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Proceedings Paper

Evaluating the impact on operator performance of quantification algorithms
Author(s): Ross Mitchell; Stephen J. Karlik; Donald H. Lee; Michael Eliasziw; George P. Rice; Aaron Fenster
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Paper Abstract

Quantifying changes in the number and extent of lesions in MR images has been used to indicate disease activity in multiple sclerosis. However, quantification is often long and arduous. This has prompted research into new quantification and image processing algorithms to speed up and simplify lesion quantification. Nevertheless, many algorithms rely upon an experienced operator, and are thus subject to inter- and intra-operator variability. We present a new technique to measure operator variability which is largely independent of the lesions selected for analysis, and is expressed in the measurement units. This new measure allows researchers to predict and compare absolute uncertainty for operators using new algorithms. We used this technique to examine the impact on operator performance of computer assisted lesion quantification and anisotropic filtering of patient exams to reduce image noise. In both cases repeated measurements of lesions in MR exams were performed and analyzed. Results indicate that assisted quantification reduced inter-operator variability by half (from 0.34 cm3 to 0.17 cm3) and reduced intra-operator variability by one-third (from 0.23 cm3 to 0.15 cm3). Anisotropic filtering reduced inter- and intra-operator variability by one-fifth (from 0.34 cm3 to 0.27 cm3, and from 0.23 cm3 to 0.19 cm3, respectively). These results may have practical implications for clinical trials which rely on quantitative measurements to assess therapeutic effect.

Paper Details

Date Published: 16 April 1996
PDF: 10 pages
Proc. SPIE 2710, Medical Imaging 1996: Image Processing, (16 April 1996); doi: 10.1117/12.237955
Show Author Affiliations
Ross Mitchell, Univ. of Western Ontario (Canada)
Stephen J. Karlik, Univ. of Western Ontario (Canada)
Donald H. Lee, Univ. of Western Ontario (Canada)
Michael Eliasziw, Univ. of Western Ontario (Canada)
George P. Rice, Univ. of Western Ontario (Canada)
Aaron Fenster, Univ. of Western Ontario (Canada)


Published in SPIE Proceedings Vol. 2710:
Medical Imaging 1996: Image Processing
Murray H. Loew; Kenneth M. Hanson, Editor(s)

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