs per additional correct diagnosis and per additional false-positive finding averted and the rates and costs of ERCP-related complications were calculated for EUS-ERCP and MRCP-ERCP. Two additional MRCP readers reviewed MRCP data to evaluate interobserver variability and estimate provider expertise. Additional economic analyses incorporated these estimates.

RESULTS

Compared with initial ERCP, EUS-ERCP demonstrated 72% of biliary abnormalities and reduced ERCP-related complications by 60%; the corresponding percentages for MRCP-ERCP were 48% and 40%. Initial EUS and initial MRCP decreased the number of ERCP procedures performed by 69% and 49%, respectively. Each correct diagnosis made with ERCP that would not have been made with initial EUS or initial MRCP cost an additional 4,875 dollars or 2,580 dollars, respectively. Each false-positive diagnosis averted with initial ERCP that would have been made with EUS-ERCP or MRCP-ERCP cost an additional 9,750 dollars or 1,548 dollars, respectively. The decision model was most sensitive to disease prevalence. As provider expertise increased, the additional cost of an additional correct diagnosis increased for ERCP compared with MRCP-ERCP, with disease prevalence accentuating provider effects.

CONCLUSION

Initial EUS and initial MRCP are less costly than initial ERCP, but provider expertise, biliary disease prevalence, and procedural costs influence incremental cost-effectiveness.

Role of magnetic resonance cholangiopancreatography in patients with suspected choledocholithiasis

OBJECTIVES

To investigate the diagnostic efficacy of magnetic resonance cholangiopancreatography (MRCP) in choledocholithiasis and to determine whether use of MRCP may eliminate the need for purely diagnostic endoscopic retrograde cholangiopancreatography (ERCP).

PATIENTS AND METHODS

A total of 116 patients with suspected biliopancreatic pathology were studied prospectively between November 1996 and February 1998. Choledocholithiasis was initially suspected in 61 patients and rated before ERCP and MRCP as being of low, intermediate, or high probability based on clinical, laboratory, and/or imaging findings (Cotton criteria).

RESULTS

The sensitivity of choledocholithiasis diagnosis was 91%, with a global efficacy of 90%. The level of duct stone obstruction was visualized in all patients. Suprastenotic dilatation also showed a good correlation to ERCP. Choledocholithiasis was found in 32 patients (65%) and 3 patients (33%) in the high- and intermediate-probability groups, respectively. None of the low-probability patients had choledocholithiasis. Endoscopic retrograde cholangiopancreatography was performed for only a diagnostic (not therapeutic) purpose in 3 patients (6%) and 2 patients (22%) of the high- and intermediate-probability cases, respectively.

CONCLUSIONS

Magnetic resonance cholangiopancreatography seems to be effective in diagnosing choledocholithiasis. It plays a fundamental role in patients with a low or intermediate risk of choledocholithiasis, contributing to the avoidance of purely diagnostic ERCP.

The role of magnetic resonance cholangiopancreatography in patients with suspected biliary obstruction

Endoscopic retrograde cholangiopancreatography (ERCP) is an accepted and accurate procedure that combines the advantage of diagnosis of biliary obstruction with possible therapeutic endobiliary intervention. However, it is an operator-dependent and invasive procedure that is associated with complications and limitations. Magnetic resonance cholangiopancreatography (MRCP) is a unique noninvasive technique for the diagnosis of biliary obstruction. It is well suited to provide the information required to plan the optimal therapeutic approach for these patients. MRCP has the potential to replace or at least precede ERCP as the first-line imaging effort in the evaluation of suspected biliary obstruction. Significant advantages and some notable limitations inherent to the modality dictate its judicious use in appropriate circumstances. The present article reviews the utility of MRCP in evaluation of biliary obstruction, with brief reference to its principles and techniques.