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Biomedical subjects

Steven D Wolff

Publications and source records attributed to Steven D Wolff.

7 recordsLinked to original sources
PubMed2005

Enhanced viability imaging: improved contrast in myocardial delayed enhancement using dual inversion time subtraction.

In delayed contrast-enhanced MRI for the assessment of myocardial viability, the TI time in a gated inversion-recovery segmented gradient echo sequence is usually selected to null signal from normal myocardium. Although this TI time generates good contrast between the enhancing infarcted tissue and normal myocardium, there is usually less contrast between the infarct and the blood pool. A subtractive technique utilizing two acquisitions at a long and short TI time is proposed to improve the delineation between infarct-blood and infarct-myocardium. The concept was demonstrated in six mongrel dogs with reperfused myocardial infarction. Infarct-normal myocardium contrast (signal difference) using the proposed enhanced viability imaging (ENVI) technique was 142 +/- 50% (P < 0.001) that of standard magnitude inversion recovery (IR), while at the same TI time for the primary image, infarct-blood contrast, was 247 +/- 136% (P < 0.002) that of magnitude IR. Accounting for increased noise due to the subtraction, signal difference-to-noise ratios (SDNR) did not show a significant change for infarct-myocardium but infarct-blood SDNR for ENVI was 174 +/- 105% that of magnitude-IR (P < 0.03). Thus, marked improvement in the delineation of the infarcted zone was noted over a range of TI times.

Animals↗
PubMed2005

Aortoiliac occlusive disease in patients with known or suspected peripheral vascular disease: safety and efficacy of gadofosveset-enhanced MR angiography--multicenter comparative phase III study.

PURPOSE: To prospectively determine the safety and efficacy of the gadolinium-based blood pool magnetic resonance (MR) imaging contrast agent gadofosveset in patients known to have or suspected of having peripheral vascular disease. MATERIALS AND METHODS: Ethical committee approval and patient written informed consent were obtained. This study was compliant with the Health Insurance Portability and Accountability Act. Adults known or suspected to have peripheral vascular disease received gadofosveset (0.03 mmol per kilogram of body weight) for MR angiography of the aortoiliac region. Gadofosveset-enhanced MR angiography and unenhanced two-dimensional time-of-flight MR angiography were compared with the reference standard, conventional angiography, for the presence of vascular stenosis. All patients were monitored for adverse events with hematologic analysis, analysis of blood chemistry, urinalysis, and electrocardiographic parameters; these methods were analyzed to determine safety. RESULTS: A total of 274 patients were enrolled at 37 centers. Gadofosveset-enhanced MR angiography showed significant improvement (P < .001) compared with unenhanced MR angiography for each of the readers for diagnosis of clinically significant (> or = 50%) stenosis. Specificity and accuracy were significantly greater for three readers, and sensitivity increased significantly for two readers. For all readers, the area under the receiver operator characteristic curve for both quantitative and qualitative measures of significant disease increased (P < .001) for gadofosveset-enhanced MR angiography versus two-dimensional time-of-flight MR angiography. All readers also expressed more confidence in diagnosis (P < .001) and found fewer images to be uninterpretable (0.5% vs 11.0%). The most common adverse events were as follows: feeling hot, 12 (4.4%) patients; nausea, 10 (3.6%) patients; headache, nine (3.3%) patients; and burning sensation, eight (2.9%) patients. Only four serious adverse events were reported, in three patients, and all events were rated as unlikely related to the drug. No patients were excluded because of adverse events or laboratory abnormalities. There were no clinically important trends in the findings of hematologic analysis, blood chemistry, urinalysis, electrocardiography, or physical examination. CONCLUSION: On the basis of substantial improvements over non-contrast MR angiography in efficacy and a minimal and transient side-effect profile, gadofosveset was found to be safe and effective for MR angiography in patients known or suspected to have peripheral vascular disease.

Aged↗
PubMed2004

MR imaging in ischemic heart disease.

This article reviews the current MR imaging literature with respect to ischemic heart disease and focuses on the clinical practicalities of cardiac MR imaging today.

Diagnosis, Differential↗
PubMed2003

Techniques for quantifying coronary artery calcification.

Coronary calcium scoring is increasingly used as a screening test for coronary artery disease. Widespread agreement exists that coronary artery calcium (CAC) is a population marker for intimal atherosclerosis, However, the numerical significance of an individual's calcium score and what impact that score should have on future patient management is subject to disagreement. Questions also exist with regard to the interpretation of serial changes in CAC score. The answers to these questions heavily depend on an accurate and reproducible method of quantifying CAC. The purpose of this article is to review the alogrithms and techniques used in CAC quantification, and to identify those variables that may significantly affect its derivation.

Algorithms↗
PubMed2003

Setting up a clinical cardiac MR imaging program: practical issues and economics.

Use of MR imaging to assess the heart has grown rapidly in recent years. MR imaging can assess cardiac anatomy, quantify ventricular and valvular function, identify regions of infarcted myocardium, and evaluate flow-limiting coronary artery stenoses better than any other single imaging modality. Despite its superior capabilities, cardiac MR imaging has yet to be adopted widely in clinical practice, in part because of the many obstacles to developing a clinical cardiac MR imaging program. The purpose of this article is to provide information that may be helpful in developing such a program. The information is based on the authors' experience in an inpatient hospital setting and an outpatient private practice. The recommendations reflect personal opinions and donot represent requirements of any organization or society unless otherwise indicated.

Cardiovascular Diseases↗