title: Quantitative assessment of atrial regional function using motion estimation computed tomography.
abstract: OBJECTIVE
  We validated a novel image-based motion estimation computed tomographic (CT) technique (iME) to quantify atrial regional function in swine in vivo.
  
  
  METHODS
  Domestic swine (n = 8) underwent CT scan with intravenous contrast before and after median sternotomy where 15 to 30 glass beads were sutured to the atria to calculate the motion estimation error. Four-dimensional motion vector field was estimated using iME. Area change ratio (%AC) was calculated over the atrial endocardium to assess the surface deformation.
  
  
  RESULTS
  The error between the measured and the calculated coordinates based on motion vector field was 0.76 ± 0.43 mm. The %AC was regionally heterogeneous. The %AC time course was significantly different between the right and the left atriums (P < 0.001) as well as between the right atrial appendage and the right atrial chamber (P = 0.004).
  
  
  CONCLUSIONS
  Quantitative assessment of atrial regional function using iME is highly accurate. Image-based motion estimation computed tomographic (CT) technique can quantify subtle regional dysfunction that is not apparent in global functional indices such as ejection fraction.
authors.affiliation: From the *Division of Cardiology, †Department of Biomedical Engineering, ‡The Russell H. Morgan Department of Radiology and Radiological Science, and §Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ashikaga
authors.forename: Jochen
authors.initials: J
authors.lastname: Cammin
authors.forename: Qiulin
authors.initials: Q
authors.lastname: Tang
authors.forename: Karly
authors.initials: K
authors.lastname: Knudsen
authors.forename: Yuko
authors.initials: Y
authors.lastname: Inoue
authors.forename: Elliot K
authors.initials: EK
authors.lastname: Fishman
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Taguchi
mesh_terms: D000465:Algorithms; D000818:Animals; D016275:Atrial Function / Q000502:physiology*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009038:Motion; D009068:Movement / Q000502:physiology*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods*