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Inter-laboratory comparison of channelized hotelling observer computation

Ba, Alexandre ; Abbey, Craig K. ; Baek, Jongduk ; Han, Minah ; Bouwman, Ramona W. ; Balta, Christiana ; Brankov, Jovan ; Massanes, Francesc ; Gifford, Howard C. and Hernandez-Giron, Irene , et al. (2018) In Medical Physics 45(7). p.3019-3030
Abstract

Purpose: The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise. Materials and Methods: Image samples to estimate model observer performance for detection tasks were generated from two-dimensional CT image slices of a uniform water phantom. A common set of images was sent to participating laboratories to... (More)

Purpose: The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise. Materials and Methods: Image samples to estimate model observer performance for detection tasks were generated from two-dimensional CT image slices of a uniform water phantom. A common set of images was sent to participating laboratories to perform and document the following tasks: (a) estimate the detectability index of a well-defined CHO and its uncertainty in three conditions involving different sized targets all at the same dose, and (b) apply this CHO to an image set where ground truth was unknown to participants (lower image dose). In addition, and on an optional basis, we asked the participating laboratories to (c) estimate the performance of real human observers from a psychophysical experiment of their choice. Each of the 13 participating laboratories was confidentially assigned a participant number and image sets could be downloaded through a secure server. Results were distributed with each participant recognizable by its number and then each laboratory was able to modify their results with justification as model observer calculation are not yet a routine and potentially error prone. Results: Detectability index increased with signal size for all participants and was very consistent for 6 mm sized target while showing higher variability for 8 and 10 mm sized target. There was one order of magnitude between the lowest and the largest uncertainty estimation. Conclusions: This intercomparison helped define the state of the art of model observer performance computation and with thirteen participants, reflects openness and trust within the medical imaging community. The performance of a CHO with explicitly defined channels and a relatively large number of test images was consistently estimated by all participants. In contrast, the paper demonstrates that there is no agreement on estimating the variance of detectability in the training and testing setting.

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published
subject
keywords
channelized hotelling observer, computed tomography, image quality, intercomparison, model observers
in
Medical Physics
volume
45
issue
7
pages
3019 - 3030
publisher
American Association of Physicists in Medicine
external identifiers
  • pmid:29704868
  • scopus:85049789575
ISSN
0094-2405
DOI
10.1002/mp.12940
language
English
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yes
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aa63416e-e809-47ad-9b41-68a79dfd7109
date added to LUP
2018-09-12 13:51:17
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2020-02-26 06:58:51
@article{aa63416e-e809-47ad-9b41-68a79dfd7109,
  abstract     = {<p>Purpose: The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise. Materials and Methods: Image samples to estimate model observer performance for detection tasks were generated from two-dimensional CT image slices of a uniform water phantom. A common set of images was sent to participating laboratories to perform and document the following tasks: (a) estimate the detectability index of a well-defined CHO and its uncertainty in three conditions involving different sized targets all at the same dose, and (b) apply this CHO to an image set where ground truth was unknown to participants (lower image dose). In addition, and on an optional basis, we asked the participating laboratories to (c) estimate the performance of real human observers from a psychophysical experiment of their choice. Each of the 13 participating laboratories was confidentially assigned a participant number and image sets could be downloaded through a secure server. Results were distributed with each participant recognizable by its number and then each laboratory was able to modify their results with justification as model observer calculation are not yet a routine and potentially error prone. Results: Detectability index increased with signal size for all participants and was very consistent for 6 mm sized target while showing higher variability for 8 and 10 mm sized target. There was one order of magnitude between the lowest and the largest uncertainty estimation. Conclusions: This intercomparison helped define the state of the art of model observer performance computation and with thirteen participants, reflects openness and trust within the medical imaging community. The performance of a CHO with explicitly defined channels and a relatively large number of test images was consistently estimated by all participants. In contrast, the paper demonstrates that there is no agreement on estimating the variance of detectability in the training and testing setting.</p>},
  author       = {Ba, Alexandre and Abbey, Craig K. and Baek, Jongduk and Han, Minah and Bouwman, Ramona W. and Balta, Christiana and Brankov, Jovan and Massanes, Francesc and Gifford, Howard C. and Hernandez-Giron, Irene and Veldkamp, Wouter J.H. and Petrov, Dimitar and Marshall, Nicholas and Samuelson, Frank W. and Zeng, Rongping and Solomon, Justin B. and Samei, Ehsan and Timberg, Pontus and Förnvik, Hannie and Reiser, Ingrid and Yu, Lifeng and Gong, Hao and Bochud, François O.},
  issn         = {0094-2405},
  language     = {eng},
  month        = {07},
  number       = {7},
  pages        = {3019--3030},
  publisher    = {American Association of Physicists in Medicine},
  series       = {Medical Physics},
  title        = {Inter-laboratory comparison of channelized hotelling observer computation},
  url          = {http://dx.doi.org/10.1002/mp.12940},
  doi          = {10.1002/mp.12940},
  volume       = {45},
  year         = {2018},
}