Quantification and compensation of eddy-current-induced magnetic-field gradients
نویسندگان
چکیده
منابع مشابه
Quantification and compensation of eddy-current-induced magnetic-field gradients.
Two robust techniques for quantification and compensation of eddy-current-induced magnetic-field gradients and static magnetic-field shifts (ΔB0) in MRI systems are described. Purpose-built 1-D or six-point phantoms are employed. Both procedures involve measuring the effects of a prior magnetic-field-gradient test pulse on the phantom's free induction decay (FID). Phantom-specific analysis of t...
متن کاملAnalysis of the eddy-current induced artifacts and the temporal compensation in nuclear magnetic resonance imaging.
Reduction of eddy currents by a temporal compensation of the input current waveform to the gradient coil is studied with an analytic solution. The technique is the inverse filtering of the eddy-current affected field response, which is calculated from the diffusion equation. The limitation of the temporal compensation due to the spatially variant eddy currents is also investigated for whole-bod...
متن کاملLocalized eddy current compensation using quantitative field mapping.
Eddy current effects induced by switched gradients in proximal conducting structures are traditionally reduced by applying preemphasis currents whose amplitudes and decay characteristics must be set to offset the eddy current fields. We present an expeditious, localized, and quantitative method for mapping and adjusting the parameters for eddy current compensation. Mapping is based on analysis ...
متن کاملInherent eddy current compensation for high-resolution DTI using bipolar diffusion gradients
Introduction: Clinical diffusion-weighted imaging (DWI) often employs a single-shot echo-planar imaging (EPI) readout to increase acquisition speed. This comes at a cost, however, since conventional DWI sequences employ a spin echo (SE) sequence with either unipolar or bipolar diffusion-sensitizing gradients on both sides of the 180º refocusing pulse. This configuration shortens the separation ...
متن کاملInversion of Eddy - Current Data via Conjugate Gradients
In a companion paper, [1], we developed a rigorous, nonlinear model for inverting eddy-current data by means of the conjugate gradient algorithm. In this paper we will present some results obtained from the linearized version of the rigorous model. In this version we assume that the electric field within the flaw is simply the incident field that exists in the absence of the flaw. Hence, if we ...
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: Journal of Magnetic Resonance
سال: 2011
ISSN: 1090-7807
DOI: 10.1016/j.jmr.2011.06.016