title: Alignment of 3-dimensional cardiac structures in O-15-labeled water PET emission images with mutual information.
abstract: BACKGROUND
  The aim of this study was to develop a method to correct the heart position between two oxygen 15-labeled water cardiac positron emission tomography (PET) image sets to be able to use the equivalent regions of interest for the quantification of the perfusion values in the same myocardial segments.
  
  
  RESULTS
  Independent component analysis was applied to the dynamic image sets (simulated phantom and 6 rest-pharmacologic stress and 10 rest-rest image sets of healthy female volunteers) acquired at different time points to separate the cardiac structures (ventricles and myocardium). The separated component images from independent component analysis from the 2 studies of the same individual were aligned with a normalized mutual information-based registration method. The alignment parameters were applied to position the regions of interest in the floating image sets for calculation of the myocardial blood flow values. In the rest case the mean myocardial blood flow value was 0.76 +/- 0.12 mL x g(-1) x min(-1) for the manual method and 0.79 +/- 0.10 mL x g(-1) x min(-1) for the proposed method (by use of the right ventricle component in the alignment), and in the stress case these values were 3.39 +/- 0.70 mL x g(-1) x min(-1) and 4.01 +/- 0.71 mL x g(-1) x min(-1), respectively. No statistically significant difference was found between the methods.
  
  
  CONCLUSIONS
  In the tests with the phantom and patient images the alignment of cardiac structures was shown to be successful. The alignment could be done without the use of information from the myocardial compartment.
authors.affiliation: Institute of Signal Processing, Tampere University of Technology, Tampere, Finland. anu.juslin@tut.fi <anu.juslin@tut.fi>
authors.forename: Anu
authors.initials: A
authors.lastname: Juslin
authors.forename: Jyrki
authors.initials: J
authors.lastname: Lötjönen
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Nesterov
authors.forename: Kari
authors.initials: K
authors.lastname: Kalliokoski
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
authors.forename: Ulla
authors.initials: U
authors.lastname: Ruotsalainen
mesh_terms: D000465:Algorithms; D003326:Coronary Circulation; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008955:Models, Cardiovascular; D010104:Oxygen Radioisotopes; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
chemical_list: D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals