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Biomedical subjects

V Raptopoulos

Publications and source records attributed to V Raptopoulos.

At least 19 recordsLinked to original sources
PubMed2001

Live donor adult liver transplantation using right lobe grafts: donor evaluation and surgical outcome.

HYPOTHESIS: Live donor adult liver transplantation (LDALT) is a safe and efficacious treatment for patients with end-stage liver disease. DESIGN: Case-control study. SETTING: Hepatobiliary surgery and liver transplantation unit. PATIENTS: From December 10, 1998, through April 10, 2000, a single team performed 15 LDALT procedures with 2 simultaneous living donor kidney transplants. During this period, 66 potential donors were screened and evaluated. INTERVENTIONS: Potential donors were evaluated with 3-dimensional helical computed tomographic scan, including volume renderings for hepatic lobar volume, vascular anatomy, virtual resection planes, and morphologic features. Suitable donors undergo complete medical and psychiatric evaluation and preoperative arteriography. MAIN OUTCOME MEASURES: Donor demographics, evaluation data, operative data, hospital length of stay, and morbidity. RESULTS: A total of 38 men (58%) and 28 women (42%) were evaluated with 15 donors participating in LDALT. Two additional donors provided kidney grafts for simultaneous transplantation at the time of LDALT. Thirty-two donors (48%) were rejected for either donor or recipient reasons, and 10 patients (15%) elected not to participate after initial screening. Three-dimensional volume renderings by helical computed tomographic scan predicted right lobe liver volume within 92% of actual graft volume. Donor morbidity, including all complications, was 67% with no mortality. Residual liver regenerated to approximately 70% of initial volume within 1 week and 80% within 1 month after surgery. CONCLUSIONS: Donor evaluation is an important component of LDALT. Significant donor morbidity is encountered even with careful selection. To minimize donor morbidity, groups considering initiating living donor programs should have expertise in hepatic resection and vena cava preservation using the "piggyback" technique during liver transplantation.

Adolescent↗
PubMed2001

Peritoneal carcinomatosis.

The peritoneum is a mesothelial lining of the abdominal cavity (parietal) and intraperitoneal viscera (visceral). The cavity contains a small amount of fluid, which circulates from cephalad to caudal to cephalad, influenced by negative pressure under the diaphragm during exhalation, gravity, and bowel peristalsis. Peritoneal reflections and mesenteries divide the cavity into various compartments (supramesocolic, inframesocolic, and pelvis). These reflections support the peritoneal organs and provide vascular and nervous connections while within the cavity they influence pathway of intraperitoneal fluid circulation. Capillary force over convex surfaces influence stasis of fluid and promotes peritoneal seeding; thus, there are numerous areas in which peritoneal masses are seen more commonly. These areas include the undersurface of the diaphragm (negative pressure and capillary force), the omentum (bathed in fluid), the right lower quadrant (oblique course from left superior to right inferior of the small bowel mesentery), the left lower quadrant (transverse course of the sigmoid), and the pelvis (gravity). Peritoneal carcinomatosis may be either primary (mesothelioma) or metastatic. The mode of spread is by direct invasion, lymphatic permeation, peritoneal seeding or hematogenous. The imaging patterns include fibronodular stranding, nodules, plaques, and masses. Mesenteric thickening may produce pleated or stellate patterns. Spiral CT is the most useful modality in diagnosis and follow-up of peritoneal tumors.

Carcinoma↗
PubMed2001

Contrast-Enhanced CT colonography.

Computed tomography (CT) colonography provides both a multiplanar and endoluminal perspective of the air-filled, distended, cleansed colon, offering an alternative to traditional approaches to colorectal cancer screening. However, there are still limitations associated with CT colonography that need to be resolved, including inadequate bowel distention and poorly prepared colons that make it difficult to distinguish between stool and mucosal lesions including submerged polyps as well as flat or sessile polyps which can often be overlooked. In an effort to help distinguish the bowel wall and mural abnormalities from luminal contents, we have found the use of intravenous contrast material significantly improves both bowel wall conspicuity and reader confidence for examining the colon. In addition, we have found that the use of intravenous contrast material improves the diagnostic accuracy for the detection of medium and probably large polyps.

Colon↗
PubMed2001

Cost-effectiveness of percutaneous radiofrequency ablation for malignant hepatic neoplasms.

PURPOSE: Percutaneous radiofrequency (RF) ablation is a promising technique for the treatment of hepatic malignancies. However, its cost-effectiveness has not been established. The purpose of this study is to determine the cost-effectiveness of RF ablation compared to palliative care in the treatment of hepatocellular cancer and colorectal liver metastases. This study also seeks to evaluate the effects of transition from traditional to newly implemented prospective outpatient reimbursement mechanisms on RF ablation cost-effectiveness. MATERIALS AND METHODS: The marginal direct costs of a percutaneous RF ablation treatment strategy were compared to palliative care over a range of survival benefits with use of a cost-effectiveness model built from the perspective of the payer. Variables used in the model, including complication rates and procedure efficacy, were obtained from the literature and the authors' experience with 46 consecutive patients. RESULTS: The cost-effectiveness of a standardized percutaneous RF ablation treatment strategy compared to palliative care was $20,424, $11,407, $5,034, and $3,492, respectively, per life-year (LY) gained when marginal median survival conferred by RF ablation is 6 months, 1 year, 3 years, and 5 years. The RF ablation treatment strategy would be required to generate 6.14, 2.26, and 1.10 months of marginal median survival benefit to achieve strict ($20,000/LY gained), moderate ($50,000/LY gained), and generous ($100,000/LY gained) cost-effectiveness thresholds. Cost-effectiveness was sensitive to the number of lifetime treatments, hours of observation time, frequency of follow-up evaluations, cost of abdominal computed tomography, and decision to perform RF ablation as an inpatient or outpatient. CONCLUSION: Percutaneous RF ablation is a cost-effective treatment strategy compared to palliative care and has likely already achieved the survival benefit required to meet even a strict cost-effectiveness criterion. Dependence on reimbursement mechanism highlights the importance of concordance between policy and RF ablation technology. The results of this study allow flexible application of cost-effectiveness data despite current uncertainties in treatment and survival data and heterogeneity in treatment populations.

Catheter Ablation↗
PubMed2001

Imaging for right lobe living donor liver transplantation.

The authors describe their experience using multidetector, multiphase computed tomography (CT) for the preoperative evaluation of donors undergoing adult right lobe liver transplantation. The marked improvement in image resolution has been extremely valuable in delineating small hepatic arterial structures, including accessory and replaced vessels. Assessment of liver parenchyma is valuable in determining the presence of steatosis or other unexpected abnormalities. Measurement of total liver volume is highly accurate and reproducible. Virtual hepatectomy can be performed in an avascular plane between the right and left lobes, to the right of the middle hepatic vein. Knowledge of the resultant right and left lobe volumes is critical in patient selection. Multidetector, multiphase CT, as a single imaging modality, provides a minimally invasive comprehensive pre-operative evaluation that can be expected to have a major impact on patient selection and surgical planning.

Hepatectomy↗
PubMed2001

Multi-detector row spiral CT pulmonary angiography: comparison with single-detector row spiral CT.

PURPOSE: To compare vascular conspicuity and ability to connect pulmonary arterial branches on pulmonary angiograms obtained with helical multi-detector row computed tomography (CT) with those on pulmonary angiograms obtained with helical single-detector row CT. MATERIALS AND METHODS: Of 93 consecutive patients suspected of having pulmonary embolism, 48 underwent scanning with multi-detector row CT and 45 with single-detector row CT; scans were obtained in 9 seconds and 28 seconds with 2.5-mm and 3.0-mm collimation, respectively. The lungs were divided into three zones: central, middle, and peripheral. Two independent observers used five-point grading scales. RESULTS: Conspicuity of pulmonary arteries in the central zone was ranked equal (median of 5), but in the middle and peripheral zones it was significantly higher at multi-detector row CT than at single-detector row CT (median 5 vs 4 and 4 vs 3, P < .001, respectively). In addition, multi-detector row CT improved the ability to connect peripheral arteries with their more centrally located pulmonary artery of origin in the peripheral but not the middle zone on transverse images and in both zones on multiplanar images. Viewing with a modified window setting (width, 1,000 HU; level, -100 HU) significantly increased pulmonary arterial conspicuity. Contrast material column in the pulmonary arteries was significantly more homogeneous at multi-detector row CT. CONCLUSION: Use of multi-detector row CT significantly improves pulmonary arterial visualization in the middle and peripheral lung zones.

Aged↗
PubMed2001

Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation.

OBJECTIVE: This study was performed to document the impact of multidetector multiphase CT in facilitating patient selection and surgical planning in potential donors being evaluated for living adult right lobe liver transplantation. SUBJECTS AND METHODS: Forty consecutive potential donors were included in the study. There were 26 men and 14 women, (age range, 18-57 years; mean, 37 years) We performed CT using a multidetector scanner, after IV injection of 180 mL of contrast material at 5 mL/sec. Arterial phase images were acquired at 18 sec (collimation, 1.25 mm; table speed, 7.5) and portal phase images, at 60 sec (collimation, 2.5 mm; table speed, 15). Postprocessing was performed on a commercially available workstation. CT data included dual-energy assessment of liver parenchyma for fatty infiltration; depiction of arterial, portal venous, and hepatic venous anatomy and identification of important vascular variants; and determination of total and lobar liver volume. RESULTS: Of the 40 potential liver donors evaluated, 15 patients (37.5%) were excluded on the basis of CT findings, with most exclusions a result of portal vein anomalies (n = 8). Fatty infiltration resulted in four exclusions (10%), and small liver volume resulted in three exclusions (7.5%). CONCLUSION: Multidetector multiphase CT provided comprehensive parenchymal, vascular, and volumetric preoperative evaluation of potential donors undergoing living adult right lobe liver transplantation. This information had a major impact on patient selection because it was used to stratify patients. It allowed the surgeons to plan their surgical approach, and this planning may reduce postoperative complications.

Adolescent↗
PubMed2001

Accuracy of volumetric measurements after virtual right hepatectomy in potential donors undergoing living adult liver transplantation.

OBJECTIVE: The purpose of this study was to evaluate accuracy for determining the total and lobar liver volumes using a multidetector CT scanner in potential donors undergoing living adult right lobe liver transplantation. SUBJECTS AND METHODS: Fifty-two adult donors underwent CT using a multidetector scanner after IV injection of 180 mL of contrast material. For volumetric determination, portal venous phase images were acquired at 60 sec. Hand-tracing was used to isolate the entire liver, and a curved hepatectomy plane was then identified in a manner simulating the surgical incision. Two observers performed hand-tracing of the entire liver to calculate total liver volume, and of the right lobe to calculate expected graft volume. RESULTS: The mean volume of the entire liver, right lobe, and left lobe was 1807 mL, 990 mL, and 817 mL, respectively, for observer 1, and 1788 mL, 1007 mL, and 781 mL, respectively, for observer 2. There was significant agreement between the two observers in determining total and lobar liver volumes (r = 0.996, 0.977, and 0.965 for total, right lobe, and left lobe volumes, respectively; p< 0.0001). There was no statistically significant difference between the two observers in measuring total or lobar liver volumes (p< 0.0001). There was significant agreement between right lobe volume measured by each observer and graft weight obtained in 14 donors at surgery (r = 0.898 and 0.879, for observers 1 and 2, respectively; p <0.001). CONCLUSION: Total and lobar volume determinations after virtual right hemihepatectomy provides accurate and reproducible information that is critical in selecting potential living liver donors.

Adolescent↗
PubMed2001

State-of-the-art ultrasonography is as accurate as helical computed tomography and computed tomographic angiography for detecting unresectable periampullary cancer.

OBJECTIVE: To compare the ability of state-of-the-art ultrasonography with that of helical computed tomography and computed tomographic angiography in detecting unresectable periampullary cancer. In most patients periampullary cancer is unresectable because of either distant metastasis or local vascular involvement. The advent of gray scale and color Doppler ultrasonography has improved the ability of ultrasonography to detect vascular involvement. METHODS: Twenty-three consecutive patients with periampullary cancer were enrolled for prospective staging of their disease by comparing helical computed tomography and computed tomographic angiography with gray scale and color Doppler ultrasonography of the abdomen. Portal vein, superior mesenteric vein, splenic vein, and superior mesenteric artery involvement was graded 0 to 4, grade 0 being no vascular involvement and grade 4 being total occlusion of the vessel. Agreement between ultrasonography and computed tomographic angiography for determining vascular involvement was measured by chi2 analysis. RESULTS: Two patients (9%) were excluded because excessive overlying bowel gas hampered the ability of ultrasonography to visualize the pancreas. For the remaining 21 patients, there was significant agreement between ultrasonography and computed tomographic angiography for detecting vascular involvement in all vessels (P < .001; portal vein, kappa = 0.67; superior mesenteric vein, kappa = 0.67; splenic vein, kappa = 0.85; and superior mesenteric artery, kappa = 0.59). Ultrasonography was in agreement with computed tomographic angiography in all cases of unresectability. Both modalities were equally poor in preoperatively showing lymphadenopathy and metastases. CONCLUSIONS: Provided that there is adequate visualization on ultrasonography of the head of the pancreas in the periampullary region, then state-of-the-art gray scale and color Doppler ultrasonography are as accurate as helical computed tomography and computed tomographic angiography for detecting the unresectability of periampullary cancer. If performed as the initial investigation and the region of the pancreatic head is clearly shown, and if vascular encasement or occlusion or distant metastasis is identified, further investigations are unnecessary.

Adult↗
PubMed2000

Role of virtual computed tomographic colonography in patients with colorectal cancers and obstructing colorectal lesions.

PURPOSE: The aim of this study was to assess the ability of computed tomographic colonography to diagnose colorectal masses, stage colorectal cancers, image the proximal colon in obstructing colorectal lesions, and evaluate the anastomoses in patients with previous colorectal surgery. METHODS: We prospectively performed computed tomographic colonography examinations in 34 patients (20 males; mean age, 64.2; range, 19-91 years): 20 patients had colorectal masses (defined at endoscopy as intraluminal masses 2 cm or larger), 7 patients had benign obstructing colorectal strictures, and 7 patients had a prior colorectal resection. Final tumor staging was available in all 16 patients who had colorectal cancers and 15 patients were referred after incomplete colonoscopy. The ability of computed tomographic colonography to stage colorectal cancers, identify synchronous lesions in patients with colorectal masses, and image the proximal colon in patients with obstructing colorectal lesions was assessed. RESULTS: Computed tomographic colonography identified all colorectal masses, but overcalled two masses in patients who were either poorly distended or poorly prepared. Computed tomographic colonography correctly staged 13 of 16 colorectal cancers (81 percent) and detected 16 of 17 (93 percent) synchronous polyps. Computed tomographic colonography over-staged two Dukes Stage A cancers and understaged one Dukes Stage C cancer. A total of 97 percent (87/90) of all colonic segments were adequately visualized at computed tomographic colonography in patients with obstructing colorectal lesions compared with 60 percent (26/42) of segments at barium enema (P < 0.01). Colonic anastomoses were visualized in all nine patients, but in one patient, computed tomographic colonography could not distinguish between local tumor recurrence and surgical changes. CONCLUSION: Computed tomographic colonography can accurately identify all colorectal masses but may overcall stool as masses in poorly distended or poorly prepared colons. Computed tomographic colonography has an overall staging accuracy of 81 percent for colorectal cancer and is superior to barium enema in visualizing colonic segments proximal to obstructing colorectal lesions.

Adult↗
PubMed2000

Mediastinal lymphadenopathy: diagnostic yield of transbronchial mediastinal lymph node biopsy with CT fluoroscopic guidance-initial experience.

PURPOSE: To determine whether the use of computed tomographic (CT) fluoroscopy to guide transbronchial needle aspiration (TBNA) of mediastinal lymph nodes can improve the diagnostic yield. MATERIALS AND METHODS: CT fluoroscopy was used to guide TBNA in 12 consecutive patients with mediastinal lymphadenopathy who had previously undergone nondiagnostic conventional TBNA. CT fluoroscopy was used to confirm the location of the biopsy needle by using a "quick-check" technique (ie, fluoroscopy was performed sparingly after needle insertion). The location of each needle, the total procedural and fluoroscopic times, and any complications were recorded. RESULTS: All CT fluoroscopic procedures were performed in less than 1 hour, and a tissue diagnosis was established in all patients. Eighteen lymph nodes with a diameter of 0.8-2.4 cm were sampled with 116 needle passes. CT fluoroscopy documented inadequate positioning in 48 of the 116 (41.3%) needle passes. Eighteen (15.5%) needles did not fully penetrate the tracheobronchial tree. Six needles (5.2%) were placed into the great vessels. Malignant disease was diagnosed in nine patients, and benign disease was diagnosed in three. The mean fluoroscopic exposure time was 20.5 seconds +/- 12.7. No pneumothoraces or substantial hemorrhage were observed. CONCLUSION: CT fluoroscopic guidance for TBNA procedures is a safe and efficient means of providing diagnostic material and should be considered for patients who have previously undergone nondiagnostic blinded TBNA.

Adult↗
PubMed2000

Right lower quadrant pain and suspected appendicitis: nonfocused appendiceal CT--review of 100 cases.

PURPOSE: To determine the value of standard, nonfocused computed tomography (CT) in examining patients with right lower quadrant (RLQ) pain and suspected appendicitis. MATERIALS AND METHODS: The CT scans and medical records of 100 consecutive patients who presented to the emergency department with RLQ pain and were clinically suspected of having appendicitis were retrospectively reviewed. Helical CT of both the abdomen and pelvis was performed at 7-mm increments after oral and intravenous contrast material administration. CT scans were evaluated for the presence of appendiceal or other disease. Results were correlated with surgical and pathologic findings in 34 patients or with 3-month clinical follow-up in 66 patients. RESULTS: CT depicted abnormalities in 66 patients (66%). In 59 (59%) patients, the abnormality was located in the pelvis; 23 (39%) of these patients had appendicitis. Seven (7%) patients had abnormalities outside of the pelvis, a region not typically scanned during focused appendiceal imaging. Four of these seven patients required surgery. Thus, if only pelvic focused RLQ CT had been performed, overall sensitivity would have decreased from 99% to 88% (P <.05) and sensitivity for cases necessitating surgery would have decreased from 96% to 82% (P <.05). CONCLUSION: Both abdominal and pelvic CT examinations are necessary to increase sensitivity and identify the many possible causes of RLQ pain in patients with clinically suspected appendicitis.

Abdominal Pain↗
PubMed2000

Utility of intravenously administered contrast material at CT colonography.

PURPOSE: To determine if intravenously administered contrast material improves overall reader confidence in the assessment of the colon, large-bowel wall conspicuity, and diagnostic accuracy in the detection of colorectal polyps and cancers at computed tomographic (CT) colonography. MATERIALS AND METHODS: Two hundred patients underwent CT colonography in both supine and prone positions. A five-point scale was used to assess the effect of contrast enhancement on overall reader confidence and bowel wall conspicuity. Eighty-one patients underwent CT colonography with complete colonoscopic or surgical correlation; diagnostic accuracy was compared in 48 patients who received contrast material and 33 who did not. RESULTS: Bowel preparation was ideal in 38 (19%) of 200 patients. Enhanced prone CT images had significantly better scores for reader confidence (4.9 +/- 0.1 vs 4.6 +/- 0.1, P: <.005) and bowel wall conspicuity (4.6 +/- 0.2 vs 4.2 +/- 0.2, P: <.005) compared with those of nonenhanced prone images despite no significant difference in bowel distention (3.8 +/- 0.2 vs 3.9 +/- 0. 1, P: =.8). Enhancement significantly improved the ability to depict medium (6-9-mm) polyps (75% vs 58%, P: <.05). Three large (10-19-mm) polyps were detected only with contrast enhancement; two remained submerged despite dual positioning. CONCLUSION: The use of intravenously administered contrast material significantly improved reader confidence in the assessment of bowel wall conspicuity and the ability of CT colonography to depict medium polyps in suboptimally prepared colons.

Adult↗
PubMed2000

Impact of abdominal CT on the management of patients presenting to the emergency department with acute abdominal pain.

OBJECTIVE: The purpose of this study is to document the impact of CT performed in the emergency department of patients presenting with nontraumatic acute abdominal pain. SUBJECTS AND METHODS: Fifty-seven patients were enrolled in this prospective study. Using a computer order entry system, emergency department physicians were required to report their most likely diagnosis, level of certainty, and management plan for their patients before ordering abdominal CT. After CT was performed, each physician was required to provide again his or her diagnosis, level of diagnostic certainty, and treatment plan. The outcome of each patient was evaluated by either surgery, other imaging studies, or clinical follow-up. RESULTS: After the abdominal CT, physicians' mean level of certainty in their diagnoses increased by 1.5 points (on a five-point scale; p < 0.0001). Patient management was changed in 33 (60.0%) of 55 patients. Planned treatment before CT was admission in 42 patients. Actual admissions after CT totaled 32 patients (excluding the two patients in whom preimaging information was not recorded). Thus, the net effect of abdominal CT scanning was to avert 10 (23.8%) of 42 hospital admissions. CONCLUSION: CT performed in the emergency department increases the physician's level of certainty, reduces hospital admission rates by 23.8%, and leads to more timely surgical intervention.

Abdominal Pain↗
PubMed2000

Alterations in hepatic perfusion resulting from splanchnic venous luminal compromise caused by pancreatic carcinoma.

OBJECTIVE: We determined whether alterations in hepatic enhancement exist on dual phase helical CT of the liver in patients with splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma. SUBJECTS AND METHODS: We examined the extent of hepatic enhancement on dual phase helical CT in 22 patients with pancreatic adenocarcinoma. Eleven patients had splanchnic venous luminal narrowing (flattening along at least 120 degrees of the circumference) of the superior mesenteric vein with (n = 3) or without (n = 8) portal vein involvement caused by tumor. In the remaining patients, splanchnic vasculature appeared normal. An additional 16 patients without pancreatic or hepatic abnormality who underwent dual phase helical CT served as control subjects. We compared the extent of arterial phase and portal venous phase enhancement among the three groups. RESULTS: The group of patients with splanchnic venous luminal compromise had significantly higher hepatic enhancement during the arterial phase (p < 0.01) and lower enhancement during the portal venous phase (p < 0.05) compared with the other two groups of patients. No significant difference in hepatic enhancement during either phase was noted between the control subjects and the patients with normal vasculature. CONCLUSION: Because hepatic enhancement correlates with perfusion, splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma likely causes decreased portal venous flow and compensatory increased hepatic arterial flow. This finding supports other evidence of a homeostatic mechanism that maintains hepatic perfusion.

Adenocarcinoma↗