Biomedical subjects

L J Sinak

Publications and source records attributed to L J Sinak.

15 recordsLinked to original sources

PubMed1991

Pyopneumopericardium attributed to an esophagopericardial fistula: report of a survivor and review of the literature.

Herein we describe a case of pyopneumopericardium that resulted from formation of an acquired esophagopericardial fistula in a patient with silent, benign esophageal ulcer disease. Atypical features on initial examination suggested congestive heart failure or a pneumonic process (or both). The delayed development of pneumopericardium disclosed on a chest roentgenogram led to the clinical recognition of the esophagopericardial fistula. Subsequent emergent pericardiocentesis relieved cardiac tamponade and enabled us to diagnose pyopneumopericardium. A radiographic contrast study with use of meglumine diatrizoate revealed the site of the fistula in the midesophagus. The esophagopericardial fistula was surgically closed, and our patient had a good final result. Formation of an esophagopericardial fistula is a relatively uncommon finding; of the 60 previously reported cases, only 10 patients have survived. As illustrated in the current case, early diagnosis and treatment, including pericardial drainage and intense antibiotic therapy followed by a well-planned operative closure of the fistula, are paramount for the successful management of esophagopericardial fistulas.

Aged↗

PubMed1991

Value and limitations of transesophageal echocardiography in assessment of mitral valve prostheses.

BACKGROUND: Transthoracic Doppler echocardiography examination has become an integral part of the investigations performed in patients with mitral valve prostheses. The limitations of the transthoracic approach are well documented. Transesophageal echocardiography provides a unique window for achieving a clear view of the mitral prosthesis. METHODS AND RESULTS: This study shows the usefulness of transesophageal echocardiography in clinical practice for assessment of patients with a mitral valve prosthesis. This technique demonstrated an abnormality in 48% of patients who had normal results on transthoracic examination. The overall sensitivity of transesophageal echocardiography was 96%. CONCLUSIONS: Transesophageal echocardiography constitutes an essential part of a comprehensive two-dimensional/Doppler echocardiographic examination in patients with suspected malfunction of mitral prostheses.

Adolescent↗

PubMed1990

Transesophageal echocardiography in critically ill patients.

The feasibility, safety and clinical impact of transesophageal echocardiography were evaluated in 51 critically ill intensive care unit patients (28 men and 23 women; mean age 63 years) in whom transthoracic echocardiography was inadequate. At the time of transesophageal echocardiography, 30 patients (59%) were being mechanically ventilated. Transesophageal echocardiography was performed without significant complications in 49 patients (96%), and 2 patients with heart failure had worsening of hemodynamic and respiratory difficulties after insertion of the transesophageal probe. The most frequent indication, in 25 patients (49%), was unexplained hemodynamic instability. Other indications included evaluation of mitral regurgitation severity, prosthetic valvular dysfunction, endocarditis, aortic dissection and potential donor heart. In 30 patients (59%), transesophageal echocardiography identified cardiovascular problems that could not be clearly diagnosed by transthoracic echocardiography. In the remaining patients, transesophageal echocardiography permitted confident exclusion of suspected abnormalities because of its superior imaging qualities. Cardiac surgery was prompted by transesophageal echocardiographic findings in 12 patients (24%) and these findings were confirmed at operation in all. Therefore, transesophageal echocardiography can be safely performed and has a definite role in the diagnosis and expeditious management of critically ill cardiovascular patients.

Echocardiography↗

PubMed1990

Determination of diastolic function by radionuclide ventriculography.

Diastolic filling can be measured by radionuclide ventriculography with use of several techniques including those based on gated and list-mode acquisitions, the first-pass method, and the nuclear probe. Radionuclide ventriculography specifically assesses volumes, rates of volume change, and intervals during ventricular filling. Normal values for diastolic filling measurement vary depending on the individual radionuclide methods used and the age of the patient. Comparative studies of the radionuclide method with contrast angiographic and Doppler echocardiographic techniques for measuring diastole are discussed, and the advantages and disadvantages of the radionuclide techniques are explored. The role of radionuclide assessment of diastolic function in specific clinical examples of hypertrophic cardiomyopathy, hypertension, anthracycline-induced cardiomyopathy, and coronary artery disease is reviewed. Radionuclide ventriculography is an accurate and easily applicable procedure for studying left ventricular volume changes in diastole.

Aged↗

PubMed1989

Influence of age and sex on left ventricular filling at rest in subjects without clinical cardiac disease.

Left ventricular (LV) filling at rest was studied by radionuclide ventriculography using alternate R-wave gating in 42 patients (29 men, 13 women) who had a low likelihood of cardiac disease. LV filling measurements differed little between men and women. Age was correlated positively with atrial filling duration (r = 0.55), atrial filling duration fraction (r = 0.52) and atrial filling fraction (r = 0.56) and negatively with rapid filling fraction (r = -0.58). Age was not correlated with peak filling rate, time to peak filling rate and first-half filling fraction. The heart rate at rest was significantly negatively correlated with rapid (r = -0.62), slow (r = -0.81) and atrial (r = -0.72) filling durations, but not with isovolumic duration. The heart rate at rest was weakly positively correlated with peak filling rate in end-diastolic volume per second (r = 0.36) and negatively correlated with first-half filling fraction (r = -0.35). Systolic pressure at rest influenced atrial filling duration. LV ejection fraction and end-diastolic volume index were not correlated significantly with LV filling in relatively normal subjects.

Adult↗

PubMed1989

Characteristic Doppler echocardiographic pattern of mitral inflow velocity in severe aortic regurgitation.

In symptomatic severe aortic regurgitation, left ventricular diastolic pressure increases rapidly, often exceeding left atrial pressure in late diastole. This characteristic hemodynamic change should be reflected in the Doppler mitral inflow velocity, which is the direct result of the diastolic pressure difference between the left ventricle and left atrium. Mitral inflow velocity was obtained by pulsed wave Doppler echocardiography in 11 patients (6 men, 5 women: mean age 53 years) with severe symptomatic aortic regurgitation and compared with normal values from 11 sex- and age-matched control subjects. The following Doppler variables were determined: velocity of early filling wave (E), velocity of late filling wave due to atrial contraction (A), E to A ratio (E/A), deceleration time and pressure half-time. In severe aortic regurgitation, E and E/A (1.13 m/s and 3.3, respectively) were significantly higher (p less than 0.001) than normal (0.60 m/s and 1.5, respectively). Deceleration time and pressure half-time (117 and 34 ms, respectively) were significantly shorter (p less than 0.001) than normal (203 and 59 ms, respectively). Late filling wave velocity (A) was not statistically different in the two groups, although it tended to be lower in the patient group (0.39 versus 0.50 m/s). Diastolic mitral regurgitation was present in eight patients (73%). M-mode echocardiography of the mitral valve, performed in 10 patients, showed that only 3 (30%) had premature mitral valve closure. In symptomatic severe aortic regurgitation, the Doppler mitral inflow velocity pattern is characteristic, with increased early filling wave velocity (E) and early to late filling wave ratio (E/A) and decreased deceleration time of the E wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Cardiac masses: assessment by MR imaging.

The purpose of this study was to assess the role of MR imaging for evaluating suspected cardiac tumors or paracardiac masses involving the heart. Sixty-one patients with clinical or radiologic evidence of cardiac masses were imaged with ECG-gated MR at 1.5 T (22 patients) or 0.15 T (39 patients). Fifty-one patients had echocardiography previously. Among the tissue diagnoses were myxoma (six); fibroma, rhabdomyoma, plasma cell granuloma, lipomatous hypertrophy of the atrial septum, mesothelioma, and thymoma (two each); and leiomyosarcoma, lymphoma, metastatic carcinoid, melanoma, malignant fibrous histiocytoma, hemangiopericytoma, and lung spindle cell sarcoma (one each). MR imaging demonstrated masses in 50 patients (82%); they were centered in the heart in 32, pericardial in nine, and juxtacardiac in nine. MR imaging provided diagnostic information that affected clinical management or surgical planning in 53 patients (87%), including 11 (18%) in whom cardiac mass was excluded by MR. The ability to provide a global view of cardiac anatomy and other unique capabilities of MR imaging give the procedure an important role in the diagnosis and preoperative assessment of cardiac masses.

Adolescent↗

PubMed1985

Three-dimensional cardiac anatomy and function in heart disease in adults: initial results with the dynamic spatial reconstructor.

The dynamic spatial reconstructor, or DSR, is a unique high-speed volume-imaging x-ray scanner based on computed tomographic principles. In this report, we present data obtained from the first feasibility DSR studies of adult patients with heart disease. Information from three patients--one with hypertrophic obstructive cardiomyopathy, one with calcific aortic valvular disease, and one with a left ventricular aneurysm--is described in detail. The mean DSR scanning time for each patient was 20 seconds, and the mean total irradiation to the sternum was 15.3 R. Transverse cross sections were reconstructed and then retrospectively reformatted to provide operator-selected oblique sections in space (for example, long-axis and short-axis sections of the left ventricle), to follow these sections through time (such as from end-diastole through end-systole), and to create three-dimensional displays (for instance, of the left ventricular chamber). Unique quantitative measurements of structure and function were made by using these images. For generation of most imaging data, only one injection of contrast material into the right side of the heart is necessary. Clinically useful three-dimensional dynamic imaging data can be acquired from adult patients with heart disease by using the DSR. Compared with conventional angiocardiography, DSR studies can provide information with less x-ray exposure and fewer angiographic injections.

Adult↗

PubMed1985

Anatomy and function of the heart and intrathoracic vessels in congenital heart disease: evaluation with the Dynamic Spatial Reconstructor.

The Dynamic Spatial Reconstructor is a unique high speed volume imaging X-ray scanner based on computed tomographic principles. It has several potential advantages over conventional angiographic methods, including reduced invasion, reduced rate of false negative results and increased accuracy of measurements of structure and function. To evaluate the utility of the Dynamic Spatial Reconstructor in the investigation of congenital heart disease, scanning was performed in several pediatric patients with pulmonary valve atresia. Early results show that three-dimensional images of the cardiac chambers and intrathoracic vessels can be acquired and displayed with the system. All the information necessary for quantitative analysis of the pulmonary arteries can be obtained with a single scan involving injection of 0.6 to 2.0 cc/kg of contrast agent and radiation exposure of 0.54 to 0.95 rad/s over 5 to 8 seconds.

Angiography↗

PubMed1984

The Dynamic Spatial Reconstructor: investigating congenital heart disease in four dimensions.

The Dynamic Spatial Reconstructor (DSR) is a high-temporal resolution, three-dimensional (3-D) X-ray scanning device based on computed tomography (CT) principles. It was designed for investigation of some problems inherent in current diagnostic imaging techniques, and to allow quantitative studies of cardiovascular structure and function. One of the research protocols in which DSR is currently used involves studying selected pediatric patients with complex congenital heart disease. Initial results show that 3-D dynamic images can be obtained from these patients with minimal invasiveness and that these images may provide useful diagnostic information.

Adolescent↗

PubMed1984

Mass of left ventricular myocardium estimated with dynamic spatial reconstructor.

Using the Dynamic Spatial Reconstructor (DSR), a unique multiple X-ray source, high-repetition-rate CAT scanner, we estimated left ventricular (LV) myocardial volume and chamber volume of eight dogs ranging from 2.5 to 32.5 kg. Dogs were given subcutaneous morphine (3 mg/kg) and anesthetized with intravenous pentobarbital sodium (22 mg/kg). A bolus of 1 ml/kg body wt contrast medium was injected into the superior vena cava and 60/s scans repeated over 7 s were performed. Each 0.0167-s scan generated image data for 120 1.8-mm-thick transverse slices, in the dextro and levo phases of the angiograms. Retrospective reformatting of the scan data was used to generate images of thin slices perpendicular to the aortoapical axis of the LV. The LV muscle and chamber volumes were estimated from their outlines in each imaged slice using a manually operated trackball interfaced to a computer. Values of the LV muscle ranged from 18.0 to 146.8 cm3 by DSR and showed a good correlation with the postmortem values (r = 0.99, y = 0.94x + 4.1). Ratios of volume of the myocardium to chamber volume ranged from 1.19 to 3.10.

Animals↗

PubMed1984

Subtraction gated computed tomography with the dynamic spatial reconstructor: simultaneous evaluation of left and right heart from single right-sided bolus contrast medium injection.

Three-dimensional (3-D) dynamic computed tomography of the heart with the dynamic spatial reconstructor (DSR) is being used for studies of cardiovascular function. Formerly, continuous infusion of bilateral bolus injections of contrast medium were required to visualize both sides of the heart simultaneously. The DSR was used to circumvent many of the drawbacks of these methods. In anesthetized dogs a bolus of 1 ml/kg body weight contrast medium was injected into the superior vena cava and 60/s scans were performed during the dextro- and levophases of the resulting angiogram. The recorded scan data were used to generate successive volume (3-D) images with a scan aperture time of 0.06 s each. Each scanned cardiac cycle was thus represented by sequential volume images with either the right or left chambers opacified. Matching equal time intervals from the R wave of the electrocardiogram, the volume images of the left heart phase were digitally subtracted (voxel for voxel) from the images of the right heart phase, with all resulting negative voxel values set to zero. Only the contrast enhanced right ventricle (RV) chamber remained in the subtraction images, whose brightness was then scaled to match the brightness of the opacified left ventricle (LV). The modified RV phase images were then added to the LV phase images. The resulting volume images contain equally enhanced LV and RV chambers and can be used for retrospective analysis, including display of static and dynamic oblique planar images. Verification of the accuracy of this technique was made by estimation of LV muscle mass in five dogs. Dynamic spatial reconstructor estimates from subtracted gated images were compared with postmortem measurements. The correlation was 0.999 with a mean discrepancy of 2.3 +/- 0.4% SEM.

Animals↗

PubMed1983

Noninvasive quantitative imaging of shape and volume of lungs.

The Dynamic Spatial Reconstructor (DSR) can be used to determine detailed structure-to-function relationships or organ systems in vivo. A basic index of lung structure (shape and dimensions) is total lung volume. We checked the accuracy with which in vivo lung volumes can be measured by comparing lung volume (air plus tissue) determined by DSR scanning with that determined by excision and water displacement. Six dogs (2.5-26 kg) under morphine-pentobarbital anesthesia were scanned supine or prone at functional residual capacity and/or total lung capacity. With the trachea clamped at the lung volume scanned, a lethal dose of pentobarbital was administered, the lung excised, and its volume determined by water displacement. In vivo scan data were used to reconstruct adjacent 0.9-mm-thick transverse sections over the entire axial extent of the thorax. A three-dimensional surface-detection algorithm was used to generate shaded surface displays of the in situ lungs. The number of voxels (volume picture elements) of known dimensions contained within the three-dimensional image of the lung was summed to estimate total lung volume. Lung volumes calculated from the in vivo images ranged from -3.4 to +2.3% of the lung volume determined in vitro. The mean difference was 1.38 +/- 0.07% (SE). Regression analysis yielded an r value (correlation) of 1.00, a slope of 0.99, and an intercept of -4.35 ml. Multiple lung inflation steps scanned and analyzed in one dog showed similar accuracy. This technique is applicable to subjects with thorax dimensions up to 42 cm in cephalocaudal height and 39 cm in ventrodorsal and transverse diameters.

Animals↗

PubMed1982

Dynamic volume imaging of moving organs.

The Dynamic Spatial Reconstructor system has been developed to dynamically (up to 60/sec) image the entire 3-D volume (up to 240 adjacent 1-mm-thick transverse sections) encompassing moving organs of the body, particularly the heart and lungs, or the circulation in any organ. This capability permits accurate regional and global measurements to be made of the important relationships between structure and function within and among these organs, which in turn facilitates achievement of new insights into the basic physiological processes of these organs, and promises increased sensitivity and specificity in the diagnosis of pathology that affects normal organ function. This article explains the biomedical and technological rationale for development of the DSR, describes the design concepts and practical operation of the system, and presents preliminary results obtained with the system, including initial data from one of the first patient studies.

Animals↗

PubMedDate not supplied

Aortic dissection: review of value and limitations of two-dimensional echocardiography in a six-year experience.

The utility of transthoracic two-dimensional echocardiography in patients with aortic dissection was assessed by retrospective analysis in 67 patients: 31 patients with DeBakey type I, 21 patients with type II, 10 patients with type III, and five patients with false-positive diagnoses. Aortic dissection was correctly identified by two-dimensional echocardiography in 49 patients; 13 had false-negative diagnoses. Therefore the sensitivity was 79%, and the positive predictive accuracy was 91%. Transthoracic two-dimensional echocardiography is a reasonable screening technique for diagnosis of aortic dissection.

Acute Disease↗