title: Comparison of manual and automated size measurements of lung metastases on MDCT images: potential influence on therapeutic decisions.
abstract: OBJECTIVE
  The goal of this study was to evaluate the influence of automated measurement of diameter, area, and volume from chest CT scans on therapeutic decisions of lung nodules as compared to manual 2-D measurements.
  
  
  METHODS
  The retrospective study involved 25 patients with 75 lung metastases. Contrast enhanced CT scans (16 row) of the lung were performed three times during chemotherapy with a mean time interval of 67.9 days between scans. In each patient, three metastases were evaluated (n=225). Automatic measurements were compared to manual assessment for the following parameters: diameter, area, and density. The influence on the therapeutic decisions was evaluated using the RECIST criteria.
  
  
  RESULTS
  The maximum diameter measured by the automatic application was on an average 27% (S.D. 39; CI: 0.22-0.32; p<0.0001) higher than the maximum diameter with manual assessment, and the differences depended on metastases size. Based on diameter calculation, manual and automated assessment disagreed in up to 32% of therapeutic decisions. Volumetric assessment tended towards more changes in therapy as compared to diameter calculation. The calculation of mean transversal area of metastases was 36% (S.D. 0.305; CI: -0.40 to -0.32; p<0.0001) less with automated measurement. Therapeutic strategy would be changed in up to 25.7% of nodules using automated area calculation. Automated assessment of nodules' area and volume could influence the therapeutic decisions in up to 51.4% of all nodules. Density of the nodules was not validated to determine the influence on therapeutic decisions.
  
  
  CONCLUSIONS
  There is a discrepancy between the manual and automated size measurement of lung metastases which could be significant.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Ulm, Robert-Koch-Strasse 8, 89081 Ulm, Germany. sandra.pauls@uni-ulm.de
authors.forename: Sandra
authors.initials: S
authors.lastname: Pauls
authors.forename: Christian
authors.initials: C
authors.lastname: Kürschner
authors.forename: Ekta
authors.initials: E
authors.lastname: Dharaiya
authors.forename: Rainer
authors.initials: R
authors.lastname: Muche
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Schmidt
authors.forename: Stefan
authors.initials: S
authors.lastname: Krüger
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Brambs
authors.forename: Andrik J
authors.initials: AJ
authors.lastname: Aschoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001331:Automation; D003287:Contrast Media; D003657:Decision Making; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media