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2 May 2003 Reconstruction algorithm effects on density mask score and volume in patients with low amounts of emphysema
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The effects of CT reconstruction algorithm on density mask score (percentage of voxels < -910 HU) and total lung volume were investigated for emphysema patients with low density mask scores (approximately 20% or below) and patients with higher scores. Based on MTF curves, reconstruction algorithms were classed as standard (i.e. non-enhancing) or over-enhancing. Each image data set was reconstructed with both the standard reconstruction algorithm and the over-enhancing algorithm. All other factors, such as slice collimation and reconstruction interval, were constant. Twenty-nine patients were divided into a high density mask score group (n=10) and low density mask score group (n=19). For the low density mask subgroup, the over-enhancing category yielded an average increase in density mask score of 12.6% compared to standard (i.e. a shift in average score from 14.8% to 27.4%). The maximum shift in score for the low density mask group was 15.9% while the minimum shift was 9.2%. The high density mask group yielded an average shift of 8.7%, with a minimum shift of 3.8% and a maximum shift of 15.3%. The low density group displayed a 1.2% decrease in volume for the over-enhancing category and a 0.8% decrease for the standard category. These volume changes are likely clinically insignificant. Reconstruction algorithm does, however, have a significant effect on the density mask quantitative measure of emphysema. This effect may be significantly larger for density mask scores in patients with smaller amounts of emphysema.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kirsten L. Boedeker, Michael F. McNitt-Gray, David W. Gjertson, Sarah R. Rogers, Dao A. Truong, Matthew S. Brown, and Jonathan G. Goldin "Reconstruction algorithm effects on density mask score and volume in patients with low amounts of emphysema", Proc. SPIE 5031, Medical Imaging 2003: Physiology and Function: Methods, Systems, and Applications, (2 May 2003);

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