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Title: Contouring Variability of the Penile Bulb on CT Images: Quantitative Assessment Using a Generalized Concordance Index

Abstract

Purpose: Within a multicenter study (DUE-01) focused on the search of predictors of erectile dysfunction and urinary toxicity after radiotherapy for prostate cancer, a dummy run exercise on penile bulb (PB) contouring on computed tomography (CT) images was carried out. The aim of this study was to quantitatively assess interobserver contouring variability by the application of the generalized DICE index. Methods and Materials: Fifteen physicians from different Institutes drew the PB on CT images of 10 patients. The spread of DICE values was used to objectively select those observers who significantly disagreed with the others. The analyses were performed with a dedicated module in the VODCA software package. Results: DICE values were found to significantly change among observers and patients. The mean DICE value was 0.67, ranging between 0.43 and 0.80. The statistics of DICE coefficients identified 4 of 15 observers who systematically showed a value below the average (p value range, 0.013 - 0.059): Mean DICE values were 0.62 for the 4 'bad' observers compared to 0.69 of the 11 'good' observers. For all bad observers, the main cause of the disagreement was identified. Average DICE values were significantly worse from the average in 2 of 10 patients (0.60more » vs. 0.70, p < 0.05) because of the limited visibility of the PB. Excluding the bad observers and the 'bad' patients,' the mean DICE value increased from 0.67 to 0.70; interobserver variability, expressed in terms of standard deviation of DICE spread, was also reduced. Conclusions: The obtained values of DICE around 0.7 shows an acceptable agreement, considered the small dimension of the PB. Additional strategies to improve this agreement are under consideration and include an additional tutorial of the so-called bad observers with a recontouring procedure, or the recontouring by a single observer of the PB for all patients included in the DUE-01 study.« less

Authors:
 [1];  [2]; ;  [1];  [3];  [4];  [1];  [5];  [6];  [4];  [7];  [1]
  1. Department of Medical Physics, San Raffaele Scientific Institute, Milano (Italy)
  2. Department of Radiotherapy, San Raffaele Scientific Institute, Milano (Italy)
  3. Medical Software Solutions GmbH, Hagendorn (Switzerland)
  4. Prostate Cancer Program, IRCCS National Institute of Cancer, Milano (Italy)
  5. Department of Radiotherapy, Cliniche Gavazzeni Humanitas, Bergamo (Italy)
  6. Department of Radiotherapy 1, IRCCS National Institute of Cancer, Milano (Italy)
  7. (Italy)
Publication Date:
OSTI Identifier:
22149610
Resource Type:
Journal Article
Journal Name:
International Journal of Radiation Oncology, Biology and Physics
Additional Journal Information:
Journal Volume: 84; Journal Issue: 3; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0360-3016
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CAT SCANNING; COMPUTER CODES; NEOPLASMS; PATIENTS; PROSTATE; RADIOTHERAPY; STATISTICS; TOXICITY

Citation Formats

Carillo, Viviana, Cozzarini, Cesare, Perna, Lucia, Calandra, Mauro, Gianolini, Stefano, Rancati, Tiziana, Spinelli, Antonello Enrico, Vavassori, Vittorio, Villa, Sergio, Valdagni, Riccardo, Department of Radiotherapy 1, IRCCS National Institute of Cancer, Milano, and Fiorino, Claudio, E-mail: fiorino.claudio@hsr.it. Contouring Variability of the Penile Bulb on CT Images: Quantitative Assessment Using a Generalized Concordance Index. United States: N. p., 2012. Web. doi:10.1016/J.IJROBP.2011.12.057.
Carillo, Viviana, Cozzarini, Cesare, Perna, Lucia, Calandra, Mauro, Gianolini, Stefano, Rancati, Tiziana, Spinelli, Antonello Enrico, Vavassori, Vittorio, Villa, Sergio, Valdagni, Riccardo, Department of Radiotherapy 1, IRCCS National Institute of Cancer, Milano, & Fiorino, Claudio, E-mail: fiorino.claudio@hsr.it. Contouring Variability of the Penile Bulb on CT Images: Quantitative Assessment Using a Generalized Concordance Index. United States. doi:10.1016/J.IJROBP.2011.12.057.
Carillo, Viviana, Cozzarini, Cesare, Perna, Lucia, Calandra, Mauro, Gianolini, Stefano, Rancati, Tiziana, Spinelli, Antonello Enrico, Vavassori, Vittorio, Villa, Sergio, Valdagni, Riccardo, Department of Radiotherapy 1, IRCCS National Institute of Cancer, Milano, and Fiorino, Claudio, E-mail: fiorino.claudio@hsr.it. Thu . "Contouring Variability of the Penile Bulb on CT Images: Quantitative Assessment Using a Generalized Concordance Index". United States. doi:10.1016/J.IJROBP.2011.12.057.
@article{osti_22149610,
title = {Contouring Variability of the Penile Bulb on CT Images: Quantitative Assessment Using a Generalized Concordance Index},
author = {Carillo, Viviana and Cozzarini, Cesare and Perna, Lucia and Calandra, Mauro and Gianolini, Stefano and Rancati, Tiziana and Spinelli, Antonello Enrico and Vavassori, Vittorio and Villa, Sergio and Valdagni, Riccardo and Department of Radiotherapy 1, IRCCS National Institute of Cancer, Milano and Fiorino, Claudio, E-mail: fiorino.claudio@hsr.it},
abstractNote = {Purpose: Within a multicenter study (DUE-01) focused on the search of predictors of erectile dysfunction and urinary toxicity after radiotherapy for prostate cancer, a dummy run exercise on penile bulb (PB) contouring on computed tomography (CT) images was carried out. The aim of this study was to quantitatively assess interobserver contouring variability by the application of the generalized DICE index. Methods and Materials: Fifteen physicians from different Institutes drew the PB on CT images of 10 patients. The spread of DICE values was used to objectively select those observers who significantly disagreed with the others. The analyses were performed with a dedicated module in the VODCA software package. Results: DICE values were found to significantly change among observers and patients. The mean DICE value was 0.67, ranging between 0.43 and 0.80. The statistics of DICE coefficients identified 4 of 15 observers who systematically showed a value below the average (p value range, 0.013 - 0.059): Mean DICE values were 0.62 for the 4 'bad' observers compared to 0.69 of the 11 'good' observers. For all bad observers, the main cause of the disagreement was identified. Average DICE values were significantly worse from the average in 2 of 10 patients (0.60 vs. 0.70, p < 0.05) because of the limited visibility of the PB. Excluding the bad observers and the 'bad' patients,' the mean DICE value increased from 0.67 to 0.70; interobserver variability, expressed in terms of standard deviation of DICE spread, was also reduced. Conclusions: The obtained values of DICE around 0.7 shows an acceptable agreement, considered the small dimension of the PB. Additional strategies to improve this agreement are under consideration and include an additional tutorial of the so-called bad observers with a recontouring procedure, or the recontouring by a single observer of the PB for all patients included in the DUE-01 study.},
doi = {10.1016/J.IJROBP.2011.12.057},
journal = {International Journal of Radiation Oncology, Biology and Physics},
issn = {0360-3016},
number = 3,
volume = 84,
place = {United States},
year = {2012},
month = {11}
}