Effect of manganese dipyridoxal diphosphate on liver magnetic resonance imaging and serum bilirubin in rats with removable biliary obstruction

Biliary Atresia: Feasibility of Mangafodipir Trisodium–enhanced MR Cholangiography for Evaluation

The study was approved by the institutional review board, and informed consent was obtained from the patients' parents. Twenty-three consecutive infants suspected of having biliary atresia (BA) were prospectively examined by using mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) cholangiography. Sequential T1-weighted spoiled gradient-echo MR cholangiograms were obtained 1, 2, and 3 hours after intravenous administration of Mn-DPDP. The possibility of BA was excluded if bowel excretion of contrast material was noted at contrast material-enhanced MR cholangiography. The diagnostic specificity and accuracy of contrast-enhanced MR cholangiography were compared with those of conventional MR cholangiography, technetium 99m Tc ((99m)Tc)-disofenin (DISIDA) scintigraphy, and the triangular cord sign at ultrasonography (US). MR cholangiography was used to accurately distinguish four cases of BA from 19 cases of other cholestatic liver diseases, without false-positive results. Conventional MR cholangiography, (99m)Tc-DISIDA scintigraphy, and the triangular cord sign at US respectively yielded false-positive results of 42% (eight of 19 infants), 35% (six of 17 infants), and 11% (two of 19 infants) in patients without BA. Mn-DPDP-enhanced MR cholangiography appears to be a promising modality for early diagnosis of BA as the cause of neonatal cholestasis.

Using contrast-enhanced MR cholangiography with IV mangafodipir trisodium (Teslascan) to evaluate bile duct leaks after cholecystectomy: a prospective study of 11 patients

OBJECTIVE

The purpose of our study was to determine whether contrast-enhanced MR cholangiography using IV mangafodipir trisodium can accurately detect the presence and location of bile duct leaks in patients who have undergone cholecystectomy.

SUBJECTS AND METHODS

Our study group included 11 patients with suspected bile duct leaks after cholecystectomy. Axial single-shot fast spin-echo and gradient-echo images were acquired in all patients before and 1-2 hr after IV administration of mangafodipir trisodium. The contrast-enhanced MR cholangiograms were evaluated for image quality, degree of ductal or small bowel opacification, and the presence and location of bile duct leaks, strictures, and stones. MR cholangiograms were correlated with conventional contrast-enhanced cholangiograms obtained in all patients, including endoscopic retrograde cholangiography (n = 10) and percutaneous transhepatic cholangiography (n = 1).

RESULTS

Excretion of mangafodipir trisodium was noted in the intrahepatic and extrahepatic bile ducts in all patients from 1 to 2 hr after IV administration. Bile ducts and fluid collections that contained excreted mangafodipir trisodium showed increased signal intensity on gradient-echo sequences and decreased signal intensity on single-shot fast spin-echo sequences. Conventional contrast-enhanced cholangiography showed the presence of bile duct leaks in six patients and the absence of bile duct leaks in five patients, with false-negative findings in one patient and false-positive findings in one patient for bile duct leak (sensitivity, 86%; specificity, 83%).

CONCLUSION

Contrast-enhanced MR cholangiography with IV mangafodipir trisodium can successfully detect the presence and location of bile duct leaks in patients suspected of having such leaks after undergoing cholecystectomy. More research is necessary before acceptance of this examination as routine in the workup of these patients.

Sequential use of gadolinium chelate and mangafodipir trisodium for the assessment of focal liver lesions: initial observations

The purpose of this study was to assess the feasibility of sequential administration of 2 different MR imaging contrast agents using a single visit protocol to image focal liver abnormalities. Twenty-one patients with known or suspected liver lesions were included in the study. All patients received a bolus intravenous injection of gadolinium chelate (Gd) and dynamically enhanced imaging performed. The patients then received an injection of mangafodipir trisodium (Mn) contrast and a second scan performed with an average delay of 62 min after the Gd bolus injection. The images were evaluated to determine the appearance of liver lesions after administration of each contrast agent, and for evidence of prior Gd administration adversely affecting evaluation of images acquired after Mn administration. Focal liver lesions were present in 19 patients, including 8 with liver metastases, 1 with liver lymphoma, 6 with hemangiomas, 3 with focal nodular hyperplasia (FNH), and 1 with hepatic abscess. In 2 other patients no liver lesions were identified in either the post-Gd or post-Gd-post-Mn scans. All malignant lesions identified on the post-Gd scan were also identified on post-Gd-post-Mn scans. Although the potential benefit for increasing detection sensitivity for hepatic metastases was not demonstrated, this is a preliminary series. This study does demonstrate the practicality for use a single visit sequential Gd-Mn protocol described here, with possible application of this technique for further assessment of the utility of combining Gd and Mn for detection of liver metastases.

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.