315 Basic Examination of Spiral Scan method in Spoiled Gradient Echo
نویسندگان
چکیده
منابع مشابه
Spoiled & Balanced Gradient Echo Methods
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 کاملSimplified Signal Equations for Spoiled Gradient Echo MRI
INTRODUCTION: This work presents simplified signal equations for spoiled gradient echo (SPGR) imaging that, to the authors' knowledge, has not been published. The framework introduces an exponential time constant TA, which reflects magnetization loss from the rf pulse. This framework is then used for to consider image SNR and T1 contrast. THEORY: Image SNR can be approximated as the product of ...
متن کاملImproved Radial Spoiled Gradient Echo Imaging with Randomized RF Phases and Gradient Moments
Introduction Radiofrequency (RF) spoiling is the most established spoiling method for gradient echo imaging. It is based on a quadratic variation of RF (and receiver) phase angles in successive TRs, coupled with a constant gradient moment at the end of each TR period to create a range of resonance offset angles within each imaging voxel (1). However, it was recognized that RF spoiling yields no...
متن کاملMR Estimation of Longitudinal Relaxation Time (T1) in Spoiled Gradient Echo Using an Adaptive Neural Network
Introduction: The acquisition of high-resolution T1 maps in a clinically feasible time frame has been demonstrated with Driven Equilibrium Single Pulse Observation of T1 (DESPOT1) [1-3]. DESPOT1 derives the longitudinal relaxation time, T1, from two or more spoiled gradient recalled echo (SPGR) images acquired with a constant TR and different flip angles [2, 3]. In general, T1 can be estimated ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Japanese Journal of Radiological Technology
سال: 1997
ISSN: 0369-4305,1881-4883
DOI: 10.6009/jjrt.kj00001356158