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Biomedical subjects

D L Gilday

Publications and source records attributed to D L Gilday.

At least 37 records · Page 2Linked to original sources
PubMed1991

Ventricular function during supine bicycle exercise in univentricular connection with absent right atrioventricular connection.

Fourteen patients with univentricular connection, absent right connection (tricuspid valve atresia) and normally related great arteries underwent rest and supine bicycle exercise equilibrium radionuclide blood pool studies. Ejection fraction, heart rate, systemic blood pressure and oxygen saturation (ear oximetry) were measured. There were 6 male and 8 female patients. Mean age +/- standard error of the mean was 14.5 +/- 1.1 years (range 6.3 to 21.1). Eight patients (group 1) had systemic to pulmonary shunts placed as palliation 8.2 +/- 2.2 years before study and 6 patients (group II) had caval to pulmonary shunts placed 11.8 +/- 1.6 years previously. Ejection fraction at rest was 54 +/- 2% and an abnormal response to exercise (failure of ejection fraction to increase greater than or equal to 5% from rest to peak exercise) was found in 9 of 14 patients. When analyzed separately, ejection fraction at rest in group I was higher than in group II; however, this difference disappeared at peak exercise. There was a significant negative correlation between ejection fraction at peak exercise and the interval since palliative surgery, although it was not apparent at rest. These data suggest that ventricular function is compromised during exercise and that abnormal performance is influenced by long-standing volume overload. Importantly, this abnormal state is concealed at rest and the choice of palliative shunting procedure appears to have little effect on normalizing pump performance.

Adolescent↗
PubMed1990

Pediatric cerebrovascular disease. Alterations of regional cerebral blood flow detected by TC 99m-HMPAO SPECT.

Regional cerebral blood flow (rCBF) alterations, as determined by single photon emission computed tomography (SPECT) using technetium Tc 99m hexamethyl propylenamine oxime (Tc 99m-HM-PAO), were studied in 15 infants and children presenting with cerebrovascular disorders between the ages of 2 weeks and 16 years. The rCBF patterns were correlated with clinical presentation, electroencephalographic patterns, radiologic studies, including computed tomography and magnetic resonance imaging of the head, and cerebral angiography. All patients presented with motor weakness that was accompanied in some with dysphasia, defects in visual fields, obtundation, seizures, and high temperature. Perturbations of rCBF with Tc 99m-HMPAO SPECT brain scanning were detected in all patients investigated, with no adverse effects related to the radiotracer. All patients had a focal area of decreased rCBF, with adjacent hyperemia in 3 patients. In 7 patients, there was an rCBF decrease in a vascular distribution, mainly that of the middle cerebral artery, that correlated with the clinical findings and a focal electroencephalogram, as well as computed tomography and magnetic resonance imaging of the head. Impairment of rCBF was more extensive in 3 children, while early abnormal SPECT findings preceded abnormal computed tomographic findings in another 2 children. In 2 patients, Tc 99m-HMPAO SPECT was the only positive radiologic test to correlate with focal clinical and electroencephalographic abnormalities, in view of repeated normal computed tomographic scans. We conclude that Tc 99m-HMPAO SPECT brain scanning is a sensitive, complementary diagnostic measure in the early detection, localization, and estimation of rCBF alterations in pediatric cerebrovascular disease.

Cerebrovascular Circulation↗
PubMed1989

A comparative study of intravenous urograms and radionuclide renal scans in diagnosis of renal trauma.

We analyzed 31 patients who underwent intravenous urograms (IVU) and radionuclide renal scans (RNRS) in the investigation of blunt abdominal trauma, and compared the IVU to the RNRS in the definition of blunt renal injuries, and their correlation with patients' symptoms and signs. Thirteen patients had abnormal IVU and 12 had abnormal RNRS (42% of the 31 patients). In 8 patients findings on IVU correlated with those on RNRS (62%), and in 5 patients findings were different (38%). Only 2 patients (6.5%) had significant differences which may have influenced further treatment. Only 1 patient required operative management. Follow-up IVUs were performed on 6 of the 13 patients who had abnormal radiologic studies. The radionuclide renal scan was shown to be as accurate as the intravenous urogram in defining renal trauma. Patients who undergo liver-spleen scans for investigation of blunt abdominal trauma, and who may have renal trauma, may well undergo RNRS at the same time and obviate the need for an IVU, without any diagnostic compromise.

Adolescent↗
PubMed1989

99mtechnetium-dimercapto-succinic acid renal scanning and excretory urography in diagnosis of renal scars in children.

We compared the ability of excretory urography (without tomography) and 99mtechnetium-dimercapto-succinic acid renal scanning to detect renal scars in 32 children with primary vesicoureteral reflux. These children did not have hydronephrosis, renal failure or urinary tract obstruction. In all cases both studies were conducted within a 10-month period. The findings from both modalities were in agreement for 51 of the 64 renal units evaluated (80 per cent). Evaluation of the excretory urogram indicated 6 cases of diffuse and 2 of focal scarring that were not detected by evaluation of the renal scan. The sensitivity of excretory urography to detect renal scars was 84 per cent and the specificity was 83 per cent. The 99mtechnetium-dimercapto-succinic acid renal scan showed 5 cases of focal renal scarring not detected by excretory urography. The sensitivity of the renal scan to detect renal scars was 77 per cent and the specificity was 75 per cent. We conclude that neither study alone could effectively replace the other for the detection of renal scars, and recommend that both be included in the initial evaluation and followup of patients with renal scars.

Adolescent↗
PubMed1987

Radionuclide imaging in histiocytosis X.

Radionuclide imaging (99mTc bone scans, 99mTc S colloid scans, 99mTc brain scans and 67gallium scans) and bone radiographs were done in 54 children with histiocytosis X. The results are discussed, compared with the literature and indications for the different nuclear medicine studies are given.

Adolescent↗
PubMed1987

Exercise radionuclide right ventriculography in children.

Supine exercise equilibrium radionuclide right ventriculography was performed in 13 children (8-18 years) with hypercholesterolemia. Phase analysis was used to construct right ventricular regions of interest, and a peri-right ventricular region was used for background correction. Right ventricular ejection fraction at rest and exercise was 50.5 +/- 9.2% and 61.5 +/- 8.1%, respectively, with a mean increase of 11.0 +/- 7.5 percentage units (range 1-27 percentage units). During exercise, end-diastolic volume remained unchanged while end-systolic volume decreased by 19.4%, producing a 21.7% increase in stroke volume. Stroke volume ratios (left ventricular stroke volume counts/right ventricular stroke volume counts) approach unity (1.00 +/- 0.27). However, interobserver and intraobserver correlations are just fair, implying only a modest degree of accuracy and reliability of the procedure. This imprecision needs to be considered when evaluating the results of nuclear equilibrium right ventriculography.

Adolescent↗
PubMed1987

Noninvasive measurement of blood flow and extraction fraction.

We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose, is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. Renal blood flow (RBF) to the normal left kidney in 18 subjects without evidence of renal disease was estimated by the technique to be 10.4% CO (S.D. 1.2), for the right kidney 9.0% CO(S.D. 1.1), and for both, 19.4% CO (S.D. 1.5). In a separate series of eight patients, RBF values were highly reproducible when obtained on successive days (standard deviation of change: 0.67% CO for the left kidney, 0.63% CO for the right and 0.78% CO for both). The extraction fraction of DTPA (filtration fraction) was 8.5% (1.7) in the left kidney and 9.7% (2.1) in the right kidney. This parameter was less reproducible than RBF, with standard deviations of the changes equal to 1.17% for the left kidney and 1.31% for the right. Stable, well-functioning, renal allografts in children had a mean blood flow of 20.6% CO (S.D. 3.7). Transplant blood flow in eight patients with rejection was less than 5.2% CO. In patients without splenomegaly, splenic blood flow, splenic extraction fraction of sulphur colloid and splenic red cell mean transit time were 4.3% CO (S.D. 0.9), 41% (S.D. 13.8), and 36.9 s (S.D. 4.6), respectively.

Blood Circulation↗
PubMed1987

Two-dimensional and pulsed Doppler echocardiography in the postoperative evaluation of total anomalous pulmonary venous connection.

The role of combined two-dimensional and pulsed Doppler echocardiography in the postoperative assessment of patients with total anomalous pulmonary venous connection was evaluated. Twenty-two cases with a median age of 9.5 weeks at the initial examination were evaluated. Serial ultrasound examinations were performed throughout the study period. The ultrasound results were compared with chest radiographs obtained during the same period. Of the 22 patients, 16 had normal pulmonary venous flow profiles characterized by low-velocity laminar flow. Of this group 12 had persistent radiographic postoperative pulmonary edema that cleared in all by 4 months. Six patients with pulmonary venous obstruction were identified, the diagnosis being confirmed at catheterization or autopsy. The venous flow pattern in this group was uniformly high velocity and turbulent. It was possible to localize the site of obstruction in each case. Although pulmonary edema was present in each patient, the chest radiograph did not provide reliable information as to the exact site of obstruction. Combined two-dimensional and Doppler echocardiography is a useful adjunct in the postoperative evaluation of patients with total anomalous pulmonary venous connection.

Child, Preschool↗
PubMed1985

The I-131 rose bengal excretion test is not dead.

One hundred and thirty I-131 Rose Bengal Excretion Studies (RBI) were performed on 84 patients over nine years. In 90% (56/60) of cases with biliary atresia, the 72-hour RBI was less than or equal to 7%. In only 12.5% (3/24) of cases with neonatal hepatitis was the 72-hour RBI less than or equal to 7%. The accuracy of the test was 91% with a specificity of 88%. Thirty patients later were studied following a Kasai procedure. The RBI test reliably predicted the patency of the anastomosis. The authors conclude that the 72-hour RBI is a reliable test in the diagnosis of biliary atresia and in the documentation of biliary patency following surgery, provided adequate care is taken in stool collection and measurement.

Bile Ducts↗
PubMed1984

Radionuclide assessment of cardiac performance in cystic fibrosis. Reproducibility and effect of theophylline on cardiac function.

A study was designed to evaluate the reproducibility of right and left ventricular ejection fraction measurements (RVEF, LVEF) by equilibrium radionuclide angiography in cystic fibrosis (CF) and to determine the effect of the acute administration of aminophylline on RVEF and LVEF in this disease. Both RVEF and LVEF were measured at rest and during incremental supine bicycle exercise by equilibrium radionuclide angiography in 18 patients with CF. In 9 of these patients, radionuclide studies were repeated after an infusion of aminophylline (9 mg/kg), whereas the remaining patients had radionuclide studies repeated after a placebo infusion. No significant increase in mean RVEF or LVEF values either at rest or at peak exercise was seen after aminophylline infusion. In the patients who underwent sequential radionuclide studies without intervening active drug intervention, the mean (+/- standard deviation) variability in RVEF and LVEF measurements between the 2 studies was 2.6 +/- 2% and 3.6 +/- 2.9%, respectively. We conclude that (1) equilibrium radionuclide angiography is a reasonably reproducible technique for serial assessment of biventricular function at rest and during exercise in CF, and that (2) the acute administration of aminophylline does not augment cardiac function either at rest or during exercise in this disease.

Adolescent↗
PubMed1983

In vivo diagnostic nuclear medicine. Pediatric experience.

The use of radiopharmaceuticals for diagnostic tests in children is increasing and interest in these is evidenced by the addition of scientific sessions devoted to pediatric medicine at annual meetings of The Society of Nuclear Medicine and by the increase in the literature on pediatric dosimetry. Data presented in this paper describe the actual pediatric nuclear medicine experience from 26 nationally representative U.S. hospitals and provide an overview of the pediatric procedures being performed the types of radiopharmaceuticals being used, and the activity levels being administered.

Adolescent↗
PubMed1982

Special considerations in the pediatric use of radionuclides for kidney studies.

Radionuclide renal studies are particularly well suited to pediatrics as renal problems in children usually are part of a dynamic process which requires serial assessment. The absence of side-effects and the low radiation dose has added to their popularity in pediatrics. A number of different renal parameters can be evaluated using the appropriate radiopharmaceutical and method of analysis. The renal study is of value to assess patients with hydronephrosis both pre-operatively and for serial follow-up post-operatively, as well as to distinguish obstructive from non-obstructive uropathy. Perfusion to the kidney may be assessed and ischemic areas detected in children with hypertension or trauma. The renal scan commonly is used in patients with congenital anomalies such as ectopic and duplex kidneys, nonvisualized kidney on IVP and in children with oliguria or anuria secondary to diseases such as acute tubular necrosis, hemolytic uremic syndrome, and renal vein thrombosis. It frequently is done as an emergency procedure in neonates. In conjunction with the IVP and ultrasound, the renal study is useful in some cases of abdominal mass to distinguish between hydronephrosis, cystic kidneys and tumors.

Adolescent↗