phase encoding direction
Spatial encoding axis in MRI that determines the direction of motion artifacts and distortion patterns.
Full Definition
Phase encoding direction refers to one of the two spatial encoding axes in MRI acquisition, typically designated as anterior-posterior, left-right, or superior-inferior. This parameter determines how spatial information is encoded using phase variations of the MR signal and directly affects where motion artifacts appear in the final image. Motion artifacts from patient movement, cardiac pulsation, or breathing appear as ghosting or streaking along the phase encoding direction. Strategic selection of phase encoding direction can minimize artifact interference with regions of diagnostic interest and is particularly important in neuroimaging where small structures require clear visualization.
Usage
Usage note: Always specify the anatomical direction (AP, RL, SI) when documenting phase encoding direction.
In Context
- "The phase encoding direction was set to anterior-posterior to minimize cardiac artifacts over the brainstem." — Technical parameter selection
- "Motion ghosting artifacts were visible along the phase encoding direction but did not obscure the lesion." — Image quality assessment