title: Comparison and evaluation of rigid, affine, and nonrigid registration of breast MR images.
abstract: OBJECTIVE
  A new nonrigid registration method, designed to reduce the effect of movement artifact in subtraction images from breast MR, is compared with existing rigid and affine registration methods.
  
  
  METHODS
  Nonrigid registration was compared with rigid and affine registration methods and unregistered images using 54 gadolinium-enhanced 3D breast MR data sets. Twenty-seven data sets had been previously reported normal, and 27 contained a histologically proven carcinoma. The comparison was based on visual assessment and ranking by two radiologists.
  
  
  RESULTS
  When analyzed by two radiologists independently, all three registration methods gave better-quality subtraction images than unregistered images (p < 0.01), but nonrigid registration gave significantly better results than the rigid and affine registration methods (p < 0.01). There was no significant difference between rigid and affine registration methods.
  
  
  CONCLUSIONS
  Nonrigid registration significantly reduces the effects of movement artifact in subtracted contrast-enhanced breast MRI. This may enable better visualization of small tumors and those within a glandular breast.
authors.affiliation: Department of Radiology, King's College Hospital, London, England.
authors.forename: E R
authors.initials: ER
authors.lastname: Denton
authors.forename: L I
authors.initials: LI
authors.lastname: Sonoda
authors.forename: D
authors.initials: D
authors.lastname: Rueckert
authors.forename: S C
authors.initials: SC
authors.lastname: Rankin
authors.forename: C
authors.initials: C
authors.lastname: Hayes
authors.forename: M O
authors.initials: MO
authors.lastname: Leach
authors.forename: D L
authors.initials: DL
authors.lastname: Hill
authors.forename: D J
authors.initials: DJ
authors.lastname: Hawkes
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001940:Breast / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D008875:Middle Aged; D015588:Observer Variation; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA