Evaluation of the longitudinal tumor extent of bile duct cancer: value of adding gadolinium-enhanced dynamic imaging to unenhanced images and magnetic resonance cholangiography

OBJECTIVE: To determine the added value of gadolinium-enhanced dynamic magnetic resonance (MR) images compared with unenhanced and MR cholangiography (MRC) images, to evaluate the longitudinal extension of bile duct cancer. MATERIALS AND METHOD: Thirty-three patients with hilar cholangiocarcinoma or common duct cancer who had undergone MRC, unenhanced, and gadolinium-enhanced dynamic MR images and surgery were included in this study. Two experienced radiologists independently reviewed 2 image sets in 2 steps, that is, the MRC set (unenhanced and MRC) and the combined image set (MRC set with dynamic images). At each step, the readers determined the tumor status according to the Bismuth-Corlette classification. The readers assigned their confidence levels on a 5-point scale regarding whether the tumor involved the secondary confluence of the bile duct and the intrapancreatic common bile duct. The radiologists' diagnostic confidence of the 2 image sets was analyzed using receiver operating characteristic analysis. RESULTS: Receiver operating characteristic analysis showed higher areas under the curve values when the combined image set was interpreted (0.990 +/- 0.017 for reader 1 and 0.951 +/- 0.027 for reader 2) than when the MRC set was interpreted (0.982 +/- 0.017 for reader 1 and 0.902 +/- 0.038 for reader 2); however, the difference was not statistically significant for either reader (P > 0.05). In addition, regarding evaluation of the tumor status according to the Bismuth-Corlette classification, the overall accuracy was higher for the combined image set than for the MRC set alone, but the difference was not significant (P > 0.05). When dynamic images were added to the MRC images, interobserver agreement improved from 0.72 to 0.84. CONCLUSIONS: The addition of contrast-enhanced dynamic images to unenhanced and MRC images did not significantly improve the diagnostic accuracy for assessment of the longitudinal extent of bile duct cancer.     

64 Multidetector CT with multiplanar reformation in evaluation of bilateral ovarian masses

Purpose

To evaluate the role of 64 multidetector CT (MDCT) with multiplanar reformation in evaluation of bilateral ovarian masses and to correlate the findings with histopathological results and surgery.

Material and methods

MDCT was performed to 23 patients with sonographically detected bilateral ovarian masses. All scans were performed on a 64 row CT scanner at the oncology center, Mansoura University. The axial and reformatted images were evaluated for lesion characterization and the relationship to adjacent structures. The radiological findings were correlated with operative and pathological findings.

Results

There were 11 bilateral malignant lesions and 9 bilateral similar benign lesions. Three cases showed different benign lesions in both sides.All malignant lesions were read by MDCT as malignant, also all benign lesions were read by MDCT as benign except for one case with endometrioid cyst which was diagnosed as malignant tumor by CT.

Conclusion

64 Multidetector CT with MPR in different planes allows good visualization and characterization of bilateral ovarian masses with greater diagnostic accuracy and improves the detection of peritoneal metastases.     

Dual energy spectral CT imaging of insulinoma-Value in preoperative diagnosis compared with conventional multi-detector CT

Objective

The aim of this study was to investigate the value of dual energy spectral CT (DEsCT) imaging in preoperative diagnosis of insulinomas in comparison with conventional multi-detector CT (MDCT).

Materials and methods

Thirty-five patients were included in this study with 14 underwent the conventional dual-phase CT imaging (from March 2009 to January 2010) and 21 underwent the dual-phase DEsCT imaging (from February 2010 to May 2011). CT images were interpreted prospectively by two radiologists in consensus before operation. All the patients had diagnosis confirmed pathologically. The accuracy of preoperative diagnosis of insulinomas between DEsCT imaging and conventional MDCT, and between different kinds of images of DEsCT was compared.

Results

There were 39 confirmed lesions among the 35 patients (23 and 16 tumors in the spectral CT group and MDCT group, respectively). MDCT detected 11 of 16 tumors. DEsCT imaging detected 20 of 23 tumors separately with the monochromatic image or the iodine density image, and 22 of 23 tumors with the combination of the two kinds of images. The sensitivity for the preoperative diagnosis of insulinoma was 95.7% with the combination of monochromatic and iodine density images in DEsCT imaging, statistically higher than that with the conventional MDCT (68.8%) (p = 0.033).

Conclusion

Dual energy spectral CT imaging has higher sensitivity in preoperative diagnosis of insulinomas compared with conventional MDCT. The combination of monochromatic image and iodine density image can improve the diagnostic sensitivity of insulinomas.     

Contrast-enhanced MDCT gastrography for detection of early gastric cancer: Initial assessment of "wall-carving image", a novel volume rendering technique

Objective

We developed a new volume rendering technique, the CT gastrography wall carving image (WC) technique, which provides a clear visualization of localized enhanced tumors in the gastric wall. We evaluated the diagnostic performance of the WC as an adjunct to conventional images in detecting early gastric cancer (EGC).

Materials and methods

Thirty-nine patients with 43 EGCs underwent contrast-enhanced MDCT gastrography for preoperative examination. Two observers independently reviewed the images under three different conditions: term 1, Axial CT; term 2, Axial CT, MPR and VE; and term 3, Axial CT, MPR, VE and WC for the detection of EGC. The accuracy of each condition as reviewed by each of the two observers was evaluated by receiver operating characteristic analysis. Interobserver agreement was calculated using weighted-κ statistics.

Results

The best diagnostic performance and interobserver agreement were obtained in term 3. The AUCs of the two observers for terms 1, 2, and 3 were 0.63, 0.73, and 0.84, and 0.57, 0.73, and 0.76, respectively. The interobserver agreement improved from fair at term 1 to substantial at term 3.

Conclusions

The addition of WC to conventional MDCT display improved the diagnostic accuracy and interobserver reproducibility for the detection of ECG. WC represents a suitable alternative for the visualization of localized enhanced tumors in the gastric wall.     

Radiological evaluation of post-traumatic tracheal stenosis using multidetector CT with multiplanar reformatted imaging and virtual bronchoscopy: Comparison with intraoperative findings

Aim

To evaluate the diagnostic utility of multidetector computed tomography (MDCT) (axial, multiplanar reformatted images and virtual bronchoscopy) in preoperative assessment of post-traumatic tracheal stenosis.

Materials and methods

Twenty-four patients with post-traumatic tracheal stenosis underwent tracheal resection anastomosis. The diagnosis was ascertained on the basis of history and rigid-bronchoscopy. All patients were preoperatively evaluated by MDCT. Intraoperative findings were used as the gold standard. Lesions were evaluated in terms of site, distance from the vocal cords, length, grade of the stenosis and length of the planned resected segment.

Results

The sensitivity of MDCT was 100%, 100%, 92.3%, 92.3%, 96% and its accuracy was, 100%, 100%, 96%, 96%, 88.8% in assessment of tracheal stenotic site, distance from the vocal cords, length, length of segment planned for resection and stenotic grade, respectively. MPR (coronal and sagittal reformatted) images were 100% sensitive in detecting stenotic site and distance from the vocal cord. It showed 92.3% sensitivity and 96% accuracy in assessment of the stenotic segment length and the length of segment planned for resection. VB showed 96% sensitivity and 88.8% accuracy.

Conclusion

MDCT with its various display modes improved the preoperative evaluation of post-traumatic tracheal stenosis. The combined interpretation of axial, multiplanar reformatted and VE leads to improved diagnostic confidence. We recommend it as a constant demand for preoperative evaluation of post-traumatic tracheal stenosis.     

Assessment of hilar and extrahepatic bile duct cancer using multidetector CT: value of adding multiplanar reformations to standard axial images

To retrospectively assess the value of multiplanar reformations (MPRs) compared with standard axial images in the assessment of hilar and extrahepatic bile duct cancer. Forty-eight patients with confirmed bile duct cancer were included as preoperative work-ups; all of these patients underwent contrast-enhanced multidetector CT consisting of axial and MPR images. Two radiologists independently assessed the axial images alone and the combined axial and MPR images in the coronal and sagittal planes for the presence of tumor, its extent, vascular involvement, and resectability. The results were compared with surgical and pathologic findings. For tumor presence and conspicuity, combined axial and MPR images had higher values than the axial only images. For evaluation of tumoral extent, there was no difference between the two image sets for either reader. The accuracy for tumor extent was lower in hilar cancer than in extrahepatic bile duct cancer. For evaluation of vascular involvement and resectability, the area under the receiver operating characteristic curve of axial images was not significantly different from that of the reformatted images.The addition of MPR images to the standard axial images did not significantly improve the diagnostic performance of MDCT in the evaluation of the bile duct cancer.     

Potential contribution of multiplanar reconstruction (MPR) to computer-aided detection of lung nodules on MDCT

Purpose

To evaluate potential benefits of using multiplanar reconstruction (MPR) in computer-aided detection (CAD) of lung nodules on multidetector computed tomography (MDCT).

Materials and methods

MDCT datasets of 60 patients with suspected lung nodules were retrospectively collected. Using “second-read” CAD, two radiologists (Readers 1 and 2) independently interpreted these datasets for the detection of non-calcified nodules (≥4 mm) with concomitant confidence rating. They did this task twice, first without MPR (using only axial images), and then 4 weeks later with MPR (using also coronal and sagittal MPR images), where the total reading time per dataset, including the time taken to assess the detection results of CAD software (CAD assessment time), was recorded. The total reading time and CAD assessment time without MPR and those with MPR were statistically compared for each reader. The radiologists’ performance for detecting nodules without MPR and the performance with MPR were compared using jackknife free-response receiver operating characteristic (JAFROC) analysis.

Results

Compared to the CAD assessment time without MPR (mean, 69 s and 57 s for Readers 1 and 2), the CAD assessment time with MPR (mean, 46 s and 45 s for Readers 1 and 2) was significantly reduced (P < 0.001). For Reader 1, the total reading time was also significantly shorter in the case with MPR. There was no significant difference between the detection performances without MPR and with MPR.

Conclusion

The use of MPR has the potential to improve the workflow in CAD of lung nodules on MDCT.     

Bile duct evaluation of potential living liver donors with Gd-EOB-DTPA enhanced MR cholangiography: Single-dose,double dose or half-dose contrast enhanced imaging

Introduction

Detailed knowledge of the biliary anatomy is essential to avoid complications in living donor liver transplantation. The aim of this study was to determine the optimal dosage of Gd-EOB-DTPA for contrast-enhanced magnetic resonance cholangiography (ce-MRC) with reference to contrast-enhanced CT cholangiography (ce-CTC).

Materials and methods

30 potential living liver donors (PLLD) underwent both ce-CTC and ce-MRC. Ten candidates each received single, double or half-dose Gd-EOB-DTPA. Ce-MRC images with and without inversion recovery pulses (T1w ± IR) were acquired 20–30 min after intravenous contrast injection. Image data was quantitatively and qualitatively reviewed by two radiologists based on a on a 5-point scale. Data sets were compared using a Mann–Whitney-U-test or Wilcoxon-rank-sum-test. Kappa values were also calculated.

Results

All image series provided sufficient diagnostic information both showing normal biliary anatomy and variant bile ducts. Ce-CTC showed statistically significant better results compared to all ce-MRC data sets. T1w MRC with single dose Gd-EOB-DTPA proved to be superior to half and double dose in subjective and objective evaluation without a statistically significant difference.

Conclusions

Ce-MRC is at any dosage inferior to ce-CTC. As far as preoperative planning of bile duct surgery is focused on the central biliary anatomy, ce-MRC can replace harmful ce-CTC strategies, anyway. Best results were seen with single dose GD-EOB-DTPA on T1w MRC+IR.     

Image quality of multiplanar reconstruction of pulmonary CT scans using adaptive statistical iterative reconstruction

Objective

We investigated the image quality of multiplanar reconstruction (MPR) using adaptive statistical iterative reconstruction (ASIR).

Methods

Inflated and fixed lungs were scanned with a garnet detector CT in high-resolution mode (HR mode) or non-high-resolution (HR) mode, and MPR images were then reconstructed. Observers compared 15 MPR images of ASIR (40%) and ASIR (80%) with those of ASIR (0%), and assessed image quality using a visual five-point scale (1, definitely inferior; 5, definitely superior), with particular emphasis on normal pulmonary structures, artefacts, noise and overall image quality.

Results

The mean overall image quality scores in HR mode were 3.67 with ASIR (40%) and 4.97 with ASIR (80%). Those in non-HR mode were 3.27 with ASIR (40%) and 3.90 with ASIR (80%). The mean artefact scores in HR mode were 3.13 with ASIR (40%) and 3.63 with ASIR (80%), but those in non-HR mode were 2.87 with ASIR (40%) and 2.53 with ASIR (80%). The mean scores of the other parameters were greater than 3, whereas those in HR mode were higher than those in non-HR mode. There were significant differences between ASIR (40%) and ASIR (80%) in overall image quality (p<0.01). Contrast medium in the injection syringe was scanned to analyse image quality; ASIR did not suppress the severe artefacts of contrast medium.

Conclusion

In general, MPR image quality with ASIR (80%) was superior to that with ASIR (40%). However, there was an increased incidence of artefacts by ASIR when CT images were obtained in non-HR mode.Multiplanar reconstruction (MPR) of CT images plays an important role in the interpretation of the three-dimensional anatomical location or extent of disease, and is an essential technique in daily clinical practice. Multidetector row CT (MDCT) is widely used, and advances in MDCT technology have facilitated better images with thinner slice thickness and extended coverage, which has allowed more MPR images to be evaluated in greater detail. Coronal MPR images produced by MDCT supply good image quality for lung assessment and show similar image quality to axial high-resolution (HR) CT images [1^,2].To further enhance CT image quality, improvements in temporal resolution and/or spatial resolution are needed. MDCT equipped with more rapid gantry rotation or more detector arrays has already evolved for the improvement of temporal resolution. GE Healthcare (Milwaukee, WI) recently produced an MDCT unit containing a new detector composed of garnet, which has a faster response than the previous detector material. This apparatus can provide improved spatial resolution by acquiring more data.Reconstruction algorithms are also important for improved image quality. Although the filtered back-projection algorithm has traditionally been used for image reconstruction, new reconstruction algorithms are being developed. The iterative reconstruction algorithm has already been used for image reconstruction of positron emission tomography (PET) or single photon emission CT (SPECT), resulting in improved image quality [3-6]. Iterative reconstruction was also used in early CT systems and is currently used by many manufacturers of clinical CT systems. Adaptive statistical iterative reconstruction (ASIR), recently developed for CT by GE Healthcare, is expected to improve low-contrast detectability by reducing noise when using the same radiation dose as would be used with filtered back-projection. It is also expected to reduce the radiation dose for a similar noise level compared with filtered back-projection. Until now, the quality of CT images from multiplanar reconstruction using ASIR had not been analysed. The purpose of this study was to evaluate the image quality of MPR using ASIR.     

Investigation of the role of computed tomography as an adjunct to autopsy in the evaluation of stillbirth

Introduction

The number of parents agreeing to autopsy following stillbirth is declining, which has undermined clinicians’ ability to assess causes of intrauterine death and can impact counselling regarding recurrence. Post-mortem radiological imaging is a potential alternative method of investigating perinatal loss. The aim of this study was to assess the role of multi-detector computed tomography (MDCT) in the investigation of stillbirth.

Study design

Following ethical approval and written consent, parents were offered MDCT of the stillborn infant. MDCT was performed with 3D reconstruction, and images were analysed for image quality, anthropomorphic measurements and pathologic findings. Body part and organ-specific measurements were performed; including head, chest and abdominal circumferences, and muscle and liver mass was also measured. Findings were correlated with obstetric history, post-mortem skeletal survey (plain radiography), and formal autopsy.

Results

Fourteen third-trimester stillborn infants were scanned. Image quality was moderate to excellent for most body structures. CT was better than plain radiography for imaging skeletal structures and large solid organs and demonstrated a range of pathologies including renal vein thrombosis, mesenteric calcification and skeletal hyperostosis that were not seen on plain radiographs. MDCT did not overlook autopsy findings and provided some additional information.

Conclusion

This study confirms the feasibility of MDCT in the investigation of third trimester stillbirth. MDCT image quality is acceptable and the examination can demonstrate a range of anatomic and pathologic findings. Initially, its value may be as an important adjunct to conventional autopsy.     

Preoperative assessment of vascular invasion in exocrine pancreatic cancer by multidetector CT

Purpose

To evaluate multidetector CT (MDCT) signs of vascular invasion in pancreatic carcinoma.

Patients and methods

Retrospective review of preoperative dynamic MDCT of 42 patients with pathologically proven pancreatic carcinoma.

Results

Surgically confirmed invaded vessels were 19 arteries and 33 veins. Multiple signs of vascular invasion were assessed.

Conclusion

Significant advances have been made in the ability of MDCT to visualize pancreatic cancer and to stage disease when close attention is paid to technique with special attention to multiple signs of vascular invasion.     

Pancreaticobiliary duct changes of periampullary carcinomas: quantitative analysis at MR imaging

Purpose

To quantitatively analyse the pancreaticobiliary duct changes of periampullary carcinomas with volumetric interpolated breath-hold examination (VIBE) and true fast imaging with steady-state precession (true FISP) sequence, and investigate the value of these findings in differentiation and preoperative evaluation.

Materials and methods

Magnetic resonance (MR) images of 71 cases of periampullary carcinomas (34 cases of pancreatic head carcinoma, 16 cases of intrapancreatic bile duct carcinoma and 21 cases of ampullary carcinoma) confirmed histopathologically were analysed. The maximum diameter of the common bile duct (CBD) and main pancreatic duct (MPD), dilated pancreaticobiliary duct angle and the distance from the end of the proximal dilated pancreaticobiliary duct to the major papilla were measured. Analysis of variance and the Chi-squared test were performed.

Results

These findings showed significant differences among the three subtypes: the distance from the end of proximal dilated pancreaticobiliary duct to the major papilla and pancreaticobiliary duct angle. The distance and the pancreaticobiliary duct angle were least for ampullary carcinoma among the three subtypes. The percentage of dilated CBD was 94.1%, 93.8%, and 100% for pancreatic head carcinoma, intrapancreatic bile duct carcinoma and ampullary carcinoma, respectively. And that for the dilated MPD was 58.8%, 43.8%, and 42.9%, respectively.

Conclusion

Quantitative analysis of the pancreaticobiliary ductal system can provide accurate and objective assessment of the pancreaticobiliary duct changes. Although benefit in differential diagnosis is limited, these findings are valuable in preoperative evaluation for both radical resection and palliative surgery.     

Detection of active bile leak with Gd-EOB-DTPA enhanced MR cholangiography: Comparison of 20–25 min delayed and 60–180 min delayed images

Objectives

The purpose of this study was to assess the value of contrast-enhanced magnetic resonance cholangiography (MRC) performed in different time delays after injection of gadoxetic acid disodium (Gd-EOB-DTPA) for the diagnosis of active bile leak.

Methods

This retrospective analysis included Gd-EOB-DTPA enhanced MR images of 34 patients suspected of bile leak. Images were acquired 20–25 min after Gd-EOB-DTPA injection. If there was inadequate contrast in the bile ducts then delayed images after 60–90 min and 150–180 min were obtained. Results were correlated with intraoperative findings, ERCP results, clinical data, laboratory tests, and follow-up examinations.

Results

Gd-EOB-DTPA enhanced MRC yielded an overall sensitivity of 96.4%, specificity of 100% and accuracy of 97.1% for the diagnosis of an active bile leak. The sensitivity of 20–25 min delayed MR images was 42.9%, of combined 20–25 min and 60–90 min delayed images was 92.9% and of combined 20–25 min, 60–90 min and 150–180 min delayed images was 96.4%.

Conclusions

Gd-EOB-DTPA enhanced MRC utilizing delayed phase images was effective for detecting the presence and location of active bile leaks. The images acquired 60–180 min post-injection enabled identification of bile leaks even in patients with a dilated biliary system or moderate liver dysfunction.     

Multidetector CT chest with bronchial and pulmonary angiography determining causes,site and vascular origin of bleeding in patients with hemoptysis

Objective

To assess the role of MDCT chest with bronchial and pulmonary angiography in determining the cause, site of bleeding, and its vascular origin in patients presenting with hemoptysis.

Materials and methods

Fifty patients suffering from hemoptysis were evaluated by MDCT with bronchial and pulmonary angiographic techniques.

Results

MDCT chest with angiography revealed the cause in 84% of cases, the site and vascular origin in 76% of cases presenting with hemoptysis.

Conclusion

MDCT of the chest with bronchial and pulmonary angiography is considered a primary noninvasive imaging modality in the evaluation of patients with hemoptysis. It also serves as a guide for other diagnostic or therapeutic procedures.     

Gadobenate Dimeglumine as an Intrabiliary Contrast Agent: Comparison with Mangafodipir Trisodium with Respect to Non-dilated Biliary Tree Depiction

Objective

To compare the efficacy of Mangafodipir trisodium (Mn-DPDP)-enhanced MR cholangiogrphy (MRC) and Gadobenate dimeglumine (Gd-BOPTA)-enhanced MRC in visualizing a non-dilated biliary system.

Materials and Methods

Eighty-eight healthy liver donor candidates underwent contrast-enhanced T1-weighted MRC. Mn-DPDP and Gd-BOPTA was used in 36 and 52 patients, respectively. Two radiologists reviewed the MR images and rated the visualization of the common duct, the right and left hepatic ducts, and the second-order branches using a 4-point scale. The contrast-to-noise ratio (CNR) of the common duct to the liver in the two groups was also compared.

Results

Mn-DPDP MRC and Gd-BOPTA MRC both showed similar visualization grades in the common duct (p = .380, Mann-Whitney U test). In the case of the proximal bile ducts, the median visualization grade was significantly higher with Gd-BOPTA MRC than with Mn-DPDP MRC (right hepatic duct: p = 0.016, left hepatic duct: p = 0.014, right secondary order branches: p = 0.006, left secondary order branches, p = 0.003). The common duct-to-liver CNR of the Gd-BOPTA MRC group was significantly higher (38.90±24.50) than that of the Mn-DPDP MRC group (24.14±17.98) (p = .003, Student''s t test).

Conclusion

Gd-BOPTA, as a biliary contrast agent, is a potential substitute for Mn-DPDP.     

Anatomic variations of intrahepatic bile ducts in the general adult Egyptian population: 3.0-T MR cholangiography and clinical importance

Objective

To describe the anatomical variations occurring in intrahepatic bile ducts (IHDs) and their frequencies in general adult Egyptian population using 3.0-T MR cholangiography (MRC) as well as its clinical importance to reduce the biliary complications of hepatobiliary surgery.

Materials and methods

MRC was applied to a study group of 106 subjects (26 potential liver donors and 80 volunteers). Anatomical variations in IHDs were classified based on the variable insertion of right posterior hepatic bile duct (RPHD) using Huang classification.

Results

According to this classification, the frequencies of each type were as follows: Huang A1 (typical pattern): 63.2% (n = 67), Huang A2: 10.4% (n = 11), Huang A3: 17% (n = 18), Huang A4, 7.5% (n = 8), and Huang A5: 1.9% (n = 2). Total frequency for atypical types (i.e. A2, A3, A4 and A5) was 36.8%. No significant difference was detected in the distance between RPHD insertion to the junction of right and left hepatic duct in-between these Huang types. This distance was short (<1 cm) in 21 of subjects under Huang A classification. Twenty-one donors underwent intraoperative cholangiograms, of which twenty (95.2%) had similar classification in both intraoperative and MRC findings.

Conclusion

The incidence of variant biliary anatomy in general Egyptian population (36.8%) as well as the presence of Huang type A with short distance (<1 cm) between RPHD insertion and junction of right and left hepatic duct (19.8%) enhance the importance of MRC as a pre-operative tool before hepato-biliary surgical procedures to reduce post-operative biliary complications.     

T-staging of gastric cancer of air-filling multidetector-row CT: Comparison with hydro-multidetector-row CT

Purpose

The purpose of this study was to evaluate the accuracy of T-staging of gastric cancer by air-filling multidetector-row CT (air-MDCT) compared with water-filling MDCT (hydro-MDCT).

Materials and methods

One hundred fifteen patients with histologically diagnosed gastric cancer were included in this study. Fifty-eight patients underwent air-MDCT, and the remaining 57 had hydro-MDCT using a 64-channel scanner. Based on the volumetric data of contrast-enhanced MDCT obtained about 75 s after intravenously injecting 525 mg iodine per kilogram patients weight (525 mgI/kg) nonionic contrast material at the rate of 2 ml/s, oblique coronal and oblique sagittal multi-planar reformatted images perpendicular to the stomach wall, including the tumor, were reconstructed on a workstation. Mural invasion of gastric cancer into the gastric wall, as visualized by CT, was classified according to the TNM classification, and the results of T-staging by MDCT were compared with those by pathologic analysis after surgery.

Results

Correct assessment of T-staging by air-CT was achieved in 48 of 58 patients (83%), and that by hydro-MDCT was 49 of 57 patients (86%). The sensitivity, specificity, and accuracy of the technique in determining the invasion of serosa were 88%, 93%, and 91% for air-CT and 83%, 95%, and 91% for hydro-CT. There were no significant differences between hydro-MDCT and air-MDCT in sensitivity (P = 0.73), specificity (P = 0.71) and accuracy (P = 0.98).

Conclusion

Air-MDCT is a very valuable tool in T-staging of gastric cancer as well as hydro-MDCT.     

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.     

Impact of butylscopolamine on image quality of magnetic resonance cholangiopancreatography

Purpose

To assess the effect of parenteral butylscopolamine on magnetic resonance cholangiopancreatography (MRCP) image quality.

Materials and methods

The 3D free-breathing respiratory-compensated MRCP images (mean acquisition time 7 min) of 94 consecutive non-paired patients (47 with and 47 without 20 mg intramuscular butylscopolamine) were analysed retrospectively. Two experienced abdominal radiologists scored the image quality of five predefined pancreaticobiliary ductal segments on the MRCP images in a blinded fashion in both cohorts using a 5 point validated scale, ranging from perfect visualization of the entire ductal structure to the ductal structure being not visible. Interobserver agreement was determined.

Results

Parenteral butylscopolamine injection significantly reduced bowel peristalsis-related artefacts of the inferior common bile duct (CBD; p = 0.031) and the pancreatic duct (PD; p = 0.034) for reader 1 and the inferior CBD (p = 0.041) for reader 2. The difference in visualization of all remaining ductal segments, and of the overall pancreaticobiliary tree, was not statistically significant between the two cohorts. Interobserver agreement between the two readers was substantial for the superior CBD, common hepatic duct (CHD) and PD, was moderate for the inferior CBD, and was fair for the peripheral intrahepatic ducts.

Conclusion

On free-breathing 3D MRCP images, parenteral butylscopolamine improves only the visualization of the inferior CBD and the PD. However, no significant improvement in visualization of other ductal segments was demonstrated.