title: ROC and localization ROC analyses of lesion detection in whole-body FDG PET: effects of acquisition mode, attenuation correction and reconstruction algorithm.
abstract: Receiver operating characteristic (ROC) and localization ROC (LROC) studies were performed to compare lesion detection at the borderline of detectability on images reconstructed with two-dimensional filtered backprojection (FBP) without attenuation correction (a common clinical protocol), three-dimensional FBP without attenuation correction, two-dimensional FBP with segmented attenuation correction and a two-dimensional iterative maximum a posteriori (MAP) algorithm using attenuation correction. Lung cancer was the model for the study because of the prominent role of 18F-fluorodeoxyglucose PET in the staging of lung cancer and the importance of lesion detection for staging.
  
  
  METHODS
  Simulated lung cancer lesions were added to two-dimensional and three-dimensional PET data from healthy volunteers. Data were reconstructed using the four methods. Four nuclear medicine physicians evaluated the images. Detection performance with each method was compared using ROC and LROC analysis. Jackknife analysis provided estimates of statistical significance for differences across all readers for the ROC results.
  
  
  RESULTS
  ROC and LROC results indicated statistically significant degradation in detection performance with three-dimensional acquisition (average area under ROC curves [Az] 0.51; average area under LROC curves [A(z,LROC)] 0.13) and segmented attenuation correction (average Az 0.59; average Az,LROC 0.29) compared with two-dimensional FBP without attenuation correction (average Az 0.79; average A(z,LROC) 0.54). ROC and LROC results indicated an improvement in detection performance with iterative MAP reconstruction (average Az 0.83; average A(z,LROC) 0.64) compared with two-dimensional FBP reconstruction; this improvement was not statistically significant.
  
  
  CONCLUSIONS
  Use of segmented attenuation correction or three-dimensional acquisition with FBP reconstruction is not expected to improve detection of lung lesions on whole-body PET images compared with images with two-dimensional FBP without attenuation correction. The potential improvement in detection obtained with an iterative MAP reconstruction method is small compared with that obtained with two-dimensional FBP without attenuation correction.
authors.affiliation: Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles 90095-6948, USA.
authors.forename: T H
authors.initials: TH
authors.lastname: Farquhar
authors.forename: J
authors.initials: J
authors.lastname: Llacer
authors.forename: C K
authors.initials: CK
authors.lastname: Hoh
authors.forename: J
authors.initials: J
authors.lastname: Czernin
authors.forename: S S
authors.initials: SS
authors.lastname: Gambhir
authors.forename: M A
authors.initials: MA
authors.lastname: Seltzer
authors.forename: D H
authors.initials: DH
authors.lastname: Silverman
authors.forename: J
authors.initials: J
authors.lastname: Qi
authors.forename: C
authors.initials: C
authors.lastname: Hsu
authors.forename: E J
authors.initials: EJ
authors.lastname: Hoffman
mesh_terms: D000465:Algorithms; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D012372:ROC Curve; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18