MRCP of congenital pancreaticobiliary malformation

Diagnostic impact of computed tomography cholangiography and magnetic resonance cholangiopancreatography on pancreaticobiliary maljunction

BACKGROUND/PURPOSE

The aim of this study was to investigate the diagnostic potential of computed tomography cholangiography (CTC) and magnetic resonance cholangiopancreatography (MRCP) in children with pancreaticobiliary maljunction (PBM).

METHODS

Fifty-three children with PBM were consecutively treated between 1997 and 2009. Among them, the patients who underwent CTC and/or MRCP preoperatively were enrolled in this study. Computed tomography cholangiography was examined after infusion of meglumine iodoxamate with subsequent 3-dimensional rendering. The visualization of the biliary and pancreatic duct systems was evaluated and compared with that visualized with MRCP. The findings of direct cholangiography were used as the standard of reference.

RESULTS

Of the 53 cases with PBM, 17 cases were examined by CTC, 10 cases by MRCP, and 17 with both. The extrahepatic bile tract was visualized in 32 (94.1%) of 34 patients in CTC and in all 27 patients in MRCP. The intrahepatic bile duct was more frequently demonstrated by MRCP than by CTC (96.3% vs 70.6%, P = .02). Pancreaticobiliary maljunction was noted in 13 (38.2%) of 34 with CTC and in 12 (44.4%) of 27 with MRCP. The minimum age for visualization of PBM was at 10 months in CTC and at 1 year and 11 months in MRCP, respectively. The main pancreatic duct was more frequently visualized by MRCP than by CTC (81.5% vs 8.8%, P < .001).

CONCLUSIONS

Magnetic resonance cholangiopancreatography provides superior visualization of the intrahepatic duct and the pancreatic system when compared with CTC. However, it is still challenging to perform a good-quality examination in young infant. The great advantage of CTC is its ability to produce high-quality images without respiratory artifacts and that it allows accurate assessment of the presence of PBM equivalent to MRCP.

Gadopentetate dimeglumine-enhanced MR cholangiopancreatography in infants with cholestasis

BACKGROUND

Biliary atresia (BA) is a progressive, obliterative cholangiopathy that occurs in neonates with hepatic portoenterostomy the treatment of choice, but early surgery is important for optimum outcomes. MRI, including MR cholangiopancreatography (MRCP) may be a diagnostically useful alternative to US, but the heavily T2-weighted sequences used include not only bile duct signals, but also other heterogeneously high signal intensities from surrounding structures.

OBJECTIVE

To evaluate the effects of gadolinium when used to decrease background signal intensity on T2-weighted MR cholangiopancreatography (MRCP) in infants and to evaluate the qualitative improvement of the depiction of the common bile duct (CBD) for evaluating neonatal cholestasis.

MATERIALS AND METHODS

Our Institutional Review Board approved this prospective study. MRCP was performed with gadopentetate dimeglumine injection using a 1.5-T scanner. Pre- and postcontrast MRCP images were compared. Forty-nine infants (male:female = 21:28; age 0-12 months, mean 2.3) were included. The final diagnoses were biliary atresia (BA) in 28 cases and non-BA in 21. Quantitative analysis was conducted using region-of-interest measurements of mean signal intensities of the liver, pancreatic head and gallbladder (if defined). Qualitative analysis was performed by four radiologists who subjectively scored image confidence in the presence of CBD on a 4-point scale (0 for definitely absent, 1 for probably absent, 2 for probably present, and 3 for definitely present).

RESULTS

The signal-to-noise ratios were significantly decreased in the liver and pancreatic head after contrast medium enhancement (mean 5.7→4.0 in liver and mean 44.9→12.7 in the pancreatic head; P < 0.0001), and this finding was constant in both the BA and the non-BA group. The mean confidence score in the presence of CBD decreased in the BA group (0.9→0.5; P < 0.0001), but did not change significantly in the non-BA group (2.0→2.1; P = 0.459) after contrast medium enhancement. Both intra- and interobserver agreement was higher after contrast medium enhancement (P = 0.046).

CONCLUSION

Gadopentetate dimeglumine-enhanced MRCP increased the diagnostic confidence of absence of the CBD in cholestatic infants with increased intra- and interobserver agreement.

Endoscopic diagnosis of pancreaticobiliary maljunction

Pancreaticobiliary maljunction (PBM) is a congenital anomaly defined as a junction of the pancreatic and bile ducts located outside the duodenal wall, usually forming a markedly long common channel. As the action of the sphincter of Oddi does not functionally affect the junction in PBM patients, continuous pancreatobiliary reflux occurs, resulting in a high incidence of biliary cancer. PBM can be divided into PBM with biliary dilatation (congenital choledochal cyst) and PBM without biliary dilatation (maximal diameter of the bile duct ≤ 10 mm). The treatment of choice for PBM is prophylactic surgery before malignant changes can take place. Endoscopic retrograde cholangiopancreatography (ERCP) is the most effective examination method for close observation of the pattern of the junction site. When the communication between the pancreatic and bile ducts is maintained, despite contraction of the sphincter on ERCP, PBM is diagnosed. In these patients, levels of pancreatic enzymes in the bile are generally elevated, due to continuous pancreatobiliary reflux via a long common channel. Magnetic resonance cholangiopancreatography and 3D-computed tomography can diagnose PBM, based on findings of an anomalous union between the common bile duct and the pancreatic duct, in addition to a long common channel. Endoscopic ultrasonography and intraductal ultrasonography can demonstrate the junction outside the duodenal wall, and are useful for the diagnosis of associated biliary cancer. Gallbladder wall thickness on ultrasonography can be a screening test for PBM.

Can MRCP replace ERCP for the diagnosis of autoimmune pancreatitis?

BACKGROUND

It is of utmost importance that autoimmune pancreatitis (AIP) be differentiated from pancreatic cancer. Irregular narrowing of the main pancreatic duct is a characteristic finding in AIP; it is useful for differentiating AIP from pancreatic cancer stenosis. This study evaluated the usefulness of magnetic resonance cholangiopancreatography (MRCP) for the diagnosis of AIP and assessed whether MRCP could replace endoscopic retrograde cholangiopancreatography (ERCP) for diagnosing AIP.

METHODS

The MRCP and ERCP findings of 20 AIP patients were compared.

RESULTS

On MRCP, the narrowed portion of the main pancreatic duct was not visualized, while the noninvolved segments of the pancreatic duct were visualized. The degree of upstream dilatation of the proximal main pancreatic duct was milder in AIP than in pancreatic cancer patients. In the skipped type, only skipped narrowed lesions were not visualized. After steroid therapy for AIP, the nonvisualized main pancreatic duct became visualized.

CONCLUSIONS

MRCP cannot replace ERCP for the diagnosis of AIP, since narrowing of the main pancreatic duct in AIP was not visualized on MRCP. MRCP findings of segmental or skipped nonvisualized main pancreatic duct accompanied by a less dilated upstream main pancreatic duct may suggest the presence of AIP. MRCP is useful for following AIP patients.

Prenatal diagnosis of annular pancreas: reliability of the double bubble sign with periduodenal hyperechogenic band

OBJECTIVE

To evaluate the power of prenatal 2-D ultrasound examination in the 2nd trimester as a method of choice for accurate diagnosis of annular pancreas.

METHODS

Co-incidence of the double bubble sign (often accompanying gastroduodenal dilatation) together with a hyperechogenic band around the duodenum (corresponding with the tissue of annular pancreas) was used as a diagnostic criterion. Findings from postnatal surgery served for verification.

RESULTS

From 7,897 screened pregnancies, annular pancreas was proven in the cases where both signs were present, but never without the hyperechogenic band (N(1) = 3, N(2) = 3, p < or = 0.05). Sensitivity and specificity were 100%.

CONCLUSIONS

More multicentric studies are required to test this approach. The following diagnostic strategy is reasonable at the present time: when the double bubble sign is discovered, always suspect annular pancreas and look for the second sign: hyperechogenic bands around the duodenum. Also look for known associated anomalies, and vice versa, if any of associated anomalies are noted, also search specifically for the signs of annular pancreas.

Annular pancreas causing localized recurrent pancreatitis in a child: report of a case

Annular pancreas is a rare congenital anomaly. We report a case of relapsing acute pancreatitis localized in the annulus of an annular pancreas in a young child. A 6-year-old boy complained of abdominal pain and we made a diagnosis of acute pancreatitis based on blood biochemistry results. Over the subsequent 12 months, he experienced two more pancreatitis-like attacks. Endoscopy revealed a duodenal stenosis in the second portion of the duodenum. Ultrasound, computed tomography, and magnetic resonance imaging depicted a ring of pancreatic tissue encircling the duodenum with a duct in the tissue, manifesting dilatation with a characteristic circular pattern around the duodenum. No dilatation of the dorsal pancreatic duct or pancreatic divisum was found. Based on these findings, we diagnosed acute pancreatitis localized in an annulus in an annular pancreas. This case report suggests that an annular pancreas may predispose to localized relapsing acute pancreatitis even in a child.

Miss rate of pancreas divisum by magnetic resonance cholangiopancreatography in clinical practice

OBJECTIVES

Pancreas divisum is the most common congenital abnormality of the pancreatic anatomy. Magnetic resonance cholangiopancreatography has emerged as a noninvasive method of examining the pancreatic ductal anatomy. We aim to assess the sensitivity of MRCP for pancreas divisum.

METHODS

Patients with pancreas divisum at endoscopic retrograde cholangiopancreatography (ERCP) and who had prior MRCP between January 2001 and February 2006 were identified. Sensitivities were calculated for relevant subgroups with binomial 95% confidence intervals. Fisher exact P values were calculated.

RESULTS

Four hundred five patients had divisum at ERCP; of these, 111 (27%) had undergone MRCP before ERCP. Seventy-two (65%) patients had MRCP at outside centers. Twenty-three of the 72 MRCPs at referring centers correctly reported divisum. In contrast, the sensitivity was higher for the 24 MRCPs without secretin at our institution: 16 (67%). The sensitivity in the secretin-stimulated group was 67% (10/15). However, this was not different from that of MRCP without secretin. Of note, 9 (18%) of the 49 negative outside MRCPs had divisum suspected by the gastroenterologist reviewing the MRCP images before ERCP.

CONCLUSIONS

Pancreas divisum seems to be often missed on MRCP, even when secretin is used. The absence of secretin, use of suboptimal magnetic resonance techniques, and inexperienced pancreatic MRCP examiners are all possible contributing factors.

Congenital anomalies and variations of the bile and pancreatic ducts: magnetic resonance cholangiopancreatography findings, epidemiology and clinical significance

PURPOSE

The objective of this paper is to document the magnetic resonance cholangiopancreatography (MRCP) findings and the epidemiology of congenital anomalies and variations of the bile and pancreatic ducts and to discuss their clinical significance.

MATERIALS AND METHODS

Three-hundred and fifty patients of both sexes (150 females, 200 males, age range 0-76 years, average age 38 years) underwent MRCP for clinically suspected lithiasic, neoplastic or inflammatory disease of the bile and pancreatic ducts. Patients were imaged with a 1.5-T superconductive magnet (Magnetom Vision, Siemens, Erlangen, Germany), a four-channel phased-array body coil, breath-hold technique, with multislice T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE), MIP reconstructions, and a single-shot T2-weighted turbo-spin-echo sequence rapid acquisition with relaxation enhancement (RARE) with different slice thicknesses. Studies in oncological patients were completed with fat saturation 3D T1 gradient-echo sequences during the intravenous injection of gadolinium diethylene triamine pentaacetate acid (DTPA) (0.2 ml/kg).

RESULTS

MRCP demonstrated recurrent and therefore normal bile and pancreatic ducts in 57% of patients. In the remaining 42.3%, it documented anatomical variants (41%) and congenital anomalies (1.3%). Variants of the intrahepatic bile duct were seen in 21% of cases: crossover anomaly (6.7%), anterior branch of the right hepatic duct draining the IV and VII segments that flow together with the left bile duct (3.1%) and anterior and posterior branches of the right hepatic duct that flow together with the common hepatic duct (3.3%). Variants of the extrahepatic bile ducts were present in 8.8% of patients: low insertion of the cystic duct into the common hepatic duct (4.5%), emptying of the cystic duct into the right hepatic duct (2.7%) and a second-order large branch draining into the cystic duct (1.6%). MRCP identified a double gall bladder in 3% of patients and anatomical variants of the biliopancreatic system in 8.2%: pancreas divisum (5.2%) and a long sphincter of Oddi (3%). Finally, congenital anomalies were diagnosed in 1.3% of cases: bile duct cysts (0.3%), atresia of the bile ducts (0.3%) and multiple biliary hamartomatosis (0.7%).

CONCLUSIONS

The congenital anomalies and anatomical variants of the bile and pancreatic ducts present a complex spectrum of frequent alterations, which are worthy of attention in both the clinical and surgical settings and are readily identified by MRCP.

Pancreas divisum and duodenal diverticula as two causes of acute or chronic pancreatitis that should not be overlooked: a case report

Introduction

Pancreas divisum is a congenital anatomical anomaly characterized by the lack of fusion of the ventral and dorsal parts of the pancreas during the eighth week of fetal development. This condition is found in 5% to 14% of the general population. In pancreas divisum, the increased incidence of acute and chronic pancreatitis is caused by inadequate drainage of secretions from the body, tail and part of the pancreatic head through an orifice that is too small. The incidence of diverticula in the second part of the duodenum is found in approximately 20% of the population. Compression of the duodenal diverticula at the end of the common bile duct leads to the formation of biliary lithiasis (a principal cause of acute pancreatitis), pain associated with biliary lithiasis owing to compression of the common bile duct (at times with jaundice), and compression of the last part of Wirsung's duct or the hepatopancreatic ampulla (ampulla of Vater) that may lead to both acute and chronic pancreatitis.

Case presentation

We describe the radiological findings of the case of a 75-year-old man with recurrent acute pancreatitis due to a combination of pancreas divisum and duodenal diverticula.

Conclusion

Magnetic resonance cholangiopancreatography is advisable in patients with recurrent pancreatitis (both acute and chronic) since it is the most appropriate noninvasive treatment for the study of the pancreatic system (and the eventual presence of pancreas divisum) and the biliary systems (eventual presence of biliary microlithiasis). Moreover, it can lead to the diagnostic suspicion of duodenal diverticula, which can be confirmed through duodenography with X-ray or computed tomography scan with a radio-opaque contrast agent administered orally.

Review of idiopathic pancreatitis

Recent advances in understanding of pancreatitis and advances in technology have uncovered the veils of idiopathic pancreatitis to a point where a thorough history and judicious use of diagnostic techniques elucidate the cause in over 80% of cases. This review examines the multitude of etiologies of what were once labeled idiopathic pancreatitis and provides the current evidence on each. This review begins with a background review of the current epidemiology of idiopathic pancreatitis prior to discussion of various etiologies. Etiologies of medications, infections, toxins, autoimmune disorders, vascular causes, and anatomic and functional causes are explored in detail. We conclude with management of true idiopathic pancreatitis and a summary of the various etiologic agents. Throughout this review, areas of controversies are highlighted.

The use of magnetic resonance cholangiopancreatography in children

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method to evaluate a wide variety of pancreatobiliary disorders. These disorders include choledochal cyst, cholelithiasis, choledocholithiasis, biliary atresia, Caroli's disease, primary sclerosing cholangitis, disorders of the pancreatobiliary junction, pancreas divisum, and pancreatic duct abnormalities related to chronic pancreatitis. The use of MRCP in children is increasing as experience with MRCP grows, and its technological accuracy rivals that of endoscopic evaluation. We review the current state of MRCP use in children.