MR cholangiopancreatography

Comparison of respiratory-triggered 3D MR cholangiopancreatography and breath-hold compressed-sensing 3D MR cholangiopancreatography at 1.5 T and 3 T and impact of individual factors on image quality

PURPOSE

To evaluate the image quality of an accelerated compressed-sensing single-breath-hold 3D magnetic resonance cholangiopancreatography (BH-CS-MRCP) prototype sequence compared to the standard 3D sequence with respiratory triggering (STD-MRCP) at 1.5 T and 3 T. To assess the individual factors that can affect image quality.

METHOD

This is a retrospective analysis. Both sequences (BH-CS-MRCP and STD-MRCP) were performed in 200 patients at 1.5 T and 200 patients at 3 T. Overall image quality and the visualization of the bilio-pancreatic ducts were rated on a 5-point scale. Image sharpness and background suppression were rated on a 4-point scale. A double reading was performed in 50 patients to assess the inter-observer reproducibility. Individual characteristics studied were gender, age, BMI, ascites, abdominal surface and breath-hold quality.

RESULTS

At 1.5 T, BH-CS-MRCP was inferior to STD-MRCP in terms of overall quality (p = 0.0046), background suppression (p < 0.0001), visualization of the cystic duct (p < 0.0001), the right bile duct (p = 0.0008), the left bile duct (p = 0.0152), and the main pancreatic duct (p < 0.0001). However, BH-CS-MRCP was sharper than STD-MRCP (p = 0.028). At 3 T, BH-CS-MRCP was superior to STD-MRCP for overall quality (p < 0.0001), sharpness (p < 0.0001), and visualization of the bilio-pancreatic ducts (p < 0.0001). Background signal was conversely better suppressed in STD-MRCP (p < 0.0001). At 1.5 T, the volume of ascites was inversely correlated with image quality for BH-CS-MRCP while BMI was inversely correlated with image quality for STD-MRCP. Breath-hold quality was correlated with image quality for BH-CS-MRCP at 1.5 T and 3 T.

CONCLUSION

BH-CS-MRCP is feasible in clinical routine at 1.5 and 3 T, yielding significantly better perceived image quality at 3 T but not at 1.5 T. BH-CS-MRCP appears to be influenced by ascites whereas STD-MRCP is influenced by BMI at 1.5 T. This study was approved by the Ethics Review Board for Research in Medical Imaging (IRB: CRM-2003-065).

Imaging during pregnancy: What the radiologist needs to know

During the last decades, there has been a growing demand for medical imaging in gravid women. Imaging of the pregnant woman is challenging as it involves both the mother and the fetus and, consequently, several medical, ethical, or legal considerations are likely to be raised. Theoretically, all currently available imaging modalities may be used for the evaluation of the pregnant woman; however, in practice, confusion regarding the safety of the fetus often results in unnecessary avoidance of useful diagnostic tests, especially those involving ionizing radiation. This review article is focused on the current safety guidelines and considerations regarding the use of different imaging modalities in the pregnant population; also presented is an imaging work-up for the most common medical conditions of pregnant women, with emphasis on fetal and maternal safety.

Magnetic resonance cholangiography: Current and future perspectives

Magnetic resonance cholangiography (MRC) has become the standard of reference for imaging of the biliary ducts. The use of three-dimensional (3D) sequences has resulted in improved spatial resolution with virtually isotropic voxel and improved signal/noise ratio. In addition to MRC images, 3D fat suppressed T1-weighted MR images should be systematically obtained to search for intrahepatic calculi. MRC plays a major role in the diagnosis of cholangiocarcinoma and assessment of its resectability. With modern MR systems the performance of MR is basically the same that of CT for evaluation of arterial and portal vein extent. MRC is a key imaging modality for the diagnosis of primary sclerosing cholangitis. Different imaging patterns may be observed including multifocal intra- and extrahepatic strictures alternating with slightly dilated ducts. Focal signal abnormality of the liver parenchyma and focal parenchymal atrophy represent the consequences of biliary duct obstruction on liver parenchyma. Diagnosis of biliary lithiasis is performed by combination of MRC and T1-weighted MR imaging. MRC can be performed for the diagnosis of secondary cholangitis including ascending cholangitis, ischemic cholangitis and IgG4-related sclerosing cholangitis. Hepatobiliary contrast agents could be used for demonstrating the site of biliary duct leakage after surgery and for functional imaging. MR imaging can also be used to determine the prognosis of PSC. The inherent limitations of MRC of bile ducts are still the suboptimal spatial resolution for evaluation of distal intrahepatic biliary ducts.

MR cholangiopancreatography of the pancreas and biliary system: a review of the current applications

MR cholangiopancreatography (MRCP) is still a rapidly evolving technique, but it has been already accepted as clinically useful and is widely used to evaluate biliary or pancreatic diseases. The advantages of this technique are that it does not use contrast media or ionizing radiation, it is noninvasive and complication free, and the examination is relatively short. MRCP has high sensitivity and specificity for diagnosing biliary dilatation and for determining the site and cause of stenosis. With further improvements of hardware and technique, MRCP is expected to replace diagnostic endoscopic retrograde cholangiopancreatography to examine the biliary and pancreatic ducts in the near future. The other applications include evaluation of primary sclerosing cholangitis, stenosis after liver transplantation, and bilioenteric anastomoses. This article reviews the current applications of MRCP in the evaluation of the pancreas and the biliary system.

Imaging of pregnant and lactating patients: part 2, evidence-based review and recommendations

OBJECTIVE

The objectives of this article are to discuss the current evidence-based recommendations regarding the use of diagnostic imaging in the evaluation of pulmonary embolism, appendicitis, urolithiasis, and cholelithiasis during pregnancy.

CONCLUSION

Diagnostic imaging should be performed during pregnancy only with an understanding of the maternal and fetal risks and benefits, the comparative advantages of different modalities, and the unique anatomic and physiologic issues associated with pregnancy.

Clinical usefulness of diffusion-weighted MR imaging for detection of pancreatic cancer: comparison with enhanced multidetector-row CT

PURPOSE

The aim of this study was to compare diffusion-weighted magnetic resonance imaging (DWI) and multidetector-row computed tomography (MDCT) for detection of primary pancreatic cancer by reviewing images of patients at high risk for pancreatic cancer with main pancreatic duct (MPD) dilatation shown by magnetic resonance cholangiopancreatography (MRCP).

METHODS

From October 2007 to September 2009, 83 patients who had undergone both DWI and MDCT with MPD dilatation were identified and were reviewed by four readers (2 radiologists and 2 gastroenterology fellows). Diagnostic performance in pancreatic cancer detection was evaluated with 95% confidence intervals. Statistically significant differences in the detection of pancreatic cancer between DWI and MDCT were compared by receiver operating characteristics and the confidence of the diagnosis by the paired t test.

RESULTS

Thirty-two of 83 patients were diagnosed with primary pancreatic cancer by histological evaluation of 15 surgical and 2 endoscopic ultrasound-guided fine needle aspiration samples, and by the clinical course for 15 lesions. Overall average accuracies of pancreatic cancer detection by the four readers were 84% with DWI and 86% with MDCT.

CONCLUSION

Performance of DWI and MDCT was equivocal for detection of pancreatic cancer in a high-risk population with MPD dilatation. The combination of MRCP and DWI for detection of pancreatic cancer allowed identification of a high-risk population and tumor detection with a single imaging modality with no need for contrast medium.

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.

Magnetic resonance cholangiopancreatography for the diagnostic evaluation of autoimmune pancreatitis

OBJECTIVE

The aim of this study was to determine the role of magnetic resonance cholangiopancreatography (MRCP) for diagnosing autoimmune pancreatitis (AIP) and the accuracy of MRCP in depicting the main pancreatic duct (MPD) morphology of AIP using endoscopic retrograde cholangiopancreatography (ERCP) as the reference standard.

METHODS

Thirty-eight AIP patients, 40 pancreatic cancer patients, and 40 patients with normal pancreas were included. MRCP was interpreted in association with cross-sectional magnetic resonance images regarding MPD morphology, pancreatic parenchyma, and extrapancreatic abnormalities. Main pancreatic duct was interpreted as narrowed when a narrowed-appearing segment on MRCP was associated with upstream dilatation or pancreatic parenchymal abnormalities in the same location.

RESULTS

Accuracy of MRCP for depicting MPD morphology of AIP (64.7% [22/34]) was lower than those for pancreatic cancer (88.5% [23/26]) (P = 0.041) or normal pancreas (100% [40/40]) (P < 0.0005). The inaccuracy in AIP was primarily (10/12) due to overestimation of MPD narrowing. Of various differing MRCP findings between AIP and pancreatic cancer, multiple MPD narrowing (AIP vs cancer, 27/38 vs 0/40) and upstream MPD dilatation greater than 5 mm in diameter (AIP vs cancer, 0/38 vs 10/40) could exclude pancreatic cancer and AIP, respectively.

CONCLUSIONS

MRCP cannot replace ERCP for the diagnostic evaluation of AIP but may deserve to be used when ERCP has been unsuccessful or is difficult to perform.

Differentiation of benign and malignant ampullary obstructions on MR imaging

OBJECTIVE

To define diagnostic criteria for differentiating malignant ampullary carcinoma from benign ampullary obstruction on MR imaging.

MATERIALS AND METHODS

Nineteen patients with ampullary carcinoma and 22 patients with benign ampullary obstruction were enrolled. At the first session, two radiologists independently evaluated specific imaging findings, and then reached consensus decisions. At the second session, another two radiologists, who were informed about useful differentiation criteria based on the results from the first session, reviewed images and determined the causes of ampullary obstruction. Sensitivity and specificity were calculated for each interpretation session, and the Cohen κ statistic was used to evaluate interobserver agreement.

RESULTS

Findings of the presence of an ampullary mass (P<0.001), papillary bulging (P<0.001), irregular (P=0.021) and asymmetric (P<0.001) common bile duct (CBD) narrowing, and proportional biliary dilatation (P<0.001) were more commonly seen in patients with an ampullary carcinoma. The sensitivity and specificity of the first session were 84.2% and 86.4% after consensus. The sensitivity increased to 100% for both the readers at the second session, while the specificity decreased to 63.6% and 59.1%, respectively.

CONCLUSIONS

Identification of an ampullary mass, papillary bulging, irregular and asymmetric narrowing of the CBD, or proportional biliary dilatation may improve the diagnosis of ampullary carcinoma in patients with ampullary obstruction.

Clinical feasibility of Açai (Euterpe olerácea) pulp as an oral contrast agent for magnetic resonance cholangiopancreatography

BACKGROUND

We evaluate the effectiveness of the Amazonian fruit pulp from Euterpe olerácea (popularly named Açaí) as a negative oral contrast agent applied to clinical routine. The use of such contrasts is particularly important in magnetic resonance cholangiopancreatography (MRCP) to reduce overlapping.

MATERIALS AND METHODS

We administered Açaí pulp to 5 nonsymptomatic subjects and 35 patients submitted to unspecific abdominal MR imaging, intending to set up optimal protocol. In 8 MRCP examinations, contrast and image effects were assessed and graded blindly by 2 independent radiologists. Quantitative analysis was performed by Wilcoxon test as to verify the potential of the Açaí to eliminate overlap signal over the pancreaticobiliary tract. Adverse effects and subject tolerance were also addressed.

RESULTS

The Açaí pulp elicited a local brightness decrease in T2-weighted images. The depiction of gallbladder, common bile duct, ampulla of Vater, and pancreatic duct was markedly improved after Açaí ingestion because of the suppression of the overlapping from bowel loops and gastric content (P < 0.01). All patients considered Açaí palatable, and no side effect was registered.

CONCLUSIONS

The Açaí pulp can be used routinely in MRCP studies as a natural, safe, and inexpensive negative oral contrast agent with high efficacy and patient acceptance.

The role of MR cholangiopancreatography in the evaluation of pregnant patients with acute pancreaticobiliary disease

This study aimed to determine the usefulness of MR cholangiopancreatography (MRCP) in the evaluation of pregnant patients with acute pancreaticobiliary disease and its additional value over ultrasound. MRI studies of pregnant patients who were referred because of acute pancreaticobiliary disease were included. MR images and patient charts were reviewed retrospectively to determine clinical outcome and the results of other imaging studies. 18 pregnant patients underwent MRCP because of right upper quadrant pain (n = 6), pancreatitis (n = 9), cholangitis (n = 1) or jaundice (n = 2). 15 patients were also evaluated with ultrasound. Biliary dilatation was detected in eight patients by ultrasound, but the cause of biliary dilatation could not be determined by ultrasound in seven patients. MRCP demonstrated the aetiology in four of these patients (choledocholithiasis (n = 1), Mirizzi syndrome (n = 1), choledochal cyst (n = 1) and intrahepatic biliary stones (n = 1)) and excluded obstructive pathology in the other four patients. MRCP was unremarkable in the seven patients who had no biliary dilatation on ultrasound. Three patients underwent only MRCP; two had choledocholithiasis and one cholelithiasis and pancreatitis. Choledocholithiasis diagnosed with MRCP (n = 3) was confirmed by endoscopic retrograde cholangiopancreatography. Mirizzi syndrome (n = 1) and a choledochal cyst (n = 1) were confirmed by surgery. The patients with normal MRCP (n = 12) and one patient with intrahepatic stones improved with medical treatment. MRCP appears to be a valuable and safe technique for the evaluation of pregnant patients with acute pancreaticobiliary disease. Especially when ultrasound shows biliary dilatation, MRCP can determine the aetiology and save the patient from unnecessary endoscopic retrograde cholangiopancreatography by excluding a biliary pathology.

Ampulla of Vater: comprehensive anatomy, MR imaging of pathologic conditions, and correlation with endoscopy

Endoscopic retrograde cholangiopancreaticography with or without an endoscopic biopsy is the method for making a definitive diagnosis of disease in or around the ampulla of Vater. However, the endoscopic findings of neoplastic and non-neoplastic conditions involving the perimapullary area may be similar and an endoscopic assessment is not entirely reliable for diagnosis. Recent MR and MRCP can allow the detection of lesions in a small complex structure such as the ampulla of Vater, and distinguish between an ampullary from periampullary lesion. This article reviews the normal anatomy of the ampulla of Vater, describes the role of MR in the detection and characterization of the lesion in or around the ampulla of Vater, and attempts to correlate them with ERCP.

Magnetic resonance imaging in the detection of pancreatic neoplasms

Recently, with the rapid scanning time and improved image quality, outstanding advances in magnetic resonance (MR) methods have resulted in an increase in the use of MRI for patients with a variety of pancreatic neoplasms. MR multi-imaging protocol, which includes MR cross-sectional imaging, MR cholangiopancreatography and dynamic contrast-enhanced MR angiography, integrates the advantages of various special imaging techniques. The non-invasive all-in-one MR multi-imaging techniques may provide the comprehensive information needed for the preoperative diagnosis and evaluation of pancreatic neoplasms. Pancreatic neoplasms include primary tumors and pancreatic metastases. Primary tumors of the pancreas may be mainly classified as ductal adenocarcinomas, cystic tumors and islet cell tumors (ICT). Pancreatic adenocarcinomas can be diagnosed in a MRI study depending on direct evidence or both direct and indirect evidence. The combined MRI features of a focal pancreatic mass, pancreatic duct dilatation and parenchymal atrophy are highly suggestive of a ductal adenocarcinoma. Most cystic neoplasms of the pancreas are either microcystic adenomas or mucinous cystic neoplasms. Intraductal papillary mucinous tumors are the uncommon low-grade malignancy of the pancreatic duct. ICT are rare neoplasms arising from neuroendocrine cells in the pancreas or the periampullary region. ICT are classified as functioning and non-functioning. The most frequent tumors to metastasize to the pancreas are cancers of the breast, lung, kidney and melanoma. The majority of metastases present as large solitary masses with well-defined margins.

A case of choledochocele mimicking choledocholithiasis on MR cholangiography: A new differential diagnosis of pseudo-filling defect

We present the case of a 79-year-old female with acute cholangitis and cholecystitis who presented with right upper quadrant pain. Thin-collimation MR cholangiogram showed a filling defect measuring 1 cm, which was less prominent on single-slab images. Endoscopy showed dynamic ballooning and collapsing of the ampulla of Vater, and a cholangiogram showed characteristic bulging at the distal common bile duct, which led to the diagnosis of choledochocele. It is important to differentiate choledochocele as a cause of filling defect of the lower common bile duct on the MR cholangiogram.

Isotropic 3D T2-Weighted MR Cholangiopancreatography with Parallel Imaging: Feasibility Study

OBJECTIVE

The aim of this study was to compare the quality of images obtained with fast 3D T2-weighted turbo spin-echo (TSE) MR cholangiopancreatography (MRCP) sequences and 1-mm isotropic voxels with the quality of conventional 2D MRCP images.

SUBJECTS AND METHODS

Thirty consecutively registered patients (14 women, 16 men; average age, 60.2 years; age range, 32-87 years) underwent imaging at 1.5 T with a 6-element body array coil. All imaging was performed with three MRCP techniques: free-breathing 3D T2-weighted TSE (TR/TE, 1,300/680; flip angle, 180 degrees; field of view, 250-300 mm; matrix size, 256 x 256; slice thickness, 1 mm; parallel acquisition technique factor, 2); breath-hold 3D T2-weighted TSE (same parameters as the free-breathing 3D technique); breath-hold coronal and oblique coronal thick-slab 2D TSE without parallel acquisition technique (2,800/1,100; flip angle, 150-180 degrees). Quantitative measures of image signal and contrast were evaluated by analysis of variance and paired Student's t tests. A 5-point scale (1, nondiagnostic, to 5, high diagnostic confidence) was used to compare the 3D and 2D data sets for image quality and definition of biliary and pancreatic ductal anatomic features. Friedman's nonparametric and Wilcoxon's rank sum tests were performed for statistical analysis of the qualitative assessments.

RESULTS

Quantitative results showed free-breathing and breath-hold 3D TSE images had significantly higher relative signal intensity and contrast than 2D TSE images (p < 0.0001). The qualitative findings showed that both free-breathing and breath-hold 3D TSE techniques gave better delineation of biliary anatomy (p < 0.0001) than the 2D technique. The overall quality of 3D images was better than that of 2D images, and 3D imaging was better at depicting pancreatic ducts, although the difference did not reach statistical significance.

CONCLUSION

Three-dimensional volumetric MRCP images are of superior quality and give better delineation of pancreaticobiliary anatomy than conventional 2D images and have the added advantage of multiplanar and postprocessing capabilities.

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.

Preoperative evaluation of pancreaticobiliary tumor using MR multi-imaging techniques

AIM: To evaluate the clinical value of MR multi-imaging techniques in diagnosing and preoperative assessment of pancreaticobiliary tumor.

METHODS: MR multi-imaging techniques, including MR cross-sectional imaging, MR cholangiopancreatography (MRCP) and 3D dynamic contrast-enhanced MR angiography (3D DCE MRA), were performed to make prospective diagnosis and preoperative evaluation in 28 patients with suspected pancreaticobiliary tumors. There were 17 cases of pancreatic adenocarcinoma, 8 cases of biliary system carcinoma and 3 cases of non-neoplastic lesions.

RESULTS: Using MR multi-imaging techniques, the accuracy in diagnosing the patients with pancreaticobiliary tumors was 89.3% (25/28). The accuracy in detecting the range of tumor invasion was 80.3% (57/71). The sensitivity, specificity, accuracy, positive and negative predictive value of MR multi-imaging techniques in preoperative assessment of the resectability of pancreaticobiliary tumor were 83.3%, 89.5%, 88.0%, 71.4%, and 94.4%, respectively. There was well diagnostic consistency between MR multi-imaging techniques and CT (κ = 0.64, P<0.01). The fusion image could be made from MRCP and 3D DCE MRA images.

CONCLUSION: MR multi-imaging techniques can integrate the advantages of various MR images. The non-invasive “all-in-one” MR imaging protocol is the efficient method in diagnosing, staging and preoperative assessment of pancreaticobiliary tumor.

MRCP evaluation of biliary system following vagotomy and gastric surgery

OBJECTIVE

The aim of this study was to show the usefulness of MR cholangiopancreatography (MRCP) in demonstrating biliary system pathologies in patients with a history of vagotomy and Billroth II operations.

METHODS

The hepatobiliary system of eight patients with a history of vagotomy and Billroth II operations was evaluated with MRCP. Three-dimensional fast spin-echo technique was used at a 1.0-T scanner with following parameters: TR=2857-4615 ms, TE=850-1117 ms, BW=31.2, FOV=40, 21-28 slices, NEX=0.5, scan time = 90 s.

RESULTS

Eight patients were evaluated with MRCP. Three patients had cholecystectomy. In one patient the gall bladder wall was thickened, accompanied with an irregular, unknown filling defect at the level of the fundus. Four of these patients had common bile duct stones. Two patients had gallstones and one patient had a stone in the common hepatic duct. A capping deformity of the distal common bile duct was observed in all of the patients.

CONCLUSION

We conclude that MRCP can be used effectively for evaluation of biliary system of patients with previous history of biliary or gastric operations.

Evaluation of magnetic resonance cholangiography in patients with suspected common bile duct stones before laparoscopic cholecystectomy

AIM: To evaluate the clinical predictive value of magnetic resonance cholangiography (MRC) in selected patients before laparoscopic cholecystectomy (LC).

METHODS: A total of 267 patients scheduled for elective LC from March 1999 to May 2001, with risk factors for common bile duct (CBD) stones, underwent MRC followed by endoscopic retrograde cholangiography (ERC) or intraoperative cholangiography (IOC) to detect the stones in common bile duct and value accuracy of MRC. Suspected patient selection was based on clinical, ultrasonographic, and laboratory criteria. All those with a history of previous jaundice, previous mild gallstone pancreatitis (acute abdominal pain and at least a fourfold increase in serum amylase activity), abnormal liver function test results (especially abnormal bilirubin result) or a dilated common bile duct (more than 8 mm) on ultrasonography were considered to have high suspicion for choledocholithiasis.

RESULTS: During a 26-month period, 267 patients were studied. MRC identified all patients (78 patients) found to have CBD stones by ERC or laparoscopic cholangiography in the study group. 7 patients were incorrectly diagnosed as having CBD stones by MRC. In our study, MRC had a sensitivity of 100.0%, specificity of 96.3%, positive predictive value of 91.8% and negative predictive value of 100.0% for the detection of common bile duct stones. There were 19 patients (7.1%) occurring the ERC procedure-related complications; 11 patients were cholangitis, 7 pancreatitis, and 1 papillary bleeding. The information obtained from MRC could be utilized to select patients who would benefit from preoperative ERC. Using the information, 68.2% (182/267) patients in our group could be away from ERC and its distress. And the complications of preoperative examination would be minimized significantly.

CONCLUSION: ERC is an invasive technique with a well-documented complication rate. MRC is an accurate and simple non-invasive imaging technique for preoperative screening for CBD stones in at-risk patients, which could minimize the need for non-therapeutic ERC.

Successful endoscopic treatment of mediastinal pseudocysts

Mediastinal pseudocysts can pose a diagnostic and therapeutic challenge to the clinician and surgeon. Recognizing their presence and instituting appropriate therapy can reduce morbidity and mortality. This report describes unusual clinical features in a patient presenting with multiple mediastinal pseudocysts due to pancreatic duct leak secondary to pancreatic duct stenosis and an entrapment of a pancreatic duct stone. Successful endoscopic therapy averted the need for surgery.

[Diagnosis of biliary tract carcinoma]

There are several diagnostic tools available in the diagnosis of bile duct cancer. Tumors of the middle and distal part of the extrahepatic bile duct are accessible to endosonography. Endoscopic retrograde cholangiopancreatography (ERC) and percutaneous transhepatic cholangiography (PTC) are the most invasive procedures for diagnosis of bile duct cancer. However, they offer the opportunity to obtain material for cytological or histological investigation. Moreover, bile flow can be assured by inserting endoprostheses during the procedure. Cholangioscopy and/or intraductal ultrasonography can be performed during ERC. They confer to the diagnosis of a malignant bile duct tumor and are the most accurate methods to diagnose the extent of longitudinal spread. Magnetic resonance imaging-cholangiography is an efficient diagnostic procedure which should be used first, if the bile duct tumor is located in the hilar region.

MRCP in the diagnosis of iatrogenic bile duct injury

Postoperative biliary tract lesions are becoming increasingly common. The diagnosis is made by direct cholangiography via endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC). The present comparative study evaluates the diagnostic efficacy of magnetic resonance cholangiopancreatography (MRCP) in application to iatrogenic bile duct injury. A prospective blind study was performed, contrasting MRCP and ERCP in 10 patients with suspected postoperative biliary tract lesions. MRCP was performed less than 72 h before ERCP. Final diagnosis was made on the basis of findings at surgery and ERCP. The presence of biliary dilatation, excision injury, stricture, fluid collection and free fluid was analyzed. The mean patient age was 66.5 years. There were three males and seven females. The type of postoperative lesion (Bergman classification) are five patients type C, three type D, one type B and one type A. Diagnostic failure was recorded in two cases with ERCP, while in five patients it was unable to define a therapeutic approach. In contrast, MRCP correctly diagnosed all patients. MRCP is effective in diagnosing postoperative biliary tract lesions, and can help decide the best therapeutic approach.