title: Standardized visual reading of F18-FDG-PET in patients with non-small cell lung cancer scheduled for preoperative thoracic lymph node staging.
abstract: OBJECTIVE
  Routine visual assessment of positron emission tomography (PET) for thoracic lymph node (LN) staging in patients with non-small cell lung cancer (NSCLC) is limited by a lack of reliable assessment criteria. This study evaluates the accuracy and inter-rater agreement of a standardized approach with unified windowing and a PET-based visual score.
  
  
  METHODS
  This retrospective analysis included pretherapeutic FDG-PET data of 86 patients with NSCLC. After standardized windowing (threshold: 2×liver SUVmean) the LN uptake was assessed visually by three independent readers with varying levels of experience using a 4-step score (1, LN uptake≤mediastinal blood pool structures (MBPS); 2, MBPS<LN<liver; 3, liver≤LN<'black'; 4, LN appears 'black'). ROC analyses and respective areas under the curve (AUC) based on histology/cytology as standard of reference. Agreement was analyzed with Cohen's kappa (κ, pairwise) and Fleiss' κ (overall). Subgroup analyses separated between hilar vs. mediastinal LNs, adenocarcinoma vs. squamous cell carcinoma and grading G1/2 vs. G3/4.
  
  
  RESULTS
  Fifty-four of the 278LNs (19.4%) were malignant (optimal cut-off to differentiate benign vs. malignant, score >3). The inexperienced (n=1), advanced (n=1), and expert readers (n=1) achieved similar accuracies of 93.5%, 91.4% and 92.1%, respectively (P>0.05 each). Cohen's κ ranged from 0.92 to 0.96 and Fleiss' κ was 0.93. ROC-analyses showed no significant differences between attendant readers within any subgroup (AUC, 0.92-0.96).
  
  
  CONCLUSIONS
  Applying unified windowing, the introduced PET-score achieved highly accurate and robust LN assessment. This approach may shorten learning curves of inexperienced readers, facilitate multicenter trials, and improve comparability of future studies.
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany. Electronic address: julianrogasch@gmx.de.
authors.forename: Julian M M
authors.initials: JM
authors.lastname: Rogasch
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Ivayla
authors.initials: I
authors.lastname: Apostolova
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Ingo G
authors.initials: IG
authors.lastname: Steffen
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Ferdinand L G A
authors.initials: FL
authors.lastname: Steinkrüger
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Genseke
authors.affiliation: Department of Cardiology, Angiology and Pulmonology, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Riedel
authors.affiliation: Lung Clinic Lostau, Lindenstrasse 2, 39291 Lostau, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Wertzel
authors.affiliation: Lung Clinic Lostau, Lindenstrasse 2, 39291 Lostau, Germany.
authors.forename: H Jost
authors.initials: HJ
authors.lastname: Achenbach
authors.affiliation: Institute for Pathology, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kalinski
authors.affiliation: Institute for Pathology Stendal, Strasse der Demokratie 1, 39576 Stendal, Germany.
authors.forename: Meinald
authors.initials: M
authors.lastname: Schultz
authors.affiliation: Department of Cardiology, Angiology and Pulmonology, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Schreiber
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Nuclear Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Amthauer
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Nuclear Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Furth
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D015588:Observer Variation; D000072078:Positron Emission Tomography Computed Tomography / Q000706:statistics & numerical data*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG-PET; Inter-rater agreement; Lymph node staging; Non-small cell lung cancer; Visual assessment criteria