title: Persistent pure ground-glass nodules in the lung: interscan variability of semiautomated volume and attenuation measurements.
abstract: OBJECTIVE
  The purpose of this article is to assess the interscan variability of semiautomated volume and attenuation measurements for pulmonary persistent pure ground-glass nodules.
  
  
  METHODS
  Thirty pure ground-glass nodules in 25 patients referred for known pure ground-glass nodules were evaluated with two consecutive unenhanced chest CT examinations performed within 10 minutes. For the second limited scan, patients were asked to first get off and then get back on the table to simulate a follow-up examination. CT images were reconstructed using two different algorithms (sharp, B60F; medium sharp, B50F). Two chest radiologists independently measured the volumes and attenuations of pure ground-glass nodules, twice on the first CT scan and once on the second CT scan, using commercial software. Interscan variability was measured using the Bland-Altman method.
  
  
  RESULTS
  Nodule segmentation was successful in 98.3% (177/180) and 97.8% (176/180) of measurements with B60F and B50F, respectively. With respect to volume measurements, interscan variability for reviewer 1 was -17.7% to 18.3% with B60F and -18.8% to 15.7% with B50F; interscan variability for reviewer 2 was -18.6% to 18.9% with B60F and -15.6% to 17.2% with B50F. With respect to attenuation measurements, interscan variability for reviewer 1 was -7.2% to 7.9% with B60F and -7.9% to 9.4% with B50F; interscan variability for reviewer 2 was -7.7% to 8.1% with B60F and -8.5% to 9.9% for B50F.
  
  
  CONCLUSIONS
  Variations in volume and attenuation measurements of persistent pure ground-glass nodules using commercial software were reasonably small, allowing the detection of clinically relevant growth.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, 101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea.
authors.forename: Chang Min
authors.initials: CM
authors.lastname: Park
authors.forename: Jin Mo
authors.initials: JM
authors.lastname: Goo
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kwang Gi
authors.initials: KG
authors.lastname: Kim
authors.forename: Mi-Jin
authors.initials: MJ
authors.lastname: Kang
authors.forename: Yong Hwan
authors.initials: YH
authors.lastname: Shin
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012984:Software; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*