title: Size Measurement and T-staging of Lung Adenocarcinomas Manifesting as Solid Nodules ≤30 mm on CT: Radiology-Pathology Correlation.
abstract: This study aimed to compare long-axis diameter to average computed tomography (CT) diameter measurements of lung adenocarcinomas manifesting as solid lung nodules ≤30 mm on CT, as referenced to pathologic measurements, and to determine the impact of the two CT measurement approaches on tumor (T)-staging of nodules.
  
  
  
  This institutional review board-approved study included all 274 radiologic solid adenocarcinomas resected at our institution over 10 years. Two observers measured long- and short-axis diameters on pre-resection chest CT in lung and mediastinal windows. T-stages were determined. CT measurements and T-stages were compared to pathology measurements and T-stages using Wilcoxon signed rank test and McNemar test. Inter- and intraobserver variability was determined with intraclass correlation coefficients (ICC) and Bland-Altman plots.
  
  
  
  For lung and mediastinal windows, nodule size was significantly larger using long-axis diameter rather than average diameter (16.93 vs. 14.92 mm, P <.001; and 14.02 vs. 12.17 mm, P <.001, respectively). The correlation of CT with pathologic measurements was stronger with long-axis than with average diameter (ICC 0.808 vs. 0.730; and 0.731 vs. 0.621, respectively). Lung window measurements correlated stronger with pathology than mediastinal window measurements. CT T-stages differed from pathology T-stages in more than 20% of nodules (P <.001). Inter- and intraobserver variability was small with long-axis and average diameter (ICC range 0.96-0.991, and 0.970-0.993, respectively), but long-axis diameter showed wider scatter on Bland-Altman plots.
  
  
  
  Long-axis CT diameter is preferable for T-staging because it better reflects the pathology T-stage. Average CT diameter might be used for longitudinal nodule follow-up because it shows less measurement variability and is more conservative in size assessment.
authors.affiliation: Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA; Department of Biomedical Imaging and Image-guided Therapy, Vienna General Hospital, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria. Electronic address: bheiding@bidmc.harvard.edu.
authors.forename: Benedikt H
authors.initials: BH
authors.lastname: Heidinger
authors.affiliation: Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Anderson
authors.affiliation: Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA.
authors.forename: Eoin M
authors.initials: EM
authors.lastname: Moriarty
authors.affiliation: Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Costa
authors.affiliation: Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Sidhu P
authors.initials: SP
authors.lastname: Gangadharan
authors.affiliation: Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Paul A
authors.initials: PA
authors.lastname: VanderLaan
authors.affiliation: Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Bankier
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Lung adenocarcinoma; T-staging; computed tomography; radiology-pathology correlation; size measurement