Three-dimensional spiral CT cholangiography with minimum intensity projection in patients with suspected obstructive biliary disease: comparison with percutaneous transhepatic cholangiography

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.

Evaluation of the usefulness of cystic duct three-dimensional computed tomography with non-contrast for before laparoscopic cholecystectomy and endoscopic transpapillary gallbladder drainage in comparison to magnetic resonance cholangiopancreatography

INTRODUCTION

The purpose of this study is to evaluate whether anatomical variations of the cystic duct and accessory bile duct can be grasped by cystic duct three-dimensional (3D)-computed tomography (CT) using non-contrast CT and to examine the possibility of omitting magnetic resonance cholangiopancreatography (MRCP).

METHODS

Of patients who underwent non-contrast abdominal CT between May and October 2019, those who underwent MRCP within 1 month before and afterwards were targeted. Seven assessors visually evaluated the cystic duct 3D-CT images on a 5-point scale. Average scores of ≥3 and <3 points were assigned as the good and poor groups, respectively. Regions of interest (ROIs) were placed inside the cystic duct and four places around it, and the CT values in those ROIs were measured. The CT value difference was calculated by subtracting the surrounding CT values from the CT value in the cystic duct and converting the result to an absolute value. The CT value difference was classified into good and poor groups, and statistical analysis was performed. Seven assessors evaluated anatomical variations of the cystic duct and the presence of the accessory bile duct. The results were compared with the MRCP interpretation results to calculate sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

The average visual evaluation score was 3.8. The good and poor groups were comprised by 53 (85.5%) and 9 (14.5%) patients, respectively. The CT difference value averages were 54.7 and 15.9 for the good and poor groups, respectively, and the value was significantly higher in the good group (p = 0.001). The comparison results with MRCP were sensitivity=83.3%, specificity=78.0%, positive predictive value=47.6%, and negative predictive value=95.1%.

CONCLUSION

Cystic duct 3D-CT using non-contrast CT is a useful technique for understanding anatomical variations of the cystic duct and accessory bile duct. Our method may reduce the number of MRCP sessions performed.

Automated Kidney Segmentation for Traumatic Injured Patients through Ensemble Learning and Active Contour Modeling

Traumatic abdominal injury can lead to multiple complications including laceration of major organs such as kidneys. Contrast-enhanced Computed Tomography (CT) is the primary imaging modality for evaluating kidney injury. However, the traditional visual examination of CT scans is time consuming, non-quantitative, prone to human error, and costly. In this work we propose a kidney segmentation method using machine learning and active contour modeling. We first detect an initialization mask inside the kidney and then evolve its boundary. This model is specifically developed and evaluated on trauma cases. Our experimental results show the average recall score of 92.6% and average Dice similarity value of 88.9%.

Impact of Preoperative Three-Dimensional Computed Tomography Cholangiography on Postoperative Resection Margin Status in Patients Operated due to Hilar Cholangiocarcinoma

INTRODUCTION

The purpose of this study was to analyse the value of 3-dimensional computed tomography cholangiography (3D-ERC) compared to conventional retrograde cholangiography in the preoperative diagnosis of hilar cholangiocarcinoma (HC) with special regard to the resection margin status (R0/R1).

PATIENTS AND METHODS

All hepatic resections performed between January 2011 and November 2013 in patients with HC at the Department of General, Visceral and Transplant Surgery of the RWTH Aachen University Hospital were analysed. All patients underwent an ERC and contrast-enhanced multiphase CT scan or a 3D-ERC.

RESULTS

The patient collective was divided into two groups (group ERC: n = 17 and group 3D-ERC: n = 16). There were no statistically significant differences between the two groups with regard to patient characteristics or intraoperative data. Curative liver resection with R0 status was reached in 88% of patients in group ERC and 87% of patients in group 3D-ERC (p = 1.00). We could not observe any differences with regard to postoperative complications, hospital stay, and mortality rate between both groups.

CONCLUSION

Based on our findings, preoperative imaging with 3D-ERC has no benefit for operative planning and R0 resection status. It cannot replace the exploration by an experienced surgeon in a centre for hepatobiliary surgery.

Preoperative Evaluation of Malignant Perihilar Biliary Obstruction: Negative-Contrast CT Cholangiopancreatography and CT Angiography Versus MRCP and MR Angiography

OBJECTIVE

The purpose of this study was to compare negative-contrast CT cholangiopancreatography (CTCP) and CT angiography (CTA) with MRCP and MR angiography (MRA) for the preoperative evaluation of malignant perihilar biliary obstruction.

MATERIALS AND METHODS

Twenty-one patients with pathologically proven malignant perihilar biliary obstructions who had undergone both CT and MRI examinations were reviewed retrospectively. Two reviewers independently analyzed the two image sets-the negative-contrast CTCP and CTA images (i.e., CT set) and the MRCP and MRA images (i.e., MRI set)-in preoperatively evaluating the classification of malignant perihilar biliary obstruction, hepatic artery and portal vein invasion, nodal metastasis, and organ spread. The results were compared with surgical and pathologic records.

RESULTS

For the classification of malignant perihilar biliary obstruction on the two image sets, the accuracy was not statistically significant (p = 1.000 for reviewer 1 and p = 0.500 for reviewer 2). For the evaluation of portal vein invasion, nodal metastasis, and organ spread, the accuracies were also not statistically significantly different (p = 0.335, 0.339, and 0.781 for reviewer 1; and p = 0.403, 0.495, and 0.325 for reviewer 2, respectively). In the assessment of hepatic artery status, the accuracy was statistically significant (p = 0.046 for reviewer 1 and p = 0.036 for reviewer 2).

CONCLUSION

Compared with the MRI set, the CT set provides equivalent performance in assessing the classification of malignant perihilar biliary obstruction, portal vein involvement, nodal metastasis, and organ spread, but has higher accuracy in assessing arterial invasion.

Comparison of mandibular first molar mesial root canal morphology using micro-computed tomography and clearing technique

OBJECTIVE

Micro-computed tomography (MCT) with alternative image reformatting techniques shows complex and detailed root canal anatomy. This study compared two-dimensional (2D) and 3D MCT image reformatting with standard tooth clearing for studying mandibular first molar mesial root canal morphology.

MATERIALS AND METHODS

Extracted human mandibular first molar mesial roots (n=31) were scanned by MCT (Skyscan 1172). 2D thin-slab minimum intensity projection (TS-MinIP) and 3D volume rendered images were constructed. The same teeth were then processed by clearing and staining. For each root, images obtained from clearing, 2D, 3D and combined 2D and 3D techniques were examined independently by four endodontists and categorized according to Vertucci's classification. Fine anatomical structures such as accessory canals, intercanal communications and loops were also identified.

RESULTS

Agreement among the four techniques for Vertucci's classification was 45.2% (14/31). The most frequent were Vertucci's type IV and then type II, although many had complex configurations that were non-classifiable. Generally, complex canal systems were more clearly visible in MCT images than with standard clearing and staining. Fine anatomical structures such as intercanal communications, accessory canals and loops were mostly detected with a combination of 2D TS-MinIP and 3D volume-rendering MCT images.

CONCLUSIONS

Canal configurations and fine anatomic structures were more clearly observed in the combined 2D and 3D MCT images than the clearing technique. The frequency of non-classifiable configurations demonstrated the complexity of mandibular first molar mesial root canal anatomy.

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.

Diagnosis of bile duct hepatocellular carcinoma thrombus without obvious intrahepatic mass

AIM

To study the diagnosis of hepatocellular carcinoma (HCC) presenting as bile duct tumor thrombus with no detectable intrahepatic mass.

METHODS

Six patients with pathologically proven bile duct HCC thrombi but no intrahepatic mass demonstrated on the preoperative imaging or palpated intrahepatic mass during operative exploration, were collected. Their clinical and imaging data were retrospectively analyzed. The major findings or signs on comprehensive imaging were correlated with the surgical and pathologic findings.

RESULTS

Jaundice was the major clinical symptom of the patients. The elevated serum total bilirubin, direct bilirubin and alanine aminotransferase levels were in concordance with obstructive jaundice and the underlying liver disease. Of the 6 patients showing evidence of viral hepatitis, 5 were positive for serum alpha fetoprotein and carbohydrate antigen 19-9, and 1 was positive for serum carcinoembryonic antigen. No patient was correctly diagnosed by ultrasound. The main features of patients on comprehensive imaging were filling defects with cup-shaped ends of the bile duct, with large filling defects presenting as casting moulds in the expanded bile duct, hypervascular intraluminal nodules, debris or blood clots in the bile duct. No obvious circular thickening of the bile duct walls was observed.

CONCLUSION

Even with no detectable intrahepatic tumor, bile duct HCC thrombus should be considered in patients predisposed to HCC, and some imaging signs are indicative of its diagnosis.

Comparison of postprocessing techniques for the detection of perfusion defects by cardiac computed tomography in patients presenting with acute ST-segment elevation myocardial infarction

BACKGROUND

Despite rapid advances in cardiac computed tomography (CT), a strategy for optimal visualization of perfusion abnormalities on CT has yet to be validated.

OBJECTIVE

We evaluated the performance of several postprocessing techniques of source data sets to detect and characterize perfusion defects in acute myocardial infarctions with cardiac CT.

METHODS

Twenty-one subjects (18 men; 60 +/- 13 years) that were successfully treated with percutaneous coronary intervention for ST-segment myocardial infarction underwent 64-slice cardiac CT and 1.5 Tesla cardiac magnetic resonance imaging (MRI) scans after revascularization. Delayed enhancement MR images were analyzed to identify the location of infarcted myocardium. Contiguous short-axis images of the left ventricular myocardium were created from the CT source images with 0.75-mm multiplanar reconstruction (MPR), 5-mm MPR, 5-mm maximal intensity projection (MIP), and 5-mm minimum intensity projection (MinIP) techniques. Segments already confirmed to contain infarction by MRI were then evaluated qualitatively and quantitatively with CT.

RESULTS

Overall, 143 myocardial segments were analyzed. On qualitative analysis, the MinIP and thick MPR techniques had greater visibility and definition than the thin MPR and MIP techniques (P < 0.001). On quantitative analysis, the absolute difference in Hounsfield unit attenuation between normal and infarcted segments was significantly greater for the MinIP (65.4 Hounsfield unit [HU]) and thin MPR (61.2 HU) techniques. However, the relative difference in Hounsfield unit attenuation was significantly greatest for the MinIP technique alone (95%; P < 0.001). Contrast to noise was greatest for the MinIP (4.2) and thick MPR (4.1) techniques (P < 0.001).

CONCLUSION

The results of our current investigation found that MinIP and thick MPR detected infarcted myocardium with greater visibility and definition than MIP and thin MPR.

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.

CT of pancreas: minimum intensity projections

OBJECTIVE

The purpose of this pictorial essay is to showcase the use of minimum intensity projection in the imaging of low attenuation structures such as the pancreatic duct.

CONCLUSION

Minimum intensity projection is a valuable adjunct to other processing techniques for the diagnosis and staging of pancreatic adenocarcinoma and cystic tumors of the pancreas.

Multidetector computed tomography cholangiography with multiplanar reformation for the assessment of patients with biliary obstruction

BACKGROUND

We sought to evaluate the diagnostic use of multidetector computed tomography (MDCT) cholangiography with multiplanar reformation (MPR) for the assessment of patients with biliary obstruction.

METHODS

MDCT cholangiography with the MPR technique was performed in 58 patients who were thought to have biliary obstruction. No cholangiographic contrast agent was administered. MRCP in 24 patients, Endoscopic retrograde cholangiopancreatography (ERCP) in 46 patients and percutaneous transhepatic cholangiography (PTC) in 24 patients were performed. Eighteen patients underwent biopsy or surgery. The findings on MDCT cholangiography were compared with those of MRCP, ERCP, PTC, biopsy or surgery.

RESULTS

The findings of MDCT cholangiography were as follows: choledocholithiasis (n = 34, 56.7%), malignant stricture (n = 14, 23.3%), benign stricture (n = 1, 1.7%), and cholelithiasis (n = 11, 18.3%). A small common bile duct (CBD) stone in one patient could not be detected on MDCT cholangiography. One patient with a small stone in distal CBD detected on MDCT cholangiography had no stone on ERCP. Two patients with initial diagnoses of CBD stones by MDCT cholangiography were disclosed to have malignant bile duct stricture by reference examination. The sensitivity and specificity of MDCT cholangiography for the diagnosis of bile duct stones were 96.9% and 96.2%, respectively. The sensitivity and specificity of MDCT cholangiography for the diagnosis of bile duct stricture were 85.7% and 100%, respectively. The overall accuracy of MDCT cholangiography for the diagnoses of the causes of biliary obstruction was 89.8%.

CONCLUSION

MDCT cholangiography with the MPR technique is a fast and non-invasive technique with relatively high sensitivity and specificity for the diagnoses of the causes of biliary obstruction.

Cholecystoenterostomy for treatment of extrahepatic biliary tract obstruction in cats: 22 cases (1994–2003)

OBJECTIVE

To identify factors associated with outcome in cats with extrahepatic biliary tract obstruction (EHBTO) that undergo biliary diversion surgery.

DESIGN

Retrospective case series.

ANIMALS

22 cats.

PROCEDURES

Medical records of cats with surgically confirmed EHBTO that underwent cholecystoenterostomy were reviewed.

RESULTS

Clinical signs and physical examination findings included vomiting, anorexia, icterus, lethargy, weakness, and weight loss. Common clinicopathologic abnormalities included high serum hepatic enzyme activities and serum bilirubin concentration. Abdominal ultrasonography was performed in 21 cats, and all 21 had findings consistent with EHBTO. Eleven of 15 cats in which blood pressure was monitored had intraoperative hypotension. Eighteen cats had anemia following surgery, and 14 cats had persistent hypotension. Extrahepatic biliary tract obstruction was a result of neoplasia in 9 cats and chronic inflammatory disease in 13. Fourteen cats survived long enough to be discharged from the hospital, but only 6 survived > 6 months after surgery, all of which had chronic inflammatory disease. Median survival time for cats with neoplasia (14 days) was significantly shorter than that for cats with inflammatory disease (255 days). No other variable was associated with outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that cats with EHBTO secondary to neoplasia have a poorer prognosis than cats with EHBTO secondary to chronic inflammatory disease. However, the overall prognosis for cats with EHBTO undergoing cholecystoenterostomy must be considered guarded to poor, and the incidence of perioperative complications is high.

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.

Biliary ductal evaluation of hilar cholangiocarcinoma: three-dimensional direct multi-detector row CT cholangiographic findings versus surgical and pathologic results--feasibility study

The study was conducted, with institutional review board approval and informed patient consent, to assess the feasibility and diagnostic effectiveness of three-dimensional direct multi-detector row computed tomographic (CT) cholangiography for determining the extent of bile duct invasion by hilar cholangiocarcinoma. Eleven patients underwent contrast material-enhanced direct multi-detector row CT cholangiography of the primary and secondary biliary confluence levels and then surgical resection. In most patients, CT cholangiography was tolerable and yielded excellent or good opacification of the biliary tree. CT cholangiography enabled a correct diagnosis of the extent of ductal involvement at all 11 primary confluence levels and at 18 of the 19 secondary confluence levels. Three secondary confluences, which could not be analyzed owing to nonopacification or poor opacification, proved to be involved by hilar cholangiocarcinoma. The authors conclude that three-dimensional direct multi-detector row CT cholangiography is accurate and feasible for defining the extent of ductal invasion by hilar cholangiocarcinoma, especially in patients with preliminary biliary drainage.

Comparison of CT duodeno-cholangiopancreatography to ERCP for assessing biliary obstruction

The authors have developed a CT protocol, CT duodeno-cholangiopancreatography (CDCP), which is performed during a single contrast-enhanced phase, proceeding cranially, allowing enhancement of the pancreas during its parenchymal phase followed by enhancement of the liver during its portal-venous phase. This retrospective pilot study evaluates CDCP compared with endoscopic retrograde cholangiopancreatography (ERCP) as a diagnostic tool for assessing the cause and level of biliary obstruction. Forty-one patients with jaundice underwent CDCP and ERCP between October 2002 and May 2004. Pathologic confirmation was obtained in 31 of the 41 (76%) patients. The sensitivity, specificity, and kappa values of CDCP and ERCP compared with pathology were calculated for tumors and stones. Pathology-proven cases included 7 cases of stones, 23 tumors, and 1 other cause of obstruction. The overall level of agreement of diagnoses between CDCP and pathology was 29 of 31 (93.5%); that between CDCP and ERCP was 36 of 41 (88%). Comparing CDCP to pathology for tumors, the sensitivity was 100%, the specificity was 89%, and the kappa was 0.92 (95% CI 0.76-1.0). For stone detection, CDCP had a sensitivity of 86%, a specificity of 100%, and a kappa value of 0.90 (95% CI 0.72-1.0). For level of obstruction of the common bile duct, comparing CDCP to ERCP, observations agreed in 31 of the 36 (86%) cases; for the pancreatic duct, observations agreed in 24 of the 25 (96%) cases. CDCP is a noninvasive diagnostic tool that can be used to assess the cause and level of obstruction. A blinded prospective study would be valuable to further assess the merits of CDCP.

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.

Diagnostic Value of Multislice Computed Tomography for Pancreas Divisum

OBJECTIVES

To assess the capabilities of high-resolution oblique coronal reconstruction images obtained by multislice computed tomography (CT) in diagnosing pancreas divisum.

METHODS

This study included 11 patients with and 53 without pancreas divisum confirmed by direct cholangiopancreatography. Two blinded readers retrospectively interpreted oblique coronal reconstruction images with 0.5-mm continuous slices generated from isotropic or nearly isotropic pancreatic phase images with the scrolling mode and assessed the continuity of the ventral pancreatic duct, dorsal pancreatic duct, and main pancreatic duct in the body. The results were correlated with the findings of direct cholangiopancreatography. Other abnormal findings of the pancreatobiliary region on CT were also recorded in patients with pancreas divisum.

RESULTS

The sensitivity and specificity of CT for diagnosing pancreas divisum were 100% and 89%, respectively. Computed tomography demonstrated all associated pancreatobiliary diseases.

CONCLUSION

High-resolution oblique coronal reconstruction images allow us to make a diagnosis of pancreas divisum by depicting the continuity of the pancreatic ducts.

Three-dimensional helical computed tomography cholangiography with minimum intensity projection in gallbladder carcinoma patients with obstructive jaundice: comparison with magnetic resonance cholangiography and percutaneous transhepatic cholangiography

OBJECTIVE

Computed tomography (CT) is traditionally used for evaluation and staging of gallbladder carcinoma (GC). However, in the subgroup of patients with obstructive jaundice, magnetic resonance cholangiography (MRC) is generally required to assess the level of biliary obstruction. The present study was undertaken to evaluate the diagnostic potential of three-dimensional helical CT cholangiography (3-D CTC) with minimum intensity projection (minIP), to determine the presence and level of biliary obstruction.

MATERIALS AND METHODS

Twenty-five consecutive patients with proven GC, presenting with clinical and biochemical features of obstructive jaundice, over a 1-year period were included in the study. Dual phase helical CT data was obtained in the arterial and venous phases, respectively, after intravenous contrast injection using a pressure injector. Axial CT data (both arterial and venous phase) was studied for staging and resectability of tumor. Three-dimensional helical CT cholangiography using minIP obtained from the venous phase data set, was used to assess the level of biliary obstruction and isolation of hepatic segmental ducts. Three-dimensional helical CT cholangiography findings were compared with MRC and percutaneous transhepatic cholangiography (PTC) (gold standard). None of the patients were operated on as they were all considered inoperable on axial CT images due to extensive local disease or distant metastasis.

RESULTS

In all patients, 3-D CTC demonstrated dilated intrahepatic ducts up to tertiary branch level. The 3-D CTC correctly diagnosed the level of biliary obstruction and demonstrated isolated segmental ducts in all patients and correlated well in all cases with MRC and PTC findings in this regard. However, the 3-D CTC did not add any additional information over the axial source images.

CONCLUSION

Three-dimensional helical CT cholangiography with minIP can correctly determine the level of biliary obstruction in patients with GC and may be a strong competitor with MRC, because it gives equivalent information with regard to the level of ductal obstruction even while being a part of an overall comprehensive CT staging study. Even though 3-D CTC did not provide additional information on top of the source images, the referring physicians found them very useful for conceptualization of the 3-D biliary anatomy.

Malignant biliary obstruction: value of imaging findings

This review focuses on the clinical impact of different modalities to image primary and secondary malignant biliary obstruction. The detection and staging of cancers of the pancreatic and biliary tract are best accomplished with endoscopic ultrasound, contrast-enhanced computed tomography, and magnetic resonance cholangiopancreatography. Three-dimensional ultrasound is a new noninvasive method that may be used increasingly as an initial test to select patients who require further diagnostic evaluation by magnetic resonance cholangiopancreatography or therapeutic endoscopic retrograde cholangiopancreatography. All-in-one computed tomography including three-dimensional reconstructions of the biliary tree may be competitive against all-in-one magnetic resonance imaging for diagnosis and staging of pancreatic tumors. Magnetic resonance cholangiopancreatography is excellent for identifying the presence and the level of biliary obstruction. With newer diagnostic imaging technologies emerging, endoscopic retrograde cholangiopancreatography is evolving into a predominantly therapeutic procedure.

Techniques, clinical applications and limitations of 3D reconstruction in CT of the abdomen

Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of thin-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist.

Hepatocellular carcinoma with obstructive jaundice: diagnosis, treatment and prognosis

Obstructive jaundice as the main clinical feature is uncommon in patients with hepatocellular carcinoma (HCC). Only 1%-12% of HCC patients manifest obstructive jaundice as the initial complaint. Such cases are clinically classified as “icteric type hepatoma”, or “cholestatic type of HCC”. Identification of this group of patients is important, because surgical treatment may be beneficial. HCC may involve the biliary tract in several different ways: tumor thrombosis, hemobilia, tumor compression, and diffuse tumor infiltration. Bile duct thrombosis (BDT) is one of the main causes for obstructive jaundice, and the previously reported incidence is 1.2%-9%. BDT might be benign, malignant, or a combination of both. Benign thrombi could be blood clots, pus, or sludge. Malignant thrombi could be primary intrabiliary malignant tumors, HCC with invasion to bile ducts, or metastatic cancer with bile duct invasion. The common clinical features of this type of HCC include: high level of serum AFP; history of cholangitis with dilation of intrahepatic bile duct; aggravating jaundice and rapidly developing into liver dysfunction. It is usually difficult to make diagnosis before operation, because of the low incidence rate, ignorant of this disease, and the difficulty for the imaging diagnosis to find the BDT preoperatively. Despite recent remarkable improvements in the imaging tools for diagnosis of HCC, such cases are still incorrectly diagnosed as cholangiocarcinoma or choledocholithiases. Ultrasonography (US) and CT are helpful in showing hepatic tumors and dilated intrahepatic and /or extrahepatic ducts containing dense material corresponding to tumor debris. Direct cholangiography including percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) remains the standard procedure to delineate the presence and level of biliary obstruction. Magnetic resonance cholangiopancreatography (MRCP) is superior to ERCP in interpreting the cause and depicting the anatomical extent of the perihilar obstructive jaundice, and is particularly distinctive in cases associated with tight biliary stenosis and along segmental biliary stricture. Choledochoscopy and bile duct brushing cytology could be alternative useful techniques in the differentiating obstructions due to intraluminal mass, infiltrating ductal lesions or extrinsic mass compression applicable before and after duct exploration. Jaundice is not necessarily a contraindication for surgery. Most patients will have satisfactory palliation and occasional cure if appropriate procedures are selected and carried out safely, which can result in long-term resolution of symptoms and occasional long-term survival. However, the prognosis of icteric type HCC is generally dismal, but is better than those HCC patients who have jaundice caused by hepatic insufficiency.

Preoperative imaging of biliary tract cancers

Many imaging techniques are available for the evaluation of patients with malignant obstructive jaundice. Ultrasonography, in experienced hands, is valuable for evaluating the local extent of the disease, but its usefulness for staging distant metastases is limited. When used properly, CT and MR imaging can provide valuable information about the extent of local tumor involvement and distant metastases. These noninvasive techniques provide images of the bile ducts and vascular images that are comparable in quality to those obtained with more invasive procedures, such as PTC, ERCP, and angiography, and do not have the risk for complications of these invasive techniques.

AAPM/RSNA physics tutorial for residents: topics in CT. Image processing in CT

Several image-processing methods for computed tomographic (CT) examinations are currently being used in clinical radiology departments. Image processing involves operations such as reformatting of original CT images, volume-rendered displays, surface-rendered displays, and physiologic imaging analysis. The reformatting process does not alter the CT voxels in any way; instead it uses them in off-axis views and displays the images produced from the original reconstruction process in an orientation other than how they were originally generated. Sagittal, coronal, oblique, and curved reformatting are standard reformatting methods. Other reformatting techniques include maximum-intensity projection, minimum-intensity projection, and variable thickness viewing. Volume and surface rendering are two different methods for reformatting axial images into three-dimensional views. CT perfusion allows the measurement of physiologic parameters over time. Additional postprocessing efforts can potentially add value to the patients and their outcomes, as can be seen in the cases that illustrate this article.

Liver fluke-associated cholangiocarcinoma

BACKGROUND

Infection with liver flukes has been reported to be associated with bile duct malignancy.

METHODS

The review is based on a literature search (Medline) and, in some cases, direct contact with authors or principal investigators.

RESULTS

A large body of evidence indicates that Opisthorchis viverrini is a definite cause of human cholangiocarcinoma, whereas Clonorchis sinensis is a probable cause. The evidence regarding Opisthorchis felineus is insufficient to assess its role in carcinogenesis. Possible mechanisms of carcinogenesis include chronic irritation, nitric oxide formation, intrinsic nitrosation and activation of drug-metabolizing enzymes. Early detection of bile duct malignancy is difficult and not clinically available at present, although cholangiocarcinoma-associated soluble antigen has been reported in an experimental study to be a useful early marker of cancer development. Long-term survival after surgical treatment of liver fluke-associated cancer is similar to that reported in patients without liver fluke infestation.

CONCLUSION

Liver fluke-associated cholangiocarcinoma is still a health problem in developing countries. Mechanisms of carcinogenesis should be explored further in order to reduce the impact of this disease.