title: Heterogeneous myocardial FDG uptake and the disease activity in cardiac sarcoidosis.
abstract: OBJECTIVE
  This study evaluated the usefulness of fasting (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in the diagnosis and management of cardiac sarcoidosis (CS) and compared it with FDG uptake in dilated cardiomyopathy (DCM).
  
  
  BACKGROUND
  Cardiac sarcoidosis may clinically present as DCM but is amenable to systemic corticosteroid therapy if disease activity is high. Although alterations of FDG uptake have been reported in CS, limited information is available on the quantitative estimates of FDG uptake.
  
  
  METHODS
  Fasting FDG-PET was performed in 24 systemic sarcoidosis patients and was compared with 8 age-matched DCM patients. FDG-PET was also performed in 15 age-matched healthy control subjects. Twelve of the 24 sarcoidosis patients had cardiac involvement based on criteria established by the Japanese Ministry of Health and Welfare; the remaining 12 of 24 patients revealed no evidence of cardiac involvement. The myocardial FDG uptake was quantified by measuring the standardized uptake value in 17 myocardial segments in each subject. Coefficient of variation (COV), which equals the standard deviation of uptake divided by the average uptake of 17 segments, was calculated as an index of heterogeneity in the heart.
  
  
  RESULTS
  The FDG uptake was distinctly heterogeneous in CS patients. The COV value was significantly greater in CS patients (0.25 ± 0.05) than control subjects (0.14 ± 0.03, p < 0.01), sarcoidosis patients without cardiac involvement (0.14 ± 0.03, p < 0.01), or DCM patients (0.15 ± 0.02, p < 0.01). The COV value in DCM patients was similar to control subjects or sarcoidosis patients without cardiac involvement. The cutoff COV value for the diagnosis of CS was 0.18 (sensitivity: 100%; specificity: 97%). After corticosteroid therapy in CS patients, the COV value was decreased to 0.14 ± 0.06 (p < 0.05) and became essentially similar to the other groups.
  
  
  CONCLUSIONS
  Heterogeneous myocardial FDG uptake may be a useful diagnostic marker of disease activity for CS.
authors.affiliation: Department of Medicine, Division of Cardio-Vascular Medicine, Kurume University School of Medicine, Kurume, Japan. ntahara@med.kurume-u.ac.jp
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tahara
authors.forename: Atsuko
authors.initials: A
authors.lastname: Tahara
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nitta
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kodama
authors.forename: Minori
authors.initials: M
authors.lastname: Mizoguchi
authors.forename: Hayato
authors.initials: H
authors.lastname: Kaida
authors.forename: Kenkichi
authors.initials: K
authors.lastname: Baba
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ishibashi
authors.forename: Naofumi
authors.initials: N
authors.lastname: Hayabuchi
authors.forename: Jagat
authors.initials: J
authors.lastname: Narula
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Imaizumi
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000188:drug therapy; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging*; D005215:Fasting; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000378:metabolism; D012507:Sarcoidosis / Q000000981:diagnostic imaging* / Q000188:drug therapy; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D000305:Adrenal Cortex Hormones; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18