Mary P Watkins

Washington University in St. Louis, San Luis, Missouri, United States

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Publications (10)83.54 Total impact

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    ABSTRACT: Bicuspid pulmonary valves and pulmonary artery aneurysms are two rare entities, reported in association, and usually attributed to hemodynamic alterations caused by the bicuspid pulmonary valve. We present magnetic resonance images of a patient with a bicuspid pulmonary valve and pulmonary artery aneurysm, and propose an alternative mechanism for this association, based on recent embryologic studies that link anomalies of the semilunar valves and great vessels with derangement of the cardiac neural crest cell development.
    No preview · Article · Apr 2014
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    Preview · Article · Jan 2013 · Journal of Cardiovascular Magnetic Resonance

  • No preview · Article · Jun 2012 · The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation
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    Preview · Article · Jan 2008 · Journal of Cardiovascular Magnetic Resonance
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    ABSTRACT: Rats and genetically manipulated mouse models have played an important role in the exploration of molecular causes of cardiovascular diseases. However, it has not been fully investigated whether mice or rats and humans manifest similar patterns of ventricular wall motion. Although similarities in anatomy and myofiber architecture suggest that fundamental patterns of ventricular wall motion may be similar, the considerable differences in heart size, heart rate, and sarcomeric protein isoforms may yield quantitative differences in ventricular wall mechanics. To further our understanding of the basic mechanisms of myofiber contractile performance, we quantified regional and global indexes of ventricular wall motion in mice, rats, and men using magnetic resonance (MR) imaging. Both regular cine and tagged MR images at apical, midventricular, and basal levels were acquired from six male volunteers, six Fischer 344 rats, and seven C57BL/6 mice. Morphological parameters and ejection fraction were computed directly from cine images. Myocardial twist (rotation angle), torsion (net twist per unit length), circumferential strain, and normalized radial shortening were calculated by homogeneous strain analysis from tagged images. Our data show that ventricular twist was conserved among the three species, leading to a significantly smaller torsion, measured as net twist per unit length, in men. However, both circumferential strain and normalized radial shortening were the largest in male subjects. Although other parameters, such as circumferential-longitudinal shear strain, need to be evaluated, and the causes of these differences in contractile mechanics remain to be elucidated, the preservation of twist appears fundamental to cardiac function and should be considered in studies that extrapolate data from animals to humans.
    Preview · Article · Dec 2006 · AJP Heart and Circulatory Physiology
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    ABSTRACT: The purpose of this study was to evaluate the reliability of the pressure half-time (PHT) method for estimating mitral valve areas (MVAs) by velocity-encoded cardiovascular magnetic resonance (VE-CMR) and to compare the method with paired Doppler ultrasound. The pressure half-time Doppler echocardiography method is a practical technique for clinical evaluation of mitral stenosis. As CMR continues evolving as a routine clinical tool, its use for estimating MVA requires thorough evaluation. Seventeen patients with mitral stenosis underwent echocardiography and CMR. Using VE-CMR, MVA was estimated by PHT method. Additionally, peak E and peak A velocities were defined. Interobserver repeatability of VE-CMR was evaluated. By Doppler, MVAs ranged from 0.87 to 4.49 cm2; by CMR, 0.91 to 2.70 cm2, correlating well between modalities (r = 0.86). The correlation coefficient for peak E and peak A between modalities was 0.81 and 0.89, respectively. Velocity-encoded CMR data analysis provided robust, repeatable estimates of peak E, peak A, and MVA (r = 0.99, 0.99, and 0.96, respectively). Velocity-encoded cardiovascular magnetic resonance can be used routinely as a robust tool to quantify MVA via mitral flow velocity analysis with PHT method.
    Full-text · Article · Aug 2004 · Journal of the American College of Cardiology
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    ABSTRACT: Valvular pathology can be analyzed quickly and accurately through the use of Doppler ultrasound. For aortic stenosis, the continuity equation approach with Doppler velocity-time integral (VTI) data is by far the most commonly used clinical method of quantification. In view of the emerging popularity of cardiac magnetic resonance (CMR) as a routine clinical imaging tool, the purposes of this study were to define the reliability of velocity-encoded CMR as a routine method for quantifying stenotic aortic valve area, to compare this method with the accepted standard, and to evaluate its reproducibility. Patients (n=24) with aortic stenosis (ranging from 0.5 to 1.8 cm2) were imaged with CMR and echocardiography. Velocity-encoded CMR was used to obtain velocity information in the aorta and left ventricular outflow tract. From this flow data, pressure gradients were estimated by means of the modified Bernoulli equation, and VTIs were calculated to estimate aortic valve orifice dimensions by means of the continuity equation. The correlation coefficients between modalities for pressure gradients were r=0.83 for peak and r=0.87 for mean. The measurements of VTI correlated well, leading to an overall strong correlation between modalities for the estimation of valve dimension (r=0.83, by means of the identified best approach). For 5 patients, the CMR examination was repeated using the best approach. The repeat calculations of valve size correlated well (r=0.94). Velocity-encoded CMR can be used as a reliable, user-friendly tool to evaluate stenotic aortic valves. The measurements of pressure gradients, VTIs, and the valve dimension correlate well with the accepted standard of Doppler ultrasound.
    Preview · Article · Nov 2003 · Circulation
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    Preview · Article · Mar 2003 · Journal of the American College of Cardiology
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    Full-text · Article · Mar 2002 · Journal of the American College of Cardiology
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    A W Bowman · S D Caruthers · M P Watkins · S J Kovbcs
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    ABSTRACT: The normal left ventricular (Lv) wall twists (apex relative to base) 12-14 degrees during ejection. The papillary muscles (PM) and chordae tendenae are force transducing elements between the LV chamber and the mitral annulus. We hypothesize that relative PM displacement and rotation (in short-axis views) is coupled to LV torsion. In ten normal subjects, PM position was measured at end-systole and end-diastole. The line connecting PM midpoints rotated 4.3 f 2.7 degrees and shortened 23 f 7% of its end-diastolic length. We conclude that PM motion reflects twist and wall thickening generated by the LV during ejection. Introduction: The helical fiber structure of the LV wall (1) requires that letl ventricular (LV) ejection generate twisting of the LV apex relative to the base (2). In normal, healthy individuals at rest, a maximum relative twist of about 12-14 degrees has been observed, while the maximum twist at the mid-papillary muscle level has averaged 4-6 degrees (2,3). The majority of systolic twist and diastolic untwist occurs during isovolumic contraction and isovolumic relaxation, respectively (45). The papillary muscles (PM) and chordae act as a systolic force member connecting the mitral annulus (through the coapted leaflets) to the apicolateral endocardial surface where the papillary muscles insert. Characterization of the displacement of the PMs relative to LV twist has not been previously performed. Cardiac magnetic resonance imaging (MRI) is ideal for quantitating the amount of LV twist via myocardial tagging (3) and allows optimal determination of PM location and motion in short-axis views. Purpose: We hypothesize that LV end-systolic versus end-diastolic twist and translation can be quantitated using non-tagged short-axis, mid-papillary images. Due to their anatomical location within the LV, the PMs must also twist and translate during the cardiac cycle. We seek to show that in normal subjects, the angular displacement of the centers of the PMs relative to each other (measured as rotation of the line that connects the centers of the PMs in short-axis images) as well as the distance between them is concordant with the net twist and wall thickening of the LV as a whole.
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