What is MRI in phase and out phase?
In-phase (IP) and out-of-phase (OOP) sequences correspond to paired MRI gradient echo (GRE) sequences obtained with the same repetition time (TR) but with two different echo time (TE) values.
What does in phase mean in MRI?
Spatial encoding in MRI The second step of spatial localization is called phase encoding. A magnetic gradient field is applied briefly in one direction. As the change in frequency is very brief, when the gradient is switched off, it causes a change in phase that is proportional to the distance.
How can I tell what sequence my MRI is?
The best way to tell the two apart is to look at the grey-white matter. T1 sequences will have grey matter being darker than white matter. T2 weighted sequences, whether fluid attenuated or not, will have white matter being darker than grey matter.
What is chemical shift MRI?
Chemical shift imaging is an MRI technique that is used to determine whether lipid and water protons are present with the same small voxel (three-dimensional pixel) of space.
What is the difference between T1 and T2 weighted images in MRI?
The most common MRI sequences are T1-weighted and T2-weighted scans. T1-weighted images are produced by using short TE and TR times. The contrast and brightness of the image are predominately determined by T1 properties of tissue. Conversely, T2-weighted images are produced by using longer TE and TR times.
What does in phase and out of phase mean?
If two things are happening in/out of phase they are reaching the same or related stages at the same time/at different times. SMART Vocabulary: related words and phrases.
What is the difference between phase and frequency MRI?
The frequency-encoding direction is along the x-axis in K-space (may or may not be that axis in the image, if it is rotated); this represents the time samples of the signal. The y-axis is the phase-encoding direction: each phase-encoding step yields a separate horizontal line.
How do I know if my MRI is T1 or T2?
What is a Dixon sequence?
The Dixon method is an MRI sequence based on chemical shift and designed to achieve uniform fat suppression. It has been gaining popularity as it has some advantages over other fat suppression techniques, namely: suppression of fat signal is more uniform and less affected by artifacts than many other techniques.
What is phase Mismapping artifact?
Phase mismapping occurs when anatomy is not collected properly. This is commonly due to motion. Frequencies are collect over a period of time. After each phase encoding step in filling our K space, a line is selected and frequencies are placed in it during data collection.
What is the most important sequence of the adrenal MRI protocol?
The most important sequence of the adrenal MRI protocol is chemical shift imaging performed with in-phase and out-of-phase sequences. Loss of signal intensity of the adrenal mass on out-of-phase images, compared to the in-phase pulse sequence, is diagnostic of the presence of intracellular lipid.
What is the role of MRI in the detection of adrenal lesions?
The detection of adrenal lesions has increased with the expanding use of cross-sectional imaging. Magnetic resonance (MR) imaging is often useful for characterizing adrenal masses.
How are adrenal masses classified on MR imaging?
Magnetic resonance (MR) imaging is often useful for characterizing adrenal masses. Adrenal masses can be classified into various groups on the basis of the presence of intracellular lipid, macroscopic fat, hemorrhage, and cystic changes and the vascularity and shape of the tumor.
Why use an accelerated pulse sequence for adrenal imaging?
This is due primarily to the modality’s inherent tissue characterizing ability, but also to a variety of accelerated pulse sequences which confer some advantages over other imaging modalities used for adrenal imaging.