title: Pulmonary nodules: preliminary experience with three-dimensional evaluation.
abstract: OBJECTIVE
  To evaluate software designed to calculate pulmonary nodule volume in three dimensions.
  
  
  METHODS
  Fifty-four solid noncalcified pulmonary nodules measuring 5-18 mm in diameter were studied with computed tomographic (CT) volumetric software. Baseline CT examinations were performed for various indications by using four-detector row multisection CT units, 1.25- or 2.50-mm sections, and a standard reconstruction algorithm. The percentage of successful nodule segmentations, as well as intraobserver variability, interreader agreement, and global repeatability of calculated volumes, was determined on the basis of consecutive measurements performed three times by three different radiologists by using the Bland and Altman method. The software was used to calculate the doubling time of 22 nodules for which a final diagnosis and comparable CT scans were available.
  
  
  RESULTS
  Fifty-two (96%) of the 54 nodules were successfully segmented, allowing their volume to be calculated. Repeatability was high: There was no variation in the nine measurements of 35 (67%) of the 52 nodules. The coefficient of variation for the remaining 17 nodules (33%) was 2.26%. Bland and Altman 95% limits of acceptability, calculated on the basis of log-transformed data, yielded a maximum software measurement error of 6.38% of the previous volume measurement. Doubling time ranged from 4 to 188 years for the 13 benign nodules and from 37 to 216 days for the nine malignant nodules.
  
  
  CONCLUSIONS
  Software volumetric analysis yielded repeatable estimates for 96% of the nodules examined. All software-calculated doubling times were in keeping with the benign or malignant nature of the nodules.
authors.affiliation: Department of Radiology, Assistance Publique des Hôpitaux de Paris/INSERM, Georges Pompidou European University Hospital, 20 Rue Leblanc, 75015 Paris, France. marie-pierre.revel@hop.egp.ap-hop-paris.fr
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Revel
authors.forename: Catherine
authors.initials: C
authors.lastname: Lefort
authors.forename: Alvine
authors.initials: A
authors.lastname: Bissery
authors.forename: Marie
authors.initials: M
authors.lastname: Bienvenu
authors.forename: Laetitia
authors.initials: L
authors.lastname: Aycard
authors.forename: Gilles
authors.initials: G
authors.lastname: Chatellier
authors.forename: Guy
authors.initials: G
authors.lastname: Frija
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data