title: Pure and part-solid pulmonary ground-glass nodules: measurement variability of volume and mass in nodules with a solid portion less than or equal to 5 mm.
abstract: OBJECTIVE
  To prospectively assess and compare the measurement variability of volume and mass for pure and part-solid ground-glass nodules (GGNs) with solid portions less than or equal to 5 mm by using a commercially available volumetric software program.
  
  
  METHODS
  This prospective study was approved by the institutional review board. Written informed consent was obtained. From November 2011 to June 2012, 73 patients (26 men and 47 women) with 94 GGNs (>5 mm and <20 mm; 72 pure and 22 part-solid GGNs) were prospectively enrolled and underwent two consecutive computed tomographic (CT) examinations. Both the volume and mass of GGNs were measured with volumetric software by two radiologists. Intraobserver, interobserver, and interscan variability were analyzed and compared by using the Bland-Altman method and coefficients of variation. The influence of the solid portion of GGNs and GGN size on interscan variability was investigated with multiple linear regression analysis and analysis of variance.
  
  
  RESULTS
  Nodule segmentation was successful in 420 of 438 (95.9%) segmentations. As for volume measurement, interscan variability ranged from -17.3% to 18.5%, while intraobserver and interobserver variability ranged from -7.6% to 8.5% and from -11.7% to 18.1%, respectively. Interscan variability in mass measurement ranged from -17.7% to 18.6%, while intraobserver and interobserver variability ranged from -8.4% to 9.4% and from -17.5% to 11.8%, respectively. In the coefficient of variation comparison, there were no significant differences in volume and mass measurements for intraobserver, interscan, and interobserver variability. Measurement variability of volume and mass was not significantly influenced by the presence of a solid portion, solid portion size, or GGN size.
  
  
  CONCLUSIONS
  Mass measurement of GGNs showed measurement variability from -17.7% to 18.6% and may be a useful method in the follow-up of GGNs with solid portions less than or equal to 5 mm.
authors.affiliation: Department of Radiology and Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Hyungjin
authors.initials: H
authors.lastname: Kim
authors.forename: Chang Min
authors.initials: CM
authors.lastname: Park
authors.forename: Sungmin
authors.initials: S
authors.lastname: Woo
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Chul-Gyu
authors.initials: CG
authors.lastname: Yoo
authors.forename: Jin Mo
authors.initials: JM
authors.lastname: Goo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012984:Software; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*