k-Space tutorial: an MRI educational tool for a better understanding of k-space

Abstract

A main difference between Magnetic Resonance (MR) imaging and other medical imaging modalities is the control over the data acquisition and how it can be managed to finally show the adequate reconstructed image. With some basic programming adjustments, the user can modify the spatial resolution, field of view (FOV), image contrast, acquisition velocity, artifacts and so many other parameters that will contribute to form the final image. The main character and agent of all this control is called k-space, which represents the matrix where the MR data will be stored previously to a Fourier transformation to obtain the desired image.This work introduces 'k-Space tutorial', a MATLAB-based educational environment to learn how the image and the k-space are related, and how the image can be affected through k-space modifications. This MR imaging educational environment has learning facilities on the basic acceleration strategies that can be encountered in almost all MR scanners: scan percentage, rectangular FOV and partial Fourier imaging. It also permits one to apply low- and high-pass filtering to the k-space, and to observe how the contrast or the details are selected in the reconstructed image. It also allows one to modify the signal-to-noise ratio of the acquisition and create some artifacts on the image as a simulated movement of the patient – with variable intensity level – and some electromagnetic spikes on k-space occurring during data acquisition.

Dynamic Contrast-Enhanced MR Imaging of Endometrial Cancer: Optimizing the Imaging Delay for Tumour-Myometrium Contrast

“…The concept of reducing the scan percentage is one such recent advance [16]; reducing the scan percentage has allowed for multiple sequential data acquisition with higher obtained from the ROIs. Note that the first measurement of the timesignal intensity data was obtained from pre-contrast MR images and the second measurement was obtained from dynamic contrast-enhanced MR images acquired simultaneously with the injection of the contrast material temporal resolution, which allows for perfusion imaging.…”

The influence of the blood pressure on the venous cerebral flow measured by magnetic susceptibility (SWI) technique

“…In this way deoxyhemoglobin levels increase mainly in the venous vasculature. With the use of new MRI sequences it is possible to take advantage of the susceptibility phenomena to give us an image of the cerebral vasculature mainly in the venous circulation due to the presence of deoxyhemoglobin [46]. As proposed, it was proceeded a quantitative assessment of CNR in three different anatomic structures, in a population of normotensives and hypertensives.…”

“…Energy released due to relaxation of the spins is collected by a receive coil (or coils) into a raw data matrix called the k-space. The raw data are then ‘reconstructed’ to create MR images after Fourier transformation [1]. Figure 1A & B show an example of a k-space and its corresponding reconstructed image.…”

Anatomical, functional and molecular biomarker applications of magnetic resonance neuroimaging

“…Energy released due to relaxation of the spins is collected by a receive coil (or coils) into a raw data matrix called the k-space. The raw data are then ‘reconstructed’ to create MR images after Fourier transformation [1]. Figure 1A & B show an example of a k-space and its corresponding reconstructed image.…”