Complementary role of helical CT cholangiography to MR cholangiography in the evaluation of biliary function and kinetics

To explore the potential role of computed tomographic cholangiography (CTC) in relation to magnetic resonance cholangiography (MRC) in cases in which knowledge of biliary kinetics and functional information are important for therapeutic decisions, 31 patients (14 men and 17 women) underwent MRC followed by CTC. We examined nine post-cholecystectomy cases with right upper quadrant abdominal pain, six cases with a previous biliary-enteric anastomosis and clinical evidence of cholangitis, eight biliary strictures with pain or symptoms of cholangitis, four cases with strong clinical evidence of sclerosing cholangitis, three cases with suspected post-laparoscopic cholecystectomy bile leakage, and one case with chronic pancreatitis and a common bile duct stent associated with cholangitis. In relation to MRC, CTC provided additional biliary functional information as follows: abnormal biliary drainage through the ampulla in 7/9 cholecystectomy cases, impaired drainage in 3/6 biliary-enteric anastomoses, and complete obstruction in 2/8 biliary strictures. CTC diagnosed early sclerosing cholangitis in 4/4 cases and confirmed suspected bile leakage in 1/3 post-laparoscopic cholecystectomy patients, and the patency of the biliary stent in the patient with chronic pancreatitis. Thus, CTC provides clinically important information about the function and kinetics of bile and complements findings obtained by MRC.     

MR cholangiography 3D biliary tree automatic reconstruction system.

An algorithm for reconstructing magnetic resonance cholangiography (MRC) biliary structure is proposed. The processing of MRC data can be divided into four phases. In the first phase, the region of interest (ROI) containing the liver and biliary ducts is extracted from the original volume data based on human anatomy and B-spline curve. The second phase involves segmenting the biliary ducts from the region identified in the previous phase. Because the image of biliary portion is brighter than the liver, the segmentation is started by choosing the brightest pixel in the ROI as the seed for 3D region growing. This procedure could be executed many times, depending on the provided stopping condition. In the third phase, the segmented biliary duct regions are traced to construct the biliary tree. An automated 3D tracking algorithm is proposed for this phase. This 3D tracking algorithm estimates the coordinates of the points along the medial axis of each biliary duct branch. The cross sections associated with the points along the medial axis are also calculated approximately during the tracking process. The biliary tree data structure is constructed in this phase. The biliary tree is reconstructed and rendered in the last phase. Although the proposed algorithm takes a longer time compared with the conventional approach, the reconstructed biliary tree 3D structure can provide more clearly image. A concise representation for the biliary tree can be achieved with the proposed method and provide both quantitative and structural information for clinical reference.     

Functional MR cholangiography: diagnosis of functional abnormalities of the gallbladder and biliary tree

OBJECTIVE: Our objective was to describe the technique and utility of functional MR cholangiography (fMRC) in the evaluation of the gallbladder and biliary tree. CONCLUSION: FMRC has the potential to provide a comprehensive examination for the anatomic and functional assessment of the gallbladder and biliary tree. Complex anatomic abnormalities and functional disorders can be shown by fMRC, including biliary obstruction and extravasation.     

Imaging of the intrahepatic biliary tree with thick slice MR cholangiography]

PURPOSE: To assess the value of single shot fast spin echo MR sequence (SS-FSE) in the evaluation of the normal and pathologic intrahepatic biliary tree. MATERIAL AND METHODS: 418 consecutive patients (457 examinations) referred for clinical and/or biological suspicion of biliary obstruction underwent MR cholangiopancreatography (MRCP). All patients were imaged with a Signa 1.5 T GE MR unit, with High Gradient Field Strength and Torso Phased Array Coil. Biliary ducts were imaged with SS-FSE sequence, coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total acquisition time was 1 second. Source images were reviewed by two radiologists blinded to clinical information. In case of disagreement, a third radiologist's opinion was requested. In all cases, MRCP results were compared with direct biliary tract evaluation, other imaging studies and clinical and biological follow-up. RESULTS: In all cases, MRCP produced high quality images. Numerous branch of division were observed although the peripheral intrahepatic ducts were well seen in more than 90% in an area 2 cm below the capsule. The number of division was statistically higher when mechanical obstruction was present. Intrahepatic calculi or peripheral cholangiocarcinoma were well detect by MRCP. For the detection of cholangitis, MRCP sensitivity was 87.5% but the positive predictive value was only 57.7% because of a high number of false positive. The diagnosis of primary sclerosing cholangitis must be made only on strict criteria and slightly dilated peripheral bile ducts unconnected to the central ducts in several hepatic segments were a characteristic MR sign of primary sclerosing cholangitis. CONCLUSION: MRCP can be proposed as a first intention imaging technique for the evaluation of intrahepatic ducts.     

Multiple biliary papillomatosis: comparison of MR cholangiography with endoscopic retrograde cholangiography

PURPOSE: The purpose of this work was to compare MR cholangiography with endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of multiple biliary papillomatosis (MBP). METHOD: Nine patients with pathologically proven MBP underwent MR cholangiography and ERCP. A comparison was made between ERCP, multislice HASTE, and single-shot RARE. Each biliary tract was divided into five sections for assessment; therefore, 45 biliary duct areas were used for lesion detection and determination of quality of depiction. RESULTS: Of the 35 segments detected by percutaneous transhepatic cholangioscopy, pathologic examinations were performed in 31 segments: papillary adenocarcinoma was proved in 28 and papillary adenoma in 3. The multislice HASTE sequence showed bile duct branches with biliary papillomatosis better than did ERCP (p = 0.0029) and single-shot RARE sequence (p = 0.0558). The multislice HASTE procedure had the highest number of lesions detected, followed by single-shot RARE and ERCP, but there was no significant difference between the imaging techniques. CONCLUSION: Our preliminary data suggest that MR cholangiography can replace ERCP for the detection of MBP.     

Malignant biliary hilar stenosis: MR cholangiography compared with direct cholangiography]

AIM: To assess the diagnostic value of three-dimensional (3D) magnetic resonance cholangiography (MRC) versus direct cholangiography such as endoscopic retrograde cholangiography (ERC) and percutaneous transhepatic cholangiography (PTC) in malignant biliary stenosis. MATERIAL AND METHODS: Twenty-nine patients (15 female and 14 male) (mean age 62 years) with malignant biliary strictures underwent MRC and ERC. Breath-hold 3D steady state free precession MR cholangiography was performed on a 1.5-T imager in the patients before ERC. In 25 patients findings at ERC/PTC were considered the standard of reference: 19 patients underwent ERC, 5 PCT and 1 both ERC and PTC due to unsuccessful papilla cannulation during the endoscopic examination. In the 4 remaining patients the surgical specimen was considered the standard of reference. In the 29 patients studied, histology performed during direct cholangiography and the examination of the surgical specimens demonstrated that the malignant hilar stenoses were caused by hilar cholangiocarcinoma (n=7), cholangiocarcinoma of the distal VBP (n=1), gallbladder cancers (n=6), endometrial metastasis (n=2), ovary metastasis (n=1), colon metastasis (n=1), breast metastasis (n=1). The correct identification of biliary stenosis and extension of the tumor (according to the Bismuth classification) by MR cholangiography and ERC were independently assessed by two readers blinded to each other's report. The results were compared. RESULTS: Identification of biliary stenosis and neoplastic extension were accurate in respectively 29/29 (100%) and 26/29 (89%) cases with MR cholangiography. The comparison of ERC/PTC and MRC images yielded the following results: Bismuth Type I (6 vs 6), Type II (5 vs 8), Type III (13 vs 10), Type IV (5 vs 5). Our results indicate that MR is less capable of identifying the extension of small lesions at the primary confluence of bile ducts than are ERC/PCT. DISCUSSION AND CONCLUSIONS: MR cholangiography is a non-invasive technique for biliary tract imaging. It does not require administration of contrast medium and allows complete visualisation of the biliary ducts. MR cholangiography allowed accurate diagnosis of malignant hilar stenosis providing equal information as direct cholangiography and may therefore obviate the need for ERC/PTC.     

Non-invasive detection of biliary leaks using Gd-EOB-DTPA-enhanced MR cholangiography: comparison with T2-weighted MR cholangiography

Objective

To evaluate the added role of T1-weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) compared with T2-weighted MRC (T2w-MRC) in the detection of biliary leaks.

Methods

Ninety-nine patients with suspected biliary complications underwent routine T2w-MRC and T1w contrast-enhanced (CE) MRC using Gd-EOB-DTPA to identify biliary leaks. Two observers reviewed the image sets separately and together. MRC findings were compared with those of surgery and percutaneous transhepatic cholangiopancreatography. The sensitivity, specificity and accuracy of the techniques in identifying biliary leaks were calculated.

Results

Accuracy of locating biliary leaks was superior with the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC (P?<?0.05).The mean sensitivities were 79 % vs 59 %, and the mean accuracy rates were 84 % vs 58 % for combined CE-MRC and T2w-MRC vs sole T2w-MRC. Nineteen out of 21 patients with biliary-cyst communication, 90.4 %, and 12/15 patients with post-traumatic biliary extravasations, 80 %, were detected by the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC images, P?<?0.05.

Conclusions

Gd-EOB-DTPA-enhanced MRC yields information that complements T2w-MRC findings and improves the identification and localisation of the bile extravasations (84 % accuracy, 100 % specificity, P?<?0.05). We recommend Gd-EOB-DTPA-enhanced MRC in addition to T2w-MRC to increase the preoperative accuracy of identifying and locating extravasations of bile.

Key Points

? Magnetic resonance cholangiography (MRC) does not always detect bile leakage and cysto-biliary communications. ? Gd-EOB-DTPA-enhanced MRC helps by demonstrating extravasation of contrast material into fluid collections. ? Gd-EOB-DTPA-enhanced MRC also demonstrates the leakage site and bile duct injury type. ? Combined Gd-EOB-DTPA-enhanced and T2w-MRC can provide comprehensive information about biliary system. ? Gd-EOB-DTPA-enhanced MRC is non-invasive and does not use ionising radiation.     

Diagnosing biliary complications of orthotopic liver transplantation with mangafodipir trisodium-enhanced MR cholangiography: comparison with conventional MR cholangiography

OBJECTIVE: This study was designed to determine whether the addition of mangafodipir trisodium-enhanced MRI could improve the image quality, visualization of ductal structures, and diagnostic confidence provided by conventional T2-based MR cholangiography (MRC) in patients with suspected biliary complications after orthotopic liver transplantation. SUBJECTS AND METHODS. Our study group consisted of 25 consecutive patients who were referred for MR evaluation of clinically suspected biliary complications after orthotopic liver transplantation. Conventional MRC in the axial and coronal planes was performed in each patient, followed by fat-suppressed volumetric gradient-echo imaging in the same planes both before and after the IV administration of mangafodipir trisodium. Imaging was performed in all patients until the contrast agent was seen in the bowel. Images were then graded for quality, visualization of bile ducts and anastomoses, presence of significant stricture or leak, and level of diagnostic confidence. RESULTS: Mangafodipir trisodium-enhanced MRC tended to outperform conventional MRC in overall image quality and extrahepatic duct visualization; it was also more effective in delineating biliary anastomoses, and the difference was statistically significant (p < 0.001). All 25 enhanced examinations were considered diagnostic. Diagnostic confidence was scored as poor or lacking in 14 of the conventional MRC examinations for biliary stenosis and in 12 examinations for biliary leak. CONCLUSION: Enhancement with mangafodipir trisodium improves the performance of MRC for the detection and exclusion of biliary abnormalities after orthotopic liver transplantation. Future investigations should compare the performance of mangafodipir trisodium-enhanced MRC with the performance of more invasive techniques.     

Diagnostic pitfalls of MR cholangiopancreatography in the evaluation of the biliary tract and gallbladder.

Magnetic resonance (MR) cholangiopancreatography is a noninvasive imaging technique that has proved accurate in the diagnosis of biliary obstruction. However, various diagnostic pitfalls have been reported with MR cholangiopancreatography that were not encountered previously at conventional biliary imaging. These pitfalls may simulate or mask various pathologic conditions of the extrahepatic bile duct or main pancreatic duct and may be caused by a variety of factors. Because of its postprocessing nature, maximum-intensity-projection reconstruction may mask a small gallstone if the stone is surrounded by hyperintense bile and may cause false ductal disconnection or duplication when a breath hold is not performed perfectly. Extraductal factors (e.g., metallic surgical clips, intravascular metallic coils, gas in the stomach or duodenum) can cause signal loss in the adjacent part of the extrahepatic bile duct, which may in turn lead to a false-positive diagnosis of ductal narrowing or obstruction. Normal vascular structures including the right hepatic and gastroduodenal arteries can cause pseudo-obstruction of the extrahepatic bile duct by pulsatile compression. Intraductal factors (e.g., gas, hemorrhage, debris, iodinated contrast material) reduce the signal intensity of the bile, which may result in pseudo-obstruction, false filling defects, or a nonvisualized gallbladder or bile duct. Knowledge of the existence and high prevalence of these diagnostic pitfalls should help prevent misinterpretation of MR cholangiopancreatograms.     

Early biliary complications of laparoscopic cholecystectomy: evaluation on T2-weighted MR cholangiography in conjunction with mangafodipir trisodium-enhanced 3D T1-weighted MR cholangiography

OBJECTIVE: Our aim was to assess preliminary experience with combined conventional T2-weighted and mangafodipir trisodium (MnDPDP)-enhanced T1-weighted MR cholangiography in evaluating early biliary complications of laparoscopic cholecystectomy. SUBJECTS AND METHODS: Conventional heavily T2-weighted MR cholangiography with MnDPDP-enhanced T1-weighted MR cholangiography and ERCP were performed in seven patients with high clinical suspicion of biliary complications after laparoscopic cholecystectomy. The final diagnoses of complications were classified according to the presence and degree of bile duct injury, bile leakage, and retained stones. RESULTS: The diagnoses on MR cholangiography were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 3), partial strictures of the common bile duct with bile leakage (n = 1), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). The final diagnoses at surgery (n = 2) and ERCP (n = 5) were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 2), partial strictures of the common bile duct with bile leakage (n = 2), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). MR cholangiography accurately yielded the same findings as the final diagnoses, except in one case with partial stricture of the bile duct with bile leakage (overdiagnosed as complete occlusion on MR cholangiography). CONCLUSION: Combined conventional T2-weighted and MnDPDP-enhanced T1-weighted MR cholangiography may eliminate the use of other studies for the imaging of biliary complications after cholecystectomy if this preliminary data can be verified in a larger study.     

MR胆道成像评价活体肝移植供体胆道结构的应用价值

目的 探讨MR胆道成像(MRC)评价活体肝移植供体肝内胆道结构的准确性以及在活体肝移植中的应用价值.方法 回顾性分析58例活体肝移植的供体,分析术前MRC资料,进行胆道分型,并与术中胆道造影(IOC)结果对照.结果 IOC诊断58例供体,发现胆道结构正常者34例(58.6%),胆道结构变异者24例(41.4%);MRC对58例供体胆道结构分型总准确率为91.4%(53/58),对胆道变异类型的诊断敏感度为83.3%(20/24),特异度为100%(34/34),阳性预测值为100%(20/20),阴性预测值为89.5%(34/38).结论 MRC能在术前准确评价活体肝移植供体的肝内胆管结构,有助于活体肝移植术前手术方案的制定.     

MR cholangiography in children and young adults with biliary disease

OBJECTIVE: Our objective was to describe the MR cholangiography findings for young patients with suspected biliary disease who underwent half-Fourier acquisition fast spin-echo technique with respiratory triggering. SUBJECTS AND METHODS: Twenty-eight MR cholangiography studies were performed in 22 patients on a 1.5-T MR unit. Ten of these 22 patients had undergone liver transplantation. RESULTS: MR cholangiography revealed abnormalities of both the extrahepatic and the intrahepatic major and minor bile duct systems, despite the small diameter of the duct system in this group of patients. Four patterns of biliary disease were shown: global dilatation of extrahepatic or intrahepatic ducts (n = 7); segmental, uniform dilatation of central or peripheral intrahepatic ducts (n = 9); segmental, nonuniform dilatation of central or peripheral intrahepatic ducts (n = 2); and fusiform ectasia with segmental, irregular intrahepatic dilatation and bile lakes (n = 2). The findings of eight studies were interpreted as normal. The four patterns of abnormalities were correlated with the results from percutaneous transhepatic cholangiography, T-tube cholangiography, and liver biopsy and with clinical and surgical information, as available. CONCLUSION: MR cholangiography is a noninvasive technique for evaluation of biliary disease. The improved resolution afforded by respiratory triggering permits evaluation of both major and minor bile ducts, even in young, uncooperative subjects. Four patterns of abnormalities were prospectively identified, correlated with other information, and used to direct clinical treatment.     

Value of MR cholangiography in the evaluation of postoperative biliary complications following orthotopic liver transplantation

The aim of this study was to describe the spectrum of abnormal biliary findings as seen with magnetic resonance cholangiography (MRC) in symptomatic patients after orthotopic liver transplantation (OLT). In our study we included 12 consecutive patients post-OLT who presented with clinical and/or biochemical suspicion of biliary complications. In all patients MRC was performed on a 1.0-T whole-body magnet and breathhold half-Fourier acquired single-shot turbo spin echo and rapid acquisition with relaxation enhancement sequences were used. Diagnostic confirmation was obtained with percutaneous transhepatic cholangiography (PTC; n = 3 patients), endoscopic retrograde cholangiography (ERC; n = 3 patients), or clinical follow-up. A vast array of biliary abnormalities were detected in 11 of 12 patients: high-grade, obstructive, anastomotic stricture was the most common unique abnormality. Findings consistent with bile duct necrosis, the second most common abnormality, were accompanied by arterial abnormalities in 2 of 5 patients on subsequent MR- and digital subtraction angiography. Compared with the findings obtained with direct cholangiography (n = 5 patients), MRC was highly accurate for the detection and characterization of postoperative biliary complications. Compared with the final diagnosis, which was based on PTC-ERC findings and/or all available clinical data, MRC imaging alone was able to provide a specific diagnosis in 9 of 12 patients. Magnetic resonance cholangiography is an accurate, time-saving, and non-invasive imaging modality in the evaluation of post-OLT patients in whom suspicion of biliary complications exists. Although the precise value of MRA in this patient group requires larger dedicated studies, single session “all-in-one” MR evaluation of both biliary and arterial system in our series proved to be a substantial benefit in obtaining an accurate and complete diagnosis. Received: 2 December 1999; Revised: 24 February 2000; Accepted: 24 February 2000     

Dynamic MR cholangiography after fatty meal loading: cystic contractility and dynamic evaluation of biliary stasis.

PURPOSE: Dynamic MR cholangiography was conducted on patients with cholelithiasis or choledocholithiasis who had consumed a fatty test meal (Molyork) and the cystic contractility and dynamics of biliary stasis was evaluated. SUBJECTS AND METHOD: The subjects were 25 with intracystic cholelithiasis, 10 with choledocholithiasis and 10 normal controls. For an imaging sequence, the rapid acquisition with relaxation enhancement (RARE) method was employed and imaging was conducted for 40 min (every 30 s following Molyork administration) without breath-holding. The gallbladder contraction ratio was computed and the contractile ratio for the common bile duct was calculated. To determine the bile flow to the duodenum, the high-intensity signal, indicating the flow from the lower common bile duct, and perfusion of the duodenum were observed in dynamic mode on the monitor with the naked eye and interpreted as positive bile flow. The frequency of this flow was visually monitored. RESULTS: The gallbladder contractile ratio was significantly reduced in patients with cholelithiasis or choledocholithiasis compared with the controls. In a comparison with the normal controls, no sequential changes were noted in the mean contractile ratio of the common bile duct of the patients with cholelithiasis or choledocholithiasis. The mean frequency of bile flow observed for each 40 min period was 13+/-2.4, 6+/-2.2, and 4+/-1.3 times for the controls, those with intracystic cholelithiasis, and those with choledocholithiasis, respectively. Compared with the controls, the latter two patient groups showed evident reductions in the frequency of bile flow to the duodenum (p<0.001). CONCLUSION: Dynamic MRC combined with Molyork loading makes it possible to compute cystic contractile ratios and perform a dynamic examination of bile flow under non-invasive, near-physiological conditions.