Recurrent pyogenic cholangitis: comparison between MR cholangiography and direct cholangiography

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography in Comparison With Endoscopic Retrograde Cholangiopancreatography for Detection of the Etiology of Obstructive Jaundice

BACKGROUND

Despite technological advances, obstructive jaundice has significant morbidity and mortality rates. When studying obstructive jaundice, endoscopic retrograde cholangiopancreatography (ERCP), the "gold standard" for biliary obstruction identification, might be replaced with magnetic resonance cholangiopancreatography (MRCP), which is a non-invasive procedure.

OBJECTIVE

Diagnostic accuracy of MRCP in comparison with ERCP for the detection of the etiology of obstructive jaundice.

METHODOLOGY

This prospective, observational study included 102 patients who presented with obstructive jaundice as proven by liver function tests. The MRCP was conducted within 24 to 72 hours before the ERCP. A torso phased-array coil (Siemens, Germany) was used for the MRCP. The duodeno-videoscope and general electric fluoroscopy were used to perform the ERCP. The MRCP was evaluated by a classified radiologist who was blinded to the clinical details. An experienced consultant gastroenterologist who was blinded to the results of the MRCP assessed the cholangiogram of each patient. The hepato-pancreaticobiliary system results from both procedures were compared based on the pathology observed, such as choledocholithiasis, pancreaticobiliary strictures, and dilatation of biliary strictures. We determined the sensitivity, specificity, and negative and positive predictive values with 95% confidence intervals. The statistical significance was set at p<0.05.

RESULTS

The most commonly reported pathology was choledocholithiasis, and MRCP diagnosed 55 patients, of which 53 were true positive cases when compared with the ERCP results of the same patients. MRCP demonstrated greater sensitivity and specificity (respectively) for screening choledocholithiasis (96.2, 91.8), cholelithiasis (100, 75.8), pancreatic duct stricture (100, 100), and hepatic duct mass (100, 100) and showed statistically significant values. The sensitivity of MRCP is lower for identifying benign and malignant strictures, but its specificity was observed to be reliable.

CONCLUSION

When it comes to determining the severity of obstructive jaundice, both in its early and later stages, the MRCP technique is widely regarded as a reliable means of diagnostic imaging. The diagnostic function of ERCP has been significantly reduced as a result of the precision of MRCP as well as its non-invasive nature. In addition to being a helpful non-invasive method to identify biliary diseases and avoid unnecessary ERCPs and their risks, MRCP offers good diagnostic accuracy for obstructive jaundice.

Biliary Strictures: Etiologies and Medical Management

Biliary strictures have several etiologies that can broadly be classified into benign and malignant causes. The clinical presentation is variable with strictures identified incidentally on imaging or during the evaluation of routine laboratory abnormalities. Symptoms and cholangitis lead to imaging that can diagnose biliary strictures. The diagnosis and medical management of biliary strictures will be discussed in this article.

Endoscopic Retrograde Cholangiopancreatography: Deciphering the Black and White

Endoscopic Retrograde Cholangiopancreatography (ERCP) remains the conventional method of imaging the pancreatic and biliary tree and is performed by direct injection of iodinated contrast material via the major papilla. This diagnostic procedure gained popularity in the 1970s and subsequently paved way for ERCP guided interventions such as sphincterotomy, stone retrieval and stent placement. Currently, therapeutic ERCP is more widespread than diagnostic ERCP primarily due to the availability of noninvasive imaging. Nevertheless, more than half a million ERCPs are performed annually in the United States and radiologists need to be comfortable interpreting them. The following review will familiarize the reader with the imaging appearances of biliary and pancreatic disorders on conventional ERCP, and elaborate on therapeutic ERCP with illustrative examples.

Infections of the Hepatobiliary System

Hepatobiliary infections account for a small but clinically important proportion of emergency department presentations. They present a clinical challenge due to the broad range of imaging characteristics on presentation. Recognition of complications is imperative to drive appropriate patient care and resource utilization to avoid diagnostic pitfalls and avert adverse patient outcomes. A thorough understanding of anatomy infectious pathology of hepatobiliary system is essential in the emergency setting to confidently diagnose and guide medical intervention. Many presentations of hepatobiliary infection have characteristic imaging features on individual imaging modalities with others requiring the assimilation of findings of multiple imaging modalities along with incorporating the clinical context and multispecialist consultation. Familiarity with the strengths of individual imaging modalities in the radiologists' arsenal is imperative to guide the appropriate utilization of resources, particularly in the emergent time sensitive setting. Accurate identification and diagnosis of hepatobiliary infections is vital for appropriate patient care and management stratification.

Cholangitis: Diagnosis, Treatment and Prognosis

Cholangitis is a serious life-threatening situation affecting the hepatobiliary system. This review provides an update regarding the clinical and pathological features of various forms of cholangitis. A comprehensive search was performed in the PubMed, Scopus, and Web of Knowledge databases. It was found that the etiology and pathogenesis of cholangitis are heterogeneous. Cholangitis can be categorized as primary sclerosing (PSC), secondary (acute) cholangitis, and a recently characterized form, known as IgG4-associated cholangitis (IAC). Roles of genetic and acquired factors have been noted in development of various forms of cholangitis. PSC commonly follows a chronic and progressive course that may terminate in hepatobiliary neoplasms. In particular, PSC commonly has been associated with inflammatory bowel disease. Bacterial infections are known as the most common cause for AC. On the other hand, IAC has been commonly encountered along with pancreatitis. Imaging evaluation of the hepatobiliary system has emerged as a crucial tool in the management of cholangitis. Endoscopic retrograde cholangiography, magnetic resonance cholangiopancreatography and endoscopic ultrasonography comprise three of the modalities that are frequently exploited as both diagnostic and therapeutic tools. Biliary drainage procedures using these methods is necessary for controlling the progression of cholangitis. Promising results have been reported for the role of antibiotic treatment in management of AC and PSC; however, immunosuppressive drugs have also rendered clinical responses in IAC. With respect to the high rate of complications, surgical interventions in patients with cholangitis are generally restricted to those patients in whom other therapeutic approaches have failed.

Surgical management decreases disease recurrence risk in recurrent pyogenic cholangitis

BACKGROUND

Recurrent pyogenic cholangitis (RPC) has a high risk of disease recurrence. We present our experience with RPC and examine the factors associated with disease recurrence.

METHODS

We performed a retrospective review of all patients with RPC treated at two tertiary institutions between January 1990 and December 2013. Patients with liver atrophy and/or abscess were categorized as being associated with parenchymal disease (PD).

RESULTS

We studied 157 patients with a median age of 59.0 (interquartile range (IQR): 47.0-70.0) years and a median follow-up duration of 71.0 (IQR: 26.0-109.0) months. There were 64 (40.8%) and 93 (59.2%) patients with and without associated PD, respectively. Disease recurrence rate was 43.9% in our overall cohort through the course of follow-up. Surgical treatment was an independent prognostic factor for decreased disease recurrence risk (hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.18-0.87, P = 0.021). Stratified analysis revealed that liver resection was prognostic for lower risk of disease recurrence among patients with PD (HR 0.38, 95% CI 0.15-0.94, P = 0.036), while biliary bypass was prognostic for lower risk of disease recurrence among patients without PD (HR 0.30, 95% CI 0.15-0.61, P = 0.001). The overall post-operative complication rate among surgically treated patients was 31.1%, and the presence of bilobar stones was found to be independently associated with higher odds of post-operative complications (odds ratio 3.51, 95% CI 1.26-9.81, P = 0.017).

CONCLUSION

Surgical treatment is associated with decreased recurrence risk in RPC, but with significant post-operative morbidity. Where surgery is deemed appropriate, patients with and without PD are likely to benefit from liver resection and biliary bypass, respectively.

Recurrent pyogenic cholangitis: a review of imaging findings and clinical management

Recurrent pyogenic cholangitis (RPC) is an infective process involving the biliary tree typified by pigmented intraductal calculi with dilatation of the intra- and extrahepatic biliary tree. Previously endemic to South-east Asia, RPC can now be seen in Western countries with the increasing access to international travel and immigration. Affected patients are often plagued by recurrent bouts of cholangitis, and commonly suffer from complications such as abscess formation and biliary strictures. In severe cases, cirrhosis with portal hypertension may develop. The disease is also a known risk factor for cholangiocarcinoma, and can be seen in up to 5% of affected patients. Its exact etiology is unknown, but parasitic infections such as Clonorchis sinensis and Ascaris lumbricoides, ascending bacterial infection with gut flora (Escherichia coli) and low socioeconomic status have been associated strongly with it. This paper reviews the imaging features of the disease, as well as the roles of interventional radiology and surgery with respect to management of the condition.

Sclerosing Cholangitis: Clinicopathologic Features, Imaging Spectrum, and Systemic Approach to Differential Diagnosis

Sclerosing cholangitis is a spectrum of chronic progressive cholestatic liver disease characterized by inflammation, fibrosis, and stricture of the bile ducts, which can be classified as primary and secondary sclerosing cholangitis. Primary sclerosing cholangitis is a chronic progressive liver disease of unknown cause. On the other hand, secondary sclerosing cholangitis has identifiable causes that include immunoglobulin G4-related sclerosing disease, recurrent pyogenic cholangitis, ischemic cholangitis, acquired immunodeficiency syndrome-related cholangitis, and eosinophilic cholangitis. In this review, we suggest a systemic approach to the differential diagnosis of sclerosing cholangitis based on the clinical and laboratory findings, as well as the typical imaging features on computed tomography and magnetic resonance (MR) imaging with MR cholangiography. Familiarity with various etiologies of sclerosing cholangitis and awareness of their typical clinical and imaging findings are essential for an accurate diagnosis and appropriate management.

Adult bile duct strictures: role of MR imaging and MR cholangiopancreatography in characterization

Bile duct strictures in adults are secondary to a wide spectrum of benign and malignant pathologic conditions. Benign causes of bile duct strictures include iatrogenic causes, acute or chronic pancreatitis, choledocholithiasis, primary sclerosing cholangitis, IgG4-related sclerosing cholangitis, liver transplantation, recurrent pyogenic cholangitis, Mirizzi syndrome, acquired immunodeficiency syndrome cholangiopathy, and sphincter of Oddi dysfunction. Malignant causes include cholangiocarcinoma, pancreatic adenocarcinoma, and periampullary carcinomas. Rare causes include biliary inflammatory pseudotumor, gallbladder carcinoma, hepatocellular carcinoma, metastases to bile ducts, and extrinsic bile duct compression secondary to periportal or peripancreatic lymphadenopathy. Contrast material-enhanced magnetic resonance (MR) imaging with MR cholangiopancreatography is extremely helpful in the noninvasive evaluation of patients with obstructive jaundice, an obstructive pattern of liver function, or incidentally detected biliary duct dilatation. Some of these conditions may show characteristic findings at MR imaging-MR cholangiopancreatography that help in making a definitive diagnosis. Although endoscopic retrograde cholangiopancreatography with tissue biopsy or surgery is needed for the definitive diagnosis of many of these strictures, certain MR imaging characteristics of the narrowed segment (eg, thickened wall, long-segment involvement, asymmetry, indistinct outer margin, luminal irregularity, hyperenhancement relative to the liver parenchyma) may favor a malignant cause. Awareness of the various causes of bile duct strictures in adults and familiarity with their appearances at MR imaging-MR cholangiopancreatography are important for accurate diagnosis and optimal patient management.

The role of diffusion-weighted MR imaging for differentiating benign from malignant bile duct strictures

OBJECTIVES

To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures.

METHODS

Twenty-seven patients with a benign stricture and 42 patients with a malignant stricture who had undergone gadoxetic acid-enhanced MRI with DWI were enrolled. Qualitative (signal intensity, dynamic enhancement pattern) and quantitative (wall thickness and length) analyses were performed. Two observers independently reviewed a set of conventional MRI and a combined set of conventional MRI and DWI, and receiver operating characteristic (ROC) curve analysis was assessed.

RESULTS

Benign strictures showed isointensity (18.5-70.4 %) and a similar enhancement pattern (22.2 %) to that of normal bile duct more frequently than malignant strictures (0-40.5 % and 0 %) on conventional MRI (P < 0.05). Malignant strictures (90.5-92.9 %) showed hypervascularity on arterial and portal venous phase images more frequently than benign strictures (37.0-70.4 %) (P < 0.01) On DWI, all malignant strictures showed hyperintensity compared with benign cases (70.4 %) (P < 0.001). Malignant strictures were significantly thicker and longer than benign strictures (P < 0.001). The diagnostic performance of both observers improved significantly after additional review of DWI.

CONCLUSIONS

Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone.

KEY POINTS

• Accurate diagnosis and exclusion of benign strictures of bile duct are important. • Diffusion-weighted MRI helps to distinguish benign from malignant bile duct strictures. • DWI plus conventional MRI provides superior diagnostic accuracy to conventional MRI alone.

A rare grade III symptomatic Tsunoda class III left lobe hepatolithiasis in a North American woman

A 44-year-old Caucasian woman without any identified predisposing factors, presented to her local emergency room with multiple episodes of recurrent ascending cholangitis. She underwent a laparoscopic cholecystectomy several years prior to her admission to the hospital for parenteral antibiotic therapy and she had no personal or family history of hypercholesterolaemia. Transferred to a tertiary hospital for surgical therapy, she underwent a left hepatic resection for a chronically infected left lobe hepatolithiasis (HL) conditioning atrophy of the parenchyma due to obstruction of the biliary tree by multiple large cholesterol stones. HL is a very rare condition in Western countries and its aetiology and predisposing factors are still unclear. We present her symptomatology, diagnostic and therapeutic management and discuss the epidemiology and risk factors of HL, that is, a common condition in South East Asia while exceptional in Caucasian patients who have not travelled in high-prevalence regions.

Malignant versus benign hepatic masses in patients with recurrent pyogenic cholangitis: MR differential diagnosis

PURPOSE

To assess MR findings and diagnostic performance for differentiating malignant from benign hepatic masses in recurrent pyogenic cholangitis (RPC).

MATERIALS AND METHODS

During a recent 6-year period, we performed MRI in 352 patients with RPC. Among them, 58 had confirmed hepatic masses; cholangiocarcinoma (n = 15), abscess (n = 37), inflammatory pseudotumor (n = 3), biloma (n = 3). Two radiologists assessed MR findings including enhancement patterns, intratumoral appearance, peritumoral changes, mass location, and multiplicity. They also graded the malignancy using common MR findings. The receiver operating characteristic analysis and Chi-square test were used. The κ statistics was used to determine interobserver agreement.

RESULTS

The common findings for cholangiocarcinoma were thin and lobulated enhancement at the periphery (n = 8, 53%, P < 0.05); ill-defined enhancement (n = 7, 47%, P < 0.05); slightly high signal on T2 (n = 13, 87%, P < 0.05); mass located in the same lobe of atrophy (n = 11, 73%, P < 0.05) and portal vein thrombosis (n = 15, 100%, P < 0.05). The common findings for benign mass were target-like enhancement (n = 36, 84%, P < 0.05); cluster appearance (n = 15, 35%, P < 0.05); central, fluid-like space (n = 29, 67%, P < 0.05); peritumoral regional high signal on T2 (n = 32, 74%, P < 0.05); multiplicity(n = 21, 49%, P < 0.05). Interobserver agreement was excellent (κ = 0.81-1.000). Area under the curve (Az) for differentiating malignant masses was 0.989, sensitivity was 95.3%, and specificity was 95.3%. There was good interobserver agreement (κ = 0.74).

CONCLUSION

MR imaging is very useful for differential diagnosis of malignant vs. benign hepatic masses in patients with RPC.

[An Asian man with recurrent abdominal pain]

Recurrent pyogenic cholangitis (RPC), or oriental cholangiohepatitis, is characterized by intrabiliary pigment stone formation, whose main manifestation consists of recurrent episodes of cholangitis, although other biliopancreatic complications can also occur. RPC develops mainly in Asian patients, in whom this entity is one of the main causes of acute abdominal pain. The differential diagnosis should be established with all other entities associated with intrahepatic stone formation, which is more common in Asian countries compared with the predominance of gallstone formation in the West. The diagnostic and therapeutic approach requires collaboration among gastroenterologists, radiologists and gastrointestinal surgeons. We review the most important clinical, diagnostic and therapeutic features of this entity, which, although clearly predominant in Asia, is increasingly diagnosed in our setting.

MRI of oriental cholangiohepatitis

Oriental cholangiohepatitis (OCH) also called recurrent pyogenic cholangitis is characterized by intrahepatic duct calculi, strictures, and recurrent infections. In turn cholangitis can result in multiple hepatic abscesses, further biliary strictures, and in severe cases, progressive hepatic parenchymal destruction, cirrhosis, and portal hypertension. Magnetic resonance cholangiopancreatography (MRCP) and conventional T1-weighted (T1W) and T2-weighted (T2W) magnetic resonance imaging (MRI) findings have been described in patients with OCH. MRCP findings include duct dilation, strictures, and calculi. MRCP can help to localize the diseased ducts and determine the severity of involvement. T1 and T2W sequences reveal the parenchymal changes of atrophy, abscess formation, and portal hypertension in addition to calculi. Post-treatment changes are also well depicted using MRI. Comprehensive, non-invasive assessment is achieved by using conventional MRI and MRCP in OCH providing a roadmap for endoscopic or surgical management.

Recurrent pyogenic cholangitis: from imaging to intervention

OBJECTIVE

The objective of this article is to familiarize the reader with the sonographic, CT, MR cholangiopancreatography, and ERCP appearances of recurrent pyogenic cholangitis and to briefly review the role of interventional radiology in the management of this disease.

CONCLUSION

Recurrent pyogenic cholangitis is a complex disease, the incidence of which is increasing in Western countries. Radiologists should be aware of the role of imaging in the diagnosis of this disease and the use of imaging as a guideline for subsequent intervention.

Mimics of cholangiocarcinoma: spectrum of disease

Cholangiocarcinoma is the second most common primary malignant hepatobiliary neoplasm, accounting for approximately 15% of liver cancers. Diagnosis of cholangiocarcinoma is challenging and the prognosis is uniformly poor, with recurrence rates of 60%-90% after surgical resection. A wide spectrum of neoplastic and nonneoplastic conditions of the biliary tract may masquerade as cholangiocarcinoma, adding to the complexity of management in patients suspected to have cholangiocarcinoma. Mimics of cholangiocarcinoma constitute a heterogeneous group of entities that includes primary sclerosing cholangitis, recurrent pyogenic cholangitis, acquired immunodeficiency syndrome cholangiopathy, autoimmune pancreatitis, inflammatory pseudotumor, Mirizzi syndrome, xanthogranulomatous cholangitis, sarcoidosis, chemotherapy-induced sclerosis, hepatocellular carcinoma, metastases, melanoma, lymphoma, leukemia, and carcinoid tumors. These entities demonstrate characteristic histomorphology and variable clinicobiologic behaviors. The imaging findings of these disparate entities are protean and may be indistinguishable from those of cholangiocarcinoma. In most cases, a definitive diagnosis can be established only with histopathologic examination of a biopsy specimen.

Contrast-enhanced MRI combined with MR cholangiopancreatography for the evaluation of patients with biliary strictures: differentiation of malignant from benign bile duct strictures

PURPOSE

To determine imaging criteria for the combined use of contrast-enhanced (CE)-MRI and MR cholangiopancreatography (MRCP) to differentiate malignant from benign biliary strictures.

MATERIALS AND METHODS

A total of 44 patients with biliary stricture who had undergone unenhanced, MRCP, and dynamic MRI were identified from radiological and surgical databases. Two radiologists analyzed MR features for asymmetry, luminal irregularity, abrupt narrowing, outer margin, signal intensity (SI) on T2-weighted (T2W) images, and hyperenhancement relative to liver parenchyma during portal phase. The wall thickness and length of the narrowed segment were measured. MR findings relevant as predictors were identified using a Chi-square or Fisher's exact test and the odds ratio (OR).

RESULTS

The presence of hyperenhancement relative to liver parenchyma, length > 12 mm, wall thickness > 3 mm, indistinct outer margin, luminal irregularity, and asymmetry of strictured bile duct were significant factors for malignancy (P < 0.05). Malignant strictures were significantly thicker (5.0 +/- 2.0 mm) and longer (27.0 +/- 13.6 mm) than benign strictures. When any three or more of these six criteria were used in combination, we could identify 100% of malignant strictures and 87.0% of benign strictures.

CONCLUSION

The combined use of CE-MRI and MRCP helped to define the criteria for differentiating malignant from benign biliary strictures in our data.

Recurrent pyogenic cholangitis due to chronic infestation with Clonorchis sinensis (2006: 8b)

Recurrent pyogenic cholangitis is a common disease in Southeast Asia, where an association with the liver fluke Clonorchis sinensis is postulated. It is characterised by repeated attacks of cholangitis with multiple recurrences of bile duct stones and strictures. We present a case of recurrent pyogenic cholangitis due to chronic infestation with Clonorchis sinensis in a young Asian immigrant, describing its radiological appearances and also therapeutic strategies with a review of additional examples from the literature.

Value of adding T1-weighted image to MR cholangiopancreatography for detecting intrahepatic biliary stones

OBJECTIVE

The purpose of this study was to assess the value of adding a T1-weighted image to MR cholangiopancreatography (MRCP) to detect bile duct stones.

MATERIALS AND METHODS

During a 30-month period, 148 patients suspected of having biliary stones and who underwent MRI including MRCP, a fat-suppressed T1-weighted fast low-angle shot (FLASH) sequence, and an axial HASTE sequence were enrolled in this study. The biliary stones were confirmed by ERCP, surgery, and percutaneous transhepatic cholangiography. Of these 148 patients, 73 had extrahepatic stones, 45 had intrahepatic stones, 20 had both extrahepatic and intrahepatic stones, and 10 had no biliary stones. Two separate sets of images, the MRCP set (composed of MRCP and axial HASTE) and the combined interpretion of the MRCP set and the T1-weighted image, were analyzed independently and separately by two observers. The diagnostic accuracy was evaluated using the receiver operating characteristic method. The sensitivity and specificity were also calculated.

RESULTS

For common duct stones, the diagnostic accuracy and the sensitivity of both image sets showed similar values without any significant difference (0.998 [97.8%] for the combined interpretation; 0.988 [97.8%] for observer 1 and 0.995 [96.8%] for observer 2 for the MRCP set). However, for the intrahepatic stones, the diagnostic accuracy (0.993) and the sensitivity (98.5%) of the combined interpretation were significantly higher than those of the MRCP set for the two observers (0.926 [83.8%] for observer 1 and 0.922 [85.3%] for observer 2) (p < 0.05). No significant difference was seen in the specificity of the two image sets for both the intrahepatic and the common duct stones.

CONCLUSION

Combining the axial T1-weighted image with MRCP is valuable for detecting intrahepatic stones.

Gallstone disease: Management of intrahepatic stones

Hepatolithiasis (oriental cholangiohepatitis) has reportedly been endemic only in East Asia. The disease is now occasionally recognized in Western societies, especially in people who have lived in the Orient. Hepatolithiasis is characterized by its intractable nature and frequent recurrence, requiring multiple operative interventions, which is in distinct contrast to gallbladder stones. In addition to frequent cholangitis and chronic sepsis, it is widely known that longstanding intrahepatic stones lead to intrahepatic cholangiocarcinoma. Symptoms of hepatolithiasis include abdominal pain, jaundice and cholangitis. Pyogenic cholangitis due to strictures and hepatolithiasis tends to recur, and sometimes patients may present with liver abscesses. Radiological studies and percutaneous procedures are keys in the diagnosis and treatment of hepatolithiasis. Non-invasive imaging modalities such as ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) accurately depict the normal anatomy and presence of intrahepatic stones. It should be stressed that each modality has its pros and cons, and imaging studies should be performed on the basis of understanding the pathophysiology. As the diagnostic role of magnetic resonance cholangiopancreatography (MRCP) evolves, the roles of both endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC), and their most significant advantage, is primarily therapeutic with their ability to extract stones, biopsy intraductal lesions, and place stents easily. The primary goals of treatment are to eliminate attacks of cholangitis and to stop the progression of the disease (which leads to biliary cirrhosis). Surgery has a primary role in hepatolithiasis because hepatolithiasis tends to recur, so that multiple sessions of the endoscopic approach (i.e. two or three times a year) are often required. PTC is an alternative when surgical resection of the affected lobe is difficult. Techniques for lithotripsy, including shockwave and laser, can be applied in endoscopic sessions, offering a better chance of clearing the stones.

From the RSNA refresher courses: imaging evaluation for acute pain in the right upper quadrant

Acute cholecystitis is the most common cause of acute pain in the right upper quadrant (RUQ), and urgent surgical removal of the gallbladder is the treatment of choice for uncomplicated disease. However, cross-sectional imaging is essential because more than one-third of patients with acute RUQ pain do not have acute cholecystitis. In addition, patients with complications of acute cholecystitis, such as perforation, are often best treated with supportive measures initially and elective cholecystectomy at a later date. Ultrasound (US) is the primary imaging modality for assessment of acute RUQ pain; US is both sensitive and specific in demonstrating gallstones, biliary dilatation, and features that suggest acute inflammatory disease. Occasionally, additional imaging modalities are indicated. Computed tomography is valuable, especially for confirming the extent and nature of the complications of acute cholecystitis. Magnetic resonance cholangiopancreatography is helpful in complicated ductal disease (eg, recurrent pyogenic cholangiohepatitis) when more detailed diagnostic information is required for treatment planning, whereas endoscopic retrograde cholangiopancreatography is used when biliary intervention is required (eg, treatment of choledocholithiasis). Successful imaging with all modalities requires familiarity with both the characteristic and the unusual features of a wide variety of pathologic conditions. In addition, potential pitfalls must be recognized and avoided.

Differentiation of extrahepatic bile duct cholangiocarcinoma from benign stricture: findings at MRCP versus ERCP

PURPOSE

To retrospectively evaluate criteria for differentiating extrahepatic bile duct cholangiocarcinoma from benign cause of stricture at magnetic resonance cholangiopancreatography (MRCP) and to compare diagnostic accuracy with this modality versus endoscopic retrograde cholangiopancreatography (ERCP).

MATERIALS AND METHODS

MRCP and ERCP images in 50 patients (27 with cholangiocarcinoma [18 men, nine women; mean age, 58 years] and 23 with benign cause of stricture [13 men, 10 women; mean age, 60 years]) were retrospectively reviewed to assess the appearance of bile duct strictures. Final diagnosis was based on surgical or biopsy findings. Strictures were described according to their imaging appearance (irregular or smooth margins, asymmetric or symmetric narrowing, abrupt narrowing or gradual tapering, and presence or absence of double-duct sign). Sensitivity, specificity, and accuracy of MRCP and ERCP were calculated by using ratings of confidence in image-based diagnosis. Lengths of stricture were electronically measured and compared by using the Student t test.

RESULTS

Among cholangiographic criteria for malignant biliary stricture, irregular margins and asymmetric narrowing were more common in cholangiocarcinomas (24 [89%] of 27 patients) than in benign strictures (six [26%] and eight [35%] of 23 patients, respectively). Sensitivity, specificity, and accuracy of the two methods for differentiation of malignant from benign causes of biliary stricture were 81% (22 of 27), 70% (16 of 23), and 76% (38 of 50), respectively, for MRCP and 74% (20 of 27), 70% (16 of 23), and 72% (36 of 50), respectively, for ERCP. Mean length (+/- standard deviation) of cholangiocarcinomas was 30.0 mm +/- 8.5, and that of benign strictures was 13.6 mm +/- 9.1 (P <.001).

CONCLUSION

Accuracy of MRCP is comparable with that of ERCP. Regardless of modality, a lengthy segment of extrahepatic bile duct stricture with irregular margin and asymmetric narrowing suggests cholangiocarcinoma, and a short segment with regular margin and symmetric narrowing suggests benign cause.

MR imaging findings of clonorchiasis

OBJECTIVE

The purpose of this study was to evaluate the MR spectrum and MR cholangiographic imaging findings of clonorchiasis.

MATERIALS AND METHODS

We reviewed 26 patients with confirmed clonorchiasis by either stool tests (n=24) or surgery (n=2). MR imaging was performed on a 1.5 T system (GE Medical Systems, Milwaukee, WI) with a torso coil. Axial T1- and T2-weighted, gadolinium-enhanced dynamic images and MR cholangiography were obtained. Image analyses were used to identify abnormalities of the intrahepatic and extrahepatic bile ducts and the presence of hepatobiliary malignancy. All MR examinations were reviewed by the consensus of two abdominal radiologists.

RESULTS

Intrahepatic bile duct abnormalities were seen in 23 (89%) of the 26 patients. The most common finding was mild dilatation of the intrahepatic bile duct which was found in 21 (81%). "Too many intrahepatic ducts" were found in 16(62%), wall enhancement and thickening in 21 (81%) and filling defects and ductal stricture in the intrahepatic bile duct in 6 (24%) and 3 (12%) patients, respectively. Extrahepatic ductal dilation was found in 5 (19%) and 9 (35%) revealed hepatobiliary malignancy.

CONCLUSION

MR imaging revealed various findings of clonorchiasis, including dilatation, wall enhancement, stricture of the intrahepatic ducts and filling defect within the intrahepatic bile duct.