Search PubMed⌕ Search

Biomedical subjects

H L Abrams

Publications and source records attributed to H L Abrams.

At least 73 records · Page 4Linked to original sources
PubMed1978

Renal vein valves: incidence and significance.

Although autopsy studies have demonstrated valves in 28-70% of right and 4-36% of left renal veins, they have rarely been detected or described during life. In an analysis of 98 renal venograms, valves were found in 16% of patients on the right side and in 15% on the left, without predilection for any particular location. Angiographically, they appeared as thin, web-like structures which may block passage of the catheter or of contrast material, and hence cause poor venographic filling. Rarely, valves produce total obstruction to the retrograde flow of contrast material.

Epinephrine↗
PubMed1978

Detection of myocardial ischemia in vitro by computed tomography.

The applicability of CT in the delineation of ischemic myocardium is defined. Twenty-six dogs had their left anterior descending coronary artery occluded, and radiolabeled microspheres were injected into the left atrium to measure myocardial blood flow. From 30 minutes to 7 weeks after coronary occlusion the hearts were excised and scanned in a CT head scanner. An unbiased observer divided selected CT scans slices into normal, abnormal, and borderline areas of attenuation coefficients; these were correlated with blood flow measurements and a progressive decrease in flow from normal to borderline and borderline to abnormal segments was found. As early as 2 hours after coronary arterial occlusion, areas of reduced attenuation coefficient, corresponding to regions of reduced blood flow, were seen. Areas of increased attenuation were seen in regions containing microcalcifications and fibrosis in several longer term experiments. Areas of reduced blood flow were visible immediately after coronary arterial occlusion with intravenous iodinated contrast material (1 ml/kg). CT detection of regions of reduced blood flow defined by radiolabeled microsphere is a promising means of detecting and sizing myocardial infarcts.

Animals↗
PubMed1978

Hemodynamically significant primary anomalies of the coronary arteries. Angiographic aspects.

Hemodynamically significant primary anomalies of the coronary arteries are those which alter myocardial perfusion. There are four major types: coronary artery fistulae, origin of the left coronary artery from the pulmonary artery, congenital coronary stenosis or atresia, and origin of the left coronary artery from the right sinus of Valsalva, with subsequent passage of the vessel between the aorta and right ventricular infundibulum. The angiographic features of these lesions are discussed.

Arteriovenous Fistula↗
PubMed1978

Computed tomography: cost and efficacy implications.

Because CT is unique, it has been accepted by physicians with unrestrained enthusiasm. However, the capital investment and cost of maintenance are high, and there has been no orderly program of dispersion despite the profound interest of the regulatory agencies in cost containment. Although the diagnostic accuracy of CT in both the head and body is high, its information gain over other competing imaging methods, particularly those in the abdomen (ultrasound, nuclear medicine), has not been fully documented. In evaluating the cost effectiveness of CT, long-term outcome, while the most important criterion, requires carefully controlled studies over many years. Short-term value may be measured by assessing the degree to which CT furnishes new diagnostic information, its accuracy, its effect on the morbidity and mortality of diagnostic and theraupeutic procedures, its impact on treatment planning, and changes in cost and saving incident to its use. Prospective studies must relate the contribution of CT to that of competing methods and document the impact of additional diagnostic information.

Capital Expenditures↗
PubMed1977

Cooperative study of radiologic aspects of renovascular hypertension. Bilateral renovascular disease.

Abnormal urographic features were present in 60.7% of 250 patients with bilateral diseases. The urogram was relatively insensitive in the minority of patients whose lesions were of approximately equivalent severity bilaterally. In bilateral renovascular disease, the urogram demonstrated some surgical prognostic value that was not evident in unilateral renovascular disease. Furthermore, in patients with bilateral disease, the urogram was helpful in deciding between unilateral or bilateral operation.

Arteriosclerosis↗
PubMed1977

The role of the radiologist in coronary angiography.

Radiology chiefs at hospitals with open heart surgery programs were queried to ascertain both current and desired degrees of participation by radiologists in coronary angiography. While current participation is limited, respondents indicated a desire to achieve increased active participation. Opposition of cardiologists and a shortage of trained cardiac radiologists were perceived as principal factors impeding increased participation. Over two thirds of the respondents felt additional cardiac radiology training programs are needed and many indicated that positions were available in their departments for a trained cardiac radiologist.

Angiography↗
PubMed1977

Participation by radiologists in coronary angiography.

Coronary angiography is one of the few radiologic procedures which remains largely under the control of another medical specialty. There are several contributing reasons, none of which justify continuation of this situation. A more active role for radiologists in performing coronary angiography is urged.

Angiography↗
PubMed1976

Differing attenuation coefficients of normal and infarcted myocardium.

There are significant differences in attenuation coefficients between normal and infarcted myocardium measurable with a computerized transaxial tomographic scanner. Additionally, iodinated contrast material administered prior to killing the tests animals resulted in excellent visualization of the blood-myocardial interface at a time when standard radiographs detected no differences between the ventricular cavity and the myocardial wall. These natural and induced changes in attenuation coefficients offer a new approach to evaluating and understanding the processes of tissue injury and death. Their clinical relevance lies in application to the twin problems of myocardial infarction and the structure and function of the cardiac wall.

Animals↗
PubMed1976

Computed tomography of the normal and infarcted myocardium.

After intravenous administration of contrast agent, in vitro cardiac scanning showed a significant difference between the attenuation coefficients of the intracavitary blood pool and the myocardial wall, permitting clear delineation of the ventricular cavity. A substantial alteration in hematocrit permitted similar visualization of the intracavitary blood pool-myocardial wall interface. The attenuation coefficient of infarcted myocardium differed sufficiently from that of normal myocardium to render computed tomographic distinction feasible. In three hour old infarctions, the differences between normal and ischemic or infarcted tissue were enhanced by prior administration of contrast agent. These differences in attenuation coefficient indicate that a properly gated CT scanner could be utilized as a noninvasive approach to evaluating suspected or known myocardial infarction and other aspects of cardiac structure and function both in man and in experimental animals.

Animals↗
PubMed1976

Report of the Inter-Society Commission for Heart Disease Resources. Optimal resources for examination of the chest and cardiovascular system. A hospital planning and resource guideline. Radiologic facilities for conventional x-ray examination of the heart and lungs. Catheterization-angiographic Laboratories. Radiologic resources for cardiovascular surgical operating rooms and intensive care units.

This is an updated and expanded planning and oprimal resource guideline for diagnostic examinations of the cardiovascular system. Catheterization-angiographic laboratories are described and detailed specifications given for radiologic and physiologic equipment. Case loads for maintaining safe and effective performance are recommended and complication rates discussed. An optimal location for the laboratory is defined and the status of affiliated laboratories reviewed. Professional staff qualifications, relationships and requirements are enumerated and recommendations are made for organization and administration of the services. There is a protocol for electrical safety and radiation protection and a data base for assessing case loads in hospitals within a community or region. This statement also defines optimal facility and equipment criteria for conventional chest x-rays and radiologic equipment requirements for cardiovascular surgical operating rooms and intensive care units.

Angiocardiography↗
PubMed1975

Renal vascular tone in essential and secondary hypertension: hemodynamic and angiographic responses to vasodilators.

The renal vascular response to graded doses of acetylcholine, dopamine and phentolamine, assessed by xenon washout and selective arteriography was used to define the relative contribution of fixed and reversible vascular abnormalities to increased renal vascular resistance in patients with essential or secondary hypertension. The increase in blood flow induced by acetylcholine and dopamine was blunted strikingly in patients with advanced nephrosclerosis, chronic pyelonephritis and polycystic kidney disease and was normal in the kidney contralateral to a significant renal artery stenosis. Conversely, the response to both was potentiated in 9 of 13 (69%) patients with mild essential hypertension. Equivalent potentiation of the response to acetylcholine was induced in normal subjects by increasing renal vascular tone pharmacologically with angiotensin. Phentolamine infused into the renal artery also increased renal blood flow significantly in 6 of 9 (67%) patients with mild essential hypertension, but in none of 15 normal subjects, over a dose reange that paralleled that for alpha-adrenergic blockade. Changes in the selective renal arteriogram were in excellent accord: potentiated response to acetylcholine, phentolamine or dopamine was associated with reversal of the small vessel abnormalities visualized in the arteriogram. The reduced blood flow response in advanced nephrosclerosis or parenchymal disease was associated with a reduced angiographic change during dilator infusion. The results suggest a quantitatively important, functional renal vascular abnormality--perhaps mediated by the sympathetic nervous system--in many patients with mild essential hypertension. Conversely the renal vascular abnormality associated with advanced nephrosclerosis or renal parenchymal disease is largely fixed and is probably due to organic changes.

Acetylcholine↗
PubMed1975

Coronary vascular patterns during occlusion arteriography.

The arteriograms from 18 studies in which the catheter accidentally occluded the right coronary artery were analyzed and compared with successful studies in 25 patients with normal coronary arteries and 20 patients with coronary artery stenosis. The occlusion arteriograms showed distinct early filling of the anterior cardiac veins and occasionally retrograde filling of the left circumflex artery. Although there were no serious complications due to occlusion arteriography in our patients, the potential for producing ventricular tachycardia, ventricular fibrillation or cardiac arrest must be borne in mind. Angiographers should be aware of these filling patterns in order to recognize them as artifacts of the technique and not as manifestations of disease.

Angiography↗