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Biomedical subjects

P J Fitzgerald

Publications and source records attributed to P J Fitzgerald.

At least 109 records · Page 6Linked to original sources
PubMed1986

Two-dimensional ultrasonic variation in myocardium throughout the cardiac cycle.

This study was performed to investigate the two-dimensional unprocessed radiofrequency (rf) ultrasonic backscatter from myocardium throughout the cardiac cycle. Eleven mongrel dogs underwent left lateral thoracotomy and had two-dimensional echocardiographic studies performed using a 5 MHz transducer. Regions of interest, selected to encompass a portion of the myocardium, were transported at 33 ms intervals to a host computer and disc. Results show a reproducible cyclic variation in backscatter power throughout the cardiac cycle for the anterior wall. The backscatter power was highest during diastolic relaxation and lowest during systolic contraction. The average change was 4.5 dB.

Animals↗
PubMed1984

Computerized quantitative analysis of left ventricular wall motion by two-dimensional echocardiography.

Quantitative detection of left ventricular segmental wall motion abnormalities by any modality depends on the reference system used because of the dynamic geometry of contraction and cardiac motion within the thorax. To assess the feasibility and accuracy of quantitative analysis of left ventricular wall motion by two-dimensional echocardiography, we studied 61 subjects with the use of 44 different reference methods in each of three echocardiographic views: the parasternal short-axis view at the levels of the mitral valve and of the papillary muscles and an apical four-chamber view. The three major groups of reference systems used were those with a fixed external reference, a floating reference correcting for translation, and systems correcting for both translation and rotation. In the first part of this study the end-diastolic and end-systolic outlines of 20 normal subjects were stored in a computer and composite data of these 20 subjects were plotted to obtain a 95% confidence interval for measured normal fractional change for each reference method. In the second part of the project an additional prospective group of 10 normal subjects and a group of 31 "abnormal" patients had their left ventricular wall motion analyzed by similar methods and the results were compared with all the confidence intervals. One reference method was selected for each two-dimensional echocardiographic view based on the highest sensitivity and specificity found by statistical analysis; a floating-reference system including translation was found to be optimal for the apical four-chamber and parasternal short-axis views at the level of the mitral valve and a fixed external reference system was optimal for the short-axis view at the papillary level. The percent fractional shortening of radial dimensions (radial methods) and the percent fractional change in area measurements (area methods) during the cardiac cycle were also calculated at 5, 10, 20, 30 and 45 degree intervals around the outline perimeter for each subject according to each of the 44 different methods. Area methods yielded the same specificity and sensitivity as radial dimension analysis methods at 5 to 45 degree intervals. Ten normal subjects underwent repeat echocardiography within 2 days of their first study to examine day-to-day variation. Average change in mean contraction from day to day was 7% to 9% for radial methods and 9% to 13% for area methods. In conclusion, we present a computerized system for unbiased selection of optimal methods of analysis of left ventricular wall motion by two-dimensional echocardiography.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1983

In vivo ultrasonic tissue characterization of human intracardiac masses.

Interactions between an ultrasonic signal and cardiac tissue have been used to characterize the histologic state of myocardium in vitro. To assess the utility of in vivo ultrasonic tissue characterization, stochastic analysis was applied to the digitized echocardiographic signals from 15 patients with 2-dimensional echocardiograms suggesting intracardiac masses. Ten subjects with echocardiograms suggesting mural thrombi underwent subsequent surgery or necropsy, which confirmed thrombi in 6 and revealed no thrombi (designated artifact) in 4. Five other patients had intracardiac tumors. The amplitudes within the digitized ultrasonic signals were displayed as histograms, which were described by a parameter k that represented the degree to which each histogram departed from a totally random probability density function. In 5 of 6 thrombi, k = 0, but in all 4 artifacts, k greater than 0. The sixth thrombus had k = 0.5 due to the specular effect of the interface between the thrombus' 2 lobes. All 5 tumors had k greater than 0. Ultrasonic tissue characterization using a stochastic analysis of backscatter can be performed in vivo and helps differentiate thrombus from artifact and tumor in the heart.

Blood Coagulation↗
PubMed1983

Rapid, semiautomated technique for estimating left ventricular volume.

A new system for rapidly quantitating left ventricular volume using two-dimensional echocardiography is tested. This system relies on a microprocessor built into a sector scanner that immediately calculates the length, area, and volume of the chamber being imaged using the mathematical model of an ellipsoid of revolution. The calculations are made after the observer superimposes a smooth calibrated ellipse outline on the endocardium imaged with the sector scanner. We report our experience with this system in 50 patients with a variety of cardiac disorders and compare the left ventricular volumes measured with those obtained using cineangiography, M-mode, and more detailed light pen tracing techniques. Correlations between volumes measured with the elliptical calipers and angiography were good (r = 0.820, SEE +/- 38.8 ml) (n = 100), but not as good as that between light pen tracing of the echo images and angiography (r = 0.847, SEE +/- 27.8 ml) (n = 22). M-mode correlated less well with angiography (r = 0.789; SEE +/- 42.1 ml) (n = 90). We conclude that the calibrated ellipse system is rapid and simple to use, while its accuracy matches previous studies using two-dimensional echocardiography to quantitate left ventricular volume.

Cardiovascular Diseases↗
PubMed1983

Variability of digitized echocardiography: size, source, and means of reduction.

Digitization of M-mode echocardiograms provides useful information on left ventricular function, but its variability has been assessed rarely. Inter- and intraobserver (technical) variability of readers digitizing the same cardiac cycles, and variability between beats, days, and subjects (biologic) was determined. Technical variability was small for both standard dimensions (correlation coefficient r values 0.82 to 1.00) and rates of change (r values 0.70 to 0.98). Biologic variability was large with expected normal differences between 2 measurements (95% confidence limits) of 11 to 55% and 37 to 106% for standard dimensions and rates of change, respectively. By averaging measurements of 5 beats from each of 2 days, the expected normal differences are reduced to 6 to 32% and 23 to 63% for standard dimensions and rates of change. This study emphasizes the large biologic variability in rates of change of digitized left ventricular measurements. Normal variation between studies can be reduced and real physiologic or pathologic changes perceived best if many beats from more than 1 day are measured.

Adult↗
PubMed1983

Standardized intracardiac measurements of two-dimensional echocardiography.

Thirty-five healthy adults were studied by two-dimensional echocardiography to attempt to standardize a simple method for measurement of intracardiac dimensions. Both ventricles and the atria and aorta were measured in five different views: parasternal long-axis, parasternal short-axis at the level of the aortic valve, the chordae tendineae and the papillary muscles and an apical four chamber view. The minor axis of each chamber was measured in all five views; the major axis in the apical four chamber view also was measured. All measurements are presented as a range of values (mean and 2 standard deviations about the mean); the mean value is given as well as the absolute range of values measured. Normalization according to body surface area is also presented. Data from these multiple views allow assessment of asymmetry of cardiac chambers in normal subjects. The mean minor axis dimension at end-diastole of the right ventricle in the parasternal long-axis view (1.9 to 3.8 cm) was 13.6% smaller than in the four chamber view (2.2 to 4.4 cm), whereas the minor axis dimension of the left ventricle in the parasternal long-axis view (3.5 to 6.0 cm) was only 1.1% larger than in the four chamber view (3.3 to 6.0 cm). Therefore, the right ventricular minor axis dimensions are not interchangeable. Reproducibility in 10 subjects for all dimensions showed a maximal variability of 4.8%. These values permit a standardized and expeditious method for measuring intracardiac dimensions by two-dimensional echocardiography.

Adolescent↗
PubMed1983

Reproducibility of left ventricular volumes by two-dimensional echocardiography.

Reproducibility may be as important as absolute accuracy in assessing the utility of an echocardiographic method of left ventricular volume estimation for epidemiologic or physiologic studies. The magnitude of differences between measurements in the same subjects from day to day must be defined before any quantitative technique can be used reliably to document "real" changes in heart volume over time. Two-dimensional echocardiograms were performed serveral days apart in 30 subjects, including 20 normal subjects and 10 patients with stable coronary heart disease. Analyses of light-pen tracings provided measurements of end-diastolic volume, endsystolic volume and derived ejection fraction on both days, and differences in individual subjects between days were quantitated. Beat to beat, interobserver and intraobserver variability also were assessed. Although group values changed little from day to day, individual volume changes were substantial in some cases. Confidence limits for individual measurements were derived from analyses of intrasubject variability and were as follows: end-diastolic volume +/- 15%, end-systolic volume +/- 25%, ejection fraction +/- 10%. Confidence limits in a larger group of subjects were narrower; in a group of 30 subjects, changes of greater than 2% in end-diastolic volume, 5% in end-systolic volume and 2% in ejection fraction most likely represent real change. Intraobserver variability was minimal, but interobserver and beat to beat variability were of sufficient magnitude to suggest that serial measurements on a given subject be made ideally by a single person and that several cycles be averaged for a given measurement.

Adult↗
PubMed1982

Mitral and aortic valve orifice area in normal subjects and in patients with congestive cardiomyopathy: determination by two dimensional echocardiography.

Previous determinations of normal valve orifice areas have been mainly from postmortem studies. In this study mitral and aortic valve orifice area were determined from two dimensional echocardiograms in 20 normal subjects and 20 patients with congestive cardiomyopathy. Mitral valve orifice area was larger than quoted in standard textbooks. Both mitral and aortic valve orifice area were reduced in patients with cardiomyopathy. Valve opening was assessed relative to left ventricular and aortic root size. The ratio of mitral valve orifice area to left ventricular cross-sectional area was markedly reduced in patients with cardiomyopathy compared with normal subjects. The ratio of aortic valve orifice area to aortic root size also was reduced in patients with cardiomyopathy. Anterior mitral leaflet E point-septal separation was similar to that in previous reports contrasting normal subjects with patients with myopathy. Among patients with cardiomyopathy, mitral E point-septal separation was primarily a function of left ventricular size and was not significantly correlated with fractional shortening or ejection fraction within this group having uniformly poor systolic function.

Adolescent↗
PubMed1981

Acinar cell cystadenocarcinoma of human pancreas.

A 7000 g cystic tumor replacing the body and tail of the pancreas was resected in a 64-year-old man. Numerous peritoneal implants confirmed its malignant nature. Light microscopy of both the primary tumor and the implants revealed distinctive cytoplasmic eosinophilia and apical granules. Ultrastructural examination demonstrated numerous zymogen granules and abundant, rough endoplasmic reticulum, which confirmed that the tumor was composed of acinar cells. No mucinous or serous differentiation was detected. We have not found report of a similar tumor.

Carcinoma↗
PubMed1979

Classification of pancreatic cancer (nonendocrine).

From the records of 757 patients listed as having had pancreatic cancer at Memorial Hospital during the years 1949 through 1972, adequate clinical data and pathologic tissue were available for study in 508 patients. Review of these cases led to a histologic classification into 11 subcategories and one unclassified group. The most common type was the duct cell adenocarcinoma (75%), and the remaining subgroups each made up less than 5% of the total. All except one of the subtypes were well-known carcinoma patterns that occur in other organs. A small-gland carcinoma, the microadenocarcinoma, has not usually been associated with the pancreas. Some types were associated with short survival periods of a few months after diagnosis--for example, duct cell, giant cell, acinar cell, and adenosquamous carcinomas and microadenocarcinoma. Patients with mucinous carcinoma had a mean survival period of a few months longer, and the few patients with mucinous cystadenocarcinoma had a much longer median survival. Two rare types--papillary cystic tumor and pancreaticoblastoma--are mentioned and illustrated. It is hoped that one or more of these types can be associated with an etiologic agent, some clinical feature, or responsiveness to a therapeutic regimen.

Adenocarcinoma↗
PubMed1978

The value of diagnostic aids in detecting pancreas cancer.

By contract with the National Cancer Institute, the accuracy of diagnostic techniques was assessed in 184 patients suspected of having pancreas cancer. Of 138 patients who were operated upon, 89 were found to have pancreas duct cancer, 30 had cancer of a different site of origin in the head of the pancreas region and in 19 there was no evidence of cancer at operation. All of the 46 patients who were not operated upon, 13 proven to have cancer and 33 patients discharged as free of cancer, were followed in our clinic. The majority of our patients presented with signs and symptoms of biliary obstruction. Computerized transaxial tomography (CTT) gave a "correct" diagnosis in 31 of 33 patients (94%) with proven cancer, there were 2 patients with a false negative report and a false positive diagnosis occurred in 8 of 20 patients (40%) without cancer. Celiac angiography (CA) gave a correct diagnosis in 78 of 94 patients (83%) with cancer, a false negative in 17%, and a false positive in 32%. 76Selenomethionine pancreas scan correctly diagnosed 27 of 36 patients (75%) with cancer, gave a false negative in 25% and a false positive in 31%. Ultrasonography gave a correct diagnosis in 18 of 27 patients with cancer (67%), a false negative in 33% and a false positive in 28%. Endoscopic retrograde cholangiopancreatography diagnosed correctly 8 of 11 cases (73%) of cancer, there were false negative diagnoses in 3 cases (27%) and false positives in 3 of 14 patients (21%). Duodenal aspiration techniques gave a very low percentage of correct diagnoses. Chronic pancreatitis most commonly gave rise to a false positive diagnosis. Serum alkaline phosphatase was elevated in 82% of patients, gave 18% false negatives and 33% false positives. Carcinoembryonic antigen (CEA) was elevated (greater than 2.5 ng/ml) in most of the pancreas cancer patients but also in patients with other cancers and with non-cancerous diseases. In our hands, CTT, CA, alkaline phosphatase, 75Se-methionine and ultrasonography, in descending order, have given the highest percentage of correct diagnoses but false positive and false negative diagnoses prevented any single test from being conclusive.

Biopsy, Needle↗