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  O23 - Imaging and Screening (ID 125)

  • Event: WCLC 2013
  • Type: Oral Abstract Session
  • Track: Imaging, Staging & Screening
  • Presentations: 1
  • Moderators:J.R. Jett, H.M. Marshall
  • Coordinates: 10/29/2013, 16:15 - 17:45, Bayside 201 - 203, Level 2

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    O23.01 - Volume doubling time measurement of pulmonary nodules: comparison between 2D- and 3D-methods (ID 178)

    16:15 - 16:25  |  Author(s): H. Numasaki
    • Abstract
    • Presentation
    • Slides

    Background
    Measurement of volume doubling time (VDT) of small pulmonary nodules is clinically useful for discrimination between benign and malignant etiology, because this discrimination capability based only on the initial CT is limited. Recent advancement of CT technology enabled direct 3D measurement of volume of pulmonary nodules using commercially available software and enabled VDT measurement with these data. However, there are only a few reports in which accuracy of the 3D method was assessed with comparing the 3D method with the traditional 2D method. Here, we compared intra- and inter-observer variability (OV) to assess the accuracy of these two methods and compared VDT of pulmonary nodules in 2D-method with those in 3D-method. We also discussed the clinical relevance of our results.

    Methods
    Forty-two pulmonary nodules of 3 cm or smaller (CT type, 11 of ground-glass opacity, 15 of mixed type, and 16 of solid type) of peripheral lung cancer (37 of adenocarcinoma, 4 squamous cell carcinoma, and one small cell carcinoma) in 41 patients (mean age±SD, 67±10 years; 25 men and 16 women) who underwent 16-slice MDCT with 1-mm collimation twice (mean interval, 369 days, range 60-1119 days) before surgical resection during June 2006 and December 2008 were included in this study. Five examiners independently calculated VDT by 2D (nodule diameter measurement) and 3D methods (nodule volume measurement using in-house programmed software) with the use of Schwaltz equation and repeated the measurements one month after. Thus, intra- and inter-OV in VDT for the two methods was compared using 95% confidence intervals (CI) in Blant-Altman plots, and VDT calculated with the two methods was compared in each examiner. In evaluating inter-OV, averaged values of the two measurements in each examiner were used for analysis. A p of less than .05 was considered to be significant.

    Results
    As for inter-OV (n=10), 95% CI (mean±SD in days, 398±123) for 3D method was significantly greater than that (231±87) for 2D method (p=0.005). Regarding intra-OV (n=5), 95% CI (291±199) for 3D method tended to be greater than that (195±36) for 2D method (p=0.388). VDT calculated with 3D method was significantly greater than that calculated with 2D method in all of the 5 examiners (all p of <0.05).

    Conclusion
    Inter-OV in VDT measurement was significantly greater in 3D method than in 2D method and VDT calculated with 3D method was greater than that calculated with 2D method. Therefore, in calculating VDT of pulmonary nodules, the same examiner should evaluate with the same method.

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