Medical Magazine

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.

Eric P. Tamm1　Aparna Balachandran1　Priya Bhosale1　Janio Szklaruk1

Background Many patients presenting with nonspecific signs and symptoms often receive CT scans using general protocols, not optimized to evaluate for pancreatic pathology. Therefore the purpose of this study was to evaluate portal venous phase 64 multi-row detector CT (MDCT) scans for detecting pancreatic duct strictures, stones, pancreas divisum, and communication between pancreatic ducts and cystic pancreatic lesions. Methods Institutional review board approval with waived informed consent was obtained for this HIPAA-compliant study. We included all patients that underwent abdominal, portal venous phase, intravenous contrast-enhanced 64 MDCT scans between 6/7/05 and 5/01/07 and MR cholangiopancreatography (MRCP) or endoscopic retrograde pancreatography (ERCP) within 2 months of the CT. This yielded 93 patients (42 males, 51 females) with a mean age of 59 years. In addition to CT, 75 patients underwent MRCP and 37 patients underwent ERCP. Two radiologists independently evaluated the CT images, including multiplanar and minimum intensity pixel projection reformations, for pancreatic duct strictures, stones, pancreas divisum, or cystic pancreatic lesions. The latter were classified as communicating or not communicating with the pancreatic ducts. Findings on ERCP or MRCP were used to calculate diagnostic performance parameters. Results On standard of reference examinations, 15 (16%) of the 93 patients had a pancreatic duct stricture. The sensitivity and the specificity for Observer 1 were 87% and 100%, respectively; for Observer 2, 100% and 100%, respectively. Six (6%) of the 93 patients had main pancreatic duct stones. The sensitivity and the specificity for Observer 1 were 83% and 100%, respectively; for Observer 2, 100% and 99%, respectively. Five (5%) patients had pancreas divisum; Observer 1 correctly identified four and Observer 2 correctly identified three cases. Eleven (12%) patients had cystic pancreatic lesions. Observer 1 correctly determined whether or not there was communication between the cystic pancreatic lesion and the pancreatic duct in ten cases; Observer 2 correctly made this determination in nine cases. Conclusion Portal venous phase 64 MDCT images are moderately sensitive and highly specific for detecting pancreatic duct stricture, stones, and pancreas divisum and moderately accurate for detecting communication between pancreatic ducts and cystic pancreatic lesions.

Stephan W. Anderson1　Jorge A. Soto1

Background In order to investigate whether 1-mm thin slices and multiplanar reconstructions (MPRs) of multi-detector computed tomography (CT) datasets interpreted in addition to isotropic 5-mm thick slices in one session improve the detection of peritoneal carcinomatosis. Methods The abdominal CT datasets of 44 patients with histologically proven tumors of the abdomen or pelvis were retrospectively evaluated for peritoneal carcinomatosis by four radiologists with variable experience (radiologist 1: ≥10 years, radiologists 2 and 3: 1.5 years, radiologist 4: 0.5 years). In three successive steps, the radiologists evaluated first the axial 5-mm slices, second the 1-mm slices, and third the MPRs and rated their diagnostic confidence. Results Specificity was nearly unchanged for all the four radiologists. Sensitivity improved for the most experienced and the least experienced radiologists and was unchanged for the two readers with intermediate skills. Except for the third step of radiologist 4, no statistically significant differences in diagnostic performance were detected. The diagnostic confidence of all the four readers benefited to variable degrees from interpretation of the 1-mm slices and MPRs. Conclusions While 5-mm slices are sufficient for the detection of peritoneal carcinomatosis, 1-mm slices and MPRs can improve sensitivity and diagnostic confidence.

Tobias Franiel1　Gerd Diederichs1　Florian Engelken1　Thomas Elgeti1　Juliane Rost2　Patrik Rogalla1

Acute appendicitis is the most common cause of abdominal pain requiring urgent surgery in the United States. The clinical diagnosis can be difficult in patients with atypical presentations and, over the past several decades, computed tomography (CT) has been increasingly utilized to improve diagnostic accuracy. Helical CT has proven to be an excellent tool in the work-up of acute abdominal pain with a diagnostic accuracy for acute appendicitis of 93–99%. However, occasionally there are equivocal or false positive or negative cases, often due to non-visualization of the appendix. The development of multi-detector row CT and recent advancements in reconstruction software has allowed rapid, high-resolution imaging of the entire abdomen and pelvis resulting in multiplanar reformations (MPR) with a spatial resolution similar to that of the axial plane. This article reviews the utility of CT in suspected acute appendicitis and the potential added diagnostic value of coronal reformations in confirming or excluding the diagnosis.

Amy M. Neville1　Erik K. Paulson1

Purpose To assess the additional value of multiplanar reformations (MPR) in comparison with axial images alone for location of the transition zone in CT of mechanical small-bowel obstruction (SBO). Materials and methods Sixty-nine consecutive patients with mechanical SBO underwent 16-slice multi detector row CT (MDCT). The gold standard for the precise location of the transition zone was established by two experienced abdominal radiologists, unblinded to clinical and surgical reports, reviewing all CT examinations. On a workstation, two blinded readers independently located the transition zone using first axial slices alone and then 1 month later MPR (axial, coronal, sagittal and oblique views) according to a three-point confidence scale. Diagnostic accuracy and mean confidence score were evaluated for both the transverse and multiplanar data sets. Results Accuracy of transition zone location for reader 1 and reader 2 was 86% and 84% with axial slices alone, and by using MPR 93% (significant: P = 0.03) and 90% (not significant: P = 0.08), respectively. Mean confidence score was significantly increased for both readers using MPR: 0.3 higher (P = 0.0001) and 0.37 higher (P = 0.0001) respectively. Conclusion MPR can increase both accuracy and confidence in the location of the transition zone in CT of SBO.

Jerome Hodel1　Marc Zins1　Loic Desmottes1　Isabelle Boulay-Coletta1　Marie Christine Jullès1　Jean Pierre Nakache2　Mathieu Rodallec1

Background The aims of this study are to evaluate and compare the accuracies of isotropic multi-detector row CT (MDCT) including multiplanar reconstruction (MPR) images for preoperative staging of endoscopically diagnosed early gastric cancer (eEGC) and advanced gastric cancer (eAGC). Methods One hundred and five patients with endoscopically proven gastric cancer underwent isotropic MDCT. Three independent radiologists evaluated T and N staging both on transverse images only and on three orthogonal MPR images. The staging of each tumor was surgico-pathologically confirmed. The receiver operating characteristic (ROC) analysis and the Wilcoxon signed ranked test were used for statistical analyses. Results In 30 eAGCs, the accuracies for T and N staging with MPR imaging were better than those with transverse imaging (each P < 0.05). In 34 eEGCs, however, only the accuracy of T2 or higher with MPR imaging was higher than that with transverse imaging (P < 0.05). Conclusions Isotropic MDCT with MPR images including coronal or sagittal reconstructions can improve the accuracies of preoperative T and N staging of eAGC, while having little impact on the accuracy for eEGC.

Yoo Na Kim1　Dongil Choi1　Seong Hyun Kim1　Min Ju Kim1　Soon Jin Lee1　Won Jae Lee1　Sung Kim2　Jae J. Kim3

The improvement in spatial, temporal, and contrast resolutions with the newest multidetector computed tomographic (MDCT) scanners opens the opportunity to explore other applications of the virtual endoscopy technique besides the colon and stomach evaluation. As a non-invasive technique, virtual esophagoscopy represents an alternative to conventional endoscopy for the assessment of esophageal stenosis. The procedure and diagnostic performance are reviewed. Findings of this modality are illustrated.

Patricia Carrascosa1　Carlos Capu#241　ay1　Elba Martín López1　Graciela Salis2　Sergio Mazzadi2　Jorge Carrascosa1

Multi-detector computed tomography (CT) offers new opportunities in the imaging of the gastrointestinal tract. Its ability to cover a large volume in a very short scan time, and in a single breath hold with thin collimation and isotropic voxels, allows the imaging of the entire esophagus with high-quality multiplanar reformation and 3D reconstruction. Proper distention of the esophagus and stomach (by oral administration of effervescent granules and water) and optimally timed administration of intravenous contrast material are required to detect and characterize disease. In contrast to endoscopy and double-contrast studies of the upper GI tract, CT provides information about both the esophageal wall and the extramural extent of disease. Preoperative staging of esophageal carcinoma appears to be the main indication for MDCT. In addition, MDCT allows detection of other esophageal malignancies, such as lymphoma and benign esophageal tumors, such as leiomyma. A diagnosis of rupture or fistula of the esophagus can be firmly established using MDCT. Furthermore, miscellaneous esophageal conditions, such as achalasia, esophagitis, diverticula, and varices, are incidental findings and can also be visualized with hydro-multi-detector CT. Multi-detector CT is a valuable tool for the evaluation of esophageal wall disease and serves as an adjunct to endoscopy.

Ahmed Ba-Ssalamah1　Johannes Zacherl2　Iris Melanie Noebauer-Huhmann1　Martin Uffmann1　Wolfgang Karl Matzek1　Katja Pinker1　Christian Herold1　Wolfgang Schima1