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CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size.

Publication ,  Journal Article
Christe, A; Torrente, JC; Lin, M; Yen, A; Hallett, R; Roychoudhury, K; Schmitzberger, F; Vock, P; Roos, J
Published in: AJR Am J Roentgenol
September 2011

OBJECTIVE: The purpose of the study was to quantify and compare the effect of CT dose and of size and density of nodules on the detectability of lung nodules and to quantify the influence of CT dose on the size of the nodules. MATERIALS AND METHODS: From 50 patients a total of 125 cuboidal regions of interest (3 × 3 × 1.5 cm volumes) showing a single nodule (≤ 8 mm) and 27 normal cuboids were selected. Image sets were reconstructed with the software from raw data simulating different dose levels: 300 (original dose), 220, 180, 140, 100, 80, 60, 50, 40, 30, 20, 10, and 5 reference mAs. A logistic regression model was used to analyze detectability for three blinded readers. Odds ratios were calculated for nodule size smaller than 3 mm versus 3 mm and larger and for nodule attenuation of -300 HU and greater versus less than -300 HU. RESULTS: Tube current-time settings of 10 mAs and greater were not associated with a significant difference in individual reader sensitivity compared with the standard setting of 300 mAs. At 5 mAs only one reader had a significant decrease in sensitivity, from 82% to 77% (p = 0.0035). According to the odds ratios and logistic regression results, the strongest negative effect on sensitivity can be assumed for low nodule density followed by small nodule size and dose level. The mean nodule volume measurement error between 5 and 300 mAs was 2.2% ± 18% (SD) and much lower than the interobserver volume measurement error rate of 38% ± 45%. CONCLUSION: The results show the feasibility of a low-dose CT protocol at 10 mAs for follow-up of lung nodules. Computer-aided volume measurement in follow-up of lung nodules decreases interobserver variability.

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Published In

AJR Am J Roentgenol

DOI

EISSN

1546-3141

Publication Date

September 2011

Volume

197

Issue

3

Start / End Page

623 / 630

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Time Factors
  • Solitary Pulmonary Nodule
  • Software
  • Sensitivity and Specificity
  • Radiographic Image Interpretation, Computer-Assisted
  • Radiation Dosage
  • Prospective Studies
  • Nuclear Medicine & Medical Imaging
  • Middle Aged
 

Citation

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Christe, A., Torrente, J. C., Lin, M., Yen, A., Hallett, R., Roychoudhury, K., … Roos, J. (2011). CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size. AJR Am J Roentgenol, 197(3), 623–630. https://doi.org/10.2214/AJR.10.5288
Christe, Andreas, Jaled Charimo Torrente, Margaret Lin, Andrew Yen, Rich Hallett, Kingshuk Roychoudhury, Florian Schmitzberger, Peter Vock, and Justus Roos. “CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size.AJR Am J Roentgenol 197, no. 3 (September 2011): 623–30. https://doi.org/10.2214/AJR.10.5288.
Christe A, Torrente JC, Lin M, Yen A, Hallett R, Roychoudhury K, et al. CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size. AJR Am J Roentgenol. 2011 Sep;197(3):623–30.
Christe, Andreas, et al. “CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size.AJR Am J Roentgenol, vol. 197, no. 3, Sept. 2011, pp. 623–30. Pubmed, doi:10.2214/AJR.10.5288.
Christe A, Torrente JC, Lin M, Yen A, Hallett R, Roychoudhury K, Schmitzberger F, Vock P, Roos J. CT screening and follow-up of lung nodules: effects of tube current-time setting and nodule size and density on detectability and of tube current-time setting on apparent size. AJR Am J Roentgenol. 2011 Sep;197(3):623–630.

Published In

AJR Am J Roentgenol

DOI

EISSN

1546-3141

Publication Date

September 2011

Volume

197

Issue

3

Start / End Page

623 / 630

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Time Factors
  • Solitary Pulmonary Nodule
  • Software
  • Sensitivity and Specificity
  • Radiographic Image Interpretation, Computer-Assisted
  • Radiation Dosage
  • Prospective Studies
  • Nuclear Medicine & Medical Imaging
  • Middle Aged