Free automatic software for quality assurance of computed tomography calibration, edges and radiomics metrics reproducibility

Autores de IIS La Fe

• Juan Daniel Saborido Moral

  Autor

• Matías Fernández Patón

  Autor

• Natalia Tejedor Aguilar

  Autor

• Andrei Cristian Marin

  Autor

• 

  Irene Torres Espallardo

  Autor

• Juan Manuel Campayo Esteban

  Autor

• José Pérez Calatayud

  Autor

• 

  Luis Martí Bonmatí

  Autor

• Montserrat Carles Fariña

  Autor

Participantes ajenos a IIS La Fe

• Baltas, D

Grupos

• Investigacion Biomédica en Imagen (GIBI 2-30)

• Investigación Clínica y Traslacional en Cáncer

• Núcleo de investigación traslacional integrado Urológico de Valencia (NITIUV)

Abstract

Purpose: To develop a QA procedure, easy to use, reproducible and based on open-source code, to automatically evaluate the stability of different metrics extracted from CT images: Hounsfield Unit (HU) calibration, edge characterization metrics (contrast and drop range) and radiomic features.Methods: The QA protocol was based on electron density phantom imaging. Home-made open-source Python code was developed for the automatic computation of the metrics and their reproducibility analysis. The impact on reproducibility was evaluated for different radiation therapy protocols, and phantom positions within the field of view and systems, in terms of variability (Shapiro-Wilk test for 15 repeated measurements carried out over three days) and comparability (Bland-Altman analysis and Wilcoxon Rank Sum Test or Kendall Rank Correlation Coefficient).Results: Regarding intrinsic variability, most metrics followed a normal distribution (88% of HU, 63% of edge parameters and 82% of radiomic features). Regarding comparability, HU and contrast were comparable in all conditions, and drop range only in the same CT scanner and phantom position. The percentages of comparable radiomic features independent of protocol, position and system were 59%, 78% and 54%, respectively. The non-significantly differences in HU calibration curves obtained for two different institutions (7%) translated in comparable Gamma Index G (1 mm, 1%, >99%).Conclusions: An automated software to assess the reproducibility of different CT metrics was successfully created and validated. A QA routine proposal is suggested.

Keywords

• Computed tomography; Automatic quality assurance; Radiomics; Reproducibility