Quantitative evaluation of a pulmonary contour segmentation algorithm in X-ray computed tomography images.
OBJECTIVE
Pulmonary contour extraction from thoracic x-ray computed tomography images is a mandatory preprocessing step in many automated or semiautomated analysis tasks. This study was conducted to quantitatively assess the performance of a method for pulmonary contour extraction and region identification.


METHODS
The automatically extracted contours were statistically compared with manually drawn pulmonary contours detected by six radiologists on a set of 30 images. Exploratory data analysis, nonparametric statistical tests, and multivariate analysis were used, on the data obtained using several figures of merit, to perform a study of the interobserver variability among the six radiologists and the contour extraction method. The intraobserver variability of two human observers was also studied.


RESULTS
In addition to a strong consistency among all of the quality indexes used, a wider interobserver variability was found among the radiologists than the variability of the contour extraction method when compared with each radiologist. The extraction method exhibits a similar behavior (as a pulmonary contour detector), to the six radiologists, for the used image set.


CONCLUSIONS
As an overall result of the application of this evaluation methodology, the consistency and accuracy of the contour extraction method was confirmed to be adequate for most of the quantitative requirements of radiologists. This evaluation methodology could be applied to other scenarios.
Sousa Santos
Beatriz
B
Serviço de Imagiologia, Hospitais da Universidade de Coimbra, Portugal.
Ferreira
Carlos
C
Silva
José Silvestre
JS
Silva
Augusto
A
Teixeira
Luísa
L
D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D008168:Lung / Q000000981:diagnostic imaging*; D015999:Multivariate Analysis; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted; D011871:Radiology / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data