Search PubMed⌕ Search

Biomedical subjects

M L Goris

Publications and source records attributed to M L Goris.

At least 55 records · Page 3Linked to original sources
PubMed1985

Skeletal scintigraphy for the diagnosis of malignant metastatic disease to the bones.

The use of skeletal scintigraphy for the detection of metastatic disease of the bone is reviewed. The review is based on published data for sensitivity, specificity, yield and prognostic value. The analysis, and interpretation of published data is complicated by the variation in criteria. It appears nonetheless, that for a number of tumors the relative (in comparison with other methods) and absolute (based on outcome prediction) sensitivity is high. For certain tumors in early stages, and in asymptomatic patients the yield (of positive studies) is low, even when the prognostic value is high. Those factors should be weighed with the availability of therapeutic options to determine the clinical efficacy of skeletal scintigraphy.

Bone Neoplasms↗
PubMed1985

Diltiazem and propranolol, alone and in combination, on exercise performance and left ventricular function in patients with stable effort angina: a double-blind, randomized, and placebo-controlled study.

Diltiazem and propranolol alone and in combination as antianginal agents were compared with placebo in 12 patients with stable exertional angina at Stanford University Medical Center. The patients performed symptom-limited, multi-stage upright bicycle ergometric exercise while undergoing radionuclide angiographic studies every two weeks while being treated with 90 mg of diltiazem four times daily, 60 mg of propranolol four times daily, a combination of 90 mg of diltiazem and 60 mg of propranolol four times daily, and placebo. Diltiazem, propranolol and a combination all significantly increased exercise duration compared to placebo (526 +/- 149, 525 +/- 115, and 549 +/- 129 vs 430 +/- 132 sec.). Although rate pressure product and heart rate decreased with diltiazem therapy at submaximal workloads, these values were unchanged at peak exercise in contrast to propranolol or the combination of propranolol or diltiazem. Diltiazem decreased the sub-maximal and maximal degree of exercise-induced ST segment depression by over 50% compared to placebo (P less than 0.01 vs placebo). Diltiazem resulted in a higher exercise left ventricular ejection fraction compared to placebo, propranolol or the combination of diltiazem or propranolol (all less than P less than 0.05). Sinus bradycardia or orthostatic hypertension occurred in four patients on the high-dose combination therapy and required dose reduction. We concluded that high-dose diltiazem, appeared to be even more effective than moderate-dose propranolol or the combination of diltiazem and propranolol in improving exercise tolerance, electrocardiographic evidence of myocardial ischaemia and left ventricular function in patients with stable effort angina due to occlusive coronary artery disease.

Aged↗
PubMed1984

Changes in rest and exercise myocardial perfusion and left ventricular function 3 to 26 weeks after clinically uncomplicated acute myocardial infarction: effects of exercise training.

The effects of exercise training on exercise myocardial perfusion and left ventricular (LV) function in the first 6 months after clinically uncomplicated acute myocardial infarction (AMI) were assessed in 53 consecutive men aged 55 +/- 9 years. Symptom-limited treadmill exercise with thallium myocardial perfusion scintigraphy and symptom-limited upright bicycle ergometry with equilibrium gated radionuclide ventriculography were performed 3, 11 and 26 weeks after AMI by 23 men randomized to training and 30 randomized to no training. Peak cycle capacity increased in both groups between 3 and 26 weeks (p less than 0.01), but reached higher levels in trained than in untrained patients (803 +/- 149 vs 648 +/- 182 kg-m/min, p less than 0.01). Reversible thallium perfusion defects were significantly more frequent at 3 than at 26 weeks: 59% and 36% of patients, respectively (p less than 0.05), without significant inter-group differences. Values of LV ejection fraction at rest, submaximal and peak exercise did not change significantly in either group. The increase in functional capacity, i.e., peak treadmill or bicycle workload, that occurred 3 to 26 weeks after infarction was significantly correlated with the increase in peak exercise heart rate (p less than 0.001), but not with changes in myocardial perfusion or LV function determined by radionuclide techniques. Changes in myocardial perfusion or LV function do not appear to account for the improvement in peak functional capacity that occurs within the first 6 months after clinically uncomplicated AMI.

Coronary Circulation↗
PubMed1984

Comparative value of maximal treadmill testing, exercise thallium myocardial perfusion scintigraphy and exercise radionuclide ventriculography for distinguishing high- and low-risk patients soon after acute myocardial infarction.

The prognostic value of symptom-limited treadmill exercise electrocardiography, exercise thallium myocardial perfusion scintigraphy and rest and exercise radionuclide ventriculography was compared in 117 men, aged 54 +/- 9 years, tested 3 weeks after a clinically uncomplicated acute myocardial infarction (MI). During a mean follow-up period of 11.6 months, 8 men experienced "hard" medical events (cardiac death, nonfatal ventricular fibrillation or recurrent MI) and 14 were hospitalized for unstable angina pectoris, congestive heart failure or coronary bypass surgery (total of 22 combined events). By multivariate analysis (Cox proportional hazards model), peak treadmill work load and the change in left ventricular ejection fraction (EF) during exercise were significant (p less than 0.01) predictors of hard medical events; these 2 risk factors and recurrent ischemic chest pain in the coronary care unit were also significantly predictive (p less than 0.001) for combined events. A peak treadmill work load of 4 METs or less or a decrease in EF of 5% or more below the value at rest during submaximal effort distinguished 22 high-risk patients (20% of the study population) from 89 low-risk patients. The rate of hard medical events within 12 months was 23% (5 of 22 patients), vs 2% (2 of 89 patients) in the high- and low-risk patient subsets, respectively (p less than 0.001). Thus, in patients who underwent evaluation 3 weeks after a clinically uncomplicated MI, exercise radionuclide ventriculography contributed independent prognostic information to that provided by symptom-limited treadmill testing and was superior to exercise thallium scintigraphy for this purpose.

Aged↗
PubMed1983

Mechanisms for decreased exercise capacity after bed rest in normal middle-aged men.

The mechanisms responsible for the decrease in exercise capacity after bed rest were assessed in 12 apparently healthy men aged 50 +/- 4 years who underwent equilibrium gated blood pool scintigraphy during supine and upright multistage bicycle ergometry before and after 10 days of bed rest. After bed rest, echocardiographically measured supine resting left ventricular end-diastolic volume decreased by 16% (p less than 0.05). Peak oxygen uptake during supine effort after bed rest was diminished by 6% (p = not significant [NS]), whereas peak oxygen uptake during upright effort declined by 15% (p less than 0.05). After bed rest, increases in heart rate were also greater during exercise in the upright than in the supine position (p less than 0.05). Values of left ventricular ejection fraction increased normally during both supine and upright effort after bed rest and were higher than corresponding values before bed rest (p less than 0.05). After bed rest, increased left ventricular ejection fraction and heart rate largely compensated for the reduced cardiac volume during supine effort, but these mechanisms were insufficient to maintain oxygen transport capacity at levels during upright effort before bed rest. These results indicate that orthostatically induced cardiac underfilling, not physical deconditioning or left ventricular dysfunction, is the major cause of reduced effort tolerance after 10 days of bed rest in normal middle-aged men.

Bed Rest↗
PubMed1983

Sensitivity and specificity of radionuclide ejection fractions in doxorubicin cardiotoxicity.

We examined radionuclide-determined left ventricular ejection fractions (LVEF) at rest and during graded exercise in 37 patients receiving doxorubicin (Adriamycin) therapy in whom the risk of developing congestive heart failure (CHF) was precisely defined by endomyocardial biopsy and right heart catheterization. Echocardiographic (Echo %FS) and phonocardiographic (PEP/LVET) measurements of LV function were also determined. An abnormal LVEF at rest (less than or equal to 45%) had a sensitivity of 53% and a specificity of 75% for detecting patients at moderate or high risk of developing CHF. The addition of exercise LVEF increased the sensitivity of detection of moderate or high-risk patients to 89% but lowered the specificity to 41%. Exercise LVEF improved the sensitivity of detection of high-risk patients from 58% to 100%. Echo %FS and PEP/LVET yielded lower sensitivities than rest or exercise LVEF. As a single test, exercise LVEF possesses the sensitivity for use as a screening method for anthracycline cardiotoxicity, but the lack of specificity prevents the use of single values as a definitive test. Single rest LVEF determinations, although more specific than exercise LVEF, do not possess the sensitivity for use as screening or definitive tests.

Adult↗
PubMed1983

Sequential equilibrium gated radionuclide angiocardiography for the detection of doxorubicin cardiotoxicity.

Right and left ventricular ejection fractions (RVEF and LVEF) were studied at rest, during exercise, and in the immediate post-exercise period (recovery) in 23 patients treated with doxorubicin. Ejection fractions were determined using equilibrium gated radionuclide angiography and non-interactive computer processing. Two effects of doxorubicin emerged: (1) The LVEF at rest and the maximal LVEF reached during the stress test decreased as a function of the cumulative dose expressed in mg/m2. (2) When two measurements were performed before and after an interval dose of less than 100 mg/m2, the resting and maximal LVEF showed an increase, but at higher interval doses, those values showed a decrease. In general, the effect of an incremental dose was not a function of the cumulative dose. No significant changes were detected in RVEF, and LVEF at standardized exercise levels did not correlate with cumulative doses or change as a function of interval dosage.

Adolescent↗
PubMed1982

Cardiovascular physiology in a case of heterotopic cardiac transplantation.

Successful heterotopic cardiac transplantation in a 24 year old man with end stage cardiomyopathy provided an opportunity to study cardiovascular physiology. The donor and native hearts, functioning independently in parallel, were studied by serial physical examination, electrocardiography, echocardiography, nuclear angiography and cardiac catheterization. Results indicated that the donor left heart assumed the predominant role in supplying systemic output, possibly contributing to decreasing function of the patient's own (native) heart. Analysis of serial nuclear angiograms revealed an initial postoperative ejection fraction of 52 and 21 percent in the donor and the native left ventricle, respectively; repeat studies 3 months postoperatively showed values of 50 and 9 percent, respectively, indicating significant deterioration in native left ventricular cardiac function. Observation of valve motion of the native heart showed major irregularities of the aortic valve in contrast to seemingly normal, regular mitral valve motion. These data rise interesting questions regarding interpretation of valve motion as an indicator of ventricular function.

Adult↗
PubMed1981

The indications for and limitations of bone scintigraphy in osteogenic sarcoma: a review of 55 patients.

The value of radioisotope bone scanning at the time of presentation and serially during follow-up has been evaluated in 55 patients with biopsy-proven osteogenic sarcoma. Many of the patients studied were treated with adjuvant chemotherapy. Bone metastases were detected at presentation in only one patient and in a second patient, proximal extension of the primary tumor not evident on radiographs was demonstrated by the radioisotope technique. During fellow-up, 20 patients experienced bone metastases and each had an abnormal bone scan. Eleven of these patients were asymptomatic for bone metastases at the time the scan became abnormal. Seven patients experienced bone metastases as their first site of tumor recurrence. The detection rate for soft tissue metastases was low, but the scan indicated stump recurrence in three patients. Although the yield is small, bone scanning is justified at presentation be cause the results may profoundly after the management. During follow-up, routine bone cans are indicated in all patients, whether they have symptoms or not.

Adolescent↗
PubMed1981

A fully automated determination of the left ventricular region of interest in nuclear angiocardiography.

The precise delineation of the left ventricular projection area is an essential part in the quantitative analysis of nuclear angiocardiograms. We have devised an algorithm that permits automation of this step, based on a one-dimensional Laplace operator whose kernel is 2, 2, -2, -4, -2, 2, 2. The operator characteristically enhances "valleys" more than edges and, therefore, favors septal and the valve plane detection. The operator is applied vertically, horizontally, and along both diagonals. Each pass is immediately followed by a local maximum search during which the image resulting from the Laplacian operator is reduced to a binary one, with zeros everywhere except where a local maximum was found along the path of the operator. This resultant image yields a closed "edge" around the left ventricle, even though many structures outside the left ventricle are also delineated. However, the centroid of the ventricle is defined from functional criteria and the region of interest is defined from centroid to first edge. The method has been applied to first-pass and gated studies in anterior and 45 degree left anterior oblique views. In 100 successive cases the ejection fraction obtained automatically was compared to the manual result. The regression equation yielded the relation: automatic method (%) = 1.7 + 1.0 manual method (%) +/-2% (r = 0.995), which is not significantly different from the identity relation. The failure rate was low (13%) but varied from 28% in the first-pass studies in the anterior view, to less than 8% in gated studies in the left ventricular oblique projection.

Cardiac Volume↗
PubMed1981

Thallium-201 myocardial imaging in patients with previous cardiac transplantation.

Thallium-201 myocardial imaging was performed in seven long-term cardiac transplant survivors who were undergoing selective coronary arteriography as a screening test for immune mediated coronary atherosclerosis. The radionuclide studies showed fixed defects in all patients, though none was known to have had a myocardial infarction. Such abnormalities may be due to previous rejection episodes. Reversible ('ischaemic') defects were present in two patients with triple vessel disease, and were also seen in three subjects with minor (less than 50% luminal diameter) stenosis. Ischaemic thallium-201 defects in cardiac transplant recipients indicate the presence of coronary artery disease, though the stenosis may be of a degree which would normally be considered haemodynamically non-significant. The possible role of small vessel disease in producing these defects is discussed.

Adult↗
PubMed1981

Krypton-81m ventilation scintigraphy for the diagnosis of pulmonary emboli.

The value of ventilation studies in conjunction with pulmonary perfusion scintigraphies for the diagnosis of pulmonary emboli is reviewed. A retrospective study of 273 consecutive cases and comparison with 42 angiographic results provides the data base. The data are compared with previously reported results and confirm the diagnostic gain obtained by ventilation studies. Possible advantages of the use of krypton-81m for the ventilation study are suggested. Finally, with the observed prevalence of six possible scintigraphic outcomes and assuming that two outcomes are diagnostic, it can be shown that the addition of a ventilation study in the diagnostic work-up decreases the average cost of the diagnosis.

Angiography↗
PubMed1981

Failure to diagnose cardiac treatment rejection with Tc99m-PYP images.

The possibility of diagnosing transplant rejection using Tc-99m-PYP imaging was examined in 12 cardiac transplant recipients. Two patients were studied on two occasions. The presence or absence of active rejection was established by endomyocardial biopsy. The intensity and pattern of myocardial uptake of the tracer did not differ significantly in the two patients studied at the time of rejection compared to the remainder. It is concluded that a single Tc-99m-PYP study cannot be used to diagnose cardiac transplant rejection.

Adult↗