Reconstruction of the portal vein with 64-slice spiral CT of bile duct obstruction

The aim of this study was to evaluate 64-slice spiral CT image reconstruction of the portal vein in biliary obstruction. A total of 34 clinical patients with biliary obstruction were confirmed by 64-slice spiral CT scanning with portal venous phase multi-planar reconstruction (MPR) of the biliary tract, curved planar reconstruction (CPR), thin-slab minimum-intensity projection (TS-MinIP) and maximum intensity projection (MIP). The reconstructed images were reviewed to further assess the position and cause of the biliary obstruction and to judge the accuracy of diagnosis. The 64-slice spiral CT image reconstruction of the biliary obstructions determined the causes with an accuracy of 88.2% (30/34) and identified the location of the obstruction with an accuracy of 100%. A 64-slice spiral CT reconstructed image of the portal bile duct lesions was generated, which indicated the lesion morphology, location and anatomical relationship with surrounding tissues, secondary biliary stricture and the degree of expansion and is of great clinical value in the characterization and preoperative evaluation of biliary disease.

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.

Magnetic resonance cholangiography in living donor liver transplantation

OBJECTIVE

Exact knowledge of biliary anatomy is essential in living donor liver transplantation. The purpose of this study was to evaluate the accuracy of pretransplant magnetic resonance cholangiography (MRC) in depicting the biliary anatomy in comparison with intraoperative cholangiography (IOC).

MATERIALS AND METHODS

From May 2006 to July 2009, 451 potential living liver donors underwent pretransplant evaluation at the Chang Gung Memorial Hospital-Kaohsiung Medical Center. Two hundred thirty-three donors underwent donor hepatectomy. Of these, only 203 donors with both preoperative MRC and IOC were included in this study.

RESULTS

Of the 451 potential donors, 218 (48.3%) were considered unsuitable for liver donation, hence was immediately disqualified after the initial evaluation for various reasons. Six of the 218 unsuitable donors (2.8%) were excluded due to complicated biliary anatomy. The overall accuracy rate of MRC for defining the biliary anatomy was 91.6%, with 84.9% sensitivity, 96% specificity, 88.2% positive predictive value, and 94.7% negative predictive value. There were 14 misidentified cases. The errors in MRC reading was largely attributed to the poor contrast between the biliary ducts and the surrounding tissues and organs. The concurrence between MRC and IOC were commendable (κ=0.9). No significant biliary complications were noted in the mismatch group.

CONCLUSION

MRC is essential for all pretransplantation evaluation with 91.6% accuracy rate.

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.

Biliary anatomy in potential right hepatic lobe living donor liver transplantation (LDLT): the utility of CT cholangiography in the setting of inconclusive MRCP

OBJECTIVE

To determine the utility of CT cholangiography (CT-Ch) in preoperative evaluation of the biliary anatomy of living-donor liver transplantation (LDLT) donors when magnetic resonance cholangiopancreatography (MRCP) is inconclusive.

MATERIALS AND METHODS

Over a 2-year period, 22 potential living liver donors underwent contrast-enhanced CT-Ch for preoperative evaluating biliary anatomy due to inconclusive results on MRCP and subsequently donated their right hepatic lobe. Nineteen of them underwent intraoperative cholangiography and were included in this study. Two radiologists retrospectively reviewed both MRCP and CT-Ch with 1-month interval and documented the types of bile duct branching patterns and visualization score of intrahepatic bile ducts (4-point scale).

RESULTS

There were no complications associated with CT-Ch examinations. CT-Ch was concordant with the reference standard in 18/19 (95%) including 7/8 typical branching type and 11/11 anomalous branching types. MRCP was concordant with the reference standard in 14/19 (74%) including 4/8 typical branching types and 10/11 anomalous branching types. The discordant case by CT-Ch was the identification of a tiny accessory right intrahepatic duct joining the common bile duct which was not visualized on intraoperative cholangiography. CT-Ch showed higher visualization score (mean, 3.9) than MRCP (mean, 2.6) (P<.001).

CONCLUSION

CT-Ch can be effectively used for the depiction of the branching pattern of the bile duct at the hepatic hilum when MRCP is inconclusive.

Intravenous 64-multi-detector row CT-cholangiography of porcine livers: a feasibility study with definition of the temporal window for optimal bile duct delineation

BACKGROUND/PURPOSE

To assess the feasibility of intravenous 64-multi-detector row computed tomography (CT)-cholangiography of porcine livers with definition of the temporal window for optimal bile duct delineation.

METHODS

Six healthy Landrace pigs, each weighing 28.97 +/- 2.99 kg, underwent 64-multi-detector row CT-cholangiography. Each pig was infused with 50 ml of meglumine iotroxate continuously over a period of 20 min and, starting with the initiation of the infusion, 18 consecutive CT scans of the abdomen at 2-min intervals were acquired. All series were evaluated for bile duct visualization scores and maximum bile duct diameters as primary study goals and bile duct attenuation and liver enhancement as secondary study goals.

RESULTS

Of the 16 analyzed biliary tract segments, maximum bile duct visualization scores ranged between 4.00 +/- 0.00 and 2.83 +/- 1.47. Time to maximum bile duct visualization scores ranged between 10 and 34 min. Average bile duct visualization scores for the 10- to 34-min interval ranged between 3.99 +/- 0.05 and 2.78 +/- 0.10. Maximum bile duct diameters ranged between 6.47 +/- 1.05 and 2.65 +/- 2.23 mm. Time to maximum bile duct diameters ranged between 24 and 34 min. Average bile duct diameters for the 10- to 34-min interval ranged between 6.00 +/- 0.38 and 2.40 +/- 0.13 mm.

CONCLUSIONS

Intravenous 64-multi-detector row CT-cholangiography of non-diseased porcine liver is feasible, with the best bile duct delineation acquired between 10 and 34 min after initiation of the contrast agent infusion.

MR imaging and CT of the biliary tract

Magnetic resonance (MR) imaging and computed tomography (CT) can be useful in the diagnosis of biliary disease, with both modalities allowing detailed evaluation of the biliary tract. Careful interrogation of the images is critical, regardless of modality. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section imaging. Smooth, concentric short-segment strictures favor a benign cause, whereas abrupt, eccentric long-segment strictures favor a malignancy. At MR imaging, extrabiliary entities such as crossing vessels or metallic clip artifact may mimic strictures and should not be mistaken for disease. A stone is the most common biliary filling defect and may occur in the absence of dilated ducts. Stones commonly have a lamellated, geometric shape and are found in a dependent portion of the duct. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Improved diagnosis of biliary disease can be achieved with a knowledge of the benefits and limitations of modern MR and CT cholangiographic techniques, including the use of biliary-excreted contrast material and of various postprocessing techniques. Familiarity with the radiologic appearances of the duct lumen, wall, and surrounding structures is also important for accurate image interpretation. The rapidly evolving technology for both MR imaging and CT of the biliary tract will continue to present radiologists with opportunities as well as challenges.