title: Deformable registration for quantifying longitudinal tumor changes during neoadjuvant chemotherapy.
abstract: OBJECTIVE
  To evaluate DRAMMS, an attribute-based deformable registration algorithm, compared to other intensity-based algorithms, for longitudinal breast MRI registration, and to show its applicability in quantifying tumor changes over the course of neoadjuvant chemotherapy.
  
  
  METHODS
  Breast magnetic resonance images from 14 women undergoing neoadjuvant chemotherapy were analyzed. The accuracy of DRAMMS versus five intensity-based deformable registration methods was evaluated based on 2,380 landmarks independently annotated by two experts, for the entire image volume, different image subregions, and patient subgroups. The registration method with the smallest landmark error was used to quantify tumor changes, by calculating the Jacobian determinant maps of the registration deformation.
  
  
  RESULTS
  DRAMMS had the smallest landmark errors (6.05 ± 4.86 mm), followed by the intensity-based methods CC-FFD (8.07 ± 3.86 mm), NMI-FFD (8.21 ± 3.81 mm), SSD-FFD (9.46 ± 4.55 mm), Demons (10.76 ± 6.01 mm), and Diffeomorphic Demons (10.82 ± 6.11 mm). Results show that registration accuracy also depends on tumor versus normal tissue regions and different patient subgroups.
  
  
  CONCLUSIONS
  The DRAMMS deformable registration method, driven by attribute-matching and mutual-saliency, can register longitudinal breast magnetic resonance images with a higher accuracy than several intensity-matching methods included in this article. As such, it could be valuable for more accurately quantifying heterogeneous tumor changes as a marker of response to treatment.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Yangming
authors.initials: Y
authors.lastname: Ou
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Weinstein
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Emily F
authors.initials: EF
authors.lastname: Conant
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Englander
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Da
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Bilwaj
authors.initials: B
authors.lastname: Gaonkar
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Meng-Kang
authors.initials: MK
authors.lastname: Hsieh
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Rosen
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Angela
authors.initials: A
authors.lastname: DeMichele
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Christos
authors.initials: C
authors.lastname: Davatzikos
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Despina
authors.initials: D
authors.lastname: Kontos
mesh_terms: D059925:Anatomic Landmarks; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D003287:Contrast Media; D003520:Cyclophosphamide / Q000008:administration & dosage; D000077143:Docetaxel; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D020360:Neoadjuvant Therapy; D012189:Retrospective Studies; D043823:Taxoids / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D043823:Taxoids; D000077143:Docetaxel; D004317:Doxorubicin; C064925:gadodiamide; D003520:Cyclophosphamide; D019786:Gadolinium DTPA
keywords: breast cancer; deformable image registration; evaluation; longitudinal breast MRI; treatment; tumor changes