Patient motion during the acquisition of a magnetic resonance image can cause blurring and ghosting artifacts in the image. This paper presents a new post-processing strategy that can reduce artifacts due to in-plane, rigid- body motion in times comparable to that required to re-scan a patient. The algorithm iteratively determines unknown patient motion such that corrections for this motion provide the best image quality, as measured by an entropy- related focus criterion. The new optimization strategy features a multi- resolution approach in the phase-encode direction, separate successive one- dimensional searches for rotations and translations, and a novel method requiring only one re-gridding calculation for each rotation angle considered. Applicability to general rigid-body in-plane rotational and translational motion and to a range of differently weighted images and k- space trajectories is demonstrated. Motion artifact reduction is observed for data from a phantom, volunteers, and patients.
|Number of pages||8|
|Journal||Magnetic Resonance in Medicine|
|Publication status||Published - 1999|
- Motion correction
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology