MR versus multislice CT cholangiography in evaluating patients with obstruction of the biliary tract

Evaluation of three-dimensional dual-energy CT cholangiopancreatography image quality in patients with pancreatobiliary dilatation: Comparison with conventional single-energy CT

Objective

This study aimed to evaluate three-dimensional (3D) negative-contrast CT cholangiopancreatography (nCTCP) image quality using dual-energy CT (DECT) with iterative reconstruction (IR) technique in patients with pancreatobiliary dilatation compared with single-energy CT (SECT).

Methods

Of the patients, 67 and 56 underwent conventional SECT (SECT set) and DECT with IR technique (DECT set), respectively. All patients were retrospectively analyzed during the portal phase to compare objective image quality and other data including patient demographics, hepatic and pancreatic parenchymal enhancement, noise, and attenuation difference (AD) between dilated ducts and enhanced hepatic parenchyma, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and CT volume dose index (CTDIvol). Two radiologists used the five-point Likert scale to evaluate the subjective image quality of 3D nCTCP regarding image noise, sharpness of dilated ducts, and overall image quality. Statistical analyses used the Mann-Whitney U test.

Results

No significant difference in patient demographics in either CT set was showed during objective evaluation (p > 0.05). However, higher hepatic and pancreatic parenchymal enhancement, AD, SNR, and CNR and lower hepatic and pancreatic noise (p < 0.005) as well as CTDIvol (p = 0.005) on DECT than on SECT were observed. Higher mean grades on DECT than on SECT were showed for image noise (4.65 vs 3.92), sharpness of dilated ducts (4.52 vs 3.94), and overall image quality (4.45 vs 3.91; p < 0.001), respectively during subjective evaluation.

Conclusion

A higher overall image quality and lower radiation dose on 3D nCTCP can be obtained by DECT with IR technique than with conventional SECT in patients with pancreatobiliary dilatation.

Trends in pre-liver transplant screening for cholangiocarcinoma among patients with primary sclerosing cholangitis

BACKGROUND

Cholangiocarcinoma (CCA) is the most common hepatobiliary malignancy complicating primary sclerosing cholangitis (PSC). Unfortunately, timely diagnosis of CCA in PSC patients remains challenging.

AIM

To investigate the strategies among liver centers regarding pre-transplant screening for CCA in patients with PSC.

METHODS

An online survey was returned from 46 US transplant centers, inquiring on the frequency of screening, the use of specific tests, or tactical approaches to high-grade dysplasia (HGD) or CCA.

RESULTS

Most centers screen their PSC patients for CCA prior to orthotopic liver transplantation (OLT) (89%). Serum carbohydrate antigen 19-9 and magnetic resonance cholangiopancreatography are first-line screening tools (93 and 84% respectively). Endoscopic retrograde cholangiopancreatography with biliary brushings is routinely performed in only 30% of the centers. In the case of HGD, 61% would choose close monitoring. In the event of non-resectable CCA, 37% have an OLT protocol, 33% resort to palliative treatment and the remaining 30% make an outside referral. Finally, half the participating centers perform CCA surveillance among their listed PSC patients every 6 months.

CONCLUSION

Screening for CCA among PSC patients prior to OLT varies greatly among centers. Serum carbohydrate antigen 19-9 and magnetic resonance cholangiopancreatography are widely used. HGD warrants surveillance rather than intervention among most experts. Protocolized chemoradiation followed by OLT has yet to become a widely accepted approach. The very poor survival of PSC patients who develop CCA underlines the importance of an effective and universally accepted screening process that will aid in its earlier detection.

Impact of magnetic resonance cholangiography in managing liver-transplanted patients: preliminary results of a clinical decision-making study

PURPOSE

This study was performed to assess the role of magnetic resonance cholangiography (MRC) in the clinical decision-making process of referring physicians when managing liver-transplanted patients.

MATERIALS AND METHODS

Over a 6-month period, 21 liver-transplanted patients with a suspected biliary complication were referred for MRC. Referring physicians were asked to prospectively state, before and after MRC, the leading diagnosis; the level of confidence (on a 0-100% scale); the most appropriate diagnostic/therapeutic plan. Data analysis assessed was the diagnostic yield of MRC; the proportion of change in the leading diagnosis; the therapeutic efficacy (i.e. proportion of change in the initial diagnostic/therapeutic plan); the diagnostic thinking efficacy (i.e., gain in diagnostic confidence). Statistical significance was assessed with the Mann-Whitney U test. MRC accuracy was also calculated.

RESULTS

Data analysis showed a diagnostic yield of 85.7%; a proportion of change in leading diagnosis of 19.0%; a therapeutic efficacy of 42.8%; a diagnostic thinking efficacy for concordant and discordant leading diagnoses of 18.8% and 78.7%, respectively (p<0.01). MRC accuracy was 92.3%.

CONCLUSIONS

MRC significantly increased the diagnostic confidence, irrespective of the concordance between pre- and posttest diagnoses. Moreover, MRC determined a change in patient management in a significant proportion of cases, leading to clinical benefits.

Comparison of three-dimensional negative-contrast CT cholangiopancreatography with three-dimensional MR cholangiopancreatography for the diagnosis of obstructive biliary diseases

PURPOSE

The purpose of our study was to compare three-dimensional (3D) negative-contrast CT cholangiopancreatography (3D-nCTCP) with 3D MR cholangiopancreatography (3D-MRCP) for the diagnosis of obstructive biliary diseases.

MATERIALS AND METHODS

3D-nCTCP and 3D-MRCP were performed on seventy clinically documented obstructive biliary diseases patients. The accuracy of each technique in determining the location and cause of biliary obstruction was evaluated compared with the final clinical diagnoses.

RESULTS

Both methods achieved 100% of accuracy in the diagnosis of the presence and location of biliary obstruction, and had a similar sensitivity, specificity, accuracy in differentiating benign from malignant biliary obstruction or calculous from noncalculous biliary obstruction (p>0.05). At 3D-nCTCP, six patients with stones were misinterpreted as cholangitis (N=2), papillitis (N=3), or bile duct adenocarcinoma (N=1); two metastases were mistaken as acute pancreatitis or pancreatic head carcinomas, and one intrahepatic cholangiocarcinoma was misled as bile duct adenoma. At 3D-MRCP, one small stone, one ampullary adenoma, and one intrahepatic cholangiocarcinoma were mistaken as cholangitis, ampullary stone, and intrahepatic bile duct stone, respectively, and three gallbladder carcinomas and another intrahepatic cholangiocarcinoma were misdiagnosed as hilar cholangiocarcinoma (N=3) or common hepatic duct stone (N=1); four metastases were mistaken as pancreatic head carcinomas (N=3) or distal cholangiocarcinoma (N=1). The overall accuracy in making specific diagnosis of the cause of biliary obstruction was 87.1% for 3D-nCTCP and 84.3% for 3D-MRCP, respectively, (p>0.05).

CONCLUSION

3D-nCTCP has the similar effects as 3D-MRCP for the diagnosis of biliary obstruction and, the location and the cause of biliary obstruction. In view of selected cases contraindications for MRI, 3D-nCTCP is a potential substitute.

3D CT imaging in clinical practice

Recent technological advances in multidetector computed tomography (MDCT) have enabled 3D diagnostic imaging with superb spatial and temporal resolution. This often provides useful information on precise detail and relationships.

Update on 3D and multiplanar MDCT in the assessment of biliary and pancreatic pathology

The development of multidetector row computed tomography (MDCT) has led to the acquisition of true isotropic voxels that can be postprocessed to yield images in any plane of the same resolution as the original axially acquired images. This, coupled with rapid MDCT imaging during peak target organ enhancement has led to a variety of means to review imaging information beyond that of the axial perspective. Postprocessing can be utilized to identify variant biliary anatomy to guide preoperative planning of biliary-related surgery, determine the level and cause of biliary obstruction and assist in staging of biliary cancer. Postprocessing can also be used to identify pancreatic ductal variants, visualize diagnostic features of pancreatic cystic lesions, diagnose and stage pancreatic cancer, and differentiate pancreatic from peripancreatic disease.

Comparative diagnostic evaluation with MR cholangiopancreatography, ultrasonography and CT in patients with pancreatobiliary disease

PURPOSE

The aim of this study was to directly compare the results of magnetic resonance cholangiopancreatography (MRCP) with those of ultrasonography (US) and multislice computed tomography (MSCT) in the diagnosis of pancreaticobiliary diseases.

MATERIALS AND METHODS

A total of 70 patients (41 men, 29 women) aged 22-89 years were studied either before (n=59) or after cholecystectomy (n=11) for biliary lithiasis. Clinical signs and symptoms were jaundice (n=15), abdominal pain (n=37) and proven biliary lithiasis (n=18). MRCP was performed in all patients, whereas abdominal US was performed in 55 (group 1) and MSCT in 37 (group 2) patients. A regional evaluation of the main structures of the pancreaticobiliary system was performed: gallbladder and cystic duct, intra- and extrahepatic bile ducts and main pancreatic duct. Histology (n=27), biopsy (n=5), endoscopic retrograde cholangiopancreatography (ERCP) (n=28) and/or clinical-imaging follow-up (n=10) were considered standards of reference. In particular, patients were classified as showing benign (n=47) or malignant (n=12) lesions or normal biliary anatomy (n=11).

RESULTS

In group 1, the results of MRCP and US were concordant in the majority (92%) of cases; however, statistically significant discordance (p<0.01) was found in the evaluation of the extrahepatic ducts, with nine cases (16%) of middle-distal common bile duct stones being detected on MRCP only. In group 2, the results of MRCP and MSCT were also concordant in most cases (87%). However, findings were significantly discordant when the intra- and extrahepatic ducts were analysed, with seven (19%) and six (16%) cases, respectively, of lithiasis being detected on MRCP only (p<0.01 for both).

CONCLUSIONS

The results of our study confirm the diagnostic potential of MRCP in the study of the pancreaticobiliary duct system. In particular, the comparison between MRCP and US and MSCT indicates the superiority of MRCP in evaluating bile ducts and detecting stones in the common bile duct.

[Cholestasis and liver dysfunction in critical care patients]

Cornerstones of the diagnostic investigations of disturbances in liver function are analysis and sophisticated evaluation of serum liver enzymes, bilirubin and ammonia. Coagulation factors, serum albumin and cholinesterase levels are indicators of the hepatic metabolic capacity. Dynamic assessment of complex liver functions allows quantification of the hepatic metabolic activity and excretory function. Imaging techniques permit visualization of the size and texture of the liver, the vascular supply and perfusion as well as an assessment of the gall bladder and the extra-hepatic and intra-hepatic bile ducts. Manifold causes for cholestasis and/or liver dysfunction are known, such as ventilation with high pressure, total parenteral nutrition, shock, hypoxia and certain drugs. Obstructive cholestasis requires reconstitution of bile duct drainage, while non-obstructive cholestasis primarily requires treatment of the causative disease. The symptomatic therapy of liver insufficiency is rarely possible via direct treatment of the cause, but mostly requires specific management of secondary organ dysfunctions related to hepatic dysfunction including circulatory failure, hepatorenal syndrome and hepatic encephalopathy. In rare cases a temporary liver surrogate is necessary. The molecular absorbent recirculating system (MARS), a form of extracorporeal albumin dialysis, is introduced as a modality for the treatment of liver failure.

MR imaging findings of early bile duct cancer

PURPOSE

To retrospectively evaluate the MR imaging features of early bile duct cancer and to correlate them with the clinicopathologic findings.

MATERIALS AND METHODS

This retrospective study was approved by our institutional review board, and informed consent was waived. Seventeen patients with surgically proven early bile duct cancer who had undergone preoperative MR cholangiopancreatography with gadolinium-enhanced MR imaging, were included in this study. Two, experienced radiologists evaluated the MR images in consensus regarding the following findings: tumor number and morphology; signal intensity of the tumor; sharpness of the outer border of the bile duct wall; enhancement pattern of the tumor; and the presence of enlarged peribiliary lymph nodes. Another radiologist measured the SNR of the tumor and bile duct wall on gadolinium-enhanced MRI during the dynamic phases to evaluate the tumor enhancement degree.

RESULTS

In all patients, MR imaging demonstrated single or multiple intraluminal bile duct masses showing a sharply defined outer margin. The most common enhancement pattern of the biliary lesions showed heterogeneous amorphous enhancement or heterogeneous enhancement with central, dot-like structures or vascular structures (76.5%, 13/17 patients). The difference of SNR between bile duct and tumor was greatest in the equilibrium phase (P < 0.05).

CONCLUSION

MRCP combined with dynamic contrast-enhanced MRI can be useful for detecting early bile duct cancers. Common MR findings of early bile duct cancer include one or more inhomogeneously enhancing intraductal masses with clear outer margins and preservation of the bile duct wall.

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the bile ducts, resulting in end-stage liver disease and reduced life expectancy. PSC primarily affects young and middle-aged men, often in association with underlying inflammatory bowel disease. The etiology of PSC includes immune-mediated components and elements of undefined nature. A cholestatic picture of liver biochemistries with elevations in serum alkaline phosphatase, nonspecific autoantibodies such as perinuclear antineutrophilic antibody, antinuclear antibodies and smooth muscle antibodies, and diffuse multifocal biliary strictures, resulting in a 'beaded' appearance on radiographic studies, are the hallmarks of the disease. No effective medical therapy is currently available, although clinical studies are in progress. Ursodeoxycholic acid at high doses (28 mg/kg/day to 30 mg/kg/day) is the most promising agent but is unproven so far. Liver transplantation is currently the only life-extending therapy for patients with end-stage disease, although recurrent disease can be observed in the transplanted liver. The multiple complications of PSC include pruritus, fatigue, vitamin deficiencies, metabolic bone disease, peristomal varices, bacterial cholangitis, dominant biliary strictures, gallbladder stones and polyps, and malignancy, particularly cholangiocarcinoma, which is the most lethal complication of PSC.

Computed tomography and magnetic resonance cholangiography

In patients with biliary obstruction, determining the level and the cause of the obstruction is essential because it can be a key factor for the next step in diagnostic or therapeutic intervention. Noninvasive cholangiography, such as computed tomography (CT) cholangiography or magnetic resonance (MR) cholangiography, allows the diagnosis of cause and level of biliary disease with minimal risk. Traditional magnetic resonance cholangiopancreatography (MRCP) is an established and effective noninvasive diagnostic modality particularly for extrahepatic biliary tract evaluation. Intrahepatic biliary duct evaluation and functional MR, including evaluating for leaks and gallbladder dyskinesia and outlet obstruction, are evolving diagnostic techniques that show promising results. CT cholangiography techniques are especially useful when MRI is not available or contraindicated or when the quality of MRCP images is suboptimal. CT cholangiography is particularly useful as an adjunct to surgery or postsurgical cases. The primary limitation of cholangiographic contrast-enhanced CT cholangiography (the most prevalent type of CT cholangiography) is its hindrance by poor liver function and/or high-grade biliary obstruction. In this setting MRCP is clearly superior. There are different types of CT cholangiography and MRCP. This article discusses the types of CT cholangiography and MRCP techniques and their clinical applications.

Detection of biliary duct narrowing and choledocholithiasis: accuracy of portal venous phase multidetector CT

PURPOSE

To retrospectively evaluate the sensitivity and specificity of 64-detector computed tomography (CT) in the portal venous phase by using transverse images and both multiplanar and minimum intensity reformations for the detection of biliary duct narrowing and choledocholithiasis, with magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP) as the reference standard.

MATERIALS AND METHODS

Approval from institutional review board was obtained for this HIPAA-compliant retrospective study; informed consent was waived. The study included all patients (42 men, 52 women; mean age, 61 years) who underwent abdominal 64-detector CT within 2 months of MRCP and/or ERCP. All patients underwent portal venous phase intravenous contrast material-enhanced abdominal CT. Sixty-one patients underwent MRCP and 54 patients underwent ERCP (21 patients underwent both). Two radiologists, blinded to the reference standard, independently evaluated the CT images, including multiplanar and minimum intensity reformations, for biliary duct narrowing and choledocholithiasis. Standard of reference examinations were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Twenty-three (24%) of 94 patients had a biliary duct narrowing at reference examinations. For detecting biliary duct narrowing, observer 1 had a sensitivity of 78.2%, specificity of 100%, PPV of 100%, and NPV of 93.4% and observer 2 had a sensitivity of 69.6%, specificity of 100%, PPV of 100%, and NPV of 91.0%. In 18 (19%) of 94 patients, choledocholithiasis was detected at reference examinations. For detecting choledocholithiasis, observer 1 had a sensitivity of 77.8%, specificity of 96.1%, PPV of 82.4%, and NPV of 94.8% and observer 2 had a sensitivity of 72.2%, specificity of 96.1%, PPV of 81.2%, and NPV of 93.6%.

CONCLUSION

Portal venous phase multidetector CT images are highly specific and moderately sensitive for the detection of biliary duct narrowing and choledocholithiasis.

Diagnosis of cholangiocarcinoma

Cholangiocarcinoma is suspected based on signs of biliary obstruction, abnormal liver function tests, elevated tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen), and ultrasonography showing a bile stricture or a mass, especially in intrahepatic cholangiocarcinoma. Magnetic resonance imaging (MRI) or computed tomography (CT) is performed for the diagnosis and staging of cholangiocarcinomas. However, differentiation of an intraductal cholangiocarcinoma from a hypovascular metastasis is limited at imaging. Therefore, reasonable exclusion of an extrahepatic primary tumor should be performed. Differentiating between benign and malignant bile duct stricture is also difficult, except when metastases are observed. The sensitivity of fluorodeoxyglucose positron emission tomography is limited in small, infiltrative, and mucinous cholangiocarcinomas. When the diagnosis of a biliary stenosis remains indeterminate at MRI or CT, endoscopic imaging (endoscopic or intraductal ultrasound, cholangioscopy, or optical coherence tomography) and tissue sampling should be carried out. Tissue sampling has a high specificity for diagnosing malignant biliary strictures, but sensitivity is low. The diagnosis of cholangiocarcinoma is particularly challenging in patients with primary sclerosing cholangitis. These patients should be followed with yearly tumor markers, CT, or MRI. In the case of dominant stricture, histological or cytological confirmation of cholangiocarcinoma should be obtained. More studies are needed to compare the accuracy of the various imaging methods, especially the new intraductal methods, and the imaging features of malignancy should be standardized.

Incidence, diagnosis, and therapy of cholangiocarcinoma in patients with primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) can lead to the development of cholangiocarcinoma (CCA). The tumor may present as an intrahepatic focal cholangiocellular carcinoma but more often as a ductal infiltrating desmoplastic lesion. CCA is found synchronously with the diagnosis of PSC in 20-30% and within 1 year in 50%. During later follow-up, the yearly developmental rate of CCA is 0.5-1.5%. Most patients with PSC and CCA do not yet have cirrhosis but present with a severe stenosis at the hilum of the liver. This type of tumor is difficult to diagnose by imaging techniques.(18)F-FDG-PET scanning and CEA or CA 19-9 are not early diagnostic tools. Regular MRI, multislice CT, and repeated endoscopically obtained brush cytology of stenotic lesions are recommended. The recent use of more extensive surgical resection techniques in patients with CCA results in 5-year survival rates of > or =50%. If tumors are small or incidental findings, liver transplantation leads to a 3- to 5-year survival rate of 35%. Pretransplant radiotherapy with 5-FU chemosensitization followed by endoscopic brachytherapy with iridium-192 seems to greatly improve the outcome of transplantation. Treatment with ursodeoxycholic acid may prevent development of CCA.

Early bile duct cancer

Bile duct cancers are frequently diagnosed as advanced diseases. Over half of patients with advanced bile duct cancer present with unresectable malignancies and their prognosis has been very poor even after curative resections. Although there has been a need to diagnose bile duct cancer at its early stage, it has been a difficult goal to achieve due to our lack of knowledge regarding this disease entity. Early bile duct cancer may be defined as a carcinoma whose invasion is confined within the fibromuscular layer of the extrahepatic bile duct or intrahepatic large bile duct without distant metastasis irrespective of lymph node involvement. Approximately 3%-10% of resected bile duct cancers have been reported to be early cancers in the literature. The clinicopathological features of patients with early bile duct cancer differ from those of patients with advanced bile duct cancer, with more frequent asymptomatic presentation, characteristic histopathological findings, and excellent prognosis. This manuscript is organized to emphasize the need for convening an international consensus to develop the concept of early bile duct cancer.

Clinicopathological review of 61 patients with early bile duct cancer

AIMS

The concept of early cancer is already established in the hollow viscus. However, there is no broadly accepted concept of early bile duct cancer. We aimed to assess whether early bile duct cancer patients have characteristic clinicopathological features and a better prognosis compared with patients with advanced bile duct cancer.

MATERIALS AND METHODS

Between June 1996 and December 2004, 614 patients were histologically confirmed with primary bile duct cancers after resection. Extrahepatic early bile duct cancers are defined as carcinoma where invasion is confined within the fibromuscular layer of the extrahepatic bile duct. Intrahepatic early bile duct cancers arising from intrahepatic large bile ducts are also defined as carcinoma confined within the fibromuscular layer. We retrospectively reviewed medical records to obtain demographic, laboratory, radiological and pathological data.

RESULTS

Sixty-one (10%) patients were categorised with early bile duct cancers. They were frequently detected at asymptomatic (39%) or non-icteric (84%) stages. The most common gross type was the intraductal-growing type (58%). Not otherwise specified adenocarcinoma was only 67%, whereas papillary carcinoma was 31% of cancers. No lymph node metastasis and no lymphovascular/perineural invasions were noted in 89% of patients. The 5-year survival rate for early bile duct cancer was excellent (80%).

CONCLUSIONS

Although early bile duct cancer is not a common disease, it is not a very rare entity either. The clinicopathological features of early bile duct cancer patients differ from those of advanced bile duct cancer patients, with asymptomatic clinical presentation, different macroscopic and microscopic findings, and excellent prognosis.

[Value of radiological methods in the diagnosis of biliary diseases]

The modern cross-sectional radiological methods of ultrasound, computed tomography, and magnetic resonance imaging provide manifold possibilities for the diagnosis of inflammatory and tumorous diseases of the gallbladder and the bile ducts as well as stone-related diseases. The invasive methods for direct imaging of the bile ducts, such as endoscopic retrograde cholangiopancreatography, are mainly used within therapeutic concepts. According to the literature, ultrasound and magnetic resonance imaging show a sensitivity of up to 100% in the diagnosis of intra- and extrahepatic cholestasis, but concerning the diagnosis of the cause of cholestasis these methods are limited. Therefore, additional MRI sequences or computed tomography are necessary. Computed tomography is particularly efficient for the diagnosis of the biliary system and adjacent anatomical and pathological structures within the pre- and postoperative period.

Advances in the diagnosis, evaluation and management of cholangiocarcinoma

PURPOSE OF REVIEW

Cholangiocarcinoma is an enigmatic malignancy of the biliary tract that has recently been shown to be increasing in incidence globally. There has been recent progress in identifying potential risk factors for the tumor, and in the use of emerging technologies for diagnosis and palliative treatment.

RECENT FINDINGS

Hepatitis B and C, cirrhosis and alcohol have been described as risk factors for cholangiocarcinoma. A morphology-based classification for cholangiocarcinoma is proposed that will facilitate future descriptive epidemiology, diagnosis and comparative therapeutic studies. Diagnosis may be improved by new approaches to enhance the diagnostic yield and utility of biliary cytology. The role of new imaging approaches such as positron emission tomography scanning, endoscopic ultrasound or optical coherence tomography for diagnosis are being examined and defined. Long-term results for transplantation protocols for curative intent in non-resectable localized disease have been described. Photodynamic therapy looks extremely promising for adjunct therapy of intrahepatic mass lesions.

SUMMARY

Recent advances in the epidemiology, classification, diagnosis and therapy of cholangiocarcinoma are expected to enhance the evaluation and management of patients with this devastating malignancy.

Minimum intensity projections of the biliary system using 16-channel multidetector computed tomography in patients with biliary obstruction: comparison with MRCP

The objective was the evaluation of minimum intensity projections (MinIP) of 16-channel multidetector computed tomography (MDCT) data for the visualization of biliary ducts with magnetic resonance cholangiopancreatography (MRCP) as reference method. Twenty-five patients with biliary obstruction who received MDCT of the abdomen and MRCP without subsequent interventions were analysed. Coronal and axial MinIP were reconstructed from the MDCT-data. The evaluation of image quality and the quantitative comparison to MRCP was performed by two observers in consensus. The additional diagnostic value of MinIP compared with conventionally visualised MDCT was assessed by three independent observers. With MRCP as the reference method, MinIP was superior to conventional MDCT concerning the visualization of the extent of bile duct dilatation (r, 1.000 vs 0.699) and the correlation of diameter measurement (r, 0.979 vs 0.942). Subsidiary to conventional MDCT, MinIP revealed an improvement of visualization of the biliary system in 73% of cases. Concerning the additional diagnostic value, MinIP allowed for a better definition of the obstruction site in 13% of patients, and in one patient a change of diagnosis was observed. Thus, MinIP can improve the diagnostic assessment of biliary obstructions in MDCT imaging.

Nonoperative imaging techniques in suspected biliary tract obstruction

Evaluation of suspected biliary tract obstruction is a common clinical problem. Clinical data such as history, physical examination, and laboratory tests can accurately identify up to 90% of patients whose jaundice is caused by extrahepatic obstruction. However, complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan. In the present summary, the literature on competing technologies including endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiopancreatography (PTC), endoscopic ultrasound (EUS), intraductal ultrasonography (IDUS), magnetic resonance cholangiopancreatography (MRCP), helical CT (hCT) and helical CT cholangiography (hCTC) with regards to diagnostic performance characteristics, technical success, safety, and cost-effectiveness is reviewed. Patients with obstructive jaundice secondary to choledocholithiasis or pancreaticobiliary malignancies are the primary focus of this review. Algorithms for the management of suspected obstructive jaundice are put forward based on current evidence. Published data suggest an increasing role for EUS and other noninvasive imaging techniques such as MRCP, and hCT following an initial transabdominal ultrasound in the assessment of patients with suspected biliary obstruction to select candidates for surgery or therapeutic ERCP. The management of patients with a suspected pancreaticobiliary condition ultimately is dependent on local expertise, availability, cost, and the multidisciplinary collaboration between radiologists, surgeons, and gastroenterologists.

Liver and Biliary System: Evaluation by Multidetector CT

CT commonly is indicated for the evaluation of suspected hepatic and biliary pathology. The recent introduction of multidetector CT (MDCT) provides unique capabilities that are valuable especially in hepatic volume acquisitions, combining short scan times, narrow collimation, and the ability to obtain multiphase data. These features result in improved lesion detection and characterization. Concomitant advances in computer software programs have made three-dimensional applications practical for a range of hepatic image analyses and displays. This article discusses the specific areas of hepatic and biliary pathology where MDCT has a significant diagnostic impact.