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Biomedical subjects

J F Sackett

Publications and source records attributed to J F Sackett.

At least 37 records · Page 2Linked to original sources
PubMed1983

Correlation of high-resolution, B-mode and continuous-wave Doppler sonography with arteriography in the diagnosis of carotid stenosis.

One hundred thirty-one carotid bifurcations in 73 symptomatic patients were prospectively studied with high-resolution, B-mode sonography (HRS) and continuous-wave Doppler ultrasound (CWD). Twenty-three bifurcations were studied because of asymptomatic bruits, 30 for transient ischemic attacks, and 36 for focal or nonfocal symptoms or signs suggesting occlusive disease. The remaining 42 bifurcations were asymptomatic, with symptoms or signs confined to the contralateral bifurcation. Findings in the common, external, and internal carotid arteries (total, 393 vessels) were tabulated separately for plaque severity (HRS), ulceration (HRS), and degree of occlusion (HRS and CWD). HRS correctly estimated plaque severity in 67% of vessels, with 13% overestimated and 20% underestimated. HRS was only 44% sensitive for detection of 81 angiographically demonstrated ulcers. Among 187 occlusive lesions (ranges, less than 50%, greater than or equal to 50%, less than 70%, greater than or equal to 70% decrease in diameter or complete occlusion) HRS correctly estimated luminal narrowing in 62%, CWD in 30%, and HRS plus CWD in 70%. Among greater than 50% occlusive lesions, HRS was correct in 48%, CWD in 59%, and HRS plus CWD in 69%. These results suggest that (a) HRS is not accurate for diagnosis of ulceration, (b) Doppler and B-mode combined are more accurate than separate use of either procedure for evaluation of occlusive lesions, and (c) the level of accuracy in evaluating plaque and stenosis provides a general estimation of severity of disease but does not allow for precise diagnosis.

Carotid Artery Diseases↗
PubMed1983

Digital subtraction angiography. Comparison of meglumine-Na diatrizoate with iohexol.

A slight improvement in image quality occurred with the use of iohexol when compared with meglumine-Na diatrizoate. There is less swallowing with iohexol, which gives better image registration when looking at the extracranial carotid arteries. A single significant tachycardia occurred with the ionic medium, but not with iohexol. Overall discomfort and minor adverse reactions were less with iohexol than with diatrizoate.

Adult↗
PubMed1982

A comparison of standard cerebral arteriography with noninvasive Doppler imaging and intravenous angiography.

Standard cervical carotid arteriography was performed on 36 patients and compared with results of noninvasive Doppler arterial imaging and intravenous angiography (IVA). The 72 carotid arteries were anatomically classified by standard angiograms as follows; group 1 (normal), 13 arteries; group 2 (wall disease [50% stenosis]), 14 arteries; group 3 (moderate stenosis [5-% to 75% stenosis]) 12 arteries; group 4 (severe stenosis [greater than 75%]), 15 arteries; and group 5 (complete occlusion), 18 arteries.

Auscultation↗
PubMed1982

Diagnosis of vertebral fractures. A comparison of conventional radiography, conventional tomography, and computed axial tomography.

Thirty patients with acute thoracic, lumbar, or thoracolumbar fractures, dislocations, or fracture-dislocations were evaluated with standard radiographs, conventional polytomography, and computerized axial tomography. The resulting ninety studies were coded, randomized, and independently interpreted by three radiologists. The diagnostic accuracy of the interpretations based on the computerized tomography scans combined with standard radiographs equaled that of the interpretations based on just the tomograms in the evaluation of fractures of posterior elements. In addition, computerized tomography was superior to the other methods in demonstrating impingement on the neural canal as well as injuries to other organ systems. Also, when compared with conventional polytomography, computerized tomography could be completed with less risk to the patient (no changes in position and ten times less radiation). We concluded that computerized tomography should replace conventional polytomography as the initial study to augment standard radiographs in the assessment of thoracic and lumbar fractures. Conventional polytomography should be reserved for patients in whom precise evaluation of the pars interarticularis is deemed necessary.

Adolescent↗
PubMed1981

Computerized arteriography of the cerebrovascular system: its use with intravenous administration of contrast material.

A unique method of computerized image enhancement makes it possible to visualize the arterial system by intravenous (IV) injection of small doses of standard contrast agent. This technique has been used to study the intracranial and extracranial circulation of more than 100 patients. Occlusion, stenosis, aneurysmal change, plaquing, and ulceration can be identified by computerized IV arteriography. Failures (less than 10%) results from inadequate venous access, extravasation of dye, or patient motion. This technique avoids the need for arteriography. The major risk of IV arteriography is contrast medium reaction. There is a close correlation between IV and standard arteriographic images. Intravenous arteriography does not require hospitalization, is suited for repetitive testing, and has promise as a method of diagnostic screening for stroke prevention.

Cerebral Angiography↗
PubMed1981

Digital video subtraction angiography for evaluation of peripheral vascular disease.

Digital video subtraction angiography (DVSA) has been employed to study a variety of peripheral vascular problems, using equipment developed at the University of Wisconsin. The technique is relatively simple and safe and has good patient acceptance. Experience indicates that in selected patients it is a satisfactory alternative to standard arteriography for screening and for definitive evaluation and on occasion may yield information not obtainable with conventional methods. It can aid in the performance of transluminal angioplasty and is suitable for serial evaluation of atherosclerotic vessels and bypass grafts.

Adult↗
PubMed1980

Explanation of metrizamide brain penetration: a review.

The penetration of intrathecally injected metrizamide into brain and spinal cord substance is a phenomenon that has surprised and puzzled radiologists. No suitable explanation has been offered in the radiologic literature. This article reviews the recent literature on the relationship between the cerebrospinal fluid (CSF) space and the extracellular fluid (ECF) space of the brain. Recent evidence has shown that these spaces are in fact one compartment with no diffusion barrier between them. Thus, penetration of metrizamide into the brain is an expected rather than surprising phenomenon. An explanation is offered as to why metrizamide does not penetrate edematous or infarcted portions of brain on the basis of a pressure gradient between damaged brain ECF and CSF spaces.

Brain↗
PubMed1980

Imaging methods in the transmission computed tomographic measurement of regional xenon kinetics in the brain.

The process of an investigation of transmission computed tomographic measurements of the kinetics of stable xenon in the brain is reported. The use of functional imaging methods to generate maps of regional washout rate estimators is introduced in an animal model. Region-of-interest analysis is introduced using regions specified by the functional maps demonstrates the sensitivity of the methods to the rapid components of cerebral xenon washout. Correspondence among the regional distributions of tissue types as demonstrated by tissue attenuation coefficient, xenon solubility, and washout rate estimators supports the validity of characterizing each pixel by a single exponential response function.

Animals↗
PubMed1980

Clinical applications of computerized fluoroscopy: the extracranial carotid arteries.

Preliminary results obtained with a new computerized fluoroscopic apparatus in examination of the extracranial carotid arteries are described. All patients had clinical signs of symptoms of extracranial occlusive vascular disease. In most cases, image quality was sufficient to display patency of the internal carotid arteries, with excellent correlation between intravenous and conventional angiography. While the new technique is not totally noninvasive, it does eliminate many of the risks and costs of conventional arteriography.

Arterial Occlusive Diseases↗
PubMed1980

Computerized fluoroscopy: digital subtraction for intravenous angiocardiography and arteriography.

Computerized fluoroscopy is a system comprising on-line digital time and energy subtraction algorithms designed to isolate and enhance the iodine signal from image intensified fluoroscopy. The apparatus is described and its use for time subtraction intravenous arteriography of the carotid, abdominal, extremely arteries, as well as the heart, is illustrated. Vascular diseases such as stenoses, obstruction, emboli, ulcerative plaques, and aneurysms are readily demonstrated. The technique has a potential for evaluating cardiac motion and the patency of coronary artery bypass grafts. The method appears to be a safe and less expensive alternative to catheter arteriography and angiocardiography in certain instances.

Adult↗
PubMed1979

Benign subdural collections of infancy.

During the past two years we studied six infants with subdural collections of fluid. All patients had macrocrania and excessive transillumination of the head. Rapid head growth was common but five patients were otherwise asymptomatic. Subdural taps performed on five children confirmed the presence of abnormal fluid over the cerebral convexities. Subdural fluid in four patients was compatible with effusion and in another with a hematoma. Computerized tomographic evaluation of all infants showed ventricular enlargement, wide cerebral sulci, decreased density in the anterior temporal regions, large sylvian cisterns, prominent interhemispheric fissures, and decreased density over the cerebral convexities. The CT findings resembled cerebral atrophy but psychomotor development and neurologic examinations have been norma.

Child Development↗
PubMed1979

Doppler evaluation of extracranial cerebrovascular disease.

The carotid Doppler examination is an accurate means of screening the extracranial carotid system for stenotic lesions. Comparison of 100 patients (200 vessels) examined by the Doppler method and arteriography showed agreement in 90% of the vessels and a significant error rate in only 3.5%.

Arterial Occlusive Diseases↗