title: The shoulder: adaptive motion correction of MR images.
abstract: OBJECTIVE
  To evaluate an adaptive-motion-correction technique to reduce global motion in shoulder magnetic resonance (MR) images.
  
  
  METHODS
  In the adaptive-motion-correction technique, interleaved navigator echoes are used to provide a measure of view-to-view displacement along the craniocaudal direction for each image echo in the acquisition. The information is then retrospectively applied to the k-space data to correct for global shoulder motion. This algorithm was evaluated in a series of 143 consecutive patient shoulder examinations by comparing the original image set for each patient with the same image set after retrospective correction by means of this algorithm.
  
  
  RESULTS
  The average amplitude of craniocaudal motion was 1.4 mm. Image degradation due to motion was apparent in 100 (70%) of the 143 examinations. Application of the adaptive-motion-correction technique improved image quality in 73 (73%) of these 100 examinations or 51% of all 143 examinations.
  
  
  CONCLUSIONS
  Adaptive motion correction improved image quality in approximately three-quarters of the examinations in which motion was present.
authors.affiliation: Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: K P
authors.initials: KP
authors.lastname: McGee
authors.forename: R C
authors.initials: RC
authors.lastname: Grimm
authors.forename: J P
authors.initials: JP
authors.lastname: Felmlee
authors.forename: J R
authors.initials: JR
authors.lastname: Rydberg
authors.forename: S J
authors.initials: SJ
authors.lastname: Riederer
authors.forename: R L
authors.initials: RL
authors.lastname: Ehman
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009068:Movement; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000502:physiology*