Inherent variability of CT lung nodule measurements in vivo using semiautomated volumetric measurements. AJR Am J Roentgenol 2006 Apr;186(4):989-94
Date
03/24/2006Pubmed ID
16554568DOI
10.2214/AJR.04.1821Scopus ID
2-s2.0-33646913058 (requires institutional sign-in at Scopus site) 138 CitationsAbstract
OBJECTIVE: The objective of our study was to evaluate repeatability and reproducibility of lung nodule volume measurements using volumetric nodule-sizing software.
MATERIALS AND METHODS: Fifty nodules, less than 20 mm in diameter, in 29 patients were scanned with 1.25-mm collimation using MDCT (time 1 = T1). During the same session, two additional scans, using identical technique, were obtained through each nodule (T2, T3). Three observers working independently then obtained volumetric measurements using a semiautomated volumetric nodule-sizing software package. Qualitative nodule characterization was also performed. The Bland-Altman method for assessing measurement agreement was used to calculate the 95% limits for agreement for nodule volumes at T1, T2, and T3.
RESULTS: Automated nodule segmentation was successful in 438 (97%) of 450 measurements. Forty-three nodules were available for final evaluation. Twenty-six nodules had well-defined edges, and 17 had irregular or spiculated margins. Seventeen were freestanding, 16 were juxtapleural, and 10 were juxtavascular in location. Average nodule volume was 345.5 mm(3) (range, 49.3-1,434 mm(3)). The mean interobserver variability (repeatability) was 0.018% (SD = 0.73%), and the SD of the mean for the three contemporaneous scans (reproducibility) was 13.1% (confidence limits, +/- 25.6%). SD and confidence limits narrowed as volumes increased.
CONCLUSION: Volumetric measurements show minimal interobserver variability (0.018%) but an interscan SEM of 13.1% (confidence limits, +/- 25.6%). Repeatability and reproducibility of volumetric measurements are better than those of linear measurements reported in the literature.
Author List
Goodman LR, Gulsun M, Washington L, Nagy PG, Piacsek KLMESH terms used to index this publication - Major topics in bold
AdultAged
Aged, 80 and over
Female
Humans
Lung Neoplasms
Male
Middle Aged
Observer Variation
Reproducibility of Results
Tomography, X-Ray Computed
