MR cholangiography in biliary obstruction using half-Fourier acquisition

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography in Comparison With Endoscopic Retrograde Cholangiopancreatography for Detection of the Etiology of Obstructive Jaundice

BACKGROUND

Despite technological advances, obstructive jaundice has significant morbidity and mortality rates. When studying obstructive jaundice, endoscopic retrograde cholangiopancreatography (ERCP), the "gold standard" for biliary obstruction identification, might be replaced with magnetic resonance cholangiopancreatography (MRCP), which is a non-invasive procedure.

OBJECTIVE

Diagnostic accuracy of MRCP in comparison with ERCP for the detection of the etiology of obstructive jaundice.

METHODOLOGY

This prospective, observational study included 102 patients who presented with obstructive jaundice as proven by liver function tests. The MRCP was conducted within 24 to 72 hours before the ERCP. A torso phased-array coil (Siemens, Germany) was used for the MRCP. The duodeno-videoscope and general electric fluoroscopy were used to perform the ERCP. The MRCP was evaluated by a classified radiologist who was blinded to the clinical details. An experienced consultant gastroenterologist who was blinded to the results of the MRCP assessed the cholangiogram of each patient. The hepato-pancreaticobiliary system results from both procedures were compared based on the pathology observed, such as choledocholithiasis, pancreaticobiliary strictures, and dilatation of biliary strictures. We determined the sensitivity, specificity, and negative and positive predictive values with 95% confidence intervals. The statistical significance was set at p<0.05.

RESULTS

The most commonly reported pathology was choledocholithiasis, and MRCP diagnosed 55 patients, of which 53 were true positive cases when compared with the ERCP results of the same patients. MRCP demonstrated greater sensitivity and specificity (respectively) for screening choledocholithiasis (96.2, 91.8), cholelithiasis (100, 75.8), pancreatic duct stricture (100, 100), and hepatic duct mass (100, 100) and showed statistically significant values. The sensitivity of MRCP is lower for identifying benign and malignant strictures, but its specificity was observed to be reliable.

CONCLUSION

When it comes to determining the severity of obstructive jaundice, both in its early and later stages, the MRCP technique is widely regarded as a reliable means of diagnostic imaging. The diagnostic function of ERCP has been significantly reduced as a result of the precision of MRCP as well as its non-invasive nature. In addition to being a helpful non-invasive method to identify biliary diseases and avoid unnecessary ERCPs and their risks, MRCP offers good diagnostic accuracy for obstructive jaundice.

Diagnostic Performance of Ultrasonography Versus Magnetic Resonance Cholangiopancreatography in Biliary Obstruction

Background In a suspected case of biliary obstruction with clinical and laboratory data suggesting obstructive jaundice, the major goal is to confirm the presence of obstruction, its nature and cause, location, and extent. Ultrasonography (USG) and magnetic resonance cholangiopancreatography (MRCP) are primarily used to diagnose suspected biliary tract illnesses. The aim of the study is to evaluate and compare the accuracy of MRCP and USG with endoscopic retrograde cholangiopancreatography (ERCP)/surgical/histopathological outcomes for finding the cause and level of obstruction in the case of clinically suspected biliary obstruction. Methods This was a prospective observational study conducted at Kalinga Institute of Medical Sciences and Pradyumna Bal Memorial Hospital, Bhubaneswar, India, from September 2020 to September 2022 on 120 patients. It included patients with clinical suspicion of biliary obstruction who underwent both USG and MRCP. Characteristics of the obstruction were evaluated for both benign and malignant lesions through USG and MRCP. The findings were then correlated with ERCP, histopathology, or surgery to calculate the diagnostic performance of the former two modalities. Results Out of 120 patients, USG was correctly able to predict the cause of obstruction in 40 patients. The sensitivity, specificity, and accuracy of detecting the nature of obstruction by USG were 33.3%, 84%, and 48.9%, respectively. The overall diagnostic accuracy of USG in predicting the site of obstruction was 64.3%. MRCP was correctly able to predict the cause of obstruction in 113 patients. The sensitivity, specificity, and accuracy of detecting the nature of obstruction by MRCP were 94.1%, 91.9%, and 94.8% respectively. The overall diagnostic accuracy of MRCP in predicting the site of obstruction was 98.33%. Out of 120 patients, no cause of biliary obstruction could be found in 71 patients by USG, out of which the correct diagnosis was made in 67 patients through MRCP. Conclusion USG should be used as the initial screening modality of choice for predicting the level and nature of obstruction in patients with a clinical suspicion of obstructive jaundice. MRCP should be the radiological investigation of choice in patients with clinical suspicion of obstructive jaundice. MRCP has the potential to become the new "Gold standard" investigation for diagnosis in patients with biliary obstruction owing to its excellent diagnostic performance, and non-invasiveness.

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.

Assessment of the main pancreatic duct using computed tomography with multiplanar reconstructions

The aim of this study was to assess the morphology of the main pancreatic duct (MPD) using multiplanar reconstructions and to compare this with the morphology of the MPD of anatomic subjects.

MATERIALS AND METHODS

The morphology of the MPD was studied by means of multiplanar reconstructions obtained on the one hand from thin tomodensitometric slices and on the other hand from the dissection of anatomic subjects. This study involved 15 subjects in each group.

RESULTS

Full multiplanar reconstruction was obtained in 13 cases. In 2 cases, the isthmus did not appear in the reconstructions. The morphology of the MPD was similar in both groups. The length of the MPD was identical at the head and isthmus of the pancreas in both groups but was greater in the dissection group than in the reconstruction group in the body and tail areas of the pancreas. The diameter of the MPD was greater at the head of the pancreas in the dissection group and was identical in both groups for the other segments of the MPD.

CONCLUSIONS

Multiplanar tomodensitometric reconstruction of the main pancreatic duct is feasible. This new technique, currently under evaluation, could allow the study of canalar pathologies of the pancreas through tomodensitometry.

MR Imaging of the Gallbladder and Biliary System

MR imaging is an established technique for the diagnosis of a spectrum of biliary and gallbladder pathologies and continues to improve with the advent of technologic advances, including new contrast agents and new sequences that are capable of improving upon the contrast resolution and signal-to-noise that are afforded by conventional MR imaging. These improvements already have shown promise for the increasing role of MRC as the initial modality in assessing living liver donors and evaluating post-operative hepato-biliary complications. Improved spatial resolution and the added functional or physiologic information afforded by MR imaging promise ever expanding clinical applicability and usefulness.

The role of magnetic resonance cholangiography in the management of patients with gallstone pancreatitis

OBJECTIVE

To examine the utility of magnetic resonance cholangiography (MRC) in the preoperative evaluation of patients with gallstone pancreatitis.

SUMMARY BACKGROUND DATA

Gallstone pancreatitis is often associated with the presence of common bile duct (CBD) stones that may require endoscopic removal prior to planned laparoscopic cholecystectomy. No reliable clinical criteria exist, however, that can accurately predict CBD stones and the need for preoperative endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

Sixty-four patients were identified with gallstone pancreatitis based on clinical presentation and imaging studies over a three-and-a-half-year period. All patients underwent MRC, and the images were evaluated for gallstones, CBD stones, cholecystitis, and pancreatitis

RESULTS

Seventeen of the 64 patients (27%) with gallstone pancreatitis were found to have CBD stones confirmed by ERCP. MRC correctly predicted CBD stones in 16 of the 17 patients (sensitivity = 94%). In 1 additional patient, MRC demonstrated CBD stones not seen at ERCP, consistent with probable passage. By comparison, the sensitivities of other criteria for predicting CBD stones were (1) elevated bilirubin >or=2.0 mg/dL = 65%; (2) dilated duct on ultrasound = 55%; and (3) CBD stones on ultrasound = 27%. MRC was able to visualize gallbladder stones in 57 of 62 patients (94%) and correctly predicted acute cholecystitis in 6 of 8 patients. MRC also detected peripancreatic edema and inflammatory changes consistent with acute pancreatitis in 45 of 64 patients (70%).

CONCLUSIONS

These results demonstrate that MRC can accurately identify CBD stones preoperatively in patients with gallstone pancreatitis and provide valuable information with respect to other biliary pathology, including cholelithiasis, acute cholecystitis, and pancreatitis. MRC is an effective noninvasive screening tool for CBD stones, appropriately selecting candidates for preoperative ERCP and sparing others the need for an endoscopic procedure with its associated complications.

Magnetic resonance cholangiopancreatography in obstructive jaundice

GOALS

To determine the ability of magnetic resonance cholangiopancreatography (MRCP) to diagnose the level and cause of obstruction in patients with obstructive jaundice.

BACKGROUND

The limitations of available imaging modalities have led to the increasing use of MRCP, which is a noninvasive and highly accurate technique in evaluating patients with biliary obstruction.

STUDY

Thirty patients were included in this study. MRCP was done using a fat suppressed, heavily T2 weighted fast spin echo sequence. The MRCP findings were confirmed on surgical exploration or clinical follow-up.

RESULTS

MRCP could correctly identify ductal dilatation and the level of obstruction in all cases, except one. All causes of obstruction, except three, were detected. It failed to detect a common bile duct calculus in a minimally dilated ductal system and misdiagnosed a case of focal chronic pancreatitis as carcinoma head pancreas and a small pancreatic head mass as cholangiocarcinoma. It had a sensitivity of 94.44%, specificity of 81.81%, positive predictive value of 89.47%, and negative predictive value of 90% for the detection of malignant causes. The overall diagnostic accuracy for detection of level and cause of obstruction was 96.3% and 89.65%, respectively.

CONCLUSION

The high diagnostic accuracy of MRCP in evaluating patients with obstructive jaundice indicates that it has the potential to become the diagnostic modality of choice in such patients.

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).

Contribution of magnetic resonance cholangiopancreatography to the management of patients with suspected common bile duct stones

OBJECTIVES

To evaluate the value of magnetic resonance cholangiography (MRC) as a systematic first-line investigation in the management of patients with suspected common bile duct stones.

METHODS

Ninety-nine consecutive patients with clinical suspicion of choledocolithiasis were prospectively explored by MRC. All MRCs were interpreted by two radiologists with knowledge of the patient's clinical condition and laboratory results. In case of discrepancy, a third opinion was obtained to reach consensus. The definitive diagnosis was established on the basis of endoscopic exploration of the common bile duct (n=40), clinical and biological follow-up at 6 Months (n=55) or other investigations (n=4). The clinician's level of confidence, management options implemented, and impact of management decisions were used to assess the contribution of MRC. The diagnostic accuracy of MRC for common bile duct stones was also determined.

RESULTS

At the observed level of confidence (85.9%), MRC identified a differential diagnosis in 7.1% of patients avoiding unnecessary endoscopic exploration in 59.6%. Systematic first-line MRC enabled appropriate management in 83.8% of patients. The sensitivity, specificity, and positive and negative predictive values of MRC for the diagnosis of common bile duct stones were 95.7%, 98.7%, 95.7% and 98.7%, respectively, with excellent inter-observer agreement (kappa=0.915).

CONCLUSION

Magnetic resonance cholangiography can be used to efficiently screen patients who may need further invasive exploration of the common bile duct. It specifically identifies patients requiring therapeutic ERCP.

Thick-section half-Fourier rapid acquisition with relaxation enhancement MR cholangiopancreatography: effects of i.v. administration of gadolinium chelate

OBJECTIVE

Our purpose was to investigate the effects of i.v. administration of gadolinium chelate on thick-section MR cholangiopancreatography performed with half-Fourier rapid acquisition with relaxation enhancement sequence.

SUBJECTS AND METHODS

Unenhanced and enhanced MR cholangiopancreatograms obtained in 50 consecutive patients were quantitatively analyzed with region-of-interest measurements and were qualitatively evaluated by three independent radiologists unaware the patient information. A phantom study was performed to verify the effects.

RESULTS

The mean contrast-to-noise ratios of the gallbladder, common bile duct, and main pancreatic duct significantly increased after gadolinium chelate administration (p < 0.005). The mean depiction score of the main pancreatic duct increased significantly with one radiologist (p < 0.05) and marginally with another (p < 0.06), and the mean depiction scores of the background structures and renal pelvis significantly decreased with all three radiologists (p < 0.001). The phantom study showed the results, indicating that T2- and T2(*)-shortening effects of gadolinium chelate caused the effects in vivo.

CONCLUSION

i.v. administration of gadolinium chelate improves the depiction of pancreaticobiliary ducts in some selected patients, while decreasing the depiction in others with less frequency. There may be a value of enhanced MR cholangiopancreatography when unenhanced MR cholangiopancreatography is not sufficient.

MR characteristics of acute cholangitis

PURPOSE

To describe the MR appearance of acute cholangitis and discuss the role of MR imaging as a diagnostic method in this disease.

MATERIAL AND METHODS

Of 60 patients with clinical acute cholangitis, 12 were examined with MR before endoscopic retrograde pancreatography (ERCP). A retrospective review was performed of MR and ERCP findings. The MR findings registered were presence of biliary duct dilatation, intraluminal filling defects due to stones or sludge, bands of mucosal oedema of the biliary ducts, intra- and retroperitoneal oedema/fluid, and definition of the cause of obstruction, e.g. stones, stenosis or tumour was made.

RESULTS

Acute cholangitis was related to obstruction from choledocholithiasis (n=8), pancreatic cancer (n=1), benign biliary duct stricture (n=1), papillary stenosis (n=1) and without evidence of an obstructing cause (n=1). One patient had an acute obstructive suppurative (toxic) cholangitis.

CONCLUSION

MR imaging has a role in the non-invasive radiographic arsenal of techniques to confirm or exclude the diagnosis of acute cholangitis, especially in older patients where the clinical symptoms may be vague.

Prospective assessment of magnetic resonance cholangiopancreatography for noninvasive imaging of the biliary tree

BACKGROUND

Traditionally, ERCP has been the only reliable method for imaging the biliary tree, but it is invasive and carries a risk of complications. Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method for imaging the biliary tree. The aim of this study was to prospectively assess the accuracy of MRCP in a large number of patients.

METHODS

Consecutive patients referred to a teaching hospital for ERCP were eligible for study entry. MRCP was performed within 24 hours before ERCP. MRCP findings were compared with ERCP findings or, when the initial ERCP was unsuccessful, with results of repeat ERCP, percutaneous transhepatic cholangiography, or surgery.

RESULTS

One hundred forty-six patients underwent 149 ERCP/MRCP procedures, of which 129 were evaluable with successful MRCP and ERCP or an ERCP-equivalent study. Diagnoses included choledocholithiasis in 46 and biliary stricture in 12 patients. The sensitivity, specificity, positive, and negative predictive values for MRCP in the diagnosis of choledocholithiasis were 97.9%, 89.0%, 83.6%, and 98.6%, respectively. All 12 strictures were diagnosed by MRCP (sensitivity 100%, specificity 99.1%).

CONCLUSIONS

MRCP is an accurate, noninvasive alternative to ERCP for imaging the biliary tree. Choledocholithiasis and biliary strictures can be reliably diagnosed or excluded by MRCP. MRCP should be used increasingly in patients with suspected biliary obstruction to select those who require a therapeutic procedure.

MR and ultrasound in screening of patients with suspected biliary tract disease

PURPOSE

The diagnostic value and cost-efficiency of MR imaging were compared with US before endoscopic retrograde cholangiopancreatography (ERCP) in patients with clinically suspected biliary tract disease.

MATERIAL AND METHODS

In a prospective study of 219 patients, 85 were examined with both MR and US before ERCP.

RESULTS

To find the correct diagnosis in the jaundiced patients the sensitivity of US, MR and ERCP was 53%, 93%, and 89%, respectively. In the patients with abdominal upper quadrant pain and normal serum bilirubin, the sensitivity of US, MR and ERCP was 50%, 100% and 70%, respectively. Examination with MR costs four times more than US. Screening with US and supplemental MR in non-diagnostic cases would cost 80% of the total amount compared to screening with MR only.

CONCLUSION

MR had a higher sensitivity than US for diagnosing biliary tract disease and MR was superior to US in visualising stones in the common bile duct and in diagnosing the cause of cholestasis. However, screening with US and supplemental MR in non-diagnostic cases is at present most cost-effective. With increased accessibility and slightly lower costs, MR will probably replace US as screening method in patients with suspected biliary tract disease.

Mr cholangiography with volume rendering: receiver operating characteristic curve analysis in patients with choledocholithiasis

OBJECTIVE

The purpose of our study was to compare observer performances for the diagnosis of choledocholithiasis using MR cholangiography with volume-rendered, maximum-intensity-projection, and thick-section half-Fourier rapid acquisition with relaxation enhancement sequences.

MATERIALS AND METHODS

The images from three types of MR cholangiography performed on 43 patients with biliary calculi were retrospectively analyzed. Image review was conducted for two anatomic compartments (upper biliary tract and common bile duct). A total of 86 compartments, including 19 with bile duct calculi, were reviewed by three independent off-site gastrointestinal radiologists. Observer performance was determined by receiver operating characteristic curve analysis. Image quality was subjectively judged by three radiologists.

RESULTS

Sensitivity was higher with volume-rendered MR cholangiography (58%) than with thick-section (54%, not significant) and maximum-intensity-projection MR cholangiography (47%, p < 0.07). Specificity was higher with volume-rendered MR cholangiography (92%) than with thick-section (86%, p < 0.03) and maximum-intensity-projection MR cholangiography (88%, not significant). Accuracy was higher with volume-rendered MR cholangiography (84%) than with thick-section and maximum-intensity-projection MR cholangiography (79% for both, not significant). Observer performance with volume-rendered MR cholangiography (A(z) = 0.791--0.952) was better than that with thick-section (A(z) = 0.722--0.834) and maximum-intensity-projection MR cholangiography (A(z) = 0.771--0.887). Image quality was better with maximum-intensity-projection MR cholangiography and thick-section MR cholangiography than with volume-rendered MR cholangiography (p < 0.0001).

CONCLUSION

Observer performance with volume-rendered MR cholangiography was better than that with maximum-intensity-projection and thick-section MR cholangiography for the diagnosis of choledocholithiasis. Volume rendering may be an efficient technique for the reconstruction of MR cholangiography.

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.

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.

[Nuclear magnetic resonance cholangiography in biliary disease. Prospective study in 60 patients]

PURPOSE

The aim of this prospective study was to evaluate a new MR cholangiography sequence, with thick slices, single shot fast spin echo (SSFSE) in biliary obstructive diseases.

PATIENTS AND METHODS

This study included 60 patients (36 males and 24 females, mean age: 69 years) with cholestatic syndrome and suspected bile duct obstruction. All patients were prospectively investigated with MR cholangiography using SSFSE sequence with thick slices. The gold standard was ERCP (n = 47), per cutaneous cholangiography (n = 1), and surgical intervention (n = 12). According to this gold standard, 22 patients had obstructive gallstones, 23 had neoplastic obstruction, eight had inflammatory or postoperative stenosis and 7 had normal bile ducts.

RESULTS

The sensitivity and specificity of MR cholangiography were 100 and 94% in the diagnosis of obstructive gallstones, and 95 and 97% in the diagnosis of neoplastic obstruction, respectively. A good agreement was observed between MR cholangiography and the gold standard, regardless of the site of obstruction (range of kappa value: 0.79-1).

CONCLUSION

MR cholangiography with SSFSE sequence is an effective and easy technique. Acquisition of thick slices in a very short time (< 2 sec) limits cardiorespiratory artefacts and eliminates the need for post-processing.

Biliary dilatation: differentiation of benign from malignant causes--value of adding conventional MR imaging to MR cholangiopancreatography

PURPOSE

To determine the value of conventional T1 - and T2-weighted images and gadolinium-enhanced dynamic magnetic resonance (MR) images as a supplement to MR cholangiopancreatographic (MRCP) images in differentiation of benign from malignant causes of biliary dilatation.

MATERIALS AND METHODS

MR studies in 62 patients with biliary dilatation with proved causes included conventional T1- and less heavily T2-weighted images, as well as gadolinium-enhanced dynamic images and heavily T2-weighted MRCP images. Two radiologists reviewed MRCP images alone, MRCP images with nonenhanced T1 - and T2-weighted MR images, and MRCP images with nonenhanced and gadolinium-enhanced dynamic images.

RESULTS

For differentiation of benign from malignant causes of biliary dilatation, the area under the receiver operating characteristic curve (A(z)) was significantly (P < .05) larger for MRCP images interpreted with T1 - and T2-weighted images (0.9547 for reader 1, 0.8404 for reader 2) than for MRCP images alone (0.8144 for reader 1, 0.8122 for reader 2). The addition of gadolinium-enhanced dynamic MR images to MRCP images with nonenhanced T1- and T2-weighted images did not significantly increase accuracy (A(z) = 0.9554 for reader 1 and 0.8650 for reader 2), but the level of confidence was increased in 17%-24% of cases.

CONCLUSION

Use of nonenhanced T1- and less heavily T2-weighted images with MRCP images significantly improved the diagnostic accuracy of MR examinations of pancreaticobiliary disease.

MR cholangiopancreatography: value of axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences

OBJECTIVE

To compare axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences with three-dimensional (3D) maximum intensity projection (MIP) images in patients with suspected pancreaticobiliary obstruction.

MATERIAL AND METHODS

MR cholangiopancreatography (MRCP) was performed in 108 consecutive patients with a non-breath-hold, fat-suppressed, 2D, heavily T2-weighted fast spin-echo sequence in coronal plane. Axial T1- and T2-weighted images were previously obtained. In addition, 3D reconstructions of the coronal images were analysed separately by using a MIP algorithm. Both two-dimensional (2D) (axial and coronal) and 3D MIP images were separately evaluated by two readers in conference and their results were compared with that of endoscopic retrograde cholangiopancreatography, percutaneous trans-hepatic cholangiography, surgery and/or imaging follow-up. Statistical analysis of 2D and 3D MRCP images in diagnosing the level and probable cause of pancreaticobiliary obstruction were separately calculated.

RESULTS

106/108 of MRCP examinations were judged diagnostic by the two reviewers for adequacy of visualisation of the biliary and pancreatic ducts. Sensitivity, specificity, positive predictive value, negative predictive value and global diagnostic accuracy of 2D (axial and coronal) and 3D MRCP images in diagnosing the pancreaticobiliary obstruction were 94 and 57%,, 95 and 93%, 97 and 92%, 91 and 60%, 94 and 72% respectively.

CONCLUSION

Our results do indicate a higher global accuracy for axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences versus 3D MIP images in diagnosis of the level and probable cause of pancreaticobiliary obstruction and stress the limitations of 3D images in depiction of small intraductal pathology such as calculi and biliary neoplastic.

A prospective comparison of magnetic resonance cholangiopancreatography with endoscopic retrograde cholangiopancreatography in the evaluation of patients with suspected biliary tract disease

AIM

To determine the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) compared with direct cholangiography in the detection of biliary tract disease.

PATIENTS AND METHODS

MRCP was performed in 100 patients in whom direct cholangiographic correlation (ERCP, n = 98; PTC, n = 9; intraoperative cholangiography, n = 3) was available for comparison. The MRCP examinations were performed using a two-dimensional multi-slice, fast spin echo (FSE) technique and a local surface coil. The diagnoses at direct cholangiography were choledocholithiasis in 30 patients, benign and malignant strictures in 28 patients and normal bile ducts in 42 patients. The nature of the strictures (benign, n = 2; tumour, n = 18; lymphnode recurrence, n = 3; unknown histology, n = 5) was determined by one or more of the following procedures: surgery (n = 8), biopsy (n = 15), cytology (n = 6) and cross-sectional imaging/follow-up findings (n = 3).

RESULTS

MRCP diagnosed choledocholithiasis with a sensitivity of 93%, specificity of 99% and accuracy of 97 %. It resulted in two false-negative and one false-positive findings when compared with direct cholangiography. MRCP accurately diagnosed the presence and level of strictures in all patients. The overall sensitivity, specificity and accuracy of MRCP in the detection of bile duct lesions were 97%, 98% and 97%, respectively.

CONCLUSION

MRCP has a high diagnostic accuracy when compared with direct cholangiography in the detection of bile duct disease.

Cholangiopathy in HIV-infected patients

HIV cholangiopathy is a disease of advanced-stage AIDS that presents with biliary symptoms and anicteric cholestasis. An abnormal ultrasound examination in a patient with low CD4 count is evaluated by endoscopic retrograde cholangiopancreatography, which demonstrates the characteristic cholangiographic abnormalities. Besides being the gold standard for diagnosis, it offers therapeutic intervention and possible pain relief in the presence of papillary stenosis. An infectious pathogen is identifiable in a majority of patients, suggesting infection-related damage to the biliary tree. Anti-infective therapy, however, usually is ineffective, and prognosis is related to the underlying stage of AIDS.

Crossed cerebellar diaschisis: assessment with dynamic susceptibility contrast MR imaging

The authors investigated the feasibility of using T2-weighted, half-Fourier rapid acquisition with relaxation enhancement, or RARE, dynamic susceptibility contrast magnetic resonance (MR) imaging to depict crossed cerebellar diaschisis. In 10 patients after unilateral supratentorial stroke, crossed cerebellar diaschisis was demonstrated in the relative regional cerebellar blood volume maps obtained with MR imaging. Cerebellar blood volume values for the nonaffected cerebellar hemisphere were significantly larger than those for the affected side (P = .0003).

MR cholangiography: technical advances and clinical applications

Magnetic resonance (MR) cholangiography is a fast, accurate, noninvasive alternative to endoscopic retrograde cholangiography (ERC) in the evaluation of biliary tract disease. Technical improvements in imaging sequences (eg, half-Fourier rapid acquisition with relaxation enhancement) and use of phased-array coils allow high-quality imaging comparable to that available with ERC. In choledocholithiasis, common bile duct stones as small as 2 mm can be detected with MR cholangiography and appear as low-signal-intensity foci within the high-signal-intensity bile. MR cholangiography may help establish the diagnosis of malignant obstruction and is useful in the evaluation of patients in whom ERC was unsuccessful or incomplete. The role of MR cholangiography in the evaluation of intrahepatic duct disease continues to evolve. MR cholangiography plays a crucial role in evaluating postsurgical biliary tract alterations and can be used to demonstrate a variety of congenital anomalies of the biliary tract (eg, aberrant ducts, choledochal cysts, pancreas divisum). In addition, intentional or incidental imaging of the gallbladder with MR cholangiography can be used to identify calculi or help determine the presence and extent of neoplastic disease.