Biomedical subjects

A S Gomes

Publications and source records attributed to A S Gomes.

At least 19 recordsLinked to original sources

PubMed1992

Biliary strictures complicating liver transplantation. Incidence, pathogenesis, management, and outcome.

Six hundred sixty-six patients received 792 liver transplants between February 1, 1984 and September 30, 1991. Biliary reconstruction was by choledochocholedochostomy (CDCD) with T-tube (n = 509) or Roux-en-Y choledochojejunostomy (CDJ) (n = 283). Twenty-five patients (4%) developed biliary strictures. Anastomotic strictures were more common after CDJ (n = 10, 3.5%) than for CDCD (n = 3, 0.6%). Intrahepatic strictures developed in 12 patients. Six patients had occult hepatic artery thrombosis (HAT). The other six patients received grafts in which cold ischemia time exceeded 12 hours. Anastomotic strictures were successfully managed by percutaneous dilation (PD) in five patients (n = 10), operation in three (n = 6), with retransplantation required in two patients. Intrahepatic strictures were managed by PD in seven, retransplantation in one, and expectantly in four patients. Of 25 patients, 19 (76%) are alive with good graft function. In three of six deaths, the biliary stricture was a significant factor to the development of sepsis and allograft failure. The authors conclude that (1) anastomotic strictures are rare after LT; (2) the development of biliary strictures may signify occult HAT; (3) PD is effective for most strictures; and (4) extended cold graft ischemia (less than 12 hours) may be injurious to the biliary epithelium, resulting in intrahepatic stricture formation.

Adult↗

PubMed1992

Magnetic resonance angiography.

Literature of the past year contains several worthwhile papers describing the application of MR angiography techniques to imaging of the vascular system. MR angiography has been performed with two-dimensional time-of-flight, two-dimensional phase-contrast, and three-dimensional time-of-flight techniques. With current methodology it appears that a variety of MR angiography techniques are necessary to image the various vascular beds of the vascular system, with the appropriate MR angiography technique determined by the velocity and flow characteristics of the vascular bed of interest. Knowledge of the change in velocity patterns in disease states appears necessary for appropriate pulse sequence selection. Signal loss due to higher motion disorders remains problematic; however, the steady progress in MR angiography techniques suggests that these limitations will be overcome. Efforts are also underway to measure the velocity of blood flow. The potential combination of imaging and functional capabilities makes it likely that MR angiography will be an important technique for assessing the vascular system.

Blood Flow Velocity↗

PubMed1991

Diagnosis of portal vein thrombosis: value of color Doppler imaging.

This study was undertaken to determine the accuracy of color Doppler imaging in the diagnosis of portal vein thrombosis. Two hundred fifteen patients were studied with color Doppler imaging to determine patency of the main portal vein. Sonographic findings were confirmed in 75 patients, aged 19 to 66 years. Correlation with angiography was obtained in 13 patients, and surgical correlation was obtained in the remaining 62. Nine patients had portal vein thrombosis on the basis of these gold standards. Sonograms were classified as showing either patency or thrombosis, depending on the ability to show color flow within the main portal vein. Agreement between sonography and angiography or surgery was found in 69 patients (61 patent, eight thrombosed). One patient with a patent portal vein at sonography was found to have a thrombosed vessel at surgery, whereas five patients without portal venous flow at sonography had patent vessels at angiography (one patient) or surgery (four patients). Overall sensitivity and specificity for detection of portal vein thrombosis were 89% and 92%, with an accuracy of 92%, a false-negative rate of 0.11, a negative predictive value of 0.98, and a positive predictive value of 0.62. We postulate that the majority of errors in our study occurred in vessels that, although patent, had only sluggish flow, which could not be resolved because of technical limitations. We conclude that color Doppler imaging is a valuable screening procedure for the assessment of portal vein patency. If the sonogram shows a patent portal vein, no further studies are required. However, a lack of demonstrable flow does not always indicate thrombosis, and other imaging studies should be performed for confirmation.

Adult↗

PubMed1990

Massive splenomegaly. Superior results with a combined endovascular and operative approach.

Splenectomy for massive splenomegaly (drained splenic weight, greater than 1000 g) has an uncommonly high morbidity and mortality because of technical challenges and problems of hemostasis. In a group of 10 patients with massive splenomegaly due to myeloproliferative disorders (average splenic weight, 4193 g), we developed a management algorithm based on preoperative angiographic embolization of the splenic artery. Average operating time was 1.7 hours (range, 1 to 2.5 hours). Average blood loss was 528 mL; six of the 10 patients had blood loss less than 250 mL. There were four minor complications and one major complication (gastric ulcer requiring reoperation). There were no deaths in the perioperative period, and no patients required reoperation for hemorrhage.

Adult↗

PubMed1990

Pulmonary arteries: MR imaging in patients with congenital obstruction of the right ventricular outflow tract.

Thirty-five patients with congenital obstruction of the right ventricular outflow tract underwent magnetic resonance (MR) imaging for evaluation of the pulmonary arteries. All patients underwent cardiac catheterization, and 33 underwent two-dimensional Doppler echocardiography. Results of the three imaging studies were compared. With regard to the presence of a pulmonary confluence, results of MR imaging and angiography were in agreement in 31 of the 35 patients (89%), results of echocardiography and MR imaging were in agreement in 27 of 33 patients (82%), and results of echocardiography and angiography were in agreement in 27 of 33 patients (82%). There was good correlation of measurements of main pulmonary artery size among all three methods and of right and left pulmonary artery size obtained at MR imaging and angiography. Echocardiographic measurements of right and left pulmonary artery size correlated poorly with those obtained at MR imaging and angiography. Results indicated that MR imaging is useful in evaluating the pulmonary arteries in patients with congenital heart disease.

Angiography↗

PubMed1990

MR imaging of the bird's nest filter.

The appearance of the Bird's Nest inferior vena cava filter on magnetic resonance (MR) images of 11 patients is described. No complication or symptomatic filter displacement was encountered as a result of MR imaging performed at 1.5 T. The filters created significant local artifact and distortion on MR images. However, diagnostic MR images of the pelvis, spine, and brain may still be obtained.

Adult↗

PubMed1990

Color Doppler imaging of portosystemic shunts.

This study was designed to investigate the utility of color Doppler sonography in the evaluation of portosystemic shunts. Thirty-one patients with a total of 32 shunts were imaged. The types of shunts examined included portacaval, five; mesocaval, eight; distal splenorenal (Warren), 14; and mesoatrial, five. Sonography was performed without knowledge of the status of the shunt, although the type of shunt was known before beginning the study. The sonographic studies were evaluated to determine their sensitivity and specificity on the basis of a prospective comparison with angiography or MR imaging (22 cases). The possible advantages of color Doppler over duplex Doppler sonography in evaluating portosystemic shunts were also investigated, as was the ability of color Doppler sonography to image specifically the shunt anastomoses. Color Doppler sonography successfully inferred shunt patency (17 cases) or thrombosis (five cases) in all 22 shunts for which correlative imaging was available (sensitivity = 100%, specificity = 100%). In comparing duplex with color Doppler sonography in all 32 shunts, the two techniques were almost equally effective in establishing patency in portacaval, mesocaval, and mesoatrial shunts. Duplex Doppler sonography, however, provided useful diagnostic information in only four of 14 splenorenal shunts. Color Doppler correctly inferred patency or thrombosis in all 14. Among all 32 shunts, the anastomosis was shown clearly by color Doppler in 23, probably in four, and not all in five. Our results suggest that color Doppler sonography is an excellent method for the evaluation of all varieties of surgically created portosystemic shunts. In particular, color Doppler sonography appears to be superior to duplex Doppler sonography in imaging splenorenal communications.

Adolescent↗

PubMed1990

Comparison of Biello, McNeil, and PIOPED criteria for the diagnosis of pulmonary emboli on lung scans.

The McNeil, Biello, and newly proposed PIOPED (from the National Institutes of Health-sponsored study, Prospective Investigation of Pulmonary Embolism Detection) interpretive methods for detection of pulmonary embolism on lung scans were compared in 96 patients who also underwent pulmonary angiography. Segmental findings on 99mTc perfusion and aerosol ventilation scans, chest radiographs, and pulmonary angiograms obtained within 48 hr of each other were encoded along with other information into a data base to facilitate analysis. The McNeil, Biello, and PIOPED criteria were applied to the encoded data. Although the PIOPED set of criteria yielded the most favorable likelihood ratio for predicting an angiogram showing pulmonary emboli and a favorable likelihood ratio for predicting an angiogram not showing pulmonary emboli, it had the highest number of indeterminate studies. The McNeil criteria demonstrated the least favorable likelihood for predicting pulmonary emboli on an angiogram. The Biello and McNeil criteria showed the most favorable likelihood ratio for predicting an angiogram not showing pulmonary emboli. Analysis of receiver-operating-characteristic (ROC) curves yielded the greatest area under the ROC curve for the Biello criteria, but there were no statistically significant differences among the three sets of criteria. This study suggests that the Biello scheme represents the best compromise of the sets of criteria studied.

Angiography↗

PubMed1989

Acute renal dysfunction in high-risk patients after angiography: comparison of ionic and nonionic contrast media.

A group of 145 high-risk patients who underwent angiography after administration of the nonionic contrast agent iohexol were monitored for the development of acute renal dysfunction. The results in this group were compared with those in 202 high-risk historical control subjects who had undergone angiography after administration of ionic contrast material. All patients in both groups received similar pre- and postangiographic treatment. A greater number of patients in the ionic group had preexisting renal disease, were of advanced age, and had received large volumes of contrast material. Acute renal dysfunction occurred in 20 of the 202 (10%) patients in the ionic group, compared with eight of the 145 (5.5%) patients in the nonionic group; this difference is not statistically significant. Five patients in the ionic group, but none of the patients in the nonionic group, ultimately required dialysis; this difference is not statistically significant. The findings suggest that a randomized trial in high-risk patients should be undertaken before a clinical advantage of the nonionic contrast agent iohexol with regard to renal function can be assumed.

Acute Kidney Injury↗

PubMed1989

Budd-Chiari syndrome: treatment with percutaneous transhepatic recanalization and dilation.

The authors describe a child with Budd-Chiari syndrome secondary to membranous obstruction of the hepatic veins and a web in the inferior vena cava. Transhepatic catheter venography demonstrated the occlusion, which was recanalized and dilated percutaneously via a transhepatic approach. Hepatomegaly and ascites decreased promptly and the prothrombin time became normal.

Angioplasty, Balloon↗

PubMed1989

MR imaging of congenital anomalies of the thoracic aorta and pulmonary arteries.

MR imaging has rapidly assumed an important role in the diagnosis of congenital anomalies of the aortic arch and pulmonary arteries. Because it is noninvasive and does not involve the use of ionizing radiation, it is particularly useful in children and in clinical settings that require serial follow-up studies, such as in patients with aortic aneurysm and in postoperative patients. In the evaluation of the pulmonary arteries of patients with pulmonary artery or right ventricular outflow tract obstructive lesions, MR imaging has become a frequently used noninvasive imaging technique for determining pulmonary artery configuration and for monitoring pulmonary artery growth. The large field of view and high-quality images afforded by MR imaging make it a useful diagnostic tool that can supplement, confirm, and in some instances supplant the use of other conventional imaging techniques.

Aorta, Thoracic↗

PubMed1988

Systemic-to-pulmonary collateral vessels and shunts: treatment with embolization.

Abnormal collateral vessels develop frequently in patients with right ventricular outflow or pulmonary artery obstruction. Surgery is usually used to obliterate these vessels but may be difficult, involve prolonged operative time, or require a different thoracotomy than that used for correction or palliation of the cardiac anomaly. Sixteen trans-catheter embolization procedures were performed in 15 patients with systemic-to-pulmonary collateral vessels and shunts. In eight embolization procedures performed because of congestive heart failure or low oxygenation, clinical improvement was obtained in seven. In all six patients who underwent embolization preoperatively, the outcome of surgical correction or palliation was satisfactory. Hemorrhage ceased in the two patients with hemoptysis. There were two complications, one transient loss of femoral pulse and one segmental pulmonary infarction. Embolization is a useful adjunct to surgery and medical management of patients with systemic-to-pulmonary collateral vessels and shunts.

Adolescent↗

PubMed1987

Magnetic resonance imaging of the thoracic aorta.

Forty-one patients with a variety of suspected aortic lesions underwent magnetic resonance imaging (MRI) of the thoracic aorta. Patients were separated into 2 groups: Group A included 19 patients who underwent MRI after arteriography for comparison purposes and were evaluated retrospectively. Surgical confirmation was obtained in 9 of these patients. Group B included 22 patients who were studied prospectively because of abnormal chest x-ray, ultrasound or computerized tomographic findings and did not undergo arteriography before MRI. Two patients from this group had surgery. In group A, MRI correlated with the surgical or angiographic findings in 18 of 19 patients (95%). In group B, MRI was considered of diagnostic quality in all patients and no other invasive or noninvasive imaging modalities were needed for diagnosis and treatment. Thus, MRI will replace arteriography in a large proportion of patients with suspected thoracic aortic lesions.

Aorta, Thoracic↗

PubMed1987

Observer variability with conventional and digital subtraction carotid angiograms.

A study was carried out to evaluate the intra- and inter-observer variability in the determination of the severity of carotid artery stenosis on conventional and digital subtraction angiograms. The primary goal was to compare the two types of contrast studies as "gold standards" for the evaluation of non-invasive tests. Linear regression analysis of the continuous variable of percentage stenosis yielded correlation coefficients from 0.90 to 0.99. Findings were also evaluated in terms of the discrete variables formed by dividing the lesions into five categories of stenosis: kappa analysis ranged from 0.53 to 0.91. Although the digital subtraction arteriograms had greater variability than conventional ones, careful measurement of the digital images can provide a reliable estimate of the degree of stenosis.

Adult↗

PubMed1987

Coronary artery bypass grafts: visualization with MR imaging.

To evaluate the use of magnetic resonance (MR) imaging in the detection of coronary artery bypass grafts (CABGs), 20 patients with grafts underwent electrocardiographic-gated MR study. The number and location of CABGs in each patient were not known at the time of study. The number of grafts seen with MR imaging was compared with the actual number of grafts determined from the operative or angiographic report. On the prospective review of the images, 54 of 64 grafts (84%) were detected, with three false-positive results. When the images were reevaluated with knowledge of the type and number of grafts in each patient, 56 of 64 grafts (88%) were detected. Forty-one of the 46 (89%) left grafts, 15 of the 18 (83%) right grafts, and five of the 11 (45%) internal mammary grafts were detected. Although resolution was not adequate to determine the presence of graft stenosis, this early experience indicates that patent CABGs can be seen with MR imaging.

Coronary Artery Bypass↗

PubMed1987

Pulmonary arteriography: comparison of cough stimulation effects of diatrizoate and ioxaglate.

Twenty-five patients were observed in a prospective crossover study to determine whether the new low-osmolality contrast agents would be less prone than conventional agents to produce coughing during pulmonary arteriography. Selective left and right pulmonary arteriography (two views of each side) was performed with alternating administrations of diatrizoate sodium meglumine and ioxaglate sodium meglumine. Twenty-one patients had all four injections while four patients received injections on only one side. Sixteen of 25 patients coughed on at least one injection of diatrizoate, with three of these experiencing explosive coughing. One of 25 patients coughed with ioxaglate, and that was only minimally. This difference is statistically significant (P less than .001, on the basis of McNemar chi 2 test for paired data). When no coughing occurred, the quality of the diatrizoate and ioxaglate radiographs was indistinguishable. We conclude that ioxaglate is useful in pulmonary arteriography because of its lack of cough stimulation.

Adult↗

PubMed1987

Nonsurgical repositioning of central venous catheters.

Long-term central venous catheters are placed for total parenteral nutrition and/or chemotherapy. These catheters are placed surgically and fixed to the subcutaneous tissues. Complications include infection, venous thrombosis, and mechanical problems. The authors developed a method to percutaneously reposition displaced central venous catheters. The procedure is performed with fluoroscopy and modified angiographic techniques. Fifteen patients underwent a total of 17 procedures. The initial success rate was 76%; the final success rate was 88%. Many central venous catheters can be salvaged with this low-morbidity procedure, which negates the need for surgical intervention.

Angiography↗

PubMed1987

Congenital abnormalities of the aortic arch: MR imaging.

Thirty-four patients, 1 month to 63 years old, with known or suspected congenital abnormalities of the aortic arch underwent magnetic resonance (MR) imaging. Sixteen patients were studied retrospectively, 18 prospectively. In all retrospective studies, the aortic arch abnormality was seen with MR imaging. In the prospective studies, MR imaging enabled diagnosis in 15 of 18 (83%) patients. Twenty-nine of 34 patients underwent two-dimensional echocardiography; nine were studied retrospectively, 20 prospectively. In the prospective studies, echocardiography enabled diagnosis in 13 of 20 (65%) patients. Although two-dimensional echocardiography has a high sensitivity in the detection of aortic arch abnormalities in the neonate, arch abnormalities in the neonate, its sensitivity is lower in older children, adults, and postoperative patients. The authors' experience shows that MR imaging is an important, noninvasive modality in the evaluation of older children, adults, and postoperative patients with congenital aortic arch abnormalities.

Adolescent↗