title: Autoclustering of Non-small Cell Lung Carcinoma Subtypes on (18)F-FDG PET Using Texture Analysis: A Preliminary Result.
abstract: OBJECTIVE
  Texture analysis on (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) scan is a relatively new imaging analysis tool to evaluate metabolic heterogeneity. We analyzed the difference in textural characteristics between non-small cell lung carcinoma (NSCLC) subtypes, namely adenocarcinoma (ADC) and squamous cell carcinoma (SqCC).
  
  
  METHODS
  Diagnostic (18)F-FDG PET/computed tomography (CT) scans of 30y patients (median age, 67; range, 42-88) with NSCLC (17 ADC and 13 SqCC) were retrospectively analyzed. Regions of interest were manually determined on selected transverse image containing the highest SUV value in tumors. Texture parameters were extracted by histogram-based algorithms, absolute gradient-based algorithms, run-length matrix-based algorithms, co-occurrence matrix-based algorithms, and autoregressive model-based algorithms. Twenty-four out of hundreds of texture features were selected by three algorithms: Fisher coefficient, minimization of both classification error probability and average correlation, and mutual information. Automated clustering of tumors was based on the most discriminating feature calculated by linear discriminant analysis (LDA). Each tumor subtype was determined by histopathologic examination after biopsy and surgery.
  
  
  RESULTS
  Fifteen texture features had significant different values between ADC and SqCC. LDA with 24 automate-selected texture features accurately clustered between ADC and SqCC with 0.90 linear separability. There was no high correlation between SUVmax and texture parameters (|r| ≤ 0.62).
  
  
  CONCLUSIONS
  Each subtype of NSCLC tumor has different metabolic heterogeneity. The results of this study support the potential of textural parameters on FDG PET as an imaging biomarker.
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Korea.
authors.forename: Seunggyun
authors.initials: S
authors.lastname: Ha
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Korea.
authors.forename: Hongyoon
authors.initials: H
authors.lastname: Choi
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Cancer Research Institute, Seoul National University, Seoul, Korea ; Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-Ro, Jongno-Gu Seoul, 110-744 Korea.
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Cancer Research Institute, Seoul National University, Seoul, Korea.
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Cancer Research Institute, Seoul National University, Seoul, Korea.
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.affiliation: Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Korea ; Department of Radiological Science, University of California at Irvine, Irvine, CA USA.
authors.forename: Euishin Edmund
authors.initials: EE
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea ; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul, Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
keywords: Carcinoma; Cluster analysis; F-18 Fluorodeoxyglucose; Non-small cell lung; Positron emission tomography; Texture analysis