MRI Imaging Techniques

In and out-of-phase imaging is used in abdominal imaging to identify fat-related pathology.
Two sets of data are acquired, one where fat and water are in phase and one where they're out of phase.
The TE determines the type of contrast obtained in the images.
Saturation bands or sat bands are used to remove unwanted tissue from images.
Sat bands can be used to suppress flow and reduce aliasing in images.
Fat saturation or fat sat is used to suppress fat in images.
Fat sat can be difficult to target in non-uniform isocenters or with high susceptibility tissues.
The use of sat bands and fat sat can increase scan time and patient heating due to increased RF pulses.
Suppression pulses can be chemical or spatial pre-saturation pulses.
Sat bands are placed in areas where unwanted tissue needs to be removed, while fat sat is used to suppress fat in images.
The text discusses different techniques for removing unwanted signals from MRI images.
One technique is using spatial pre-saturation, where RF pulses are delivered at the frequency of the unwanted signal to excite and then remove it from the image.
Another technique is using chemical pre-saturation, also known as fat saturation, to remove fat signals from the image.
The text also discusses 2D and 3D imaging techniques and their respective benefits and disadvantages.
2D imaging is faster and can achieve high in-plane resolution, while 3D imaging has higher signal-to-noise and post-reconstruction options.
Sequential data collection and interleaving are two ways to acquire data for 2D and 3D imaging.
Sequential data collection can lead to cross-excitation between slices, so a gap is added between slices.
Interleaving involves collecting data from non-adjacent slices, which can reduce cross-excitation.
3D volumetric data collection can be done using different techniques, such as Cartesian, radial, or spiral.
The choice of imaging technique depends on the desired outcome and the characteristics of the patient and the imaging equipment.
Skipping a slice in MRI imaging can prevent cross-excitation artifacts.
Each slice in MRI imaging is typically 3 millimeters thick.
There are different techniques for collecting MRI data, including 2D sequential imaging.
In 2D sequential imaging, each slice has its own k space and data is collected in sequential order.
Interleaving can be used to fill slices in 2D sequential imaging.
Echoes must be placed within each k space to meet phase encoding direction limits.
2D-volumetric data collection involves filling multiple slices at once.
3D-volumetric data collection involves filling an entire volume at once.
The choice of MRI data collection technique can impact image quality and scan time.
Understanding the different options for MRI data collection is important for optimizing imaging results.