Magnetic Resonance Cholangiopancreatography Sequences Research Articles

A Study to Assess the Role of Date Syrup, Pineapple Juice, and Hematinic Syrup as Magnetic Resonance Oral Contrast Agents in Improving the Image Quality of Magnetic Resonance Cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is an imaging technique that has advanced over the past few years.It still plays a crucial role in the study of numerous pancreaticobiliary diseases.This study aimed to evaluate the effects of hematinic syrup, date syrup, and pineapple juice on MRCP image quality. This study involved a total of 90 participants, distributed evenly among three groups, with each group comprising 30 patients.Negative oral contrast solutions containing paramagnetic substances like Mn+2 andFe+3, such aspineapple juice, date syrup, and hematinic syrup were imaged by 1.5 Tesla (T) magnetic resonance imaging (MRI) with T2-weighted (T2W) and MRCP sequences. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were computed. Ninety patients underwent MRCP 20-30 min after ingestion of 100 mL of datesyrup, 30 ml of hematinic syrup diluted to 200 ml of water, and 200 mL of pineapple juice. MRCP images were taken to visualize various pancreaticobiliary structures (bile duct, stomach, and duodenum). The in vitro evaluation of the solutions showed that date syrup and hematinic syrup were hypointense in T2W sequences.The images obtained showed no significant difference in the CNR between the three solutions. However, the SNR was significantly higher for pineapple juice compared to date syrup and hematinic syrup in T2W and MRCP sequences.Images acquired post-administration of the oral contrast agents significantly improved the gastrointestinal tract signal suppression and increased visibility of the pancreaticobiliary structures (bile duct, stomach, and duodenum). No adverse events were observed among the participants. Pineapple juice was the best contrast agent. However, date syrup and hematinic syrup can also be used to improve the imaging quality.

NON-INVASIVE IMAGING OF CHOLANGIO-PANCREATIC DISEASES USING MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY AND CORRELATION WITH ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY

NON-INVASIVE IMAGING OF CHOLANGIO-PANCREATIC DISEASES USING MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY AND CORRELATION WITH ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY

Biliary excretion of gadobenate dimeglumine causing degradation of magnetic resonance cholangiopancreatography (MRCP)

To assess the effect of gadobenate dimeglumine on magnetic resonance cholangiopancreatography (MRCP) and determine an appropriate time frame for performing MRCP sequences. 2D MRCP sequences obtained after intravenous administration of gadobenate dimeglumine or gadobutrol over 14months were reviewed retrospectively in randomized order by five abdominal radiologists, using a 3-point scale to rate biliary and pancreatic duct clarity (1 = no-, 2 = limited-, 3 = good visualization). Intraclass correlation coefficients were computed and mean scores were compared for both agents. For gadobenate dimeglumine exams, time delays between arterial phase and MRCP acquisition times were analyzed concerning duct clarity. For gadobutrol, only exams with delays ≥ 15min were included. 134 exams (107 gadobenate dimeglumine, 27 gadobutrol) were included. Moderate reliability for pancreatic duct visualization and excellent reliability for visualization of intrahepatic bile ducts and upper and lower extrahepatic bile ducts were noted. No difference in mean scores was noted for pancreatic duct visualization (p = 0.66). Bile duct segment scores were lower with gadobenate dimeglumine (mean: 2.1-2.6) compared with gadobutrol (mean: 2.8-2.9) (p ≤ 0.006). For gadobenate dimeglumine, visualization scores varied depending on the delay between the arterial phase and MRCP acquisition (p ≤ 0.047). Good visualization for all bile duct segments was noted with delays of 7.2-9.4min (95% confidence interval; mean 8.3min). Bile duct clarity degraded on MRCP images with an increasing delay following gadobenate dimeglumine injection. 2D MRCP, thus, should be performed within 7.2min after obtaining the arterial phase sequence to ensure good visualization of the entire biliary system.

The efficacy of pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography.

BackgroundDuring magnetic resonance cholangiopancreatography (MRCP), the pancreatobiliary ducts can be obscured by the high-intensity signal from the stomach and duodenum. Pineapple juice may be an alternative to commercially available negative contrast agents, but has not been evaluated locally.ObjectivesTo evaluate the efficacy of a local, off-the-shelf pineapple juice preparation as a negative oral contrast agent for MRCP.MethodAn observational, analytical study was conducted during January–December 2017. A 1.5 Tesla MRCP sequence was performed immediately before and after ingestion of 250 mL of a local, commercially-available pineapple juice preparation. Image evaluation was performed by two radiologists with independent, blind assessment of gastric/duodenal signal intensity and biliary /pancreatic duct visibility, before and after pineapple juice.ResultsFifty adult patients (F = 44, 88%) with median age 44 years (IQR: 34.75, 57) were included. After pineapple juice administration, there was significant measured (1661.51 vs. 1409.94, p < 0.01) and perceived (2.16 vs. 2.72, p < 0.01) duodenal signal reduction but no significant change in measured (1081.17 vs. 1044.38, p = 0.34) or perceived (2.73 vs. 2.84, p = 0.14) gastric signal intensity. Visibility of the common bile duct was significantly improved (3.67 vs. 3.86, p < 0.01), whilst that of the main pancreatic duct showed no significant change (2.92 vs. 2.86, p = 0.44).ConclusionThe local pineapple juice preparation used in this study is an effective, affordable and natural negative oral contrast agent for enhancement of MRCP images, and specifically improves visualisation of the common bile duct.

Role of Magnetic Resonance Cholangiopancreatography in Evaluation of Biliary Obstruction

Background: obstructive jaundice which is caused by bile duct obstruction can be clinically and biochemically indistinguishable from cholestatic jaundice caused by hepatocellular disease. The management of both these conditions being radically different, the principle task of the radiologist is to differentiate between hepatocellular and obstructive jaundice, by using available imaging modality and help in further management. With the availability of non-invasive modality like magnetic resonance imaging (MRI), it is possible to diagnose obstructive jaundice early and accurately without any patient discomfort. The purpose of this article is to describe the protocol for evaluation of obstructive jaundice with use of magnetic resonance cholangio pancreatography sequence of MRI and to describe the imaging features of the most common causes of obstructive jaundice like biliary calculi, bile duct strictures, choledochal cyst, gall bladder carcinoma, cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic head carcinoma. Aim of work: this work aimed to study and evaluate the role of MRCP in patients with biliary obstruction. Patients and Methods: this study included 30 patients with biliary obstruction during the period from December 2017 to October 2018. MRCP was performed on a 1.5 T MRI system, using a phased-array body coil. Fasting for 4 hours prior to the examination is required to reduce gastro-duodenal secretions, reduce motility to eliminate motion artifacts and to promote distension of gall bladder.For optimum visualization of ducts, acquired images were reformatted in different planes using multiplanar reconstruction (MPR) and maximum intensity projection (MIP). Results: in all cases, MRCP displayed the different parts of the biliary tract and localized the exact site of obstruction in all of the obstructed cases. According to the morphology encountered at the site of obstruction, MRCP was found highly specific in differentiating the calcular, malignant and benign causes of obstruction. The quality of images were degraded by the presence of massive ascites, marked patient obesity in our study by the instability to hold breath in a reproducible manner. Lack of the therapeutic role and the inability to perform functional studies mainly at the papilla remain the main limitation of the technique. Conclusion: MRCP should be the next step following depiction of biliary obstruction by U/S. Consequently in the near future there will be no place for the diagnostic use of the ERCP which shall be then restricted to a therapeutic role.

What is the best fruit juice to use as a negative oral contrast agent in magnetic resonance cholangiopancreatography?

To identify, invitro, the best fruit juice to use as oral contrast agent in magnetic resonance cholangiopancreatography (MRCP) and to test, invivo, the best natural juice and the new parameters in MRCP sequences identified invitro. The invitro evaluations consisted of measuring the T2 values of a pure solution of manganese (Mn) and iron (Fe) at different concentrations, measuring the content of Mn and Fe in five commercial juices and their T2 relaxation times, and identifying the optimal juice dilution for suppressing the gastrointestinal fluid signal. The new parameters of MRCP sequences were tested invivo. Manganese alone strongly influenced the shortening of the T2 values (p=0.004). The T2 value with an echo time (TE) of ≥1,000 ms enabled sufficient intestinal fluid suppression in the case of high juice dilution. A flip angle of 90° maximised the differences between the high signal from static fluids, such as the bile and the fluid in the gastrointestinal tract, using fast imaging employing steady-state acquisition (FIESTA) sequences (p<0.001). The shortening of the T2 relaxation time depended only on the Mn concentration. All the commercial juices had an Mn concentration sufficient to suppress the gastrointestinal fluid signal using long TE sequences. The oral ingestion of commercial juice before MRCP was enough to suppress the signal from the gastrointestinal fluids, regardless of its dilution after ingestion. When using FIESTA sequences, a flip angle of 90° allowed the best suppression of gastrointestinal fluid signals.

Acceleration of Magnetic Resonance Cholangiopancreatography Using Compressed Sensing at 1.5 and 3 T: A Clinical Feasibility Study.

Magnetic resonance cholangiopancreatography (MRCP) is an established technique in routine magnetic resonance examination. By applying the compressed sensing (CS) acceleration technique to conventional MRCP sequences, scan time can be markedly reduced. With promising results at 3 T, there is a necessity to evaluate the performance at 1.5 T due to wide scanner availabilities. Aim of this study is to test the feasibility of accelerated 3-dimensional (3D) MRCP with extended sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) using CS in navigator triggering and in a single breath-hold in a clinical setting at 1.5 T and 3 T and compare it with a conventional navigator-triggered 3D SPACE-MRCP. Phantom measurements were performed to adapt sequence parameters. Conventional 3D SPACE-MRCP in navigator triggering (STD_MRCP) as well as CS-accelerated 3D SPACE-MRCP acquired in navigator triggering and in a single breath-hold (CS_MRCP and CS_BH_MRCP) was performed in 66 patients undergoing clinically induced MRI of the pancreatobiliary system at 1.5 T and 3 T. Image quality evaluation was performed by 2 independent radiologists. Dedicated statistics were performed (P < 0.05 considered significant). In patient imaging, CS_MRCP was superior to STD_MRCP and CS_BH_MRCP in aspects of overall image quality at 1.5 T (P = 0.01; P < 0.001) and 3 T (P = 0.002; P = 0.013). Overall image quality in CS_BH_MRCP was inferior compared with STD_MRCP and CS_MRCP at 1.5 T. At 3 T, overall image quality in CS_BH_MRCP was superior to STD_MRCP (P = 0.001). Scan time was reduced by 25% to 46% covering 5% of k-space (CS_MRCP at 1.5 and 3 T) and 97% covering 3.6% of k-space (CS_BH_MRCP at 1.5 and 3 T). Compressed sensing-accelerated MRCP is feasible in clinical routine at 1.5 and 3 T offering major reduction of acquisition time. When applying a single breath-hold CS imaging, field strengths of 3 T are recommended.

DIFFERENCES IMAGE QUALITY OF SIGNAL TO NOISE RATIO (SNR) IN SENSITIVITY ENCODING (SENSE) APPLIED ON MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY (MRCP) EXAMINATION SEQUENCES TSE T2 CORONAL

Background : Magnetic Resonance Cholangiopancreatography (MRCP) is a non invasive imaging examinations, which are used to evaluate the tractus billiaris, pancreatic ducts and gall bladder. In the last decade, one way to lower the scan time is with the method of parallel imaging. Parallel imaging has a basic function is the reduction of the time of the scan, as well as maintain the contrast of the image without the need for a system of higher performance gradients. Reduction of scan time in parallel imaging has some benefits. First, it is very useful for sequences that depends on the scanning time is short as a single breath hold. Second, the overall inspection time can be reduced, especially in patients with complaints of pain are great at certain positions such as pain when lying down, in patients of children or in cases of civil defence emergency. Breath hold itself has the purpose to avoid the image of the blur of movement organs. When breathing there is movement of the thoracic and abdominal organs in the cavum. However, the characteristics of each person has different breath hold. When the patient's breath hold insufficient at the time scanning takes place then the resulting image results become less than optimal and may cause artifacts in the picture. The scanning time on the MRCP examination sequences long enough to cause patients to press the emergency buzzer, this caused the patient to feel less comfortable at the time of the examination to take place, and the resulting examination in repeated from the beginning. Therefore researchers wanted to apply the technique of parallel imaging in examination of MRCP on T2 Coronal because of parallel imaging has benefits that are very useful for sequences that depends on the scanning time is short like a breath hold. Methods : This type of research is research experiments. This research was conducted on MRI 1.5 Tesla in Hospitals Tarakan from Jakarta and carried out in 8 volunteers. The results of the performed image ROI value to get SNR, ROI was performed on the area of the right hepatic duct, left hepatic duct, gall bladder, common bile duct and cystic duct so the obtained average value for signal compared to the ROI on background (standard deviation noise). Data analysis was done by using different test with a test of T-test to tell the difference between the use of SENSE against SNR. Results : The results of the calculation of the value of the average SNR of image sequence, MRCP Sequences TSE T2 Coronal without the SENSE on the anatomy of the right hepatic ductus 54.49; left hepatic ductus 55.54; gall bladder 91.07; the common bile duct 68.94 and cystic duct 60.46. While the value of SNR in image sequence, MRCP Sequences TSE T2 Coronal TSE that use the SENSE on the anatomy of the right hepatic duct 45.77; left duct heatic 46.88; gall bladder 77.87; the common bile duct 60.72 and cystic duct 50.58 Scan time difference that is the average value of the scan time on Coronal T2 TSE piece sequences without SENSE for 1 minute 32 seconds while in the Coronal T2 TSE piece sequences using SENSE during 49 seconds or reduced by 46.7% compared with sequences TSE standards without SENSE on examination MRCP T2 Coronal. Conclusion : Based on the results of the study explains that there is a difference between the use of SENSE against SNR in the T2 Coronal TSE sequence in MRCP examination with the highest level of the overall significance of the p-value &lt; 0.05. On the use of SENSE decline SNR but scan time becomes shorter 46,7% compared with no use of SENSE

Automatic gallbladder segmentation using combined 2D and 3D shape features to perform volumetric analysis in native and secretin-enhanced MRCP sequences.

We aimed to develop the first fully automated 3D gallbladder segmentation approach to perform volumetric analysis in volume data of magnetic resonance (MR) cholangiopancreatography (MRCP) sequences. Volumetric gallbladder analysis is performed for non-contrast-enhanced and secretin-enhanced MRCP sequences. Native and secretin-enhanced MRCP volume data were produced with a 1.5-T MR system. Images of coronal maximum intensity projections (MIP) are used to automatically compute 2D characteristic shape features of the gallbladder in the MIP images. A gallbladder shape space is generated to derive 3D gallbladder shape features, which are then combined with 2D gallbladder shape features in a support vector machine approach to detect gallbladder regions in MRCP volume data. A region-based level set approach is used for fine segmentation. Volumetric analysis is performed for both sequences to calculate gallbladder volume differences between both sequences. The approach presented achieves segmentation results with mean Dice coefficients of 0.917 in non-contrast-enhanced sequences and 0.904 in secretin-enhanced sequences. This is the first approach developed to detect and segment gallbladders in MR-based volume data automatically in both sequences. It can be used to perform gallbladder volume determination in epidemiological studies and to detect abnormal gallbladder volumes or shapes. The positive volume differences between both sequences may indicate the quantity of the pancreatobiliary reflux.

Added value of diffusion-weighted imaging to MR cholangiopancreatography for the diagnosis of bile duct dilatations.

To investigate the added value of diffusion-weighted imaging (DWI) when used with conventional T2-weighted magnetic resonance (MR) imaging (T2WI) and MR cholangiopancreatography (MRCP) for diagnosing bile duct dilatations. Our institutional review board approved this retrospective study protocol and waived the informed consent requirement. The study included 151 consecutive patients (70 men, 81 women) with intra- and/or extra-hepatic bile duct dilatation examined using MR imaging. Two radiologists independently and randomly reviewed 3 image sets (A: MRCP and T2WI; B: DWI; and C: combined T2WI, MRCP, and DWI) at different occasions to differentiate between malignancy, biliary lithiasis, and benign dilatation. The sensitivity, specificity, and diagnostic accuracy of these imaging sets were calculated and compared. For both readers, combined T2WI, MRCP, and DWI exhibited significantly higher sensitivity and diagnostic accuracy for malignant dilatation, compared with conventional T2WI and MRCP (P<0.01 for both readers). However, DWI did not significantly affect the sensitivity and diagnostic accuracy for biliary lithiasis or benign dilatation. The addition of DWI to T2WI and MRCP sequences yields significantly higher sensitivity and diagnostic accuracy when examining bile duct dilatations, particularly malignant dilatations.

Balanced MR cholangiopancreatography with motion-sensitized driven-equilibrium (MSDE) preparation: Feasibility and optimization of imaging parameters

PurposeTo show the feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography and to determine the optimal velocity encoding (VENC) value. Materials and methodsSixteen healthy volunteers underwent MRI study using a 1.5-T clinical unit and a 32-channel body array coil. For each volunteer, images were obtained using the following seven respiratory-triggered sequences: (1) balanced magnetic resonance cholangiopancreatography without motion-sensitized driven-equilibrium, and (2)–(7) balanced magnetic resonance cholangiopancreatography with motion-sensitized driven-equilibrium, with VENC=1, 3, 5, 7, 9 and ∞cm/s for the x-, y-, and z-directions, respectively. Quantitative evaluation was obtained by measuring the maximum signal intensity of the common hepatic duct, portal vein, liver tissue including visible peripheral vessels, and liver tissue excluding visible peripheral vessels that were evaluated. We compared the contrast ratios of portal vein/common hepatic duct, liver tissue including visible peripheral vessels/common hepatic duct and liver tissue excluding visible peripheral vessels/common hepatic duct among the five finite sequences (VENC=1, 3, 5, 7, and 9cm/s). Statistical comparisons were performed using the t-test for paired data with the Bonferroni correction. ResultsSuppression of blood vessel signals was achieved with motion-sensitized driven-equilibrium sequences. We found the optimal VENC values to be either 3 or 5cm/s with the best suppression of relative vessel signals to bile ducts. At a lower VENC value (1cm/s), the bile duct signal was reduced, presumably due to minimal biliary flow. ConclusionThe feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography was suggested. The optimal VENC value was considered to be either 3 or 5cm/s. The clinical usefulness of this new magnetic resonance cholangiopancreatography sequence needs to be verified by further studies.

Role of CT and MRCP in Evaluation of Biliary Tract Obstruction

Obstructive jaundice which is caused by bile duct obstruction can be clinically and biochemically indistinguishable from cholestatic jaundice caused by hepatocellular disease. The management of both these conditions being radically different, the principle task of the radiologist is to differentiate between hepatocellular and obstructive jaundice, using available imaging modality and help in further management. With the availability of non-invasive modality like computed tomography and magnetic resonance imaging (MRI), it is possible to diagnose obstructive jaundice early and accurately without any patient discomfort. The purpose of this article is to describe the protocol for evaluation of obstructive jaundice with use of MDCT and magnetic resonance cholangio pancreatography sequence of MRI and to describe the imaging features of the most common causes of obstructive jaundice like biliary calculi, bile duct strictures, choledochal cyst, gall bladder carcinoma, cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic head carcinoma.

A prospective pilot study: Can the biliary tree be visualized in children younger than 3 months on Magnetic Resonance Cholangiopancreatography?

Magnetic resonance cholangiopancreatography (MRCP) could aid in the diagnosis of biliary atresia, a hepatic pathology with thin, irregular or interrupted biliary ducts. There is little published evidence of MRCP appearances in normal neonates and young infants. To assess the use of MR cholangiopancreatography in visualizing the biliary tree in neonates and infants younger than 3 months with no hepatobiliary disorder, and to assess this visibility in relationship to the child's age, weight, and sedation and fasting states. Between December 2008 and October 2010 our department performed MRI of the brain, orbits and face on 16 full-term neonates and infants. Each child was younger than 3 months (90 days) and without any hepatobiliary disorders. The children were scanned with a respiratory-gated 0.54 × 0.51 × 0.4-mm(3) 3-D MRCP sequence. We used a reading grid to assess subjectively the visibility of the extrahepatic bile ducts along with extrahepatic bile duct confluence. The visibility of the extrahepatic bile duct confluence was assessed against age, weight, and sedation and fasting states. The extrahepatic bile duct confluence was seen in 10 children out of 16 (62.5%). In the neonate sub-group (corrected age younger than 30 days), the MRCP was technically workable and the extrahepatic bile duct confluence was seen in four cases out of eight (50%). This visualization was up to 75% in the subgroup older than 30 days. However, statistically there was no significant difference in visibility of the extrahepatic bile duct confluence in relationship to age, weight or MRCP performance conditions (feeding, fasting or sedation). The complete normal biliary system (extrahepatic bile duct confluence included) is not consistently visualized in infants younger than 3 months old on non-enhanced MRCP. Thus the use of MRCP to exclude a diagnosis of biliary atresia is compromised at optimal time of surgery.

How reliable is MRCP with an SS-FSE sequence at 3.0 T: comparison between SS-FSE BH and 3D-FSE BH ASSET sequences

PurposeThe purpose of the present study was to evaluate the visibility and the image quality of the biliary and pancreatic duct system on magnetic resonance cholangiopancreatography (MRCP) images based on two breath-hold (BH) methods using array spatial sensitivity technique: a single-shot fast spin-echo (SS-FSE) sequence and a three-dimensional single slab fast spin-echo (3D-FSE) sequence. Materials and methodsIn the present prospective comparative study, 47 patients (22 male and 25 female, mean age=50 years, age range=22–82 years) that were referred for MRCP during a 12-month period are included. All of them were referred with suspected pancreaticobiliary disease. All patients underwent MRCP with both a SS-FSE BH sequence and a 3D-FSE BH sequence. Qualitative evaluation regarding the depiction of three segments of the pancreaticobiliary tree and the frequency of artifacts was performed. Two radiologists graded each sequence of the obtained studies in a blinded fashion. Quantitative evaluation including calculation of relative signal intensity (rSI) and relative contrast (RC) ratios at seven segments of the pancreaticobiliary tree between fluid-filled ductal structures and organ parenchyma at the same ductal segments was performed. In order to evaluate the parameters' differences of the two sequences, either in qualitative or in quantitative analysis, the Wilcoxon paired signed-rank test was performed. ResultsOn quantitative evaluation, both rSI and RC ratios of all segments of the pancreaticobiliary tree at SS-FSE BH sequence were higher than those at 3D-FSE BH sequences. This finding was statistically significant (P<.01). On qualitative evaluation, the two radiologists found intrahepatic ducts and pancreatic ducts to be better visualized with SS-FSE BH than with 3D-FSE BH sequence. This finding was statistically significant (P<.02). One of them found extrahepatic ducts to be significantly better visualized with SS-FSE BH sequence. Moreover, the frequency of artifacts was lower in the SS-FSE sequence, a finding that was of statistical significance. Interobserver agreement analysis found at least substantial agreement (κ>0.60) between the two radiologists. ConclusionThe SS-FSE sequence is performed faster and significantly improves image quality; thus, it should be included into the routine MRCP sequence protocol at 3.0 T. Furthermore, we recommended SS-FSE BH MRCP examination to be applied to uncooperative patients or patients in emergency because of its short acquisition time (1 s).

Comparison of respiratory-triggered 3-D fast spin-echo and single-shot fast spin-echo radial slab MR cholangiopancreatography images in children

The two most commonly performed magnetic resonance cholangiopancreatography (MRCP) sequences, 3-D fast spin-echo (3-D FSE) and single-shot fast spin-echo radial slabs (radial slabs), have not been compared in children. The purpose of this study was to compare 3-D FSE and radial slabs MRCP sequences on a 3-T scanner to determine their ability to show various segments of pancreaticobiliary tree and presence of artifacts in children. We reviewed 79 consecutive MRCPs performed in 74 children on a 3-T scanner. We noted visibility of major ducts on 3-D FSE and radial slabs. We noted the order of branching of ducts in the right and left hepatic ducts and the degree of visibility of the pancreatic duct. Statistical analysis was performed using McNemar and signed rank tests. There was no significant difference in the visibility of major bile ducts and the order of branching in the right hepatic lobe between sequences. A higher order of branching in the left lobe was seen on radial slabs than 3-D FSE (mean order of branching 2.82 versus 2.27; P-value = 0.0002). The visibility of pancreatic duct was better on radial slabs as compared to 3-D FSE (mean value of 1.53 vs. 0.90; P-value < 0.0001). 3-D FSE sequence was artifact-free in 25/79 (31.6%) MRCP exams as compared to radial slabs, which were artifact-free in 18/79 (22.8%) MRCP exams (P-value = 0.0001). There is no significant difference in the visibility of major bile ducts between 3-D FSE and radial slab MRCP sequences at 3-T in children. However, radial slab MRCP shows a higher order of branching in the left hepatic lobe and superior visibility of the pancreatic duct than 3-D FSE.

Magnetic resonance (MR) imaging and MR cholangiopancreatography findings in cats with cholangitis and pancreatitis.

Cholangiohepatitis/cholangitis is second only to hepatic lipidosis as the most common liver disease in cats and is often associated with concurrent pancreatitis. Magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP) have developed into an accurate, highly sensitive and specific imaging tool for the diagnosis of biliary and pancreatic duct disorders in humans. In this prospective case series, 10 cats with suspected cholangitis and/or pancreatitis were enrolled based on clinical history, physical examination and appropriate diagnostic test results. MRI and MRCP sequences with secretin stimulation of the cranial abdomen were performed, and sonography and laparoscopic biopsies for histologic diagnosis were obtained for comparison. MRI detected pancreatic abnormalities in cats suspected of pancreatitis, including T1 pre-contrast hypointense and T2 hyperintense pancreatic parenchyma and a dilated pancreatic duct. The MRI findings of the liver were non-specific. Nine of 10 cats had biliary abnormalities, including gall bladder wall thickening, gall bladder wall moderate contrast enhancement and/or gall bladder debris. Eight of 10 cats had histologic evidence of pancreatitis, as well as hepatitis or cholangitis, with one cat diagnosed with hepatic lymphoma. The advantages of MRI/MRCP over sonography of these cats included the striking pancreatic signal changes associated with pancreatitis and the ability to comprehensibly assess and measure the pancreas and hepatobiliary structures without operator dependence or interference from bowel gas. MRI/MRCP imaging of the feline abdomen may be beneficial in cases with equivocal ultrasound imaging findings.

Use of carbon dioxide as negative contrast agent for magnetic resonance cholangiopancreatography

To evaluate the effects of using CO(2) as negative contrast agent in decreasing the overlapping on the pancreaticobiliary system from intestinal fluids. We evaluated the magnetic resonance cholangiopancreatography (MRCP) images in 117 patients divided into two groups (group 1, without taking gas producing crystals to produce CO(2), n = 64; group 2, with CO(2), n = 53) in a 1.5T unit using MRCP sequence. Anatomic locations of intestinal fluids distribution, overlapping with common bile duct (CBD) and pancreatic duct (PD), were evaluated. In the group with CO(2), the decrease in distribution of intestinal fluids was significant in the gastric antrum (P = 0.001) and duodenal bulb (P < 0.001), but not in the gastric fundus and body and in the second portion of the duodenum (P = 1.000, P = 0.171, and P = 0.584 respectively). In the group with CO(2), the decrease in overlapping with CBD was significant (P < 0.001), but the decrease in overlapping with PD was not (P = 0.106). MRCP with carbon dioxide as negative contrast agent would decrease intestinal fluids in the gastric antrum and duodenal bulb, thereby decreasing overlapping with the CBD.

Comparison of different MRCP techniques for the depiction of biliary complications after liver transplantation

Biliary strictures after liver transplantation are common. We aimed to compare different magnetic resonance cholangiopancreatography (MRCP) sequences with regard to their diagnostic accuracy in depicting anastomotic stenoses (AST), ischaemic-type biliary lesions (ITBL) and cholelithiasis. In patients with clinically suspected biliary obstruction after liver transplantation, MRCP was performed at 1.5 T using two-dimensional (2D) single-shot RARE, 2D T2-weighted (T2w) HASTE, 2D TrueFISP and 3D T2w TSE RESTORE sequences. The presence and localisation of lesions were assessed for each sequence independently and all sequences together. Endoscopic retrograde cholangiopancreatography (ERCP) served as the "gold standard". Biliary strictures were detected with a sensitivity of 96% by MRCP and most accurately depicted when all sequences were analysed together. AST was visualised with highest sensitivity on TrueFISP and 3D T2w TSE sequences (79%). For ITBL highest sensitivity was found with the HASTE sequence (81%). Highest sensitivity for filling defects was revealed by the 3D T2w TSE sequence (54%). Receiver operating characteristic (ROC) curve/area under the curve (AUC) analysis revealed the best results for the 3D T2w TSE sequence. Our results underline the value of different MRCP sequence types for the depiction of biliary lesions. A clinical protocol consisting of different sequences may be helpful depending on the clinical question and the likely underlying abnormality.

Role of diffusion-weighted magnetic resonance imaging in the diagnosis of extrahepatic cholangiocarcinoma

To determine the clinical value of diffusion-weighted imaging (DWI) for the diagnosis of extrahepatic cholangiocarcinoma (EHCC) by comparing the diagnostic sensitivity of DWI and magnetic resonance cholangiopancreatography (MRCP). Magnetic resonance imaging examination was performed in 56 patients with suspected EHCC. T1-weighted imaging, T2-weighted imaging, MRCP and DWI sequence, DWI using single-shot spin-echo echo-planar imaging sequence with different b values (100, 300, 500, 800 and 1000 s/mm(2)), were performed. All cases were further confirmed by surgery or histopathological diagnosis. Two radiologists jointly performed the analysis of the DWI and MRCP images. Apparent diffusion coefficient (ADC) value and signal-noise ratio were calculated for EHCC. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value were tested using DWI with a b value of 500 s/mm(2) and MRCP images, respectively. Histopathological diagnosis confirmed that among the 56 cases, 35 were EHCC (20 hilar and 15 distal extrahepatic), 16 were cholangitis, and 5 were calculus of bile duct. Thirty-three out of the 35 EHCC cases were detected by DWI. EHCC exhibited differential levels of high signal intensity in DWI and low signal intensity in the ADC map. The mean value for ADC was (1.31 +/- 0.29) x 10(-3) mm(2)/s. The detection rate of EHCC was significantly higher by DWI (94.3%) than by MRCP (74.3%) (P < 0.05). There was a significant difference in sensitivity (94.3% vs 74.3%), specificity (100% vs 71.4%), accuracy (96.4% vs 73.2%), positive predictive value (100% vs 81.3%), and negative predictive value (91.3% vs 62.5%) between DWI and MRCP in diagnosing EHCC. DWI has a high sensitivity for the detection of EHCC as it shows the EHCC lesion more unambiguously than MRCP does. DWI can also provide additional clinically important information in EHCC patients when added to routine bile duct MR imaging protocols.

Effects of Gadolinium-ethoxybenzyl-diethylenetriamine Pentaacetic Acid on T2-weighted MRCP

Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) is a recently developed liver-specific contrast agent for magnetic resonance (MR) imaging that is excreted equally via the kidneys and the biliary system. To our knowledge, its effects on T(2)-weighted MR cholangiopancreatography (MRCP) images have not been explored. Acquisition of the hepatobiliary phase is recommended 20 min after administration of Gd-EOB-DTPA. Examination time cannot be extended if the contrast does not take effect on T(2)-weighted MRCP within 20 min after administration. We attempted to assess the change in signal of T(2)-weighted MRCP by excretion of Gd-EOB-DTPA. Between March and July 2008, 40 patients (15 women, 25 men; mean age 70.8 years) were examined with abdominal MR imaging. T(2)-weighted MRCP was performed before and 10 and 20 min after administration of Gd-EOB-DTPA. We analyzed signal intensity of the bile duct, gallbladder, cystic duct, and pancreatic duct on MRCP for changes in intensity. T(2)-weighted MRCP 20 min after contrast administration showed loss of signal of the bile duct (intrahepatic bile duct in all cases, upper extrahepatic duct in 36 [90%], middle extrahepatic duct in 33 [85%], and lower extrahepatic duct in 26 [67%]), the gallbladder in 23 cases (72%), and the cystic duct in 25 (64%). This signal change increased with time. We observed no change in signal of the pancreatic duct. T(2)-weighted MRCP sequences should not be obtained after administration of Gd-EOB-DTPA because this contrast agent decreases signal intensity of the biliary structure on these images.