Academic Radiology
Volume 17, Issue 2 , Pages 146-156, February 2010

Effects of CT Section Thickness and Reconstruction Kernel on Emphysema Quantification:

Relationship to the Magnitude of the CT Emphysema Index

  • David S. Gierada, MD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • Corresponding Author InformationAddress correspondence to: D.S.G.
    • ,
  • Andrew J. Bierhals, MD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Cliff K. Choong, MBBS

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Seth T. Bartel, MS

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Jon H. Ritter, MD

      Affiliations

    • Department of Pathology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Nitin A. Das, MD

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Cheng Hong, MD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Thomas K. Pilgram, PhD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Kyongtae T. Bae, MD, PhD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Bruce R. Whiting, PhD

      Affiliations

    • Mallinckrodt Institute of Radiology, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Jason C. Woods, PhD

      Affiliations

    • Department of Physics, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • James C. Hogg, MD, PhD

      Affiliations

    • James Hogg iCapture Center, St. Paul's Hospital, Vancouver, BC, Canada
    • ,
  • Barbara A. Lutey, MD

      Affiliations

    • Division of Pulmonary and Critical Care Medicine, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Richard J. Battafarano, MD, PhD

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Joel D. Cooper, MD

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • Bryan F. Meyers, MD

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105
    • ,
  • G. Alexander Patterson, MD

      Affiliations

    • Division of Cardiothoracic Surgery, 510 S. Kingshighway Blvd., Washington University, St. Louis, MO 63105

Received 24 December 2008; accepted 24 August 2009. published online 20 November 2009.

Rationale and Objectives

Computed tomography (CT) section thickness and reconstruction kernel each influence CT measurements of emphysema. This study was performed to assess whether their effects are related to the magnitude of the measurement.

Materials and Methods

Low-radiation-dose multidetector CT was performed in 21 subjects representing a wide range of emphysema severity. Images were reconstructed using 20 different combinations of section thickness and reconstruction kernel. Emphysema index values were determined as the percentage of lung pixels having attenuation lower than multiple thresholds ranging from −960 HU to −890 HU. The index values obtained from the different thickness-kernel combinations were compared by repeated measures analysis of variance and Bland-Altman plots of mean versus difference in all subjects, and correlated with quantitative histology (mean linear intercept, Lm) in a subset of resected lung specimens.

Results

The effects of section thickness and reconstruction kernel on the emphysema index were significant (P < .001) and diminished as the index attenuation threshold was raised. The changes in index values from changing the thickness-kernel combination were largest for subjects with intermediate index values (10%–30%), and became progressively smaller for those with lower and higher index values. This pattern was consistent regardless of the thickness-kernel combinations compared and the HU threshold used. Correlations between the emphysema index values obtained with each thickness-kernel combination and Lm ranged from r = 0.55–0.68 (P = .007–.03).

Conclusion

The effects of CT section thickness and kernel on emphysema index values varied systematically with the magnitude of the emphysema index. All reconstruction techniques provided significant correlations with quantitative histology.

Key Words: Emphysema, computed tomography, histology

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 Current affiliations: Monash University, Australia (C.K.C); University of Chicago, Chicago, IL (C.H.); University of Pittsburgh, Pittsburgh, PA (K.T.B.); University of Maryland, Baltimore, MD (R.J.B.).

 Supported by National Institutes of Health grant R01 HL72369.

PII: S1076-6332(09)00492-9

doi:10.1016/j.acra.2009.08.007

Academic Radiology
Volume 17, Issue 2 , Pages 146-156, February 2010

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