title: 18F-FDG Uptake in Less Affected Lung Field Provides Prognostic Stratification in Patients with Interstitial Lung Disease.
abstract: This study evaluated the clinical significance of18F-FDG PET/CT in patients with interstitial lung disease (ILD), by investigating the relationships between18F-FDG PET/CT parameters and clinical indicators and by evaluating the prognostic implications of18F-FDG PET/CT results.
  
  
  METHODS
  Ninety patients (51 men, 39 women; mean age, 55.4 y; age range, 26-78 y) with ILD who underwent18F-FDG PET/CT were retrospectively analyzed. SUVmeanwas defined as the mean SUV of the less-affected lung field, SUVTFas adjusted SUVmeanusing tissue fraction (TF), and CTmeanas the mean attenuation of the corresponding region of interest on high-resolution CT. SUVmean, SUVTF, and CTmeanwere compared in the 90 ILD patients and in 15 age- and sex-matched controls. Correlations of SUVmax, SUVmean, SUVTF, and CTmeanwith clinical indicators, including estimated percentage of forced vital capacity (%FVC), estimated percentage of diffusion capacity of the lungs for carbon monoxide (%DLco), sialylated carbohydrate antigen Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D), C-reactive protein (CRP), lactate dehydrogenase (LDH), and ILD-sex-age-physiology (GAP) index, were evaluated using the Spearman rank correlation test and the Tukey-Kramer test. A Cox proportional hazards model was used for univariate and multivariate analyses of factors associated with lung transplantation-free survival.
  
  
  RESULTS
  SUVmean, SUVTF, and CTmeanwere significantly higher in ILD patients than in healthy controls, except for CTmeanin patients with a nonusual interstitial pneumonia pattern. SUVmeanand CTmeanwere significantly correlated with %FVC, %DLco, KL-6, and SP-D; SUVTFwas significantly correlated with %DLco, KL-6, SP-D, and LDH; and SUVmaxwas weakly correlated with KL-6 and CRP. Univariate analysis showed that SUVmean, SUVTF, sex, %FVC, %DLco, KL-6, and ILD-GAP index were significantly prognostic of lung transplantation-free survival; and multivariate analysis showed that SUVmeanand ILD-GAP index were independently prognostic of lung transplantation-free survival. A higher SUVmeanindicated a poorer prognosis, especially in patients with moderate risk based on ILD-GAP index.
  
  
  CONCLUSIONS
  SUVmeanwas significantly but moderately correlated with clinical indicators, providing independent prognostic information in patients with ILD.18F-FDG PET/CT may be helpful for monitoring and risk stratification of ILD patients.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nobashi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and ynakamo1@kuhp.kyoto-u.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.affiliation: Department of Respiratory Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Handa
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.
authors.forename: Sho
authors.initials: S
authors.lastname: Koyasu
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ishimori
authors.affiliation: Department of Respiratory Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; and.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D001692:Biological Transport; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D000072078:Positron Emission Tomography Computed Tomography; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: FDG; PET/CT; interstitial lung disease; prognosis