身心疲惫
发表于 2025-3-28 18:05:52
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interrogate
发表于 2025-3-28 20:11:25
Making an Image: Locating and Encoding Signals in Spaceg (known as a phase encoding step). The MR image is reconstructed using an algorithm, known as a two-dimensional (2D) Fourier transform. This is applied to the resultant signals to decode the contributions from different locations based on their frequency and the change in phase with each phase enco
暖昧关系
发表于 2025-3-29 01:09:45
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diabetes
发表于 2025-3-29 04:01:28
Imaging Parameters and Image Attributesreasing receiver bandwidth leads to faster echo sampling, shorter TE and TR hence shorter image acquisition time, but reduces SNR. In comparison to 2D imaging, 3D imaging allows thinner, contiguous slices to be acquired with improved SNR but with a longer acquisition time.
OREX
发表于 2025-3-29 08:56:08
Gradient Echo Versus Spin Echo180° refocusing pulse in the gradient echo sequence leads to a greater influence of magnetic susceptibility effects, different appearances of the chemical shift artefact and flow blood in comparison with spin echo.
可憎
发表于 2025-3-29 12:30:36
Black Blood Versus Bright Blood Imagingight blood appearance from flowing blood. The short TR causes saturation of the magnetisation and a reduction in signal of stationary tissue within the slice. Flowing blood entering the slice is fully magnetised and is able to yield a higher signal than the surrounding tissue, resulting in a bright
Vldl379
发表于 2025-3-29 17:47:01
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放牧
发表于 2025-3-29 23:05:28
Fast Imaging: How Do We Speed Up the Image Acquisition?lf of k-space, either by omitting phase encoding steps, or by not sampling first part of the echo. Parallel imaging makes use of multi-element array coils to reduce the amount of phase encoding required, resulting in faster image acquisition times.
周兴旺
发表于 2025-3-30 01:07:33
Special Pulse Sequences for Cardiac Imagingith respiratory navigator gating. Retrospectively-gated cine gradient echo imaging is used for functional imaging, while velocity-encoded cine gradient echo imaging is used for flow quantification. The assessment of intra-myocardial contraction is possible using myocardial tagging pulses combined wi
他很灵活
发表于 2025-3-30 04:32:12
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