Living adult right lobe liver transplantation: imaging before surgery with multidetector multiphase CT.
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Adult↗
Biomedical subjects
V Raptopoulos
Publications and source records attributed to V Raptopoulos.
Abdominal helical CT: milk as a low-attenuation oral contrast agent.
One hundred ten consecutive patients were given either whole (4%) milk, 2% milk, water, barium suspension, or no oral contrast agent before abdominal computed tomography (CT). Results with whole milk were superior to those with all other agents for gastrointestinal distention, mural visualization, and pancreas-duodenum discrimination. In bowel loop discrimination, results with 4% milk were equal to those with barium but superior to those with all other agents. Whole (4%) milk is an effective low-attenuation oral contrast agent.
Administration, Oral↗
Liver metastases from melanoma: detection with multiphasic contrast-enhanced CT.
PURPOSE: To assess the clinical utility of multiphasic computed tomography (CT) of the liver in patients with metastatic melanoma. MATERIALS AND METHODS: Nonenhanced and biphasic hepatic CT examinations were performed in 28 patients with metastatic melanoma, and liver lesion conspicuity was graded. CT studies in 20 patients met the eligibility criteria, and 13 patients had liver lesions. RESULTS: A total of 57 liver lesions were seen on CT studies: 48 on hepatic arterial phase images, 49 on portal venous phase phase images, and 30 on delayed phase images. Of eight lesions overlooked on portal venous phase images, six were seen on nonenhanced images, and six were seen on arterial phase images. Twenty-eight lesions were graded as more conspicuous on portal venous phase images; 10 were graded as more conspicuous on arterial phase images. CONCLUSION: CT images obtained only during the portal venous phase would have resulted in eight (14%) overlooked lesions, which implies that more than one phase is needed for hepatic CT in patients with malignant melanoma. The combination of nonenhanced and portal venous phase CT was as effective as the combination of arterial and portal venous phase CT in these patients. Delayed phase CT did not improve lesion detection either alone or in combination with CT at other phases.
Adult↗
Endoluminal CT colonography after an incomplete endoscopic colonoscopy.
OBJECTIVE: We evaluated the clinical usefulness of endoluminal CT colonography after an incomplete colonoscopy. SUBJECTS AND METHODS: We prospectively studied 40 patients in whom the cecum could not be reached endoscopically despite adequate bowel preparation. Endoluminal CT colonography (120 kVp, 120 mA, 3-mm collimation, pitch of 2, 1.5-mm interval reconstruction) was performed within 2 hr of incomplete colonoscopy. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal images were analyzed. Twenty-six patients (65%) underwent barium enema immediately after endoluminal CT colonography. We analyzed colonic distention; duration of endoluminal CT colonography; patient tolerance; number of colonic segments seen at colonoscopy, endoluminal CT colonography, and barium enema; and reasons for incomplete colonoscopy as well as colonic and extracolonic findings. RESULTS: Duration of endoluminal CT colonography was 14.2 +/- 4.6 min (mean +/- SD). Endoluminal CT colonography was better tolerated than colonoscopy or barium enema (p < .001). Probable causes for incomplete colonoscopy were identified at endoluminal CT colonography in 74% of 40 patients. Baseline colonic distention in the region of the transverse and right colon was considered adequate before additional air insufflation; however, the addition of air significantly enhanced colonic distention throughout the entire colon (p < .001). Endoluminal CT colonography adequately revealed 96% of all colonic segments; in comparison, barium enema adequately revealed 91% of all segments (p < .05). CONCLUSION: In patients with incomplete colonoscopy, endoluminal CT colonography successfully showed the previously unrevealed colon in more than 90% of patients. Endoluminal CT colonography is a rapid, well-tolerated technique that provides clinically useful colonic and extracolonic information and should be considered for all patients who undergo incomplete colonoscopy.
Adult↗
Teardrop superior mesenteric vein: CT sign for unresectable carcinoma of the pancreas.
OBJECTIVE: Our objective was to investigate whether a tethered, teardrop-shaped superior mesenteric vein (SMV) is a reliable CT indicator of unresectable adenocarcinoma of the head of the pancreas. MATERIALS AND METHODS: CT scans of 92 patients with high suspicion for pancreatic head adenocarcinoma were retrospectively reviewed by two radiologists who were unfamiliar with the patients' outcomes. The reviewers were asked to assess whether the teardrop SMV sign was present or not; agreement was reached by consensus. Teardrop SMV was considered absent in patients with an obstructed vessel. RESULTS: Of 92 patients, 30 had a normal pancreas without a teardrop SMV. A mass in the head of the pancreas was seen in all 62 patients with cancer. Of these 62 patients, 30 (seven with teardrop SMV) were deemed to have inoperable disease by standard CT or clinical criteria. The remaining 32 patients underwent surgery; only 15 of these 32 had successful pancreatoduodenectomies. No patient with resectable tumor had an unequivocal teardrop SMV sign. In 17 patients (13 with teardrop SMV), resection of the tumor could not be accomplished because of vascular encasement (n = 12) or metastasis (n = 5). Added to conventional signs, teardrop SMV significantly increased CT's sensitivity (from 60% to 91%) and accuracy (from 79% to 95%) without significantly changing its specificity (from 100% to 98%) for resectability of pancreatic head cancer. CONCLUSION: The teardrop SMV is a reliable sign for predicting unresectability of adenocarcinoma of the head of the pancreas and can significantly contribute to preoperative planning.
Adenocarcinoma↗
Virtual colonography: techniques and current clinical applications.
The advent of volumetric helical computed tomography (CT), coupled with the almost universal use of oral and intravenous contrast agents, has resulted in CT becoming the diagnostic and therapeutic cornerstone for alimentary tract disease. Recent technical advances, further enhanced by innovative software developments, now permit multiplanar and endoluminal projections of the entire abdomen, and have resulted in the development of novel diagnostic applications in the abdomen.
Journal Article↗
Multiplanar CT pancreatography and distal cholangiography with minimum intensity projections.
PURPOSE: To develop a technique of projectional computed tomographic (CT) cholangiopancreatography (CTCP). MATERIALS AND METHODS: Sixty-one patients underwent CT for suspected biliary or pancreatic abnormalities. The axial CT and CTCP techniques included spiral scanning during the portal venous phase and thick-slab minimum intensity projections. Visualization of pancreatic and extrahepatic bile ducts (divided in five duct segments per patient) was graded blindly on a scale of 1-5 by a consensus of two radiologists. Two hundred seventy-seven duct segments were used to compare axial CT and CTCP in the depiction of duct segments and dilatation; 109 segments were used to compare CTCP with ERCP. RESULTS: Fifty-six of 277 duct segments were not visualized on axial CT images; 15 segments were not visualized on CTCP images (P < .001). There was no statistically significant difference between the number of segments missed with ERCP and the number missed with CTCP: nine and three of 109 segments, respectively. Duct visualization was equal on axial CT and CTCP images in 35 of 109 duct segments and was superior on CTCP images in all but one of the remaining segments (P < .001). Duct visualization on CTCP images was equal to that on ERCP images in 35 segments, superior in nine, and significantly inferior in 66 (P < .001). CONCLUSION: CTCP improves CT depiction of pancreatic and bile ducts with a quality that approaches that of ERCP.
Aged↗
Development of virtual CT cholangiopancreatoscopy.
Endoluminal virtual computed tomographic (CT) cholangiopancreatoscopic views of the pancreatic and common bile ducts were generated in 16 patients by using helical CT data sets and endoscopic three-dimensional reconstruction images. In all patients with ductal dilatation, virtual images were obtained and findings correlated with those at helical CT and endoscopic retrograde cholangiopancreatography. Virtual CT cholangiopancreatoscopy is a feasible technique, and initial experience shows promising results.
Cholangiopancreatography, Endoscopic Retrograde↗
Possible causes of inconclusive results on CT-guided thoracic and abdominal core biopsies.
OBJECTIVE: We sought to determine possible technical causes of inconclusive results on CT-guided core biopsies of lesions suggestive of malignancy and to determine the frequency with which such lesions are eventually found to be malignant. MATERIALS AND METHODS: We retrospectively reviewed 116 consecutive CT-guided thoracic and abdominal core biopsies performed with a 20-gauge automatic biopsy system. Biopsy results were conclusive (n = 94) if pathology confirmed malignancy and inconclusive (n = 22) if pathology results were negative for malignancy or were nondiagnostic. Lesion volume, location, number of cores, and biopsy technique (paraxial or coaxial) were compared for the conclusive and inconclusive biopsy results. Malignancy within the group of inconclusive biopsy results was determined from a second biopsy, radiographic follow-up, or surgery. RESULTS: Regression analysis identified only the biopsy method as a significant factor affecting biopsy outcome: The paraxial method was more likely to yield a conclusive result than the coaxial method (p < .002). For the two biopsy methods, lesions had similar volumes, locations, and numbers of cores obtained. For single core biopsies, both methods were equivalent. However, if two or more cores were obtained, a conclusive result was achieved in more than 90% of biopsies with the paraxial method versus 65% for the coaxial method. On follow-up, results of 14 (64%) of 22 inconclusive biopsies were malignant, indicating an overall false-negative rate of 12%. CONCLUSION: CT-guided core biopsy performed with 20-gauge automatic biopsy systems and the paraxial method will yield conclusive results significantly more often than the coaxial method. In the event of inconclusive results, malignancy will exist often enough to warrant follow-up.
Abdominal Neoplasms↗
Nonopaque crystal deposition causing ureteric obstruction in patients with HIV undergoing indinavir therapy.
OBJECTIVE: We describe the unique CT features of ureteric calculi in six HIV-infected patients receiving indinavir, the most commonly used HIV protease inhibitor, which is associated with an increased incidence of urolithiasis. CONCLUSION: Ureteric obstruction caused by precipitated indinavir crystals may be difficult to diagnose with unenhanced CT. The calculi are not opaque, and secondary signs of obstruction may be absent or minimal and should be sought carefully. Images may need to be obtained using i.v. contrast material to enable diagnosis of ureteric stones or obstruction in patients with HIV infection who receive indinavir therapy.
Adult↗
CT detection of layering of i.v. contrast material in the abdominal aorta.
OBJECTIVE: We sought to determine whether IV contrast material would layer dependently within the abdominal aorta if administered from a location and at a rate routinely used for CT angiography. SUBJECTS AND METHODS: In 22 patients, three equal-sized regions of interest (ROIs) were symmetrically spaced across the abdominal aortic lumen at the level of the celiac axis. These positions corresponded to a dependent, a central, and a nondependent position. Time-enhancement curves were generated for each ROI after IV injection of 10 ml of nonionic contrast material, which was administered at a rate of 3.5 ml/sec, through an antecubital vein. The magnitude of and the time to peak enhancement for each ROI were determined. The 22 peak enhancement values obtained for each of the three ROIs were compared using the Newman-Keuls test. RESULTS: A statistically significant increase in peak enhancement was identified when traversing the abdominal aortic lumen from the nondependent to the central ROI (p < .05) and from the central to the dependent ROI (p < .01). Levels of mean peak enhancement were 48.3+/-19.0, 38.9+/-18.2, and 33.0+/-19.7 for the dependent, central, and nondependent ROIs, respectively. The amount of time needed to reach peak enhancement of each of the three ROIs in an individual patient was similar. CONCLUSION: A small dose of contrast material administered IV through an antecubital vein will layer dependently in the abdominal aorta--thus creating a gradient in enhancement--despite mixing in the heart. If layering of contrast material is subsequently detected during routine abdominal CT angiography, then patient positioning may need to be adjusted to maximize enhancement of targeted vessels.
Aorta, Abdominal↗
[CT subtraction angiography (CTSA). Results with an automated "elastic" subtraction algorithm].
PURPOSE: To develop and implement a method to obtain digital subtraction (DS) spiral computed tomography angiograms (SCTA) in order to avoid superimposition of bony structures and vascular calcifications on SCTA maximum intensity projections (MIPs) and shaded surface display (SSD). METHOD: Two SCTA data sets, one before and one during the injection of a contrast agent bolus, were obtained with identical scan parameters. Since ordinary subtraction of the two data sets fails to reliably separate bones and calcifications from the vascular lumen because of motion, a so-called elastic subtraction procedure was designed to correct 3D misregistration between the two data sets. It automatically accommodates for local position changes between baseline and contrast images, including regionally inconsistent non-linear displacements and arbitrary rotations. This method was tested in seven patients and evaluated against ordinary DS in terms of image quality and artifacts. RESULTS: In all patients "elastic" CTSA proved superior to ordinary DS. It provides automated and reliable separation of vessels from bones and calcifications. This improves the delineation of vessels in the neck and the skull base and of intracranial vessels. DS-SCTA facilitates MIPs and SSD without artifacts introduced by thresholding. CONCLUSION: Elastic DS-SCTA is a robust method for automated unmasking of vessels from bones and warrants clinical trials and comparison with MR- and conventional angiography.
Algorithms↗
Extent of myocardial collateralization: determination with three-dimensional elastic-subtraction spiral CT.
RATIONALE AND OBJECTIVES: This study was undertaken to develop a standard that can be used to assess new high-resolution collateral zone imaging methods. MATERIALS AND METHODS: The authors performed ex vivo helical CT in seven pig hearts after microsphere studies of blood flow and coronary angiography. They compared the zones of collateralization depicted at CT and at microsphere studies. RESULTS: The extent of the collateral zone at CT, computed by using elastic subtraction, correlated well with the coronary blood flow distribution determined with microsphere analysis (r = .95). The root-mean-square error was 6.5%, which indicates good agreement. CONCLUSION: Accurate assessment of collateralization extent has become an important goal because of the discovery of agents that stimulate the growth of coronary collateral vessels. The precision of elastic-subtraction CT and its validation with respect to the blood flow distribution at microsphere analysis indicate that elastic-subtraction CT can serve as a standard for the measurement of collateralization extent.
Animals↗
Radiographic determination of total lung capacity in patients with pneumonectomy.
To determine whether total lung capacity (TLC) can be measured from plain chest radiographs in patients with pneumonectomy, we examined 20 such patients (17 male, 3 female) who had pneumonectomy for lung carcinoma. In 16 patients the right lung was preserved, and in 4 the left. The TLC was measured with the helium dilution method and by planimetry of the anterior and lateral projections of the lung on chest radiographs, summing the anterior and lateral projected areas of the lung to a single value, S. The correlation between S and TLC by helium gas dilution was r = 0.95. Linear fit of TLC to S explained 99.5% of the variance in TLC, with the equation. The side resected did not influence the predictive value (p < 0.001). The interquartile range of the residual error was +/-130 ml, and standard error was 64 ml. Therefore in patients with pneumonectomy, TLC of the preserved lung may be estimated within +/-130 ml by planimetry of the anterior and lateral chest radiographs.
Aged↗
Medial border of the perirenal space: CT and anatomic correlation.
PURPOSE: To explore the mode of spread of disease between the perirenal space and the perivascular central retroperitoneum and to determine the anatomy along the medial border of the perirenal space. MATERIALS AND METHODS: Anatomic dissection, injection of latex, and observation of cross sections of the abdomen were performed in nine cadavers. Attention was paid to the juncture of the central prevertebral, perivascular, and extraperitoneal regions, and the perirenal space. Anatomic findings were correlated with observations made at computed tomography (CT) in 82 patients with retroperitoneal hemorrhage (n = 24), inflammation (n = 37), and neoplasia (n = 21) involving the perirenal spaces or the central retroperitoneum. RESULTS: Along most of the length of each kidney, no apparent fascia separates the perirenal space from the central retroperitoneum. At this location, septa between fat lobules form a fenestrated multitier barrier. These septa were imperceptible on CT scans obtained in healthy individuals. After injection of latex in cadavers, this potential barrier was seen. In the clinical study, spread of disease was allowed in only 38 (30%) of 128 instances of potential spread. Spread was facilitated along the renal vessels and the interlobular septa. CONCLUSION: Beyond the kidneys, the renal fascia is closed, forming a cone superiorly and an inverted cone inferiorly. A network of interlobular septa acted as a barrier or pathway to the free spread of disease from the perirenal space to the central retroperitoneum or from the central retroperitoneum to the perirenal space.
Adult↗
Impact of CT on diagnosis and management of acute abdomen in patients initially treated without surgery.
OBJECTIVE: The purpose of this study was to evaluate the effect of CT on the diagnosis and management of acute abdominal pain in patients who did not undergo surgery and to determine what population of patients would profit most from CT examination. MATERIALS AND METHODS: Clinical data and CT reports of 91 patients with acute abdomen (41 men and 50 women, 22-96 years old) were analyzed retrospectively. The accuracies of clinical evaluation and CT in revealing the cause of acute abdomen were compared, and the effect of CT on patient management was assessed. Analysis included the entire population of patients and these subgroups: (1) patients who had symptoms for fewer than 24 hr versus patients who had symptoms for 24 hr or more and (2) patients who had a history of abdominal diseases versus patients who had no such history. RESULTS: Twenty-nine patients had signs or symptoms for fewer than 24 hr, and 62 patients had signs or symptoms for 24 hr or more. Fifty-nine patients had a history of abdominal disease, and 32 had no history of abdominal disease. In the entire population of patients, CT was superior to clinical evaluation for diagnosing the cause of acute abdomen (sensitivity was 90% for CT and 76% for clinical evaluation, p < .0005). Management was changed after CT in 25 patients (p < .0005). Similar differences were observed in the subgroups of patients with signs and symptoms for fewer than 24 hr, patients with signs and symptoms for 24 hr or more, and patients with no history of abdominal disease (p < .05). In the subgroup of patients with a history of abdominal disease, the differences between clinical evaluation and CT were not statistically significant. CONCLUSION: CT is an excellent examination technique for patients with acute abdomen, regardless of the duration of signs and symptoms. CT is particularly useful in defining the cause and therapeutic strategy in patients with acute abdomen who have no history of abdominal disease.
Abdomen, Acute↗
The use of helical CT and CT angiography to predict vascular involvement from pancreatic cancer: correlation with findings at surgery.
OBJECTIVE: The purpose of this study was to test the accuracy of helical CT with and without CT angiography to predict vascular involvement from pancreatic cancer and correlate the resultant images with findings at surgery. SUBJECTS AND METHODS: Helical CT and CT angiography was done in 84 patients who had adenocarcinoma of the pancreas to refine an integrated CT angiography protocol. Of these patients 38 underwent radical pancreatoduodenectomy. Vessel integrity of the superior mesenteric artery, superior mesenteric vein, and portal vein was assessed prospectively on both axial CT scans and CT angiograms and correlated with findings at surgery and in particular with the ability of the surgeon to dissect the tumor from these vessels along the vascular planes. RESULTS: CT angiograms were obtained in 82 (98%) of 84 studies. Of the 38 patients who underwent radical pancreatoduodenectomy, resection was aborted in 11 (29%) because of vascular encasement, Compared with axial CT images, CT angiography was more accurate at revealing unresectable cases. In all but one of 11 patients with vessel encasement (narrowing of the lumen) revealed on CT angiography, the lesion was unresectable. Vessel encasement was shown in only two of these 11 patients on axial CT images (of these two patients, one underwent tumor resection). The negative predictive value of a resectable tumor was 96% for CT angiography and axial helical CT compared with 70% for axial helical CT images alone (p = .021). CONCLUSION: Helical CT with CT angiography of the pancreas provides useful information about local vascular involvement from pancreatic carcinoma. Compared with conventional axial helical CT, the addition of CT angiography improves radiologists' ability to predict the resectability of pancreatic tumors.
Adenocarcinoma↗