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

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.

Preoperative evaluation of malignant pancreatobiliary obstruction: A novel technique for multiphase fusion 3D CT images

The purpose of this article is to describe a novel technique of multiphase fusion three-dimensional (3D) images in patients with malignant pancreatobiliary obstruction. Multiphase fusion 3D images of CT arteriography, portovenography and hepatic venography combined with negative-contrast CT cholangiopancreatography can be done with enhanced multiphase CT scan using intravenous contrast agent at once. This technique may be feasible for one-stop evaluation of malignant pancreatobiliary obstruction.

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.

Value of minimum intensity projections for chest CT in COVID-19 patients

PURPOSE

To investigate whether minimum intensity projection (MinIP) reconstructions enable more accurate depiction of pulmonary ground-glass opacity (GGO) compared to standard transverse sections and multiplanar reformat (MPR) series in patients with suspected coronavirus disease 2019 (COVID-19).

METHOD

In this multinational study, chest CT scans of 185 patients were retrospectively analyzed. Diagnostic accuracy, diagnostic confidence, image quality regarding the assessment of GGO, as well as subjective time-efficiency of MinIP and standard MPR series were analyzed based on the assessment of six radiologists. In addition, the suitability for COVID-19 evaluation, image quality regarding GGO and subjective time-efficiency in clinical routine was assessed by five clinicians.

RESULTS

The reference standard revealed a total of 149 CT scans with pulmonary GGO. MinIP reconstructions yielded significantly higher sensitivity (99.9 % vs 95.6 %), specificity (95.8 % vs 86.1 %) and accuracy (99.1 % vs 93.8 %) for assessing of GGO compared with standard MPR series. MinIP reconstructions achieved significantly higher ratings by radiologists concerning diagnostic confidence (medians, 5.00 vs 4.00), image quality (medians, 4.00 vs 4.00), contrast between GGO and unaffected lung parenchyma (medians, 5.00 vs 4.00) as well as subjective time-efficiency (medians, 5.00 vs 4.00) compared with MPR-series (all P < .001). Clinicians preferred MinIP reconstructions for COVID-19 assessment (medians, 5.00 vs 3.00), image quality regarding GGO (medians, 5.00 vs 3.00) and subjective time-efficiency in clinical routine (medians, 5.00 vs 3.00).

CONCLUSIONS

MinIP reconstructions improve the assessment of COVID-19 in chest CT compared to standard images and may be suitable for routine application.

Multiphase multidetector-row CT reveals different patterns of hepatic portal venous gas and pneumobilia

Hepatic portal venous gas and pneumobilia (PB) are uncommon findings, indicating the accumulation of gas in the portal vein and its branches and in the biliary tree, respectively. Aims of this retrospective, descriptive study were to describe the computed tomographic (CT) features and visualization techniques of hepatic portal venous gas (HPVG) and PB in a group of small animal veterinary patients. The CT data of patients with HPVG and PB were retrospectively reviewed. Thin-section multiplanar reformatting and minimum intensity projection (MinIP) views were used to assess the acquired volume dataset. The CT features recorded were as follows: amount, aspect, distribution, and localization of the gas in the liver. Five patients were included (four dogs and one cat), two presenting HPVG and three with PB. Gas in HPVG presented a peripheral location, whereas in PB was characterized by a central location. The aspect of the gas was tubular in case of HPVG and mixed tubular and rounded in PB. An analogous number of animals between the two groups showed comparable amount (mild, moderate, and severe) and distribution (diffuse and focal). Thin-section CT can detect the presence of gas in the liver, and a combination of two-dimensional and thin-slab MinIP can differentiate between HPVG and PB in dogs and cats. The distinctive features are peripheral versus central location and tubular versus rounded aspect of the gas.

Impacts on outcomes and management of preoperative magnetic resonance cholangiopancreatography in patients scheduled for laparoscopic cholecystectomy: for whom it should be considered?

Purpose

We evaluated the impact of preoperative magnetic resonance cholangiopancreatography (MRCP) on patient outcomes, and found which patients should be considered for MRCP before cholecystectomy.

Methods

We performed retrospective analysis of 2,072 patients that underwent cholecystectomy for benign gallbladder disease from January 2014 to June 2017. Patients were grouped as CT only group (n = 737) and MRCP group (n = 1,335), including both CT and MRCP (n = 1,292) or MRCP only (n = 43). The main outcome measure was associated with complications after cholecystectomy, and the secondary outcomes were hospital stay, readmission, and events that could impact patient management due to addition of MRCP.

Results

There were no statistical differences in occurrence of intraoperative or postoperative complications or readmission rate between the 2 groups. Hospital stay was about 0.6 days longer in the MRCP group. However, MRCP group was more susceptible to complications due to underlying patient demographics (older age, higher frequency of diabetes, and higher level of the inflammatory markers). MRCP diagnosed common bile duct (CBD) stones in 6.5% of patients (84/1,292) without CBD stones in CT, and bile duct anomalies were identified in 41 patients (3.2%). Elevated γ-GT was the only independent factor for additional detection of CBD stones (adjusted odds ratio [OR], 2.89; P = 0.029) and subsequent biliary procedures (adjusted OR, 3.34; P = 0.018) when additional MRCP was performed.

Conclusion

MRCP is valuable for identification of bile duct variation and CBD stones. Preoperative MRCP can be considered, particularly in patients with elevated γ-GT, for proper preoperative management and avoidance of complications.

Inter-reader agreement of interpretation of radiological course of bile duct changes between serial follow-up magnetic resonance imaging/3D magnetic resonance cholangiopancreatography of patients with primary sclerosing cholangitis

Objectives: Interpretation of MRI/MRCP in primary sclerosing cholangitis (PSC) at a single time point has low inter-reader agreement. Agreement of interpretation of the dynamic course of duct changes in follow-up MRI/MRCP is of clinical importance but remains unknown. Our aims are therefore to assess the inter-reader agreement of interpretation of the course of duct changes in PSC and investigate if elimination of 3 D MRCP affects inter-reader agreement.Materials and Methods: We studied 40 consecutive PSC-patients who underwent two liver MRI/MRCPs at two time points. Two readers independently evaluated the course of duct changes between the two time points in two imaging sets, one with and one without 3 D MRCP. The intraclass correlation coefficient (ICC) was calculated for evaluation of inter-reader and intra-reader agreement between the two time points and two imaging sets accordingly.Results: Inter-reader agreement of the interpretation of the course of duct changes between the two time points was poor (ICC up to 0.224). Elimination of 3 D MRCP neither improved inter-reader agreement which was again poor (ICC up to 0.26) nor did it change considerably the way readers interpret the course of ducts changes (ICC for intra-reader agreement between 0.809 and 0.978).Conclusions: Inter-reader agreement of the interpretation of radiological course of duct changes is poor in serial follow-up MRI/MRCP of PSC-patients. Elimination of 3 D MRCP does not increase inter-reader agreement but maintains an excellent intra-reader agreement for the interpretation of the dynamic course of bile duct changes.Key pointsInter-reader agreement of interpretation of radiological course of bile duct changes between serial follow-up MRI/MRCP examinations of patients with PSC is poor.Absence of 3D MRCP does not affect considerably the way readers interpret the radiological course of bile ducts changes.When MRCP is absent or of low quality, utilization of other sequences seems to be helpful as an alternative for bile duct evaluation.

Efficacy of oral contrast agents for upper gastrointestinal signal suppression in MRCP: A systematic review of the literature

Background

Orally administered substances which suppress signals from gastrointestinal fluid can be used to enhance image quality in magnetic resonance cholangiopancreatography (MRCP). In daily practice, the available substances range from commercial products to regular viands such as fruit juices.

Purpose

To provide an overview on the significance of and the substances used as gastrointestinal fluid signal suppressors in MRCP.

Material and Methods

A systematic review of the existing literature was performed to evaluate the efficacy and efficiency of oral T2-signal suppressors in MRCP.

Results

Twenty-five publications on 16 different oral contrast media were identified. The most commonly used substances were ferumoxsil, ferric ammonium citrate, and pineapple juice. Twenty-three out of 25 publications supported the use of oral signal suppressors in MRCP. Advantages of oral signal suppressors include improved visualization of the pancreatobiliary ductal system, increased help with differential diagnoses, and higher detection rates of relevant diagnoses due to a reduction of overlaying signals.

Conclusion

The application of oral substances for gastrointestinal signal suppression in MRCP is recommendable. A variety of substances are used in daily routine with good but varying effectivity and patient tolerance.

MDCT assessment of resectability in hilar cholangiocarcinoma

PURPOSE

The purpose of this study is to investigate the value of multidetector computed tomography (MDCT) assessment of resectability in hilar cholangiocarcinoma, and to identify the factors associated with unresectability and accurate evaluation of resectability.

METHODS

From January 2007 to June 2015, a total of 77 consecutive patients were included. All patients had preoperative MDCT (with MPR and MinIP) and surgical treatment, and were pathologically proven with hilar cholangiocarcinoma. The MDCT images were reviewed retrospectively by two senior radiologists and one hepatobiliary surgeon. The surgical findings and pathologic results were considered to be the gold standard. The Chi square test was used to identify factors associated with unresectability and accurate evaluation of resectability.

RESULTS

The sensitivity, specificity, and overall accuracy of MDCT assessment were 83.3 %, 75.9 %, and 80.5 %, respectively. The main causes of inaccuracy were incorrect evaluation of N2 lymph node metastasis (4/15) and distant metastasis (4/15). Bismuth type IV tumor, main or bilateral hepatic artery involvement, and main or bilateral portal vein involvement were highly associated with unresectability (P < 0.001). Patients without biliary drainage had higher accuracy of MDCT evaluation of resectability compared to those with biliary drainage (P < 0.001).

CONCLUSION

MDCT is reliable for preoperative assessment of resectability in hilar cholangiocarcinoma. Bismuth type IV tumor and main or bilateral vascular involvement highly suggest the unresectability of hilar cholangiocarcinoma. Patients without biliary drainage have a more accurate MDCT evaluation of resectability. We suggest MDCT should be performed before biliary drainage to achieve an accurate evaluation of resectability in hilar cholangiocarcinoma.

Presurgical Evaluation of Pancreatic Cancer: A Comprehensive Imaging Comparison of CT Versus MRI

OBJECTIVE

The purpose of this study was to compare comprehensive CT and MRI in the presurgical evaluation of pancreatic cancer.

MATERIALS AND METHODS

Thirty-eight patients with pathologically proven pancreatic cancer were included in a retrospective study. CT with negative-contrast CT cholangiopancreatography and CT angiography (CTA) (CT image set) versus MRI with MRCP and MR angiography (MRI image set) were analyzed independently by two reviewers for tumor detection, extension, metastasis, vascular invasion, and resectability. These results were compared with the surgical and pathologic findings.

RESULTS

The rate of detection of tumors was higher with MRI than with CT but not significantly so (reviewer 1, p = 1.000; reviewer 2, p = 0.500). In the evaluation of vessel involvement, nodal status, and resectability, although CT had higher ROC AUC values than did MRI (reviewer 1, 0.913 vs 0.858, 0.613 vs 0.503, and 0.866 vs 0.774; reviewer 2, 0.879 vs 0.849, 0.640 vs 0.583, and 0.830 vs 0.815), the differences were not statistically significant (p = 0.189 vs 0.494, 0.328 vs 0.244, and 0.193 vs 0.813 for reviewers 1 and 2). In the evaluation of tumor extension and organ metastases in the 38 patients, correct diagnosis of one of two liver metastases was achieved with both image sets, one case of omental and one case of peritoneal seeding were underestimated, and one case of stomach invasion was overestimated.

CONCLUSION

MRI and CT had similar performance in the presurgical evaluation of pancreatic cancer.

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.

Common bile duct stones on multidetector computed tomography: Attenuation patterns and detectability

AIM: To investigate the attenuation patterns and detectability of common bile duct (CBD) stones by multidetector computed tomography (MDCT).

METHODS: Between March 2010 and February 2012, 191 patients with suspicion of CBD stones undergoing both MDCT and endoscopic retrograde cholangiopancreatography (ERCP) were enrolled and reviewed retrospectively. The attenuation patterns of CBD stones on MDCT were classified as heavily calcified, radiopaque, less radiopaque, or undetectable. The association between the attenuation patterns of CBD stones on MDCT and stone type consisting of pure cholesterol, mixed cholesterol, brown pigment, and black pigment and the factors related to the detectability of CBD stones by MDCT were evaluated.

RESULTS: MDCT showed CBD stones in 111 of 130 patients in whom the CBD stones were demonstrated by ERCP with 85.4% sensitivity. The attenuation patterns of CBD stones on MDCT were heavily calcified 34 (26%), radiopaque 31 (24%), less radiopaque 46 (35%), and undetectable 19 (15%). The radiopacity of CBD stones differed significantly according to stone type (P < 0.001). From the receiver operating characteristic curve, stone size was useful for the determination of CBD stone by MDCT (area under curve 0.779, P < 0.001) and appropriate cut-off stone size on MDCT was 5 mm. The factors related to detectability of CBD stones on MDCT were age, stone type, and stone size on multivariate analysis (P < 0.05).

CONCLUSION: The radiopacity of CBD stones on MDCT differed according to stone type. Stone type and stone size were related to the detectability by MDCT, and appropriate cut-off stone size was 5 mm.

Impact of three-dimensional analysis of multidetector row computed tomography cholangioportography in operative planning for hilar cholangiocarcinoma

BACKGROUND

A detailed evaluation of portal triad structures, especially the biliary anatomy at the hepatic hilus, is essential to ensure curative resection for hilar cholangiocarcinoma.

METHODS

Patients underwent 3-dimensional analysis using multidetector row computed tomography cholangioportography preoperatively. The number of bile duct orifices in the cut end of the hilar plate was estimated and compared with the actual number of bile ducts. Furthermore, the estimated length of the surgical margin and its relationship to the pathological margin status was evaluated.

RESULTS

The number of bile duct orifices was correctly estimated in 14 of 19 patients. Of 18 hepatic ducts in which the estimated length of the hepatic side surgical margin was calculated 17 hepatic ducts (94.4%) were diagnosed pathologically as margin negative.

CONCLUSIONS

This investigatory technique has the advantages of precise visualization of anatomic structures and multidirectional assessment of biliary branches and vessels, allowing improved operative planning for the treatment of hilar cholangiocarcinoma.

Diagnostic performance of multidetector CT for acute cholangitis: evaluation of a CT scoring method

OBJECTIVE

The aim of this study was to retrospectively assess the diagnostic performance of multidetector CT (MDCT) for the diagnosis of acute cholangitis using a new scoring method.

METHODS

Of 80 patients with suspected biliary disease who underwent biphasic CT and endoscopic retrograde cholangiography, 39 were diagnosed as having acute cholangitis (Group 1) and 41 patients were classified as suspected biliary disease (Group 2). 100 age-matched patients without evidence of biliary disease were selected randomly as a control group (Group 3). Each patient's axial scan was scored by two independent radiologists for the extent of transient hepatic attenuation difference, the presence of biliary dilatation and identification of a biliary obstructive lesion. The difference in the scores among the three groups was evaluated and the optimal cut-off score for the diagnosis of acute cholangitis was determined. Interobserver agreement was also evaluated.

RESULTS

The total scores (mean ± standard deviation) for Groups 1, 2 and 3 were 7.0 ± 2.0, 4.4 ± 2.4 and 0.9 ± 1.2, respectively, for Reviewer 1 and 7.2 ± 2.7 and 0.7 ± 1.1, respectively, for Reviewer 2. Significant differences were found for the subscores and the total scores among the three groups (p < 0.001). Using a cut-off score of ≥ 5, the sensitivity and specificity for diagnosing acute cholangitis were 84.6% and 83.7%, respectively, for Reviewer 1 and 89.7% and 83.7%, respectively, for Reviewer 2. Agreement for the subscores between readers was good to excellent (κ = 0.74-0.86).

CONCLUSION

Based on dynamic MDCT and the described CT scoring method, the diagnosis of acute choangitis can be made with high sensitivity and specificity.

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.

Duplication of the extrahepatic bile duct in association with choledocholithiasis as depicted by MDCT

We report here on an extremely rare case of duplicated extrahepatic bile ducts that was associated with choledocholithiasis, and this malady was visualized by employing the minimum intensity projection images with using multi-detector row CT. The presence of duplicated extrahepatic bile ducts with a proximal communication, and the ducts were joined distally and they subsequently formed a single common bile duct, has not been previously reported.

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.

Spectral near-infrared fluorescence imaging of curved surfaces using projection reconstruction algorithms

In vivo spectral fluorescence imaging has made it possible to non-invasively visualize superficial curved structures as well as structures deep to the skin. However, the defocus created by blurring has been an obstacle to creating anatomically interpretable surface images. Herein we present a methodology to correct for blurring induced by curved structures during spectral fluorescence imaging using signal intensity projection algorithms. In a phantom and an animal model in which the lymphatic system was visualized after the interstitial injection of quantum dots with emission spectra in the near-infrared (NIR) range, the planes of focus were sequentially adjusted to obtain a z-stack of images which contains images acquired from multiple focal points. Maximum, minimum, median and average intensity projections were applied to the resulting images. Using the phantom, the minimum and the median intensity projection images demonstrated improved deblurring whereas during in vivo imaging the median intensity projection images more clearly visualized important structures than did the other projection techniques. Image stacking with subsequent application of appropriate projection techniques provides a simple method for deblurring in vivo optical images obtained from curved surfaces, thus improving their anatomic resolution.

Role of three-dimensional imaging in operative planning for hilar cholangiocarcinoma

BACKGROUND

Complex, highly variable, anatomic relationships in the portal hilum complicate the surgical management at hilar cholangiocarcinoma. Preoperative three-dimensional (3D) imaging to stage the tumor and define anatomy may help in planning for curative resection.

METHODS

Between 2003 and 2006, 20 consecutive patients with hilar cholangiocarcinoma underwent preoperative multidetector row computed tomography (MDCT) cholangiography; 3D images of the portal vein, hepatic artery, and bile ducts were created and viewed simultaneously. Longitudinal tumor extension was evaluated by direct cholangiography and 3D cholangiography, and contiguous spread by 2D computed tomography (CT). Of 20 patients, 15 underwent surgical resection. Liver resection was planned based on 3D imaging that allowed visualization of the relationship between the tumor and the umbilical portion of the left portal vein, or the bifurcation of the anterior and posterior branch of the right portal vein. Preoperative and operative findings were compared.

RESULTS

All patients tolerated 3D CT without serious complication. The accuracy rates of longitudinal tumor extension, using the Bismuth-Corlette classification system, were 85% (11/13) and 87% (13/15) with direct cholangiography and 3D cholangiography, respectively. The sensitivity, specificity, and accuracy rates were 100%, 80%, and 87% for portal invasion and 75%, 91%, and 87% for hepatic arterial invasion. The number of bile duct orifices in the cut end of the hilar plate was estimated correctly in 13 of 15 patients. There were no operative deaths. Potentially curative resection was achieved in 14 of 15 patients.

CONCLUSIONS

3D images provide accurate information about the relationship between hilar cholangiocarcinoma and adjacent vessels. This technique is a powerful new tool for improving the proportion of potentially curative resection.