Fentanyl-augmented MRCP

Magnetic resonance cholangiopancreatography evaluation of intrahepatic bile duct variations with updated classification

PURPOSE

Preoperative detection of intrahepatic bile duct (IHBD) variations is essential to reduce surgical morbidity and mortality rates. Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive and reliable method for demonstrating the normal IHBD anatomy and its variations. This retrospective study aimed to identify and classify novel variations, except those already reported in the literature, using MRCP.

METHODS

MRCP examinations, which were conducted in two different centers in the last five years, were retrospectively evaluated. IHBD variations were recorded with respect to the Yoshida classification. In addition, newly detected variations that were not included in this classification were identified and classified.

RESULTS

MRCP examinations of 2624 patients were screened, and 2143 were determined to be eligible for evaluation. Of 2143 patients, 987 were males (average age, 54±18 years) and 1156 were females (mean age, 57±17 years). In this study, 10 novel variations that were not included in the Yoshida classification were identified in 14 patients.

CONCLUSION

MRCP is an effective, reliable, and noninvasive imaging method for evaluating the IHBD anatomy and its variations. Novel variations described in this study may help to better understand the biliary anatomy.

Biliary and pancreatic ductal dilation in patients on methadone maintenance therapy

PURPOSE

To determine whether the diameter of intrahepatic and extrahepatic bile ducts and pancreatic ducts in patients on methadone maintenance therapy is increased when compared with control subjects.

METHODS

Between January 1, 2000 and March 15, 2013, a total of 97 patients (mean age 49.9, range 22-79, 65 male, 32 female) were identified who were receiving chronic methadone maintenance therapy (MMT) when they underwent imaging with abdominal MRI or a contrast-enhanced abdominopelvic CT. A group of 97 consecutive non-MMT control patients (mean age 51.4, range 21-86, 45 male, 52 female) who underwent imaging with abdominal MRI or contrast-enhanced abdominopelvic CT were identified. Patients with known pancreaticobiliary pathology that may confound biliary ductal measurements were excluded. Blinded interpretation was performed, documenting the diameters of the intrahepatic and extrahepatic bile ducts and pancreatic ducts. Descriptive statistics were performed.

RESULTS

Patients on MMT demonstrated increased bile duct diameter, with an average increase in duct diameter of 2.39 mm for the common bile duct (p < 0.001; 95% CI 1.88-2.90 mm), 1.43 mm for the intrahepatic bile ducts (p < 0.001; 95% CI 1.12-1.74 mm), and 0.90 mm for the pancreatic duct (p < 0.001; 95% CI 0.64-1.16 mm). No statistically significant correlation was found between ductal diameters and the daily dose of methadone.

CONCLUSION

Patients on methadone maintenance therapy demonstrate significantly increased intra- and extrahepatic bile duct and pancreatic duct diameter when compared with controls. There was no correlation between the dose of methadone and ductal diameter.

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.

Effects of thienorphine on contraction of the guinea pig sphincter of Oddi, choledochus and gall bladder

Opioid analgesics are widely believed to cause spasm of the bile duct sphincter and so impede bile flow. Thienorphine is a partial opioid agonist that is a good candidate for the treatment of opioid dependence; however, to date, no studies have reported the effects of thienorphine on the function of the biliary tract. This study examined the in vivo effects of thienorphine on the guinea pig isolated sphincter of Oddi, choledochus and gall bladder and on bile flow. The area under the curve (AUC) of isolated sphincter of Oddi was not influenced by thienorphine or buprenorphine, whereas morphine increased the AUC of the isolated sphincter of Oddi in a concentration-dependent manner. Thienorphine and buprenorphine concentration-dependently decreased the AUC of isolated choledochus, while morphine increased the AUC of isolated choledochus. Thienorphine had no effect on the contractile amplitude or basal tension of isolated gall bladder muscle strips. In contrast, buprenorphine and morphine increased the contractile basal tension of isolated gall bladder muscle strips in a concentration-dependent manner. Thienorphine (0.01-1.0mg/kg) had no significant inhibitory effect on bile flow. However, morphine (1.0-10mg/kg) and buprenorphine (1.0mg/kg) significantly inhibited bile flow. The maximum inhibition of bile flow by buprenorphine was 63.9±12.9% and by morphine was 74.1±11.3%. In summary, thienorphine has little influence on the guinea pig isolated sphincter of Oddi, choledochus and gall bladder or on bile flow, which may result in a lack of adverse biliary colic effects.

Morphine three-dimensional T1 gadoxetate MR cholangiography of potential living related liver donors

PURPOSE

To assess low-dose morphine for distension and improved visualization of intrahepatic bile ducts on T1 MR cholangiography (MRC) in preoperative imaging of potential liver donors.

MATERIALS AND METHODS

Sixty-nine consecutive potential living related liver donors (mean age, 39 years; age range, 20 to 59 years) referred for pre-transplant MRI evaluation were evaluated without (n=30) or with (n=39) intravenous morphine injection (0.04 mg/kg). Morphine was injected pre-MRI while establishing intravenous access to allow ∼1 h for biliary distension before T1 MRC. Three radiologists reviewed intrahepatic biliary branch order visualization, common bile duct (CBD) diameter, and overall image quality. In 25 patients undergoing liver donation surgery, T1 MRC findings were correlated with intraoperative findings. This retrospective study was approved by the institutional review board.

RESULTS

Biliary visualization was improved post-morphine administration with biliary duct branch order visualization score of 3.2 and 3.3 at 45 and 60 min, respectively, compared with 2.7 without morphine (P<0.002); CBD diameter measured 5.3 and 5.5 versus 4.1 mm (P<0.005), and overall image quality score was 2.4 and 2.6 versus 1.8 (P<0.0006). Operative notes confirmed T1 MRC findings in 6/11 donors without morphine and 14/14 donors with morphine.

CONCLUSION

Intravenous low-dose morphine distends and improves visualization of bile ducts on T1 gadoxetate MRC.

Pancreaticobiliary disorders: comparison between magnetic resonance cholangiopancreatography images before and after fentanyl injection

OBJECTIVE

This study was designed to determine the effects of intravenous fentanyl on magnetic resonance cholangiopancreatography image quality in the treatment of pancreaticobiliary disorders.

MATERIALS AND METHODS

Forty consecutive patients referred for the evaluation of pancreaticobiliary disorders underwent magnetic resonance cholangiopancreatography in the coronal and oblique-coronal planes before and after fentanyl injection (every 2 up to 9 min). The images were analyzed qualitatively and quantitatively. Diameter and signal intensity were measured at the widest point and distal to the common bile duct and main pancreatic duct.

RESULTS

The mean common bile duct diameters at the widest and distal points and mean pancreatic duct diameter were measured 7.53, 4.72, and 2.14 and 8.33, 5.35, and 2.57 before and after fentanyl injection, respectively. Mean signal intensity at the widest and distal point of the common bile duct and mean pancreatic duct signal intensity measured 278, 199, and 113 and 296, 218, and 121 before and after fentanyl injection, respectively. Minor improvements in image quality were detected qualitatively.

CONCLUSION

Fentanyl injection improves images qualitatively and quantitatively. In agreement with previous studies, our results confirm the beneficial effects of fentanyl as a simple adjunct to traditional magnetic resonance cholangiopancreatography.

Dual-energy CT-cholangiography in potential donors for living-related liver transplantation: improved biliary visualization by intravenous morphine co-medication

PURPOSE

To prospectively evaluate whether intravenous morphine co-medication improves bile duct visualization of dual-energy CT-cholangiography.

MATERIALS AND METHODS

Forty potential donors for living-related liver transplantation underwent CT-cholangiography with infusion of a hepatobiliary contrast agent over 40 min. Twenty minutes after the beginning of the contrast agent infusion, either normal saline (n=20 patients; control group [CG]) or morphine sulfate (n=20 patients; morphine group [MG]) was injected. Forty-five minutes after initiation of the contrast agent, a dual-energy CT acquisition of the liver was performed. Applying dual-energy post-processing, pure iodine images were generated. Primary study goals were determination of bile duct diameters and visualization scores (on a scale of 0 to 3: 0--not visualized; 3--excellent visualization).

RESULTS

Bile duct visualization scores for second-order and third-order branch ducts were significantly higher in the MG compared to the CG (2.9±0.1 versus 2.6±0.2 [P<0.001] and 2.7±0.3 versus 2.1±0.6 [P<0.01], respectively). Bile duct diameters for the common duct and main ducts were significantly higher in the MG compared to the CG (5.9±1.3 mm versus 4.9±1.3 mm [P<0.05] and 3.7±1.3 mm versus 2.6±0.5 mm [P<0.01], respectively).

CONCLUSION

Intravenous morphine co-medication significantly improved biliary visualization on dual-energy CT-cholangiography in potential donors for living-related liver transplantation.

Morphine- and glucagon-augmented magnetic resonance cholangiopancreatography to evaluate living liver donors

The purpose of this study was to investigate the effectiveness of the combined use of intravenous morphine and intramuscular glucagon in improving magnetic resonance cholangiopancreatography (MRCP) image quality in donors for living-related liver transplantation. Sixteen healthy donor candidates underwent an MRCP study. Coronal, single-shot, fast spin-echo, heavily T2-weighted dynamic MRCP images were obtained before and 3 minutes after the intravenous administration of morphine HCl with a dose of 0.04 mg/kg. Thirty minutes after the injection of morphine, intramuscular glucagon was used. Another MRCP image of the same pulse sequence was generated 15 minutes after the injection of glucagon with a dose of 1 mg. The diameter, signal intensity, and number of branches of bile ducts in MRCP images taken immediately before and after the injection of morphine and after the injection of glucagon (plus delayed morphine effects) were compared and analyzed. In all 16 donor candidates, the diameters of the right and left hepatic ducts, common bile duct, and main pancreatic duct were significantly increased (P < 0.05) in the MRCP images taken 3 minutes after the injection of morphine and 15 minutes after the injection of glucagon (plus delayed morphine effects) in comparison with MRCP images taken before any drug administration. The qualitative grading scores of the signal intensity and order of branches of bile ducts revealed improvements in the MRCP images after the injection of glucagon (plus delayed morphine effects; P < 0.05). In conclusion, combining the intravenous administration of low-dose morphine and the intramuscular use of glucagon before MRCP examination improves the visualization of the nondilated biliary ductal anatomy, which is important for the preoperative biliary evaluation of donor candidates for living-related liver transplantation.

Orally administered lemon/orange juice improved MRCP imaging of pancreatic ducts

BACKGROUND

The aim of this study was to determine the effectiveness of oral administration of lemon/orange juice in improving the visualization of pancreatic ducts on MRCP.

MATERIALS AND METHODS

MRCP images were generated before and at every 15 min for 90 min after oral administration of lemon/orange juice in a dose of 2 ml/kg in 20 volunteers and 26 patients. The pre- and post-administration images were compared and analyzed qualitatively and quantitatively.

RESULTS

In 20 volunteers and 26 patients, the visualization at pancreatic duct of head, body, tail, accessory pancreatic duct, and branch duct was improved after juice administration. The diameter of pancreatic ducts was augmented, and the differences in the mean values before and after oral juice were highly significant at both sites in volunteers and patients (P < 0.01). In 20 volunteers and 26 patients, after juice administration, the best visualization of the pancreatic duct was achieved at (58.98 +/- 14.96) min and (59.41 +/- 13.79) min, respectively, and the overlap imaging of oral juice was especially observed at (42.86 +/- 10.92) min and (41.63 +/- 9.32) min, respectively.

CONCLUSIONS

Orally lemon/orange juice is an effective method to improve MRCP imaging of pancreatic ducts. The lemon/orange juice should be administered at 60 min prior to MRCP.

Magnetic resonance cholangiopancreatography: current use and future applications

Magnetic resonance pancreatography (MRCP) is now established as a robust noninvasive tool for the evaluation of biliary and pancreatic pathology. Its diagnostic performance is comparable with endoscopic retrograde cholangiopancreatography without the associated risks. This article aims to familiarize the reader with the technique, clinical indications, and limitations of the investigation. Common pitfalls in interpretation also are addressed. Emerging applications and techniques are discussed that include recent advances in technology and the development of functional imaging.