title: Is it Feasible to Use the Commercially Available Autoquantitation Software for the Evaluation of Myocardial Viability on Small-Animal Cardiac F-18 FDG PET Scan?
abstract: OBJECTIVE
  To evaluate the reliability of quantitation of myocardial viability on cardiac F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) scans with three different methods of visual scoring system, autoquantitation using commercially available autoquantitation software, and infarct-size measurement using histogram-based maximum pixel threshold identification on polar-map in rat hearts.
  
  
  METHODS
  A myocardial infarct (MI) model was made by left anterior descending artery (LAD) ligation in rat hearts. Eighteen MI rats underwent cardiac FDG-PET-computed tomography (CT) twice within a 4-week interval. Myocardium was partitioned into 20 segments for the comparison, and then we quantitated non-viable myocardium on cardiac FDG PET-CT with three different methods: method A-infarct-size measurement using histogram-based maximum pixel threshold identification on polar-map; method B-summed MI score (SMS) by a four-point visual scoring system; method C-metabolic non-viable values by commercially available autoquantitation software. Changes of non-viable myocardium on serial PET-CT scans with three different methods were calculated by the change of each parameter. Correlation and reproducibility were evaluated between the different methods.
  
  
  RESULTS
  Infarct-size measurement, visual SMS, and non-viable values by autoquantitation software presented proportional relationship to each other. All the parameters of methods A, B, and C showed relatively good correlation between each other. Among them, infarct-size measurement (method A) and autoquantitation software (method C) showed the best correlation (r = 0.87, p < 0.001). When we evaluated the changes of non-viable myocardium on the serial FDG-PET-CT- however, autoquantitation program showed less correlation with the other methods. Visual assessment (method B) and those of infarct size (method A) showed the best correlation (r = 0.54, p = 0.02) for the assessment of interval changes.
  
  
  CONCLUSIONS
  Commercially available quantitation software could be applied to measure the myocardial viability on small animal cardiac FDG-PET-CT scan. This kind of quantitation showed good correlation with infarct size measurement by histogram-based maximum pixel threshold identification. However, this method showed the weak correlation when applied in the measuring the changes of non-viable myocardium on the serial scans, which means that the caution will be needed to evaluate the changes on the serial monitoring.
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1, Anam-Dong 5-Ga, Seongbuk-Gu, Seoul, 136-705 South Korea.
authors.forename: Kisoo
authors.initials: K
authors.lastname: Pahk
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1, Anam-Dong 5-Ga, Seongbuk-Gu, Seoul, 136-705 South Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Oh
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1, Anam-Dong 5-Ga, Seongbuk-Gu, Seoul, 136-705 South Korea.
authors.forename: Eugene
authors.initials: E
authors.lastname: Jeong
authors.affiliation: Department of Cardiovascular Surgery, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.
authors.forename: Sang Keun
authors.initials: SK
authors.lastname: Woo
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea.
authors.forename: Jung Woo
authors.initials: JW
authors.lastname: Yu
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1, Anam-Dong 5-Ga, Seongbuk-Gu, Seoul, 136-705 South Korea.
authors.forename: Jae Gol
authors.initials: JG
authors.lastname: Choe
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1, Anam-Dong 5-Ga, Seongbuk-Gu, Seoul, 136-705 South Korea ; Department of Nuclear Medicine, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 110-744 South Korea.
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
keywords: Autoquantitation; FDG PET; Myocardial infarct model; Myocardial viability