title: Pulmonary kinematics from tagged hyperpolarized helium-3 MRI.
abstract: OBJECTIVE
  To propose and test the feasibility of a novel method for quantifying 3D regional pulmonary kinematics from hyperpolarized helium-3 tagged MRI in human subjects using a tailored image processing pipeline and a recently developed nonrigid registration framework.
  
  
  METHODS
  Following image acquisition, inspiratory and expiratory tagged (3)He magnetic resonance (MR) images were preprocessed using various image filtering techniques to enhance the tag surfaces. Segmentation of the three orthogonal sets of tag planes in each lung produced distinct point-set representations of the tag surfaces. Using these labeled point-sets, deformation fields and corresponding strain maps were obtained via nonrigid point-set registration. Kinematic analysis was performed on three volunteers.
  
  
  RESULTS
  Tag lines in inspiratory and expiratory images were coregistered producing a continuous 3D correspondence mapping. Average displacement and directional strains were calculated in three subjects in the inferior, mid, and superior portions of the right and left lungs. As expected, the predominant direction of displacements with expiration is from inferior to superior.
  
  
  CONCLUSIONS
  Kinematic quantitation of pulmonary motion using tagged (3)He MRI is feasible using the applied image preprocessing filtering techniques and nonrigid point-set registration. Potential benefits from regional pulmonary kinematic quantitation include the facilitation of diagnosis and local assessment of disease progression.
authors.affiliation: Penn Image Computing and Science Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA. tustison@picsl.upenn.edu
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Tustison
authors.forename: Suyash P
authors.initials: SP
authors.lastname: Awate
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.forename: Talissa A
authors.initials: TA
authors.lastname: Altes
authors.forename: G Wilson
authors.initials: GW
authors.lastname: Miller
authors.forename: Eduard E
authors.initials: EE
authors.lastname: de Lange
authors.forename: John P
authors.initials: JP
authors.lastname: Mugler
authors.forename: James C
authors.initials: JC
authors.lastname: Gee
mesh_terms: D000280:Administration, Inhalation; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006371:Helium / Q000008:administration & dosage*; D006801:Humans; D007554:Isotopes / Q000008:administration & dosage; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D007554:Isotopes; D006371:Helium