Flip angle calculation for consistent contrast in spoiled gradient echo imaging
نویسندگان
چکیده
منابع مشابه
Optimal Flip Angle Set in Spoiled Gradient-Echo MR Imaging Technique
Introduction: In dynmiac contrast enchanted-MRI (DCE-MRI), T1-Weghited spoiled Gradient-Echo (SPGR) sequences are utilized to monitor the distribution of the paramagnetically labeled CAs (contrast agent) in cerebral tumors due to high temporal and spatial resolution [1]. The tissue concentration of CAs measured by CAs effects on the longitudinal relaxation rate of water protons R1 is used by tr...
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Imaging with spoiled, balanced or nonbalanced gradient echo (GRE) refers to a class of fast imaging sequences that use a dynamic equilibrium or steady state signal for imaging. As originally introduced in 1958 by Carr (1) for NMR spectroscopy, a dynamic equilibrium or steadystate can be established by a train of radio-frequency (RF) excitation pulses interleaved by periods of ‘free precession’,...
متن کاملSpoiled & Balanced Gradient-Echo Sequences
1 Introduction Rapid imaging sequences are characterized by a fast train of excitation and gradient pulses. Between excitation pulses or within TR, the magnetization is not able to return to its thermal equilibrium. As a consequence, excitation pulses will influence both the remaining transversal and the remaining longitudinal magnetization. The steady-state magnetization of a multi pulse exper...
متن کاملAutomatic Brain Segmentation using Fractional Signal Modelling of a Multiple Flip Angle Spoiled Gradient-Recalled Echo Acquisition
Object: The aim of this study was to demonstrate a new automatic brain segmentation method in MRI. Materials and Methods: The signal of a spoiled gradient-recalled echo (SPGR) sequence acquired with multiple flip angles was used to map T1, and a subsequent fit of a multicompartment model yielded parametric maps of partial volume estimates of the different compartments. The performance of the pr...
متن کاملHexagonal gradient scheme with RF spoiling improves spoiling performance for high‐flip‐angle fast gradient echo imaging
PURPOSE To present a framework in which time-varying gradients are applied with RF spoiling to reduce unwanted signal, particularly at high flip angles. METHODS A time-varying gradient spoiler scheme compatible with RF spoiling is defined, in which spoiler gradients cycle through the vertices of a hexagon, which we call hexagonal spoiling. The method is compared with a traditional constant sp...
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ژورنال
عنوان ژورنال: Magnetic Resonance in Medicine
سال: 2005
ISSN: 0740-3194,1522-2594
DOI: 10.1002/mrm.20420