title: Practical approach for comparative analysis of multilesion molecular imaging using a semiautomated program for PET/CT.
abstract: We propose a standardized approach to quantitative molecular imaging (MI) in cancer patients with multiple lesions.
  
  
  METHODS
  Twenty patients with castration-resistant prostate cancer underwent (18)F-FDG and (18)F-16β-fluoro-5-dihydrotestosterone ((18)F-FDHT) PET/CT scans. Using a 5-point confidence scale, 2 readers interpreted coregistered scan sets on a workstation. Two hundred three sites per scan (specified in a lexicon) were reviewed. (18)F-FDG-positive lesion bookmarks were propagated onto (18)F-FDHT studies and then manually accepted or rejected. Discordance-positive (18)F-FDHT lesions were similarly bookmarked. Lesional SUV(max) was recorded. Tracer- and tissue-specific background correction factors were calculated via receiver-operating-characteristic analysis of 65 scan sets.
  
  
  RESULTS
  Readers agreed on more than 99% of (18)F-FDG- and (18)F-FDHT-negative sites. Positive-site agreement was 83% and 85%, respectively. Consensus-lesion maximum standardized uptake value (SUV(max)) was highly reproducible (concordance correlation coefficient > 0.98). Receiver-operating-characteristic curves yielded 4 correction factors (SUV(max) 1.8-2.6). A novel scatterplot (Larson-Fox-Gonen plot) depicted tumor burden and change in SUV(max) for response assessments.
  
  
  CONCLUSIONS
  Multilesion molecular imaging is optimized with a 5-step approach incorporating a confidence scale, site lexicon, semiautomated PET software, background correction, and Larson-Fox-Gonen graphing.
authors: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. foxj@mskcc.org
authors: Josef J
authors: JJ
authors: Fox
authors: Estelle
authors: E
authors: Autran-Blanc
authors: Michael J
authors: MJ
authors: Morris
authors: Somali
authors: S
authors: Gavane
authors: Sadek
authors: S
authors: Nehmeh
authors: André
authors: A
authors: Van Nuffel
authors: Mithat
authors: M
authors: Gönen
authors: Heiko
authors: H
authors: Schöder
authors: John L
authors: JL
authors: Humm
authors: Howard I
authors: HI
authors: Scher
authors: Steven M
authors: SM
authors: Larson
mesh_terms: D001331:Automation; D014408:Biomarkers, Tumor / Q000378:metabolism; D013196:Dihydrotestosterone / Q000031:analogs & derivatives; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000592:standards; D008297:Male; D057054:Molecular Imaging / Q000379:methods* / Q000592:standards; D064847:Multimodal Imaging / Q000379:methods* / Q000592:standards; D009919:Orchiectomy; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D012015:Reference Standards; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: C494901:16-fluorodihydrotestosterone; D014408:Biomarkers, Tumor; D013196:Dihydrotestosterone; D019788:Fluorodeoxyglucose F18