Choledocholithiasis: evaluation with MR cholangiography

A Predictive Tool for Choledocholithiasis in Patients Undergoing Emergency Cholecystectomy

Background: Management of acute cholecystitis with emergency laparoscopic cholecystectomy has been established; however, detection and management of concurrent choledocholithiasis are debated. The aim of this study is to develop a more accurate choledocholithiasis predictive model. Materials and Methods: A 9-year audit of emergency cholecystectomies and evaluation of preoperative factors in predictive models. Receiver Operating Curve (ROC) analysis/Youdon Index was used to identify thresholds maximizing these associations for continuous variables. Results: 1601/1828 patients were analyzed. Patients who were diagnosed with choledocholithiasis were more likely to be febrile on admission, have a higher C-reactive Protein, and higher median bilirubin (25.0 μmol/L versus 11.0 μmol/L, P < .001). When excluding bilirubin, multivariate analysis detected several significant variables, including fever, biliary tree dilatation, or a common bile duct stone seen on ultrasound. When bilirubin was included into the model, bilirubin of 20-39 μmol/L (odds ratio [OR] 2.44, 95% confidence interval [CI]: 1.74-3.44) and ≥40 μmol/L (OR 4.84, 95% CI: 3.40-6.91) were shown to have increased likelihood of choledocholithiasis detection on intraoperative cholangiogram, with the ROC model having a significant C-statistic of 0.796 (P < .001). Discussion: A perfect predictive model for concurrent choledocholithiasis in acute cholecystitis does not exist; however, the results from this study are encouraging that high and low predictive groups can be established.

Improved diagnosis of common bile duct stone with single-shot balanced turbo field-echo sequence in MRCP

PURPOSE

To evaluate the value of adding single-shot balanced turbo field-echo (b-TFE) sequence to conventional magnetic resonance cholangiopancreatography (MRCP) for the detection of common bile duct (CBD) stone.

METHODS

One hundred thirty-seven consecutive patients with suspected CBD stone underwent MRCP including single-shot b-TFE sequence. Twenty-five patients were confirmed with CBD stone by endoscopic retrograde cholangiopancreatography or ultrasonography. Two radiologists reviewed two image protocols: protocol A (conventional MRCP protocol: unenhanced T1-, T2-, and respiratory-triggered three-dimensional fat-suppressed single-shot turbo spin-echo MRCP sequence) and protocol B (protocol A plus single-shot b-TFE sequence). The sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and area under the receiver-operating-characteristic (ROC) curve (AUC) for the detection of CBD stone were compared.

RESULTS

The sensitivity (72%) and NPV (94%) were the same between the two protocols. However, protocol B was greater in the specificity (99%) and PPV (94%) than protocol A (92% and 67%, respectively) (P = 0.0078 and 0.031, respectively). The AUC was significantly greater for protocol B (0.93) than for protocol A (0.86) (P = 0.026).

CONCLUSIONS

Inclusion of single-shot b-TFE sequence to conventional MRCP significantly improved the specificity and PPV for the detection of CBD stone.

Yield of magnetic resonance cholangiopancreatography for the investigation of bile duct dilatation in asymptomatic patients

BACKGROUND

Biliary dilatation in the asymptomatic patient is a frequent incidental finding in the work-up for which there are no current guidelines.

OBJECTIVES

The purpose of this study was to determine the yield of magnetic resonance cholangiopancreatography (MRCP) in asymptomatic patients with an incidental finding of biliary duct dilatation.

METHODS

The study included 68 consecutive patients for evaluation of biliary duct dilatation found incidentally on computed tomography (CT) or ultrasound (US). MRCP scans were reviewed, and data were retrospectively collected on demographics and laboratory work-up. Patients were divided by the presence of a significant or non-significant MRCP findings explaining the biliary duct dilatation and compared for normal or abnormal liver function.

RESULTS

Liver function was normal in 47 patients and abnormal in 21 patients. MRCP identified the cause of the bile duct dilatation in 41 patients (60.3%). Rates of insignificant causes were 51% in the normal-liver-function group and 7% in the abnormal-function group. Corresponding rates of significant causes were 27.7% and 61.9% (p = 0.007).

CONCLUSIONS

MRCP is a valuable tool in the work-up of biliary duct dilatation. Although significantly more significant causes of bile dilatation are identified in patients with abnormal liver function, almost one-third of patients with normal liver function need further work-up. This has important implications for establishing criteria for the use of MRCP in asymptomatic patients with biliary dilatation.

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.

The Value of Magnetic Resonance Cholangio-Pancreatography (MRCP) in the Detection of Choledocholithiasis

INTRODUCTION

Magnetic Resonance Cholangio-Pancreatography (MRCP) is a non-invasive radiological investigation which can be performed rapidly and which does not expose the patients to ionised radiations or iodinated contrast material. The present study was conducted to evaluate the role of MRCP in detection of Common Bile Duct (CBD) stones in patients with suspected choledocholithiasis.

MATERIAL AND METHODS

This prospective study included 30 patients with a suspicion of choledocholithiasis which was based on clinical evaluation, biochemical or radiological investigations. Ultrasonography and MRCP were performed in all patients. All patients underwent open surgery. CBD exploration was performed in all patients, either due to presence of palpable stones or due to the presence of dilated CBD (> 7 mm). Demonstration of CBD stones intra-operatively was considered the 'gold standard' for their presence, defined as stones visualised and extracted or attempted for extraction during surgical CBD exploration.

RESULTS

Intra-operatively, 21 (70%) out of 30 patients had cholelithiasis. 26 (86.67%) out of 30 patients had dilated CBD stones intra-operatively. In 20 (66.67%) out of 30 patients, choledocholithiasis was detected intra-operatively. The sensitivity, specificity, positive and negative predictive value of ultrasonography in detecting CBD stones in the present study was 65%, 60%, 76.47% and 46.15% respectively. The sensitivity, specificity, positive and negative predictive value of MRCP in diagnosis of CBD stones in the present study was 95%, 90%, 95% and 90% respectively.

CONCLUSIONS

MRCP is a non-invasive investigation without complications and it has high sensitivity, specificity and positive and negative predictive values in detection of CBD stones. MRCP should be done in all cases with a suspicion of CBD stones, where facilities and expertise are available.

Imaging of biliary disorders in children

Biliary atresia and related disorders of the biliary tree, such as choledochal cyst, must be considered in the differential diagnosis of prolonged conjugated hyperbilirubinemia in infants and children. Pediatric biliary tract diseases include a variety of entities with a wide range of clinical presentations. Radiology plays an important role in the diagnosis and management of these pathologies. Unrecognized causes of biliary disease, like biliary atresia, can lead to liver transplantation during the first year of life. The aim of this article is to review the imaging of pediatric biliary disorders, including the implications of interventional radiology in some biliary diseases.

Is ERCP really necessary in case of suspected spontaneous passage of bile duct stones?

AIM: To investigate the usefulness of magnetic resonance cholangiopancreatography (MRCP) and the need for endoscopic retrograde cholangiopancreatography (ERCP) in cases of suspected spontaneous passage of stones into the common bile duct.

METHODS: Thirty-six patients with gallbladder stones were clinically suspected of spontaneous passage of stones into the common bile duct because they presented with clinical symptoms such as abdominal pain and fever, and showed signs of inflammatory reaction and marked rise of hepatobiliary enzymes. These symptoms resolved and they showed normalized values of blood biochemical parameters after conservative treatment without evidence of stones in the common bile duct on MRCP. All these patients were subjected to ERCP within 3 d of MRCP to check for the presence of stones.

RESULTS: No stones were detected by ERCP in any patient, confirming the results of MRCP.

CONCLUSION: When clinical symptoms improve, blood biochemical parameters have normalized, and MRCP shows there are no stones in the common bile duct, it can be considered the stone has spontaneously passed and thus ERCP is not necessary.

Computed tomography and magnetic resonance cholangiography

In patients with biliary obstruction, determining the level and the cause of the obstruction is essential because it can be a key factor for the next step in diagnostic or therapeutic intervention. Noninvasive cholangiography, such as computed tomography (CT) cholangiography or magnetic resonance (MR) cholangiography, allows the diagnosis of cause and level of biliary disease with minimal risk. Traditional magnetic resonance cholangiopancreatography (MRCP) is an established and effective noninvasive diagnostic modality particularly for extrahepatic biliary tract evaluation. Intrahepatic biliary duct evaluation and functional MR, including evaluating for leaks and gallbladder dyskinesia and outlet obstruction, are evolving diagnostic techniques that show promising results. CT cholangiography techniques are especially useful when MRI is not available or contraindicated or when the quality of MRCP images is suboptimal. CT cholangiography is particularly useful as an adjunct to surgery or postsurgical cases. The primary limitation of cholangiographic contrast-enhanced CT cholangiography (the most prevalent type of CT cholangiography) is its hindrance by poor liver function and/or high-grade biliary obstruction. In this setting MRCP is clearly superior. There are different types of CT cholangiography and MRCP. This article discusses the types of CT cholangiography and MRCP techniques and their clinical applications.

Diagnostic value of magnetic resonance cholangiopancreatography for clinically suspicious spontaneous passage of bile duct stones

BACKGROUND AND AIM

We investigated the usefulness of magnetic resonance cholangiopancreatography (MRCP) and the need for endoscopic retrograde cholangiopancreatography (ERCP) in patients with clinically suspicious spontaneous passage of bile duct stones.

METHODS

The study population consisted of 113 patients suspected of having common duct bile stones. Of them, 50 patients were clinically suspected of spontaneous passage of bile duct stones based on the presence of gallbladder stones on ultrasound examination or a history of common bile duct stones after cholecystectomy, clinical symptoms including abdominal pain and fever associated with inflammatory reaction and marked rise of hepatobiliary enzymes which resolved or normalized after conservative treatment without evidence of stones in the common bile duct on MRCP. These 50 patients were prospectively followed up for a median of 10.2 months.

RESULTS

All patients except for one had had no symptoms related to cholangitis. Only one patient received ERCP due to recurrence of symptoms after 6 months.

CONCLUSION

When clinical symptoms improve, hematological parameters normalize, and MRCP indicates that there are no stones in the common bile duct, it can be considered that the stones have passed naturally.

MR imaging for diagnosing cysto-biliary fistulas in cystic echinococcosis

OBJECTIVE

To evaluate the sensitivity and specificity of magnetic resonance imaging (MR imaging) including MR cholangiography for the identification of cysto-biliary fistulas in patients with hepatic hydatid disease.

PATIENTS AND METHODS

Retrospective analysis of 3 groups of patients (20 patients with 51 echinococcal cysts) in a cohort of 103 patients with cystic echinococcosis with different pretest probabilities for cysto-biliary fistulas. Patients who had MR imaging/MR cholangiography with symptoms and signs of biliary obstruction (5 patients with 16 cysts, group I), before surgery for other reasons than biliary obstruction (9 patients with 14 cysts, group II) and for cyst staging (6 patients with 21 cysts, group III). All MR images were evaluated before surgery for the presence of cyst wall defects and hydatid debris in bile ducts. In groups I and II MR results were compared with surgical, parasitological, and biochemical findings of each individual cyst.

RESULTS

Based on direct (i.e. defects in the cyst wall and continuity of dilated biliary ducts into adjacent cysts), and indirect MR imaging/MR cholangiography imaging signs (i.e. intraluminal debris) our best estimate of sensitivity and specificity (stage-specific, WHO type CE3 and CE4) for cysto-biliary fistulas was 75% and 95%, respectively.

CONCLUSIONS

MR imaging with MR cholangiography is a valuable non-invasive imaging technique to assess the risk of cysto-biliary fistula-related complications and for planning of surgery.

Magnetic resonance cholangiopancreatography: A useful tool in the evaluation of pancreatic and biliary disorders

Magnetic resonance cholangiopancreatography (MRCP) is being used with increasing frequency as a noninvasive alternative to diagnostic retrograde cholangiopancreatography (ERCP). The aim of this pictorial review is to demonstrate the usefulness of MRCP in the evaluation of pancreatic and biliary system disorders. Because the recently developed techniques allows improved spatial resolution and permits imaging of the entire pancreaticobiliary tract during a single breath hold, MRCP is of proven utility in a variety of pancreatic and biliary disorders. It uses MR imaging to visualize fluid in the biliary and pancreatic ducts as high signal intensity on T2 weighted sequences and is the newest modality for pancreatic and biliary duct imaging. Herein, we present the clinical applications of MRCP in a variety of pancreaticobiliary system disorders and conclude that it is an important diagnostic tool in terms of imaging of the pancreaticobiliary ductal system.

Diagnosis of intrahepatic and common duct stones: combined unenhanced and contrast-enhanced helical CT in 1090 patients

BACKGROUND

We determined the accuracy of combined unenhanced and contrast-enhanced helical computed tomography (CT) for diagnosis of bile duct stones.

METHODS

During a 12-month period, 1090 patients who underwent combined CT and endoscopic retrograde cholangiography (ERC) or percutaneous transhepatic cholangioscopy (PTC) were enrolled in this study. The results of prospective CT interpretation regarding the presence of bile duct stones were compared with results of endoscopic stone removal, PTC and with surgical results. In 70 patients, detectability of stones on CT was evaluated depending on stone types.

RESULTS

Of 1090 study patients, 175 and 299 patients were confirmed to have intrahepatic and common duct stones, respectively. The sensitivity and specificity of combined CT were 73% and 98% for diagnosis of intrahepatic stones and 71% and 97% for common duct stones. Of 70 patients 24, 25, and 21 patients had cholesterol, black pigment, and brown pigment stones, respectively. Eleven of 24 cholesterol stones, 21 of 25 black pigment stones, and 15 of 21 brown pigment stones were detected on combined CT.

CONCLUSION

Combined CT is of limited sensitivity for detection of bile duct stones, especially in Western countries where cholesterol stones predominate. It may be of greater value in populations with a higher incidence of pigment stones. Other complementary imaging modalities are needed for patients with negative CT findings who are highly suspected to have biliary stones.

Value of adding T1-weighted image to MR cholangiopancreatography for detecting intrahepatic biliary stones

OBJECTIVE

The purpose of this study was to assess the value of adding a T1-weighted image to MR cholangiopancreatography (MRCP) to detect bile duct stones.

MATERIALS AND METHODS

During a 30-month period, 148 patients suspected of having biliary stones and who underwent MRI including MRCP, a fat-suppressed T1-weighted fast low-angle shot (FLASH) sequence, and an axial HASTE sequence were enrolled in this study. The biliary stones were confirmed by ERCP, surgery, and percutaneous transhepatic cholangiography. Of these 148 patients, 73 had extrahepatic stones, 45 had intrahepatic stones, 20 had both extrahepatic and intrahepatic stones, and 10 had no biliary stones. Two separate sets of images, the MRCP set (composed of MRCP and axial HASTE) and the combined interpretion of the MRCP set and the T1-weighted image, were analyzed independently and separately by two observers. The diagnostic accuracy was evaluated using the receiver operating characteristic method. The sensitivity and specificity were also calculated.

RESULTS

For common duct stones, the diagnostic accuracy and the sensitivity of both image sets showed similar values without any significant difference (0.998 [97.8%] for the combined interpretation; 0.988 [97.8%] for observer 1 and 0.995 [96.8%] for observer 2 for the MRCP set). However, for the intrahepatic stones, the diagnostic accuracy (0.993) and the sensitivity (98.5%) of the combined interpretation were significantly higher than those of the MRCP set for the two observers (0.926 [83.8%] for observer 1 and 0.922 [85.3%] for observer 2) (p < 0.05). No significant difference was seen in the specificity of the two image sets for both the intrahepatic and the common duct stones.

CONCLUSION

Combining the axial T1-weighted image with MRCP is valuable for detecting intrahepatic stones.

High-resolution magnetic resonance cholangiography (MRC) with adaptive averaging: diagnostic performance evaluation

AIM

To evaluate the diagnostic performance of an interactive, adaptively averaged (AA) two-dimensional (2D) magnetic resonance cholangiography (MRC) technique in patients with suspected biliary disease by comparison to the standard MRC technique.

MATERIALS AND METHODS

The AA 2D MRC method registers the images after acquisition, allowing summation of multiple images to improve the signal:noise ratio (SNR) and thereby potentially improve the visualization of bile ducts. One hundred and twenty-eight patients underwent both 2D conventional and AA magnetic resonance cholangiopancreatography (MRCP). Twenty-seven patients were excluded from the analysis as AA images could not be properly obtained due to technical failures. All examinations were performed using a 1.5 T whole-body MR system and a four-channel torso phased array coil. Images of 101 patients were adaptively averaged using an in-house developed program written in IDL. Two readers qualitatively evaluated the studies in consensus, blinded to acquisition details and without knowledge of clinical information.

RESULTS

The AA technique was significantly better than the conventional 2D MRC for the visualization of the second-order branch intrahepatic ducts (p<00001). Overall, there was no significant difference in the diagnostic confidence between two techniques (p=0.12). However, the AA technique showed a trend towards more confident diagnosis of biliary strictures (p=0.055), likely due to better diagnostic confidence in identifying second order branch intrahepatic duct strictures (p=0.054).

CONCLUSION

Excluding those patients those patients in whom either satisfactory respiratory gating or a suitable kernel placement was not achieved, AA 2D MRC demonstrated a significant improvement in visualization of intrahepatic duct branches compared to standard MRC.

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.

Interactive magnetic resonance cholangiography (MRC) with adaptive averaging

PURPOSE

To implement and evaluate a technique for adaptively averaging 2D magnetic resonance cholangiography (MRC) images obtained using an interactive imaging system with a view to improving image quality at reduced fields of view (FOVs).

MATERIALS AND METHODS

Images were obtained using an interactive implementation of a single-shot half-Fourier rapid acquisition with relaxation enhancement (RARE) technique. Software was developed for adaptively averaging images, and an evaluation was performed in a phantom and a cohort of 10 patients referred for standard MRC. Adaptively averaged and standard single-shot MRC images were evaluated with respect to their ability to demonstrate the common bile duct and main left and right intrahepatic duct branches.

RESULTS

In all patient studies there was no difference in the ability of either the adaptive technique or the standard single-shot method to demonstrate the common bile duct and the main left and right intrahepatic duct branches. However, in seven of the 10 patient studies the adaptive technique provided better visualization of the peripheral bile duct system (P = 0.035; sign test). There was no difference in the diagnostic confidence of the two techniques (P = 0.32, Wilcoxon signed-rank test).

CONCLUSION

Adaptive averaging of MRC images obtained using an interactive imaging paradigm significantly improves visualization of peripheral intrahepatic ducts.

Volume rendering of three-dimensional drip infusion CT cholangiography in patients with suspected obstructive biliary disease: a retrospective study

The purpose of this study was to evaluate the diagnostic potential of prolonged drip infusion CT cholangiography (DIC-CT) using meglumine iotroxate (Biliscopin) and 3D volume rendering in patients with suspected obstructive biliary disease. From a material of 142 patients who had undergone a drip infusion CT, all cases with a verified surgical or endoscopic retrograde cholangiography (ERC) diagnosis (n=33) were selected. Age-matched controls were selected from the remaining examinations. Three radiologists reviewed all 66 examinations in retrospect, independently as well as in consensus. The image quality and the estimated diagnostic quality were rated as good or moderate in 91% of the 198 reviews. The consensus sensitivity and specificity for diagnosing biliary stones was 88% and 94%, respectively (with sensitivities ranging from 88% to 94% for individual observers, and specificities from 86% to 96%). Two out of three strictures were observed. No false positive strictures were described. The use of volume rendering technique (VRT) improved diagnostic certainty in 28/198 (14%) of the evaluations. The visualization of ductal stones was improved in 18/48 (38%). No differences in diagnostic quality between single and multislice CT were observed. We conclude that a detailed image of the biliary tree with good sensitivity and specificity can be obtained by means of bilirubin-governed infusion time DIC-CT with volume rendering reconstruction.

Preoperative evaluation of common bile duct stones in patients with gallstone disease

OBJECTIVE

Our objective was to suggest criteria for selection of a preoperative diagnostic technique for patients with gallstone disease.

CONCLUSION

Use of MR cholangiography preferentially before laparoscopic cholecystectomy, on patients who have a moderate or high risk of common bile duct stones, can significantly reduce purely diagnostic endoscopic retrograde cholangiography.

Improving the safety of laparoscopic cholecystectomy: the routine use of preoperative magnetic resonance cholangiography

BACKGROUND

The aim of this study was to determine the value of routinely performed preoperative magnetic resonance cholangiography (MRC) in detecting common bile duct (CBD) stones in patients stated to undergo elective laparoscopic cholecystectomy. In addition, we used MRC to investigate possible variants of the cystic duct.

METHODS

Magnetic resonance cholangiography was performed preoperatively in 773 patients (311 male and 462 female; median age 55 years, range 16-91) who had no clinical signs of cholestasis prior to undergoing elective laparoscopic cholecystectomy. In cases where the MRC was positive for CBD stones, endoscopic retrograde cholangiopancreatiography (ERCP) was then performed. A total of 532 patients were available for continuous postoperatively follow-up (median 54 months, range 36-85). In 462 patients (247 female, and 215 male), MR images were also reviewed for variants of the cystic duct.

RESULTS

In 705 patients (91%), MRC was negative for CBD stones. In 64 patients (9%) MRC was positive. Of these patients, 47 (6%) had CBD stones on ERCP. In 12 patients (2%), MRC was false positive. In five cases (0.6%), ERCP had an inconclusive result postoperative follow-up (532 patients, or 69%) revealed evidence of CBD stones in three patients (10.4%) despite a preoperative negative MRC result. Anatomical variants in the course of the cystic duct and its confluence with the common bile duct were found in 27 of 462 patients (6%).

CONCLUSIONS

Magnetic resonance cholangiography proved to be a reliable screening technique in the preoperative evaluation of patients with silent CBD stones. Imaging of the course of the cystic duct is possible in a high percentage of cases. Therefore, MRC can be recommended as a screening technique before laparoscopic cholecystectomy.

Histologic assessment of biliary obstruction with different percutaneous endoluminal techniques

Background

Despite the sophisticated cross sectional image techniques currently available, a number of biliary stenosis or obstructions remain of an uncertain nature. In these pathological conditions, an "intrinsic" parietal alteration is the cause of biliary obstruction and it is very difficult to differentiate benign from malignant lesions using cross-sectional imaging procedures alone. We evaluated the efficacy of different endoluminal techniques to achieve a definitive pathological diagnosis in these situations.

Methods

Eighty patients underwent brushing, and or biopsy of the biliary tree through an existing transhepatic biliary drainage route. A subcoort of 12 patients needed balloon-dilatation of the bile duct and the material covering the balloon surface was also sent for pathological examination (balloon surface sampling). Pathological results were compared with surgical findings or with long-term clinical and instrumental follow-ups. Success rates, sensitivity, specificity, accuracy, confidential intervals, positive predictive value and negative predictive value of the three percutaneous techniques in differentiating benign from malignant disease were assessed.

The agreement coefficient of biopsy and brushing with final diagnosis was calculated using the Cohen's "K" value.

Results

Fifty-six patients had malignant strictures confirmed by surgery, histology, and by clinical follow-ups. Success rates of brushing, balloon surface sampling, and biopsy were 90.7, 100, and 100%, respectively. The comparative efficacy of brushing, balloon-surface sampling, and biopsy resulted as follows: sensitivity of 47.8, 87.5, and 92.1%, respectively; specificity of 100% for all the techniques; accuracy of 69.2, 91.7 and 93.6%, Positive Predictive Value of 100% for all the procedures and Negative Predictive Value of 55, 80, and 75%, respectively.

Conclusions

Percutaneous endoluminal biopsy is more accurate and sensitive than percutaneous bile duct brushing in the detection of malignant diseases (p < 0.01).

Biliary motor function in gallstone patients evaluated by fatty-meal MR cholangiography

PURPOSE

To investigate the possibility of evaluating biliary motor function with magnetic resonance cholangiography (MRC).

MATERIALS AND METHODS

Twenty patients with gallstones and 30 control subjects were studied using fatty-meal MRC. After baseline MRC, they were encouraged to drink 250 mL of milk and underwent postprandial MRC every 10 minutes for 60 minutes. Postprandial changes in gallbladder volume and the diameter of the common duct were assessed as indicators of gallbladder contractility and biliary obstruction, respectively. Postprandial dilatation at 60 minutes was considered indicative of persistent biliary obstruction.

RESULTS

Gallbladder ejection fraction was calculated at 66.0% +/- 12.2% (range, 40.3%-88.6%) in the controls. Gallbladder volume expressed as a percentage of the baseline value was significantly larger at 20-60 minutes in the gallstone patients than in the controls. Gallbladder ejection fraction varied widely (mean, 46.4% +/- 24.4%; range, 2.8%-81.5%) and was significantly reduced in comparison with that of the controls (P < 0.01). In two gallstone patients with co-existing ductal stones, transient postprandial dilatation associated with ampullary impaction was observed. Persistent biliary obstruction was not indicated in any subjects.

CONCLUSION

The results of this study suggest the feasibility of fatty-meal MRC, as well as its potential for evaluating biliary motor function.

The fetal safety and clinical efficacy of gastrointestinal endoscopy during pregnancy

More than 12,000 pregnant patients in the United States per annum have conditions that are normally evaluated by EGD. More than 6000 pregnant patients in the United States per annum have conditions that are normally evaluated by sigmoidoscopy or colonoscopy. About one thousand more have symptomatic choledocholithiasis during pregnancy, which is a strong indication for endoscopic sphincterotomy in nonpregnant patients. Endoscopy during pregnancy raises the unique issue of fetal safety. Endoscopic medications comprise a significant component of fetal endoscopic risks. Safety of EGD during pregnancy has been examined in a case-controlled study of 83 patients, a mailed survey of 73 patients, and 28 case reports. Safety of sigmoidoscopy during pregnancy has been examined in a case-controlled study of 46 patients, a mailed survey of 13 patients, and 10 case reports. Safety of therapeutic ERCP during pregnancy has been analyzed in studies of 23, 10, 6, and 5 patients, and in 32 case reports. These studies suggested that EGD, sigmoidoscopy, and ERCP should be performed when strongly indicated: EGD for significant upper gastrointestinal bleeding, sigmoidoscopy for nonhemorrhoidal rectal bleeding, and ERCP for symptomatic choledocholithiasis when sphincterotomy is contemplated. PEG and colonoscopy are currently considered experimental during pregnancy because of insufficient data on fetal safety. Several cases of PEG and colonoscopy were successfully performed during pregnancy. Performance of endoscopy during pregnancy should increase with further technical refinements, and greater awareness of procedure safety.

Prospective evaluation of magnetic resonance cholangiopancreatography in patients with biliary disease: comparative study with conventional ultrasonography and endoscopic retrograde cholangiopancreatography diagnostic algorithm

BACKGROUND

Magnetic resonance cholangiopancreatography is an accurate technique that can replace invasive diagnostic methods of the biliary and pancreatic duct.

AIMS

Our aim was to assess sensitivity and specificity of magnetic resonance cholangiopancreatography and ultrasonography using the results of endoscopic retrograde cholangiopancreatography as reference, and to establish a diagnostic algorithm under which circumstances magnetic resonance cholangiopancreatography can replace endoscopic retrograde cholangiopancreatography.

PATIENTS

Eighty-three patients with suspicion of biliary disease based on clinical, biochemical and ultrasonography findings were studied.

METHODS

Ultrasonography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were performed, comparing the results of the techniques for the determination of their sensitivity and specificity.

RESULTS

Sensitivity and specificity results obtained by magnetic resonance cholangiopancreatography were: 100 and 92.8% when dilated ducts were detected (n=61); 97.4 and 97.2% in the diagnosis of choledocholithiasis (n=38); 100 and 96.7% in malignant lesions (n=14) and 81.8 and 98.4% when biliary ducts were normal. The percentage of images of diagnostic quality was 97.6%. Sensitivity and specificity achieved by ultrasonography was: 100 and 57.1% in detection of dilatation, 71 and 97.2% in choledocholithiasis, 92.8 and 96.7% in malignancy and 66.6 and 96.8% in normal ducts.

CONCLUSIONS

Magnetic resonance cholangiopancreatography is a technique with high sensitivity and specificity in the evaluation of biliary ducts. Thus, magnetic resonance cholangiopancreatography may replace diagnostic endoscopic retrograde cholangiopancreatography for purely diagnostic purposes, following an initial clinical and ultrasonographic exam.

MR cholangiopancreatography

Although MRCP is still an evolving technique, it has established itself as clinically useful and comparable with ERCP for the evaluation of various biliary or pancreatic ductal diseases. MRCP is not only comparable with ERCP in its diagnostic ability, but it has the tremendous advantage of being noninvasive. Furthermore, MR imaging is useful in patients with incomplete or failed ERCP, and in patients with certain biliary or gastrointestinal surgical procedures it is the imaging modality of choice. ERCP will remain an extremely important modality because of the great clinical importance for interventional biliary procedures with this technique. Nonetheless, MRCP may in the near future replace most of the diagnostic imaging of the biliary tree, with diagnostic results even more improved with further developments of hardware and technique.

MR cholangiopancreatography: evaluation of common pancreatic diseases

In the evaluation of common pancreatic diseases, MRCP is a noninvasive alternative to ERCP. Ductal anatomy can be ascertained without risk of complications. MRCP is valuable in defining common anatomic variants, determining the state of the pancreatic duct in pancreatitis, and characterizing neoplasms, especially combined with other MR imaging sequences. With the advent of MRCP, techniques requiring endoscopy and percutaneous access are largely reserved for histologic diagnosis and treatment, or for cases in which MRCP fails to establish a diagnosis.

MR cholangiopancreatography

In summary, over the past decade, MRCP has evolved not only as a feasible means of noninvasively evaluating the pancreaticobiliary tract but also as a technique with documented clinical utility. With the evolution of MRCP, there has been, by necessity, an evolution of ERCP. In fact, at some institutions MRCP has replaced diagnostic ERCP such that ERCP is reserved primarily for therapeutic interventions. When MRCP is performed in conjunction with abdominal MR and MRA, a comprehensive examination results that permits evaluation of the solid organs and vessels of the abdomen as well as the ductal systems.

Detection of common bile duct stones before laparoscopic cholecystectomy. Evaluation with MR cholangiography

PURPOSE

To assess the diagnostic value of MR cholangiography (MRC) for detecting common bile duct (CBD) stones in candidates for laparoscopic cholecystectomy (LC).

MATERIAL AND METHODS

A series of 95 selected patients with gallstones and suspected CBD lithiasis (abnormal serum liver tests and/or CBD size > or = 6.5 mm at US) were referred to our institution for MRC, before LC. MRC was performed on a 0.5 T magnet through a non-breath-hold, respiratory-triggered, fat-suppressed, thin-slab, heavily T2-weighted fast spin-echo sequence and through a breath-hold, thick-slab, single-shot T2-weighted sequence in the coronal plane. Axial T1- and T2-weighted sequences were first obtained. Two observers in conference reviewed source images and maximum intensity projections to determine the presence or absence of choledocholithiasis. MR findings were compared with endoscopic retrograde cholangiography and intraoperative cholangiography (IOC); IOC was always performed during LC.

RESULTS

CBD calculi (single or multiple) were identified in 41 out of 95 patients (43%). Two false-positive and 4 false-negative cases were found on MRC. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of MRC for choledocholithiasis were 90%, 96%, 94%, 95%, and 93%, respectively.

CONCLUSION

MRC is a highly effective diagnostic modality for evaluation of patients with risk factors for CBD stones prior to LC.

MR cholangiography in symptomatic gallstones: diagnostic accuracy according to clinical risk group

PURPOSE

To determine the diagnostic accuracy of magnetic resonance (MR) cholangiography in the detection of common bile duct (CBD) stones in patients with symptomatic gallstones.

MATERIALS AND METHODS

Single-shot half-Fourier MR cholangiographic images were obtained in 121 consecutive patients who were referred for MR cholangiography prior to cholecystectomy for symptomatic gallstones. One radiologist interpreted the MR cholangiographic images without prior knowledge of laboratory test results or findings from examinations with other imaging modalities. Patients were retrospectively divided into three groups with high, moderate, and low risk (n = 70, 22, and 29, respectively) for CBD stones. The sensitivity, specificity, and accuracy of MR cholangiography in the detection of CBD stones in each group were calculated. The accuracy of laboratory and sonographic findings in the identification of CBD stones was also calculated.

RESULTS

CBD stones were diagnosed in 49 (70%) of 70 patients in the high-risk group. One false-positive diagnosis was made, and two false-negative diagnoses were made. Of the 22 patients in the moderate-risk group, seven (32%) had CBD stones, and there was one false-positive and one false-negative diagnosis. In the low-risk group, CBD stones were correctly identified with MR cholangiography in one patient, and there was one false-positive diagnosis. A combination of positive laboratory and sonographic findings yielded a sensitivity of 98% but a specificity of only 34% if any unusual finding in any one of the tests was regarded as a positive finding.

CONCLUSION

MR cholangiography is highly accurate in the detection of CBD stones in all patients, regardless of the grade of risk, and should be considered in patients with a moderate to high risk of CBD stones before cholecystectomy.

Diagnosis of intrahepatic stones: superiority of MR cholangiopancreatography over endoscopic retrograde cholangiopancreatography

OBJECTIVE

The purpose of this study was to compare the efficacy of MR cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) for the diagnosis of intrahepatic stones.

MATERIALS AND METHODS

Of the 318 patients who underwent MRCP examinations at our institution during an 18-month period, we identified 49 patients who subsequently underwent surgery or cholangioscopic stone removal with proof of intrahepatic stones. Thirty-four of these patients also underwent ERCP; they made up our study population. All images were interpreted for the presence of bile duct stones: MRCP images were interpreted independently by two reviewers, and ERCP studies were interpreted by one reviewer who was unaware of the MRCP findings.

RESULTS

The sensitivity and specificity of MRCP for detecting intrahepatic stones were 97% and 93%, respectively, whereas those of ERCP were 59% and 97%, respectively. MRCP showed a significantly higher sensitivity than ERCP in the diagnosis of intrahepatic stones (p < 0.001). We found no significant difference between MRCP and ERCP in sensitivity or specificity for detecting calculi in the common duct or gallbladder.

CONCLUSION

MRCP is a more effective diagnostic method than ERCP for the evaluation of intrahepatic stones.

MR cholangiopancreatography in patients with primary sclerosing cholangitis: interobserver variability and comparison with endoscopic retrograde cholangiopancreatography

OBJECTIVE

The purpose of our study was to determine the degree of interobserver variability and correlation between MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) for the presence of bile duct strictures in patients with primary sclerosing cholangitis.

MATERIALS AND METHODS

For this retrospective study involving 26 patients with primary sclerosing cholangitis, 31 MR cholangiopancreatograms were compared with 30 endoscopic retrograde cholangiopancreatograms. The MR cholangiopancreatograms were independently interpreted by two abdominal radiologists in a blinded, randomized manner for overall image quality, extent of ductal visualization, and the presence and location of bile duct strictures. Unweighted multirater kappa coefficient values were estimated for each comparison.

RESULTS

Visualization of more than 50% of the expected ductal length was possible in the extrahepatic, central intrahepatic, and peripheral intrahepatic bile ducts in 99%, 88%, and 69% of the MR cholangiopancreatograms and 100%, 86%, and 52% of the endoscopic retrograde cholangiopancreatograms, respectively. Strictures were detected in the extrahepatic, central, and peripheral ducts in 53%, 68%, and 87% of the MR cholangiopancreatograms and 73%, 67%, and 63% of the endoscopic retrograde cholangiopancreatograms, respectively. The interobserver agreement for stricture detection was 61% for MR cholangiopancreatography and 76% for ERCP. MR cholangiopancreatographic findings were consistent with ERCP findings for the presence of strictures in 69% of the cases.

CONCLUSION

In patients with primary sclerosing cholangitis, MR cholangiopancreatography better shows the bile ducts and can depict more strictures, especially of the peripheral intrahepatic ducts, than ERCP. MR cholangiopancreatography can be used to noninvasively diagnose and follow up patients with primary sclerosing cholangitis.

A prospective comparison of the diagnostic accuracy of ERCP, MRCP, CT, and EUS in biliary strictures

BACKGROUND

The differential diagnosis of biliary strictures remains a challenge. This study evaluated magnetic resonance cholangiopancreatography (MRCP) as a new procedure in comparison with the established methods of diagnosis including ERCP or percutaneous transhepatic cholangiography (PTC), CT, and EUS.

METHODS

Fifty patients (21 men, 29 women, mean age 65.7 years) with jaundice but no pain suspected to have biliary strictures were enrolled in this prospective study. MRCP, ERCP/PTC, CT, and EUS were performed prospectively; images and videotapes (EUS) of these tests were reviewed blindly under standardized conditions. Reference standards for comparison were surgery, a biopsy confirming malignancy, or the clinical course during follow-up (at least 12 months) in cases without histopathologic proof of malignancy.

RESULTS

Seven patients ultimately proved to have jaundice caused by parenchymal liver disease and 43 had a biliary stricture (17 benign, 26 malignant). Forty patients underwent all 4 imaging tests. There were 10 patients in whom patient-specific problems precluded some procedures but who were included in an intention-to-diagnose analysis. The sensitivity and specificity for diagnosis of malignancy in the 50 patients were as follows: 85% / 75% for ERCP/PTC, 85% / 71% for MRCP, 77% / 63% for CT, and 79% / 62% for EUS, with similar values in the 40 patients who underwent all 4 imaging methods. The combination of MRCP and EUS improved specificity.

CONCLUSIONS

Although MRCP provides the same imaging information as direct cholangiography, it has limited specificity for the diagnosis of malignant strictures. In the differential diagnosis of biliary strictures, several tests including ERCP-guided tissue diagnosis are still required, and MRCP has only a limited clinical role.

Endoscopic retrograde cholangiopancreatography should no longer be used as a diagnostic test: the case in favour

The requirement for diagnostic endoscopic retrograde cholangiopancreatography has decreased considerably in the past 10 years. Alternative imaging techniques are now available for the diagnosis of bile duct stones, pancreatic and biliary tract malignancy and inflammatory diseases such as sclerosing cholangitis and chronic pancreatitis. The imaging techniques include endoscopic ultrasonography, magnetic resonance cholangiopancreatography and helical computed tomography. There is good evidence that these techniques have an accuracy comparable to endoscopic retrograde cholangiopancreatography in the diagnosis of diseases of the bile and pancreatic ducts. All of these methods are less invasive than endoscopic retrograde cholangiopancreatography and have extremely low or negligible complication rates. The choice of technique used depends on local availability and expertise. In future, endoscopic retrograde cholangiopancreatography will be reserved exclusively for therapeutic applications.

Comparison of MR cholangiopancreatographic techniques with contrast-enhanced cholangiography in the evaluation of sclerosing cholangitis

OBJECTIVE

The purpose of our study was to compare MR cholangiopancreatography and contrast-enhanced cholangiography in patients with sclerosing cholangitis.

MATERIALS AND METHODS

Twenty patients with sclerosing cholangitis were evaluated on MR cholangiopancreatography using the single-shot fast spin-echo technique at 1.5 T. A group of 19 healthy volunteers underwent MR cholangiopancreatography as controls. Thick-slab (2-cm sections) coronal oblique and thin-slab (5-mm sections) interleaved straight coronal MR images were obtained. All patients with sclerosing cholangitis had an MR cholangiopancreatogram within 12 months of a contrast-enhanced cholangiogram (mean, 3.8 months). Seventy-five percent of patients had an MR cholangiopancreatogram within 3 months of the contrast-enhanced cholangiogram. The MR cholangiopancreatograms and contrast-enhanced cholangiograms were reviewed independently in a random fashion by two radiologists who were unaware of clinical history for the degree of ductal visualization and for the presence and location of strictures of the intrahepatic and extrahepatic bile ducts. All discrepancies were resolved by a consensus, and the contrast-enhanced cholangiograms were regarded as the gold standard. Statistically significant data were calculated using the signed rank test (p < 0.01), and agreement analysis was calculated using Cohen's kappa.

RESULTS

All findings on MR cholangiopancreatograms in healthy subjects were interpreted as normal, and all findings on MR cholangiopancreatograms in patients with sclerosing cholangitis were interpreted as abnormal. When compared with the control group, scans of patients with sclerosing cholangitis usually showed good visualization (>50%) of the intrasegmental (86% vs 9%) and peripheral (67% vs 0%) intrahepatic ducts on thick-slab MR cholangiopancreatography. Thick-slab MR cholangiopancreatography showed good visualization in more ducts than contrast cholangiography (84% vs 70%; p = 0.10) and showed more strictured ducts than contrast cholangiography (47% vs 36%; p = 0.22). When comparing those ducts with good visualization on both MR cholangiopancreatography and contrast cholangiography, we found that disagreement occurred regarding 32% of ducts. Most of the discrepancies (60%) resulted when a stricture was noted on MR cholangiopancreatography but not on contrast-enhanced cholangiography. Good interobserver agreement (kappa > 0.4) was noted for detecting strictures of the extrahepatic, left hepatic, left medial, and right posterior ducts, with the greatest agreement for extrahepatic ductal strictures (kappa = 0.8).

CONCLUSION

Thick-slab MR cholangiopancreatography is the best technique for depicting normal and strictured bile ducts and allows the differentiation of healthy patients from patients with sclerosing cholangitis. Although endoscopic retrograde cholangiopancreatography was considered the standard, MR cholangiopancreatography was superior for intrahepatic biliary ductal visualization. Therefore, this technique is of value in the diagnosis and follow-up of patients with sclerosing cholangitis.

Endoscopic management of biliary tract disease

New investigations, evaluation of controversial issues, and advances in technology continue to shape the endoscopic management of biliary disorders. This article discusses recent literature related to the diagnosis and therapy of biliary tract disease. Specifically, the diagnosis and management of choledocholithiasis, complications of biliary endoscopy and potential preventive measures, roles for endosonography in the evaluation of biliary disease, and endoscopic therapy of postoperative liver transplantation complications are reviewed. Recent advances in biliary stents and the use of cholangioscopy in biliary disorders are also assessed.

Value of magnetic resonance cholangiography in the preoperative diagnosis of common bile duct stones

OBJECTIVE

The aim of this study was to assess the performance of magnetic resonance cholangiography (MRC) in the preoperative diagnosis of choledocholithiasis.

METHODS

A total of 147 consecutive patients underwent MRC for clinical and biological signs of common bile duct stones. ERCP was then carried out in 101 patients in whom there was a past history of cholecystectomy. The remaining 46 patients without a past history of biliary surgery underwent cholecystectomy and intraoperative cholangiography (IOC). The diagnosis obtained by MRC was compared with the final diagnosis established after endoscopic or surgical removal of calculi.

RESULTS

A total of 113 patients had choledocholithiasis (single or multiple, including 15 cases of microlithiasis). There were no false-positive results with MRC. The false-negative results were caused mainly by small stones <3 mm in diameter, and to a lesser extent, cholangitis. Overall, the sensitivity was 93% and the specificity 100% for MRC in detecting common bile duct stones. The sensitivity and specificity of ERCP were respectively 94% and 100%, versus 93.5% and 93.3% for IOC. There was no statistically significant difference, however, between MRC and the other techniques.

CONCLUSION

MRC is a key technique in the preoperative diagnosis of choledocholithiasis. Its diagnostic value is comparable to ERCP, but it appears to be more specific than IOC. Nevertheless, its diagnostic capability remains limited in cases of microlithiasis and cholangitis.

MR imaging findings of infectious cholangitis

The purpose of this study was to evaluate the appearance of infectious cholangitis on MRI. The MR images of 13 patients (9 women, 4 men; age range, 14-79 years) with clinically confirmed infectious cholangitis, who represent our complete 9.5 year experience with this entity, were retrospectively evaluated. All MR studies were performed at 1.5 T and included: in-phase and out-of-phase T(1)-weighted spoiled gradient echo (SGE), T(2)-weighted fat-suppressed echo train spin echo, single shot T(2)-weighted sequences, and serial postgadolinium T(1)-weighted SGE sequences without and with fat-suppression. The biliary ductal system was evaluated regarding presence of dilatation, stenosis, wall irregularities, wall thickening, and gadolinium enhancement of duct walls. The liver parenchyma was evaluated regarding focal signal abnormalities on precontrast and serial postgadolinium images. Biliary ductal dilatation was observed in 100% of patients. Mild to moderate thickening of bile duct walls combined with increased enhancement on postgadolinium images was observed in 92% of patients. The liver parenchyma showed periportal or wedge-shaped areas of hyperintense signal on T(2)-weighted images in 69% of patients. On T(1)-weighted images, 54% of patients showed areas of hypointense signal and 15% of patients showed wedge-shaped hyperintense areas. Areas with increased enhancement on immediate postgadolinium SGE were observed in 58% of patients, and in 42% of patients increased enhancement persisted on 2 min postgadolinium fat-suppressed images. Distinctive MRI findings on pre- and postgadolinium images are appreciated for infectious cholangitis.

MR cholangiopancreatography of pancreaticobiliary diseases: comparison of single-shot RARE and multislice HASTE sequences

AIMS

We prospectively compared two breath-hold magnetic resonance cholangiopancreatography (MRCP) sequences: single-shot rapid acquisition with relaxation enhancement (RARE) and multislice half-Fourier acquisition single-shot turbo spin echo (HASTE) in imaging the pancreaticobiliary system.

PATIENTS AND METHODS

The diagnostic accuracy of single-shot RARE and multislice HASTE was studied in 34 subjects who had undergone conventional cholangiopancreatography. Overall image quality, duct conspicuity, image artifact, signal intensity and contrast-to-noise ratios were assessed independently by two radiologists who were unaware of the underlying diagnosis.

RESULTS

Both sequences had comparable diagnostic accuracy regarding a normal biliary system, choledocholithiasis, extra-hepatic and intra-hepatic strictures. Single-shot RARE was superior to multislice HASTE in diagnosing a normal pancreatic system, pancreatic and intrahepatic duct strictures, while providing significantly better image quality (mean +/- SE 3.7 +/- 0.07 vs 3.3 +/- 0.08: P = 0.02) and significantly less image artifact (mean +/- SE 3.6 +/- 0.07 vs 3.2 +/- 0.08: P = 0.01). Single-shot RARE provided significantly better duct conspicuity regarding the pancreatic duct within the body (2.7 +/- 0.2 vs 2.1 +/- 0.2: P = 0.003) and tail (2.4 +/- 0.2 vs 1.6 +/- 0.2;P = 0.0001), as well as the intrahepatic ducts (3.0 +/- 0.1 vs 2.6 +/- 0.1: P = 0.004) but there was no significant difference regarding the remainder of the biliary tree.

CONCLUSION

Single-shot RARE provides superior image quality, duct conspicuity with the added advantage of less image artifact and shorter acquisition time. However, volume averaging can cause common bile duct stones to be missed. Therefore, multislice HASTE sequences should still be acquired if choledocholithiasis is suspected. Larger studies are required to assess the diagnostic efficacy of single-shot RARE sequences in pancreatic duct and intra-hepatic duct disease.Morrin, M. M. (2000). Clinical Radiology55, 866-873.

Magnetic resonance cholangiography in patients with biliary disease: its role in primary sclerosing cholangitis

BACKGROUND/AIM

Magnetic resonance cholangiography (MRC) is a non-invasive diagnostic procedure whose role in the management of patients with primary sclerosing cholangitis (PSC) is unclear. The aim of this study was to determine the usefulness of MRC in the evaluation of the biliary tree in patients with suspected biliary disease, and in particular, PSC.

METHODS

MRC and invasive cholangiography (ERCP or PTC) were both performed in 73 patients, (33 male, 40 female, mean age 56 years) with clinical and/or biochemical evidence of cholestasis. Images were interpreted by two radiologists unaware of the results of other studies.

RESULTS

Forty-two patients (58%) had benign biliary disease, including 23 patients (32%) with PSC; 9 patients (12%) had malignant biliary disease; and 22 patients (30%) had a normal biliary tree. Diagnostic quality images were obtained in 73/73 (100%) of MRC, and in 70/73 (96%) of invasive cholangiography (68 ERCP's, 2 PTC's) procedures. Using ERCP/PTC findings as the reference standard, MRC had an accuracy greater than 90% in the diagnosis of normal bile ducts, biliary dilatation, biliary obstruction, bile duct stones, and PSC. Using the final diagnosis, MRC had an overall diagnostic accuracy of 90% in the detection of biliary disease compared to 97% for invasive cholangiography. Additional diagnostic/therapeutic interventions were performed during ERCP in 73% of patients with PSC and in 43% of patients without PSC (p=0.02).

CONCLUSIONS

MRC has excellent diagnostic accuracy in the presence of biliary disease. Because of its noninvasive nature, MRC may have advantages over invasive cholangiography when diagnosis is the major goal of the procedure.

Diagnosing bile duct stones: comparison of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography

OBJECTIVE

In this investigation we compared the diagnostic performance of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography for the diagnosis of choledocholithiasis.

SUBJECTS AND METHODS

Fifty-one patients referred for endoscopic retrograde cholangiography of suspected biliary stones were studied with unenhanced helical CT, MR cholangiography, and helical CT performed after oral administration of a cholangiographic contrast agent (iopodic acid). The studies were randomized for interpretation. Two radiologists evaluated the images by consensus and determined the presence and location of stones. We used retrograde cholangiography findings as the standard of reference. Sensitivity and specificity (with 95% confidence intervals [CIs]) of the three examinations were calculated and compared using the exact form of the McNemar test.

RESULTS

Bile duct stones were revealed with retrograde cholangiography in 26 patients (51%). Sensitivity was 65% (95% CI, 44.4-82%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 96% (95% CI, 78-99%) for MR cholangiography. Specificity was 84% (95% CI, 63-95%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 100% (95% CI, 83-100%) for MR cholangiography. The sensitivity of CT cholangiography and MR cholangiography was significantly higher than that of unenhanced helical CT (p<0.01). Differences in specificity were not significant.

CONCLUSION

Our results indicate that oral contrast-enhanced CT cholangiography and MR cholangiography are significantly more sensitive than unenhanced helical CT for the detection of bile duct calculi.

Magnetic resonance imaging and diseases of the liver and biliary tract. Part 2. Magnetic resonance cholangiography and angiography and conclusions

Magnetic resonance cholangiography (MRC) relies on the strong T2 signal from stationary liquids, in this case bile, to generate images. No contrast agents are required, and the failure rate and risk of serious complications is lower than with endoscopic retrograde cholangiopancreatography (ERCP). Data from MRC can be summated to produce an image much like the cholangiogram obtained by using ERCP. In addition, MRC and conventional MRI can provide information about the biliary and other anatomy above and below a biliary obstruction. This provides information for therapeutic intervention that is probably most useful for hilar and intrahepatic biliary obstruction. Magnetic resonance cholangiography appears to be similar to ERCP with respect to sensitivity and specificity in detecting lesions causing biliary obstruction, and in the diagnosis of choledocholithiasis. It is also suited to the assessment of biliary anatomy (including the assessment of surgical bile-duct injuries) and intrahepatic biliary pathology. However, ERCP can be therapeutic as well as diagnostic, and MRC should be limited to situations where intervention is unlikely, where intrahepatic or hilar pathology is suspected, to delineate the biliary anatomy prior to other interventions, or after failed or inadequate ERCP. Magnetic resonance angiography (MRA) relies on the properties of flowing liquids to generate images. It is particularly suited to assessment of the hepatic vasculature and appears as good as conventional angiography. It has been shown to be useful in delineating vascular anatomy prior to liver transplantation or insertion of a transjugular intrahepatic portasystemic shunt. Magnetic resonance angiography may also be useful in predicting subsequent variceal haemorrhage in patients with oesophageal varices.

MR cholangiopancreatography of bile and pancreatic duct abnormalities with emphasis on the single-shot fast spin-echo technique

Magnetic resonance cholangiopancreatography (MRCP) is used for noninvasive work-up of patients with pancreaticobiliary disease. MRCP is comparable with invasive endoscopic retrograde cholangiopancreatography (ERCP) for diagnosis of extrahepatic bile duct abnormalities. In patients with choledocholithiasis, calculi appear as dark filling defects within the high-signal-intensity fluid at MRCP. Benign strictures due to sclerosing cholangitis are multifocal and alternate with slight dilatation or normal-caliber bile ducts, producing a beaded appearance. Dilatation of both the pancreatic and bile ducts at MRCP is highly suggestive of a pancreatic head malignancy. Side-branch ectasia is the most prominent and specific feature of chronic pancreatitis. MRCP is more sensitive than ERCP in detection of pancreatic pseudocysts because less than 50% of pseudocysts fill with contrast material. Because the mucin secreted by biliary cystadenomas and cystadenocarcinomas causes filling defects and partial obstruction of contrast material at ERCP, MRCP is potentially more accurate in demonstrating the extent of these tumors. In patients with biliary-enteric anastomoses, MRCP is the imaging modality of choice for the work-up of suspected pancreaticobiliary disease. A potential use of MRCP is the demonstration of aberrant bile duct anatomy before cholecystectomy. MRCP is also accurate in detection of pancreas divisum.

Radiologic manifestations of sclerosing cholangitis with emphasis on MR cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) is a relatively new, noninvasive cholangiographic technique that is comparable with invasive endoscopic retrograde cholangiopancreatography (ERCP) in the detection and characterization of extrahepatic bile duct abnormalities. The role of MRCP in evaluation of the intrahepatic bile ducts, especially in patients with primary or secondary sclerosing cholangitis, is under investigation. The key cholangiographic features of primary sclerosing cholangitis are randomly distributed annular strictures out of proportion to upstream dilatation. As the fibrosing process worsens, strictures increase and the ducts become obliterated, and the peripheral ducts cannot be visualized to the periphery of the liver at ERCP. In addition, the acute angles formed with the central ducts become more obtuse. With further progression, strictures of the central ducts prevent peripheral ductal opacification at ERCP. Cholangiocarcinoma occurs in 10%-15% of patients with primary sclerosing cholangitis; cholangiographic features that suggest cholangiocarcinoma include irregular high-grade ductal narrowing with shouldered margins, rapid progression of strictures, marked ductal dilatation proximal to strictures, and polypoid lesions. Secondary sclerosing and nonsclerosing processes can mimic primary sclerosing cholangitis at cholangiography. These processes include ascending cholangitis, oriental cholangiohepatitis, acquired immunodeficiency syndrome-related cholangitis, chemotherapy-induced cholangitis, ischemic cholangitis after liver transplantation, eosinophilic cholangitis, and metastases.

Detection of choledocholithiasis with MR cholangiography: comparison of three-dimensional fast spin-echo and single- and multisection half-Fourier rapid acquisition with relaxation enhancement sequences

PURPOSE

To compare the performance of three pulse sequences commonly used at magnetic resonance (MR) cholangiography in the diagnosis of choledocholithiasis.

MATERIALS AND METHODS

MR cholangiography was performed in 57 patients who were suspected of having choledocholithiasis and referred for endoscopic retrograde cholangiography. Non-breath-hold three-dimensional fast spin-echo, breath-hold single-section half-Fourier rapid acquisition with relaxation enhancement (RARE), and breath-hold multisection half-Fourier RARE sequences were compared. Two radiologists independently interpreted the MR cholangiograms. Evaluated diagnostic performance parameters included sensitivity, specificity, receiver operating characteristic (ROC) curves, and interobserver agreement (kappa statistics). Endoscopic retrograde cholangiography was the standard of reference.

RESULTS

Eight patients were excluded because of incomplete MR examinations (n = 4) or failure in the cannulation of the bile duct at retrograde cholangiography (n = 4). In 49 patients, the three MR cholangiographic sequences were completed successfully. In 24 (49%) of these patients, retrograde cholangiography demonstrated stones. Sensitivity and specificity of MR cholangiography exceeded 90%, and the area under the ROC curve was greater than 0.95 for both radiologists and for the three sequences. Interobserver agreement for presence of bile duct stones was at least 0.80 (very good) for the three sequences.

CONCLUSION

The three MR cholangiographic sequences had similarly high sensitivities and specificities for the detection of choledocholithiasis.