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Biomedical subjects

R Eugene Zierler

Publications and source records attributed to R Eugene Zierler.

9 recordsLinked to original sources
PubMed2006

Training and credentialing in vascular laboratory diagnosis.

Physicians interpreting vascular laboratory studies require proper training and credentialing. It is suggested minimal training requirements include but, may not be limited to, the following: a medical license and knowledge of the fundamental concepts of vascular physiology, anatomy, and ultrasound physics. In addition, there should be evidence of training in vascular diagnostics beyond medical school, clinical experience in the treatment of vascular disease, supervised experience with specific numbers of vascular laboratory interpretations in the areas in which the physician wishes to interpret, and evidence of ongoing continuing medical education (CME) in noninvasive vascular diagnostics. Credentialing requirements are determined locally, but it is suggested that successful completion of the American Registry of Diagnostic Medical Sonographers' Registered Physician in Vascular Interpretation (RPVI) examination will provide evidence of core knowledge of vascular laboratory topics that is independent of medical or surgical specialty. Completion of the RPVI exam, completion of core training requirements, along with ongoing CME, is a basis for establishing minimal requirements for interpretation of vascular laboratory studies.

Certification↗
PubMed2005

Display of spatially-registered Doppler spectral waveforms and three-dimensional vein graft geometry.

A method has been developed to display Doppler spectral waveforms in lower extremity vein grafts in conjunction with 3-D vessel geometry. Doppler spectral waveforms and cross-sectional images of the vein graft are collected with a custom 3-D ultrasound imaging system. Computer processing generates a display of the Doppler sample volumes registered in 3-D space with a surface reconstruction of the vein graft lumen. An interactive computer interface displays spectral waveforms at user-selected sites in the graft. Summary displays combining spectral waveforms, maximum velocity and cross-sectional area provide a pictorial record of the state of the vein graft along its full length. The method is demonstrated for two patient studies, each at two time points after graft revisions. The graphic display of both hemodynamics and geometry allows rapid assessment of vein graft changes over time.

Aged↗
PubMed2005

Measurement of anastomosis geometry in lower extremity bypass grafts with 3-D ultrasound imaging.

The attachment sites of lower extremity bypass grafts are known to exhibit a wide range of geometries. Factors that determine the geometry of a given anastomosis include graft material, graft site, native vessel size, graft size and individual patient anatomy. Therefore, it is difficult to specify a standard anastomosis geometry before surgery and difficult to predict the effect of the geometry on long-term graft patency. We have used 3-D ultrasound imaging to study 46 proximal anastomoses of lower limb bypass grafts. We have developed methods to characterize the 3-D geometry of the anastomosis in terms of component sizes and angles. These detailed geometric measurements describe a range of anastomosis geometries and establish standardized parameters across cases that can be used to relate anastomosis geometry to outcome.

Adult↗
PubMed2003

Carotid artery stenosis: gray-scale and Doppler US diagnosis--Society of Radiologists in Ultrasound Consensus Conference.

The Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts in the field of vascular ultrasonography (US) to come to a consensus regarding Doppler US for assistance in the diagnosis of carotid artery stenosis. The panel's consensus statement is believed to represent a reasonable position on the basis of analysis of available literature and panelists' experience. Key elements of the statement include the following: (a) All internal carotid artery (ICA) examinations should be performed with gray-scale, color Doppler, and spectral Doppler US. (b) The degree of stenosis determined at gray-scale and Doppler US should be stratified into the categories of normal (no stenosis), <50% stenosis, 50%-69% stenosis, > or =70% stenosis to near occlusion, near occlusion, and total occlusion. (c) ICA peak systolic velocity (PSV) and presence of plaque on gray-scale and/or color Doppler images are primarily used in diagnosis and grading of ICA stenosis; two additional parameters, ICA-to-common carotid artery PSV ratio and ICA end-diastolic velocity may also be used when clinical or technical factors raise concern that ICA PSV may not be representative of the extent of disease. (d) ICA should be diagnosed as (i) normal when ICA PSV is less than 125 cm/sec and no plaque or intimal thickening is visible; (ii) <50% stenosis when ICA PSV is less than 125 cm/sec and plaque or intimal thickening is visible; (iii) 50%-69% stenosis when ICA PSV is 125-230 cm/sec and plaque is visible; (iv) > or =70% stenosis to near occlusion when ICA PSV is greater than 230 cm/sec and visible plaque and lumen narrowing are seen; (v) near occlusion when there is a markedly narrowed lumen at color Doppler US; and (vi) total occlusion when there is no detectable patent lumen at gray-scale US and no flow at spectral, power, and color Doppler US. (e) The final report should discuss velocity measurements and gray-scale and color Doppler findings. Study limitations should be noted when they exist. The conclusion should state an estimated degree of ICA stenosis as reflected in the above categories. The panel also considered various technical aspects of carotid US and methods for quality assessment and identified several important unanswered questions meriting future research.

Carotid Artery, Internal↗
PubMed2003

Remodeling in peripheral vein graft revisions: serial study with three-dimensional ultrasound imaging.

OBJECTIVE: Remodeling of vein grafts in the lower limb can lead to stenotic lesions that threaten long-term graft patency. Progressive changes in vein graft geometry were measured at sites of repaired stenoses with three-dimensional (3D) ultrasound imaging. METHODS: Ten vein graft revisions with patch angioplasty were followed up for 31 to 47 weeks. Four revisions were at valve sites, and six were at sites of diffuse intimal hyperplasia. Sets of spatially registered two-dimensional (2D) cross-sectional ultrasound images were assembled to create 3D computer models of each vein graft. Cross-sectional area measurements in planes normal to the vessel center axis were calculated from the 3D surface reconstructions. Data sets from serial studies were registered in a common coordinate system, and cross-sectional area measurements were compared at matched sites. RESULTS: Three of the four vein graft revisions at valve sites changed by less than 18%, and one decreased in cross-sectional area by 61%. Five of the six revisions at sites of diffuse intimal hyperplasia demonstrated significant decreases in lumen area ranging from 26% to 61%, and one revision exhibited no significant change in cross-sectional area. Reproducibility of the cross-sectional area measurements derived from the 3D imaging technique was 6.9%. CONCLUSIONS: Sequential area measurements from 3D ultrasound scans demonstrated different remodeling patterns and rates of change among revision sites within the vein grafts. Lumen narrowing documented with 3D scanning was not associated with consistent flow velocity changes on conventional duplex graft surveillance scans.

Adult↗
PubMed2003

The prevalence and natural history of aortic aneurysms in heart and abdominal organ transplant patients.

OBJECTIVE: The purpose of this study was to document the prevalence and clinical features of aortic aneurysms in heart and abdominal transplant patients. METHODS: We undertook a retrospective review of 1557 patients who had heart, liver, or kidney transplantation between January 1, 1987, and December 31, 2000. Aortic aneurysms were identified by computed tomographic scan, ultrasound scan, or at the time of surgery for rupture. An aortic diameter of 3.5 cm was used as the threshold for the definition of aneurysmal disease. We compared dichotomous variables with Fisher's exact test and continuous variables with the Wilcoxon rank-sum test. RESULTS: There were 296 heart, 450 liver, and 811 kidney transplants performed on adult patients during the study period. We identified 18 transplant patients who had an aortic aneurysm (13 heart, three liver, two kidney). Seven patients (41%) had rupture of the aortic aneurysm, and five of these patients died. There were no deaths from causes other than aortic aneurysm rupture. The rate of aneurysm rupture was 22.5% per year. Eight patients had the aortic aneurysm repaired electively with no deaths and no hospital stay greater than 15 days. The mean aortic aneurysm size at rupture was 6.02 +/- 0.86 cm, and the smallest aneurysm that ruptured was 5.1 cm. The pretransplant rate of aortic aneurysm expansion was 0.46 cm/y, but this increased to 1.00 cm/y after transplantation (P =.08). The rate of aortic aneurysm expansion among heart transplant patients and abdominal transplant patients was the same (P =.51). The prevalence of aortic aneurysm was 4.1% in cardiac transplant patients and 0.4% in abdominal transplant patients. Earlier in our series (1987 to 1996), 11% of the cardiac transplant patients were screened for aortic aneurysms, and the prevalence rate of diagnosis was 3.0%. Screening of cardiac transplant candidates became more frequent in 1997 (87% screened), with an associated increase in the aortic aneurysm prevalence rate to 5.8% in the patients who were screened. CONCLUSION: Aortic aneurysms in cardiac and abdominal transplant patients have an aggressive natural history with high expansion and rupture rates. Screening transplant patients for aortic aneurysms will increase detection and facilitate elective repair, which is generally well tolerated. These findings support programs for early detection and elective treatment of aortic aneurysms in organ transplant patients, particularly those having heart transplants.

Aortic Aneurysm↗
PubMedDate not supplied

Fractured aorta--a case report.

A 66-year-old, restrained driver involved in a high-speed motor vehicle crash sustained a transmural infrarenal fracture of a circumferentially calcified aorta. Blunt abdominal aortic injury is exceedingly rare, about twenty times less common than its thoracic counterpart, and the current case report is therefore unusual. A high index of suspicion in combination with a suggestive clinical history or examination should prompt diagnostic intervention, as both morbidity and mortality are high.

Accidents, Traffic↗