Biomedical subjects

Vassilios Raptopoulos

Publications and source records attributed to Vassilios Raptopoulos.

34 records · Page 2Linked to original sources

PubMed2003

Acute appendicitis: effect of increased use of CT on selecting patients earlier.

PURPOSE: To explore the possibility of a relationship between increased use of computed tomography (CT) for diagnosis of appendicitis and increased occurrence of minimal or subtle CT and surgical findings. MATERIALS AND METHODS: Two groups, each with 50 consecutive patients who underwent CT before appendectomy in 1997 and 2000, were compared. CT scans and surgery-pathology reports were evaluated on a six-grade scale from normal to abscess or inflammatory mass. The demographics, surgical techniques, hospital stay, and grade distribution for the two groups were compared, and the CT results were correlated with surgical findings. RESULTS: In 1997, CT was performed in 33% (50 of 152) of patients undergoing appendectomy, as compared with 59% (50 of 85) 3 years later (P <.001). There was excellent correlation between surgical-pathologic and CT grades (weighted kappa, 0.75; P <.001; Spearman rank correlation, 0.83). There was no significant difference in demographics, rate of surgery, or surgical techniques used, but there was a significant decrease in the median surgical-pathologic grades, from 3.0 to 2.5 (P =.05) for all patients and from 3.5 to 2.6 (P =.003) for patients who underwent CT. Similarly, the median CT grade decreased from 4 to 3 (P <.001). Seven patients had subtle CT findings in 1997 compared with 16 in 2000 (P =.004), and there was a significant decrease in mean hospital stay, from 2.8 days +/- 4 (SD) to 1.5 days +/- 2 (P =.008). CONCLUSION: With increased CT use, there were less severe imaging findings, including absence of periappendiceal stranding, and a significant decrease in surgical-pathologic severity of appendiceal disease and hospital stay.

Acute Disease↗

PubMed2003

CT predictors of failed laparoscopic appendectomy.

PURPOSE: To identify computed tomographic (CT) signs that may help predict possible failure of laparoscopic appendectomy and subsequent conversion to open appendectomy. MATERIALS AND METHODS: Of 234 consecutive patients who underwent preoperative CT and in whom laparoscopic appendectomy was attempted, 26 required conversion to open appendectomy. Conversion was correlated with the following CT findings: appendix location, appendicolith, cecal wall thickening involving the base of the appendix, lymphadenopathy, and appendiceal diameter. The extent of inflammation was graded by using a six-point scale: 0 meant normal appendix; 1, possibly abnormal appendix (6-mm diameter without other abnormality); 2, abnormal appendix (diameter > or = 6 mm with wall enhancement) without adjacent fat stranding; 3, abnormal appendix surrounded by fat stranding; 4, abnormal appendix surrounded by fat stranding and fluid; and 5, inflammatory mass or abscess. Student t and chi2 tests were used for statistical analysis of interval and nominal values, respectively. RESULTS: Although there was a significant difference in appendiceal diameter between the patients in whom laparoscopic appendectomy was successfully completed (11.3 mm +/- 3.5 [SD]) and those who required conversion (12.9 mm +/- 3.9), no distinct cutoff point was identified. Of the five CT findings evaluated, none was a significant predictor of conversion to open appendectomy. Eleven (7%) of 164 patients with a CT inflammation grade of 0-3 required conversion, whereas 15 (21%) of 70 patients with a grade of 4 or 5 required conversion (P <.04). CONCLUSION: The majority of patients with appendicitis can be treated with laparoscopic appendectomy. Nevertheless, patients who require conversion to open appendectomy tend to have high CT inflammation grades of 4 or 5, which indicate the presence of periappendiceal fluid or an inflammatory mass or abscess.

Acute Disease↗

PubMed2003

Multi-detector row CT of relevant vascular anatomy of the surgical plane in split-liver transplantation.

PURPOSE: To evaluate relevant arterial and venous anatomy of the hepatectomy plane lateral to segment IV by using multi-detector row computed tomography (CT) with respect to adult living related transplantation of the right lobe of the liver. MATERIALS AND METHODS: In potential liver donors, 100 consecutive hepatic CT angiograms were obtained after intravenous bolus administration of 150-180 mL of nonionic contrast material. Arterial phase images (1.25-mm collimation, 7.5 mm/ 0.8-second table speed) were acquired after test dose injection. Portal phase images were acquired at 60 seconds (2.5-mm collimation, 15 mm/0.8-second table speed). Postprocessing depicted arterial, portal, and hepatic vein anatomy traversing the anticipated surgical hepatectomy plane to the right of the middle hepatic vein (MHV) and separating the right and left lobes of the liver. Two radiologists interpreted the images, and data were agreed on by consensus. Data collected included intrahepatic anatomy and origin of the artery and vein supplying segment IV; the venous drainage from segments V and VIII; and the presence, size, and distance from the right hepatic vein (RHV) confluence of accessory hepatic veins in the surgical plane. RESULTS: Thirty-one donors had conventional hepatic vascular anatomy. Vessels that traversed the hepatectomy plane included the artery supplying segment IV in seven (7%) patients, dominant portal vein supply to segment IV from the right portal vein in two (2%) patients or from both right and left portal vein branches in three (3%) patients, segment VIII draining into the MHV in 67 (67%) patients or both the MHV and RHV in 18 (18%) patients (the major draining vein was >7 mm in diameter in 23%), segment V draining into the MHV in 10 (10%) patients, or both the MHV and RHV in 19 (19%) patients (the major draining vein from segment V was 7-10 mm in diameter in 70 patients, and larger than 10 mm in five). Forty-four accessory hepatic veins were identified in 40 patients; seven drained segment V, while the majority drained segments VI and VII. The mean diameter was 5.3 mm and 45% were larger than 6 mm. The average distance to the RHV-inferior vena cava confluence was 28.7 mm. Of 70 patients with drainage from segment V into RHV, 22 (31%) had an accessory RHV. However, atypical drainage into the MHV was noted in seven (70%) of 10 patients and into the MHV and RHV in 11 (58%) of 19 patients. CONCLUSION: In the majority of potential donors, CT angiography depicted a wide range of vascular anatomic variations that traverse the hepatectomy plane.

Adult↗

PubMed2003

Living donor liver transplantation in adults: vascular variants important in surgical planning for donors and recipients.

OBJECTIVE: The purpose of our study was to explore the frequency with which surgically important hepatic vascular variants occur independently as well as in genetically related adult candidates for donation or receipt of a liver transplant. MATERIALS AND METHODS: We conducted a retrospective study of 107 adult living donor liver transplant candidates. From this pool of candidates, 50 sets of close relatives were selected to undergo transplantation. As part of the preoperative evaluation, all underwent multidetector CT angiography for evaluation of arterial and venous anatomy. Nonionic IV contrast material (180 mL) was given at a rate of 5 mL/sec, and collimations of 1.25 and 2.50 mm were used for true arterial and portal hepatic venous phase scanning, respectively. Image processing included three-dimensional volume renderings and multiplanar reformations. Two radiologists assessed the prevalence of vascular variants that were important for surgical planning and execution. RESULTS: We identified surgically important hepatic vascular variants in 70 (65%) of the 107 patients. A total of 129 variants were identified, of which 27 were important surgical considerations for recipients, 37 were important for donors, and 65 were important for both recipients (19 variants) and donors (46 variants). Of the 50 pairs of close relatives, 10 (20%) of the pairs were found to have the same hepatic vascular variant or one that was similar. However, when the pairs were set randomly, with no genetically related pairs included, similar variants were noted in 11 pairs (22%). The most common hepatic arterial variant in all candidates was an accessory right or left hepatic artery. The most common hepatic venous variant was an accessory right inferior hepatic vein. CONCLUSION: We observed a high prevalence of surgically important vascular variants in living adult candidates for living liver transplant donation and receipt. Because of the frequent occurrence, similar variants are to be expected among these sets of patients, regardless of whether they are closely related.

Adult↗

PubMed2003

Tracheomalacia incidentally detected on CT pulmonary angiography of patients with suspected pulmonary embolism.

OBJECTIVE: The aim of this study was to determine the frequency of tracheomalacia incidentally detected on CT pulmonary angiography in patients with suspected pulmonary embolism. MATERIALS AND METHODS: CT records of 163 consecutive patients imaged with CT pulmonary angiography for suspected pulmonary embolism were retrospectively reviewed at our institution. The patients underwent CT pulmonary angiography with three different types of CT scanners. All images were visually assessed by two thoracic radiologists for excessive collapse of the trachea and the main bronchi. The cross-sectional area of the lumen at the site of maximal collapse of the airway was measured, and the percentage of luminal narrowing was calculated by comparing it with the cross-sectional area of the airway lumen at an adjacent area without collapse. We defined tracheomalacia as a 50% or greater decrease in tracheal lumen. RESULTS: Sixteen (10%) of 163 patients showed evidence of tracheomalacia (seven men, nine women; age range, 41-95 years; mean age, 72 years). The most common presenting symptom was shortness of breath, which was observed in 13 (81%) of 16 patients. Known causes of tracheomalacia were found in 15 (94%) of 16 patients, prior intubation was confirmed in 12 patients, and history of asthma or chronic obstructive pulmonary disease was observed in five patients. CONCLUSION: Tracheomalacia is a relatively common incidental finding on CT pulmonary angiography studies. The central airways, as well as pulmonary vasculature, should be reviewed carefully for clinical interpretation in patients with suspected pulmonary embolism. Paired expiratory-inspiratory CT is recommended if patients present with known causes of tracheomalacia such as prior intubation, chronic obstructive pulmonary disease, or asthma.

Adult↗

PubMed2003

CT colonography of colorectal polyps: a metaanalysis.

OBJECTIVE: For proper evaluation of the accuracy of CT colonography, prospective multiinstitutional trials would be ideal. Until these trials are available, data can be collectively analyzed. The purpose of this study is to use metaanalysis to assess the reported accuracy of CT colonography compared with conventional colonoscopy for detecting colorectal polyps. MATERIALS AND METHODS: Articles comparing CT colonography and conventional colonoscopy were identified, and a standardized form was used to extract relevant study data. Fisher's exact test and the Mantel-Haenszel test were used for pooling of data. A 95% confidence interval (CI) was selected to determine sensitivity and specificity, and the Kruskal-Wallis exact test was used to identify trends relating to polyp size. Meta-analysis methods were used to test strength of results. Comparisons were made for the percentage of polyps detected grouped by size (> or = 10 mm, 6-9 mm, < or = 5 mm) and the percentage of patients identified who had polyps of the same size. RESULTS: Fourteen studies fulfilled all the study inclusion criteria and gave a total of 1,324 patients and 1,411 polyps. The pooled per-patient sensitivity for polyps 10 mm or larger was (sensitivity [95% CI]) 0.88 (0.84-0.93), for polyps 6-9 mm it was 0.84 (0.80-0.89), and for polyps 5 mm or smaller it was 0.65 (0.57-0.73). The pooled per-polyp sensitivity for polyps 10 mm or larger was 0.81 (0.76-0.85), for polyps 6-9 mm it was 0.62 (0.58-0.67), and for polyps 5 mm or smaller it was 0.43 (0.39-0.47). Sensitivity for detection of polyps increased as the polyp size increased (p < 0.00005). The pooled overall specificity for detection of polyps larger than 10 mm was 0.95 (0.94-0.97). CONCLUSION: The specificity and sensitivity of CT colonography are high for polyps larger than 10 mm.

Colonic Polyps↗

PubMed2003

Computed tomography colonography (virtual colonoscopy): update on technique, applications, and future developments.

Computed topography colonography (CTC) was first described in 1994 as a rapid, non-invasive imaging method to investigate the colon and rectum. Since the advent of CTC, it has been regarded as a potential alternative technique to conventional colonoscopy for detection of colorectal polyps and cancers. Patients undergo standard bowel preparation 24 to 48 hours before the procedure, using either a standard barium enema preparation or balanced polyethylene glycol (PEG) solution. This rapid examination, without the use of sedation or intervention, is well-tolerated by patients. The potential for limited bowel preparation can reduce discomfort associated with traditional purging techniques significantly, and result in an improved perception of the screening study. CTC is performed using a single or multislice CT scanner, with acquisition of volumetric data from the entire colon. Multislice technology enables fast scanning with high resolution. To minimize the radiation dose, efforts have been made to adapt the tube current to the minimum accepted dose while not diminishing study performance. Acquired CT data are transferred onto a dedicated workstation equipped with navigator software, which permits the radiologist to obtain multiplanar reformations as well as construct an endoluminal model of the air-distended colon. Currently, the most widely accepted application for CTC is following incomplete colonoscopy. Other indications that await further clinical validation include colorectal screening. The collective experience of published studies shows CTC to be an accurate tool for detection of clinically significant colorectal polyps. Specificity and sensitivity of CTC are excellent for polyps larger than 10 mm.

Colectomy↗

PubMed2002

Value of abdominal CT in the emergency department for patients with abdominal pain.

The purpose of our study is to demonstrate the value of CT in the emergency department (ED) for patients with non-traumatic abdominal pain. Between August 1998 and April 1999, 536 consecutive patients with non-traumatic abdominal pain were entered into our study. Using a computer order entry system, physicians were asked to identify: (a) their most likely diagnosis; (b) their level of certainty in their diagnosis; (c) if they thought CT would be normal or abnormal; (d) their treatment plan (prior to knowledge of the CT results); and (e) their role in deciding to order CT. This information was correlated with each patient's post-CT diagnosis and subsequent management. Pre- and post-CT diagnoses were concordant in 200 of 536 (37%) patients. The physicians' certainty in the accuracy of their pre-CT diagnosis was less than high in 88% of patients. Prior to CT, the management plan included hospital admission for 402 patients. Following CT, only 312 patients were actually admitted; thus, the net impact of performing CT was to obviate the need for hospital admission in 90 of 536 (17%) of patients with abdominal pain. Prior to CT, 67 of 536 (13%) of all patients would have undergone immediate surgery; however, following CT only 25 (5%) actually required immediate surgery. Among patients with the four most common pre-CT diagnoses (appendicitis, abscess, diverticulitis, and urinary tract stones) CT had the greatest impact on hospital admission and surgical management for patients with suspected appendicitis. For patients with suspected appendicitis, CT reduced the hospital admission rate in 28% (26 of 91) of patients and changed the surgical management in 40% (39 of 91) of patients. Our study demonstrates the advantage of performing abdominal CT in the ED for patients with non-traumatic abdominal pain.

Abdomen, Acute↗

PubMed2002

How I do it: pre-operative CT scanning for adult living right lobe liver transplantation.

In response to the ongoing shortage of cadaveric livers, living-related liver transplantation is being performed with increasing frequency. The preoperative imaging work-up must document important vascular and parenchymal variants that may alter the anticipated surgical procedure, or even preclude a healthy donor from undergoing surgery. This review summarizes our experience and CT technique for the preoperative imaging of patients being evaluated for right lobe liver transplantation. It is important to recognize that MR also plays a very useful preoperative role.

Humans↗

PubMed2002

CT colonography: colonic distention improved by dual positioning but not intravenous glucagon.

The aim of this study was to determine whether intravenous (IV) glucagon and dual positioning administered prior to CT colonography enhances colonic distention. We assessed the effect of dual positioning and IV glucagon on colonic distention in 96 patients who underwent CT colonography examinations. The CT colonography was performed in both supine and prone positions. Seventy-four patients received glucagon (1 mg i.v.) immediately prior to CT scanning and 22 patients did not. The bowel was divided into ten segments and colonic distention was scored by two radiologists in the supine, prone, and combined supine/prone positions using a five-point scale: 1=collapsed; 2=poorly visualized; > or = 3=adequate distention; 4=entire segment visualized and well distended; 5=excellent distention). A combined segmental and overall supine/prone distention score was calculated based on the sum of the mean score for each position. There was no significant difference in the degree of colonic distention between patients who received glucagon and those who did not [supine/prone distention score (mean +/- SE): 3.63 +/- 0.2 vs 3.85 +/- 0.2; p=n.s.]. The degree of colonic distention was greater in the prone position in both the glucagon (3.87 +/- 0.2 vs 3.38 +/- 0.2; p<0.05) and non-glucagon groups (4.01 +/- 0.2 vs 3.69 +/- 0.2; p=N.S.) particularly in the proximal colon. There was almost perfect agreement between both radiologists in their scoring of colonic distention on a per-patient basis ( k=0.9; p<0.001). Of 1480 bowel segments, 1261 (85.2%) were adequately distended in the glucagon group compared with 370 of 440 bowel segments (84%) in the non-glucagon group ( p=n.s.) Colonic distention at CT colonography is improved by dual positioning but not by the administration of intravenous glucagon. While our results suggest that other smooth muscle relaxants, including butyl scopolamine, may only have a limited role in improving colonic distention in CT colonography, further studies are required.

Adult↗

PubMed2002

Factors associated with conversion to laparotomy in patients undergoing laparoscopic appendectomy.

BACKGROUND: Laparoscopic appendectomy (LA) has been increasingly adopted for its advantages over the open technique, but there is a possibility of conversion to open appendectomy (OA) if complications occur or the extent of inflammation prohibits successful dissection. This study aimed to identify the preoperative predictors for conversion from laparoscopic to open appendectomy. STUDY DESIGN: Medical records of 705 consecutive patients who underwent surgery for suspected appendicitis were reviewed retrospectively. LA was attempted in 595 patients by 25 different surgeons. Factors evaluated were age, gender, body mass index, previous abdominal surgery, previous appendicitis attack, pain, nausea, vomiting, fever, duration of symptoms, local or diffuse tenderness, leukocyte count and surgeon's experience in LA. RESULTS: Conversion to OA occurred in 58 patients (9.7%). The most common reason for conversion was dense adhesions due to inflammation, followed by localized perforation and diffuse peritonitis. Based on 261 patients evaluated by CT scan preoperatively, significant factors in the final multivariate analysis associated with conversion to OA were age > or = 65 [Odds ratio (OR) = 3.78, 95% CI:1.11-12.84], diffuse tenderness on physical examination (OR = 11.32, 95% CI: 1.32-96.62), and a surgeon with less experience in LA (< or = 10 operations, OR = 3.38, 95% CI:1.02-11.17). The presence of significant fat stranding associated with fluid accumulation, inflammatory mass or localized abscess in CT scan also significantly increased the possibility of conversion (OR = 5.60, 95% CI:2.48-12.65). CONCLUSIONS: Identifying the potential factors for conversion preoperatively may assist the surgeons in making decisions concerning the management of patients with appendicitis and in the judicious use of LA.

Adult↗

PubMed2002

Preoperative imaging of donor patients for adult right-lobe liver transplantation.

A major discrepency exists between the number of available cadaveric livers and patients requiring liver transplants, which has resulted in the innovative procurement of liver segments taken from healthy donors being implanted into cirrhotic patients. Most recently, liver surgeons have started resecting the entire right lobe (segments V-VIII) from healthy adult donor livers, and implanting these segments into recipients where the graft is able to sustain and maintain metabolic function and fully regenerate.

Adult↗

PubMedDate not supplied

Value of volumetric data acquisition in expiratory high-resolution computed tomography of the lung.

OBJECTIVE: The purpose of this study is to determine the potential advantages of volumetric expiratory high-resolution computed tomography (HRCT) over noncontiguous expiratory HRCT in visualizing the airway conducting to the areas of air trapping and in providing additional significant information in patients with diffuse lung disease with small airway abnormalities. METHODS: Forty-one consecutive patients with suspected diffuse lung diseases with airway abnormalities who underwent volumetric expiratory HRCT scans from April to June 2003 were studied. Respiratory motion artifacts were evaluated at 3 anatomic levels (aortic arch, carina, and lung bases). The detectability of air trapping and its conducting airway were compared on contiguous versus noncontiguous (6 evenly spaced images per patient) end-expiratory HRCT images. Additional findings on contiguous HRCT images were also assessed regarding their diagnostic significance. RESULTS: The volumetric expiratory HRCT was diagnostically acceptable in 93% (38/41) of patients at arch level, 95% (39/41) at carina level, and 83% (34/41) at the lung bases, even with respiratory motion artifacts. In 35 patients with air trapping, the contiguous HRCT images enabled better identification of the conducting airway to the areas of air trapping and added diagnostically significant findings compared with noncontiguous images (P < 0.0001). CONCLUSION: Volumetric expiratory HRCT allows for better identification of the airway conducting to the areas of air trapping compared with noncontiguous images as well as additional findings of diagnostic significance.

Adult↗

PubMedDate not supplied

Evaluation of pulmonary embolisms using coronal reformations on 64-row multidetector-row computed tomography: Comparison with axial images.

OBJECTIVE: To evaluate coronal reformations of the chest on 64-row multidetector-row computed tomography (MDCT) for detection of pulmonary embolisms compared with axial images. METHODS: Thirty-eight consecutive patients who underwent pulmonary computed tomography angiography (CTA) on 64-row MDCT for a suspected pulmonary embolism were retrospectively studied. Contiguous 2-mm axial and coronal images were reviewed independently. A pulmonary embolism was assessed in the main, lobar, or segmental pulmonary arteries and was scored using a 5-point scale. RESULTS: A pulmonary embolism was demonstrated in 10% (4 of 38) of axial images and 16% (6 of 38) of coronal images. Interpretation was concordant in 95% to 100% of cases for a main or lobar pulmonary embolism and in 80% to 82% of cases for a segmental pulmonary embolism. Agreement of scores was almost perfect for a a main or lobar pulmonary embolism (mean weighted kappa value = 0.969) and moderate to good for a segmental pulmonary embolism (mean weighted kappa value = 0.560). CONCLUSION: Coronal reformations of the chest on 64-row MDCT were as informative as axial images for the detection of main, lobar, and segmental pulmonary embolisms.

Adult↗

PubMedDate not supplied

Excessive collapsibility of bronchi in bronchiectasis: evaluation on volumetric expiratory high-resolution CT.

OBJECTIVE: To evaluate the frequency and severity of bronchomalacia, defined as excessive collapsibility of bronchi, in bronchiectasis; to compare the extent of air trapping in bronchiectasis patients with/without bronchomalacia; and to correlate the severity of bronchomalacia and the extent of air trapping versus pulmonary function. MATERIALS AND METHODS: Forty-six patients with bronchiectasis evaluated by volumetric expiratory high-resolution computed tomography (CT) and pulmonary function tests were studied. The presence and severity of bronchomalacia were evaluated on contiguous axial high-resolution CT images using a 4-point scale. The extent of air trapping was graded on coronal reformations using a 5-point scale. Differences in the extent of air trapping in patients with/without bronchomalacia and the correlation between the severity of bronchomalacia and the extent of air trapping were investigated. The severity of bronchomalacia and the extent of air trapping were correlated with pulmonary function. RESULTS: Of 46 patients with bronchiectasis, 32 patients (70%) had bronchomalacia. Air trapping was present in 43 patients (93%). The extent of air trapping in patients with bronchomalacia was significantly greater compared with the patients without bronchomalacia (P=0.0308). The correlation between the severity of bronchomalacia and extent of air trapping was not statistically significant (rs=0.029, P=0.8457). CONCLUSIONS: The extent of air trapping in bronchiectasis patients with bronchomalacia was significantly greater compared with bronchiectasis patients without bronchomalacia, suggesting that the bronchomalacia is one of the underlying mechanisms of air trapping in bronchiectasis.

Adult↗

PubMedDate not supplied

3-dimensional adaptive raw-data filter: evaluation in low dose chest multidetector-row computed tomography.

OBJECTIVES: To evaluate a 3-dimensional adaptive raw-data filter in reducing streak artifacts in low dose chest computed tomographic (CT) images. METHODS: Fourteen adult patients who underwent low dose chest CT examination (parameters: 25 or 50 mAs, 120 kV) on 64-detector CTscanner were included in this study. We prepared 2 sets of contiguous 5-mm thick images by reconstruction with and without 3-dimensional adaptive raw-data filter (filter-processed and unprocessed images). Streak artifacts and visualization of peripheral vessels in both filter-processed and unprocessed images were evaluated using a 5-point scale. Upper, middle, and lower thorax were evaluated separately. RESULTS: The difference in artifact severity was statistically significant in upper and lower thorax (P = 0.002 and 0.03, respectively), whereas it was not significant in middle thorax (P = 0.13). The difference in the visibility of peripheral pulmonary vessels was not statistically significant in all anatomical regions. CONCLUSIONS: The 3-dimensional adaptive raw-data filter reduced streak artifacts in low dose chest CT in upper and lower thorax.

Adult↗