نتایج جستجو برای: لایه واسط mbf 20

تعداد نتایج: 631172  

Journal: :JACC. Cardiovascular imaging 2014
Ines Valenta Alessandra Quercioli Thomas H Schindler

OBJECTIVES The purpose of this study was to evaluate the diagnostic value of a positron emission tomography (PET)/computed tomography (CT)-determined longitudinal decrease in myocardial blood flow (MBF) gradient during hyperemia and myocardial flow reserve (MFR) for the identification of epicardial stenosis ≥50%. BACKGROUND Although PET-determined reductions in MFR are increasingly applied to...

ژورنال: :مهندسی متالورژی 2014
عباس جهانبخش بیژن عباسی خزایی رضا بختیاری

در این پژوهش، فرآیند اتصال فاز مایع گذرا (tlp) در اتصال نامتجانس سوپر آلیاژ پایه نیکلin-738 به سوپر آلیاژ پایه کبالت fsx-414 با استفاده از لایه واسط پایه نیکل mbf-80 با ضخامت μm50 بکار گرفته شده است. اتصال دهی در دمای بهینه  ℃1150 و مدت زمان 5 دقیقه در کوره تحت خلا صورت گرفت. در ادامه، عملیات همگن سازی، به منظور بهبود ریزساختار و خواص مکانیکی ناحیه اتصالtlp،در دماهای  1175،  1200 و ℃1225 و به م...

Journal: :Journal of magnetic resonance imaging : JMRI 2008
Timothy F Christian Anthony H Aletras Andrew E Arai

PURPOSE To compare the dual-bolus to single-bolus quantitative first-pass magnetic resonance myocardial perfusion imaging for estimation of absolute myocardial blood flow (MBF). MATERIALS AND METHODS Dogs had local hyperemia of MBF in the left anterior descending (LAD) coronary artery (intracoronary adenosine). Animals (n = 6) had sequential single- and dual-bolus perfusion studies with micro...

2015
Takashi Ichihara Richard T. George Richard Mather Joao A. C. Lima Albert C. Lardo

Materials and Methods: Nine canine models of left anterior descending artery stenosis were prepared and underwent MDCT perfusion imaging during adenosine infusion to study a wide range of flow parameters. Neutron-activated microspheres were injected to document MBF during adenosine infusion. Six animals underwent dynamic MDCT perfusion imaging, and K1 and k2 (which represent the first-order tra...

2017
Adrian Ocneanu Robert A. deKemp Jennifer M. Renaud Andy Adler Rob S. B. Beanlands Ran Klein

Purpose. Myocardial blood flow (MBF) quantification with 82Rb positron emission tomography (PET) is gaining clinical adoption, but improvements in precision are desired. This study aims to identify analysis variants producing the most repeatable MBF measures. Methods. 12 volunteers underwent same-day test-retest rest and dipyridamole stress imaging with dynamic 82Rb PET, from which MBF was quan...

Journal: :Journal of the American College of Cardiology 1999
C S Duvernoy C Meyer V Seifert-Klauss F Dayanikli I Matsunari J Rattenhuber C Höss H Graeff M Schwaiger

OBJECTIVES The purpose of the study was to compare myocardial blood flow (MBF) in hyperlipidemic postmenopausal women and age-matched hyperlipidemic men, and to analyze the relationship between cholesterol subfractions and myocardial blood flow in men and women. BACKGROUND Women are protected from coronary artery disease (CAD) events until well after menopause, in part due to gender-specific ...

2010
S. Sourbron W. Morton D. L. Buckley J. P. Greenwood S. Plein

INTRODUCTION Measurement of myocardial blood flow (MBF) with DCE-MRI is conventionally performed on a region-of-interest (ROI) basis: time curves are averaged over a ROI, and tracer kinetic analysis is applied to the ROI curve to derive the MBF [1, 2]. In principle, a voxelwise analysis is more attractive since it produces higher resolution images of MBF and may thus increase the diagnostic pow...

2014
Bara Erhayiem Ananth Kidambi David P Ripley Adam K McDiarmid Steven Sourbron John P Greenwood Sven Plein

Background First pass myocardial perfusion CMR allows quantification of myocardial blood flow (MBF). MBF estimation with whole-heart tissue response may be useful in a variety of systemic diseases, but can be limited by suboptimal imaging in one or more segments. The interventricular septum (IVS) offers an attractive target for MBF imaging, as it offers higher signal and less partial volume art...

2017
P. Chilra S. Gnesin G. Allenbach M. Monteiro J. O. Prior L. Vieira J. A. Pires Jorge

BACKGROUND Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Rest and stress list-mode dynamic 82Rb PET acquisition data from 10 patients without ...

Journal: :Circulation 1999
O Rimoldi S M Burns S D Rosen T E Wistow P M Schofield G Taylor P G Camici

BACKGROUND Transmyocardial laser revascularization (TMLR) has been proposed for treatment of refractory angina. It has been hypothesized that transmural left ventricular channels created by laser improve myocardial blood flow (MBF) in the treated zones. We aimed to assess the effect of TMLR on MBF and coronary vasodilator reserve (CVR). METHODS AND RESULTS We measured MBF by means of PET with...

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