title: Reconstruction of semiautomated cardiac regions of interest using iodine-123 metaiodobenzylguanidine myocardial scintigraphy.
abstract: BACKGROUND
  Analysis using cardiac iodine-123 metaiodobenzylguanidine (MIBG) scintigraphy with regions of interest (ROIs) is useful for assessing myocardial sympathetic activity. However, manual placement of the cardiac ROI is sometimes difficult because myocardial MIBG uptake is reduced in patients with heart failure. A new method was developed to reconstruct the semiautomated cardiac ROI in a sympathetic denervated heart.
  
  
  METHODS
  Using dynamic planar data, a summed image was generated and the matrix size was changed. Then, the radial count profiles originating from the center of the left ventricle were generated to extract the myocardial count profiles. An asymmetric Gaussian distribution was fitted to each profile and the epicardial border was defined by the threshold method. This program was tested in 50 patients, and its reproducibility was validated when compared with the manual tracing method.
  
  
  RESULTS
  The semiautomated method yielded a better quality image compared with the standard image with higher counts. Cardiac ROIs were generated successfully in each patient within normal limits. The intraobserver and interobserver agreements were excellent (P<0.0001 each). This approach showed a significantly higher consistency in measuring the heart-to-mediastinum ratio as compared with the manual tracing method (P<0.05).
  
  
  CONCLUSIONS
  The semiautomated method is useful in generating cardiac ROIs with high reproducibility in myocardial MIBG imaging.
authors.affiliation: aDepartment of Nuclear Medicine and Radiology, National Cerebral and Cardiovascular Center bDepartment of Medical Physics and Engineering, Division of Medical Technology and Science, Course of Health Science, Graduate School of Medicine, Osaka University, Suita cDepartment of Health Science, Gifu University of Medical Science, Gifu dDepartment of Cardiovascular Medicine, Kaizuka City Hospital, Kaizuka, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Kazuki
authors.initials: K
authors.lastname: Fukuchi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Katafuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujisaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kiso
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ishida
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
mesh_terms: D019797:3-Iodobenzylguanidine; D001331:Automation; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006333:Heart Failure / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D019047:Phantoms, Imaging; D015203:Reproducibility of Results
chemical_list: D019797:3-Iodobenzylguanidine