Coronary Artery Disease: Woodard PK

Bluemke DA, Achenbach S, Budoff M, Gerber TC, Gersh B, Hillis LD, Hundley WG, Manning WJ, Printz BF, Stuber M, Woodard PK. · No affiliation provided · Circulation. · Pubmed #18586979 links to  free full text

This publication has no abstract.

Saeed IM, Rao PM, Barzilai B, Woodard PK. · Department of Medicine, Division of Cardiovascular Diseases Washington University School of Medicine, St Louis, MO 63110, USA. · J Cardiometab Syndr. · Pubmed #17786087 links to  free full text

This publication has no abstract.

Weinreb JC, Larson PA, Woodard PK, Stanford W, Rubin GD, Stillman AE, Bluemke DA, Duerinckx AJ, Dunnick NR, Smith GG. · Yale University School of Medicine, New Haven, Connecticut, USA. <> · J Am Coll Radiol. · Pubmed #17411862 No free full text.

Abstract: Coronary artery disease and other acquired and congenital cardiac diseases are major medical and socio-economic problems. Historically, imaging has had a critical role in the diagnosis and evaluation of acquired and congenital cardiac disease. Advances in computed tomography (CT), with multidetector CT and electron beam CT technology, and magnetic resonance (MR) imaging, now make it possible to noninvasively image the coronary arteries, cardiac chambers, valves, myocardium, and pericardium and assess cardiac function, and CT and MR imaging are becoming increasingly important in the evaluation of cardiac disease. Radiologists, because of their extensive experience in CT and MR imaging, have an important role in imaging cardiac patients using these modalities. This clinical statement of the ACR discusses various technical and patient safety issues related to cardiac CT and MR imaging, and it suggests appropriate qualifications for radiologists until such time as ACR practice guidelines for the performance of cardiac CT and cardiac MR imaging are written and approved through the usual ACR process. It stresses that the interpreting physician is responsible for examining not only the cardiac structures of interest but also all the visualized noncardiac structures and must report any clinically relevant abnormalities of these adjacent structures.

Tsekos NV, Atalar E, Li D, Omary RA, Serfaty JM, Woodard PK. · Cardiovascular Imaging Laboratory, Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110, USA. · J Magn Reson Imaging. · Pubmed #15170780 No free full text.

Abstract: Magnetic resonance imaging (MRI) guidance for coronary interventions offers potential advantages over conventional x-ray angiography. Advantages include the use of nonionizing radiation, combined assessment of anatomy and function, and three-dimensional assessment of the coronary arteries leading to the myocardium. These advantages have prompted a series of recent studies in this field. Real-time coronary MR angiography, with low-dose catheter-directed intraarterial (IA) infusion of contrast media, has achieved in-plane spatial resolution as low as 0.8 x 0.8 mm2 and temporal resolution as short as 130 msec per image. Catheter-based IA injection of contrast agent has proven useful in the collection of multislice and three-dimensional images, not only for coronary intervention guidance, but also in the assessment of regional myocardial perfusion fed by the affected vessel. Actively visible guidewires and guiding catheters, based on the loopless antenna concept, have been effectively used to negotiate tortuous coronary vessels during catheterization, permitting placement of coronary angioplasty balloon catheters. Passive tracking approaches have been used to image contrast agent-filled coronary catheters and to place susceptibility-based endovascular stents. Although the field is in its infancy, these early results demonstrate the feasibility for performing MRI-guided coronary interventions. Although further methodological and technical developments are required before these methods become clinically applicable, we anticipate that MRI someday will be included in the armamentarium of techniques used to diagnose and treat coronary artery disease.

Kates AM, Vedala G, Woodard PK, Davila-Roman VG, Gropler RJ. · Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA. · Curr Opin Cardiol. · Pubmed #10448612 No free full text.

Abstract: The inherent limitations of x-ray coronary angiography have led to the development for both noninvasive and minimally invasive techniques for imaging the coronary arteries to assist in the diagnosis and management of patients with ischemic heart disease. Significant advances in transesophageal echocardiography, electron beam computed tomography, and magnetic resonance imaging now permit imaging of the proximal to mid-coronary arteries. Moreover, results of initial studies demonstrate the promise of these methods to detect coronary artery stenoses. In addition, each of these methods provides biochemical or physiologic data about the stenoses that are not obtainable through x-ray angiography. Quantification of coronary calcification via electron beam computed tomography has shown promise as a surrogate marker of coronary atherosclerosis. Transesophageal echocardiography and magnetic resonance imaging appear useful in evaluating the physiologic significance of angiographically detectable coronary artery stenoses via assessment of coronary blood flow. However, it should be noted that significant improvements in technology or acquisition parameters must occur before these techniques can be used on a routine clinical basis for coronary artery imaging. The relative merits and ultimate clinical potential of each of these techniques are discussed in this article.

Woodard PK, Li D, Zheng J, Haacke EM, Gropler RJ. · Mallinckrodt Institute of Radiology, Cardiovascular Imaging Laboratory, Washington University School of Medicine, St Louis, Missouri 63110, USA. · Coron Artery Dis. · Pubmed #10352891 No free full text.

This publication has no abstract.

Douglas PS, Budoff M, Tunis S, Woodard PK, Justman RA, Honigberg R. · Duke University Medical Center, Durham, NC, USA. · JACC Cardiovasc Imaging. · Pubmed #19356455 No free full text.

This publication has no abstract.

Barry MO, Woodard PK, Saeed IM. · Cardiovascular Division, Washington University School of Medicine, St. Louis. · Mo Med. · Pubmed #18630311 No free full text.

Abstract: The media's frenzy towards the imaging capabilities of 64-slice cardiac computed tomography (CCT) is not without cause. CCT allows non-invasive visualization of the coronary arteries, coronary artery bypass grafts, and the presence of atherosclerosis. CCT is not limited to the assessment of coronary vasculature, but can yield information about other causes of chest pain such as aortic dissection, or pericardial disease. Other applications for the high resolution scanner include anatomical assessment of congenital heart disease, post myocardial infarction complications, pulmonary embolism and aortic and peripheral arterial atherosclerosis and aneurysm evaluation. Finally, non-contrast CCT allows for quantification of coronary calcification which provides important prognostic information. As CT technology evolves, it is paramount for clinicians to understand when it is clinically appropriate to use CT coronary angiography (CTCA).

Stillman AE, Rubin GD, Teague SD, White RD, Woodard PK, Larson PA. · Emory University School of Medicine, Atlanta, Georgia 30322, USA. · J Am Coll Radiol. · Pubmed #18585655 No free full text.

Abstract: With the growing use of electronic medical records, the trend of diagnostic imaging reporting is toward a more structured format. Advantages include improved quality and consistency of the reporting and ease of data mining. The essential elements of a structured report are provided and illustrated for coronary artery computed tomographic angiograms.

Tang D, Yang C, Zheng J, Woodard PK, Saffitz JE, Sicard GA, Pilgram TK, Yuan C. · Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA. · J Biomech Eng. · Pubmed #16502661 links to  free full text

Abstract: BACKGROUND: Atherosclerotic plaques may rupture without warning and cause acute cardiovascular syndromes such as heart attack and stroke. Methods to assess plaque vulnerability noninvasively and predict possible plaque rupture are urgently needed. METHOD: MRI-based three-dimensional unsteady models for human atherosclerotic plaques with multi-component plaque structure and fluid-structure interactions are introduced to perform mechanical analysis for human atherosclerotic plaques. RESULTS: Stress variations on critical sites such as a thin cap in the plaque can be 300% higher than that at other normal sites. Large calcification block considerably changes stress/strain distributions. Stiffness variations of plaque components (50% reduction or 100% increase) may affect maximal stress values by 20-50%. Plaque cap erosion causes almost no change on maximal stress level at the cap, but leads to 50% increase in maximal strain value. CONCLUSIONS: Effects caused by atherosclerotic plaque structure, cap thickness and erosion, material properties, and pulsating pressure conditions on stress/strain distributions in the plaque are quantified by extensive computational case studies and parameter evaluations. Computational mechanical analysis has good potential to improve accuracy of plaque vulnerability assessment.

Tang D, Yang C, Zheng J, Woodard PK, Saffitz JE, Petruccelli JD, Sicard GA, Yuan C. · Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA. · Ann Biomed Eng. · Pubmed #16389527 links to  free full text

Abstract: It is believed that atherosclerotic plaque rupture may be related to maximal stress conditions in the plaque. More careful examination of stress distributions in plaques reveals that it may be the local stress/strain behaviors at critical sites such as very thin plaque cap and locations with plaque cap weakness that are more closely related to plaque rupture risk. A "local maximal stress hypothesis" and a stress-based computational plaque vulnerability index (CPVI) are proposed to assess plaque vulnerability. A critical site selection (CSS) method is proposed to identify critical sites in the plaque and critical stress conditions which are be used to determine CPVI values. Our initial results based on 34 2D MRI slices from 14 human coronary plaque samples indicate that CPVI plaque assessment has an 85% agreement rate (91% if the square root of stress values is used) with assessment given by histopathological analysis. Large-scale and long-term patient studies are needed to further validate our findings for more accurate quantitative plaque vulnerability assessment.

Zheng J, El Naqa I, Rowold FE, Pilgram TK, Woodard PK, Saffitz JE, Tang D. · Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. · Magn Reson Med. · Pubmed #16265643 links to  free full text

Abstract: The risk of atherosclerotic plaque disruption is thought to be closely related to plaque composition and rupture triggers such as external mechanical forces. The purpose of this study was to integrate MR imaging and computational techniques for the quantification of plaque vulnerability with morphologic data and biomechanical stress/strain distributions that were all based on high-resolution MR images of coronary artery plaque specimens ex vivo. Twenty-two coronary artery plaque specimens were selectively collected from 10 cadavers. Multislice T(2)-weighted spin echo images were acquired with a resolution of 100 x 100 microm(2). Histopathological images were used as the gold standard for the identification of plaque components and vulnerability. Plaque components were classified on MR images, and the stress/strain components were calculated with a two-dimensional computational model with fluid-structure interactions. As expected, vulnerable plaques appeared to result from a large lipid pool, a thin fibrous cap, and some critical stress/strain conditions. An empiric vulnerability marker was derived and was closely related to the vulnerability score that was determined through pathologic examination. Noninvasive quantification of the MR contrast and mechanical properties of plaque may provide a comprehensive biomarker for the assessment of vulnerability of atherosclerotic plaques.

Zheng J, Wang J, Rowold FE, Gropler RJ, Woodard PK. · Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Boulevard, Box 8225, St. Louis, MO 63110, USA. · J Magn Reson Imaging. · Pubmed #15269948 No free full text.

Abstract: PURPOSE: To explore the relationship of myocardial T(2) and oxygenation for the quantification of myocardial oxygen extraction fraction (OEF). MATERIALS AND METHODS: A proposed myocardial T(2)-OEF relationship was evaluated by computer simulation and in nine normal dogs in vivo. The relationship was based on a simplified two-compartment T(2) model. In the dogs, dipyridamole was infused intravenously to increase blood flow and change in myocardial oxygen content. The accuracy of the measurement in myocardial OEF in vivo by magnetic resonance imaging (MRI) was determined by arterial and coronary sinus blood sampling. RESULTS: Global myocardial T(2) increased 16.1% from rest to the peak of dipyridamole-induced vasodilation (44.6 +/- 2.1 msec vs. 51.4 +/- 2.1 msec, P < 0.001). Corresponding OEF measured by arterial and venous (AV) sampling decreased from 0.64 +/- 0.15 at rest to 0.18 +/- 0.08 during the dipyridamole vasodilation, whereas OEF calculated by MRI at the peak effect of dipyridamole was 20 +/- 4%. Global myocardial OEF measured dynamically by MRI showed a strong correlation with OEF measured by blood sampling (correlation coefficient (CC) = 0.83) during pharmacologic vasodilation. CONCLUSION: When combined with vasodilator stress, assessment of OEF may provide a putative measure of myocardial flow reserve, allowing consecutive monitoring of myocardial dose-responses to a variety of interventions and offering a new tool for the detection of coronary artery disease.