Not applicable, Retrospective, Cancer, Observer performance, Dosimetry, CT, Conventional radiography, Thorax, Lung, Imaging Informatics, Multicentre study
Z. Passand, C. Hoeschen; Magdeburg/DE
Methods and materials
Thorax CT images were collected from more than 450 cases within a European project (MEDIRAD). The long-term goal within the MEDIRAD project is to correlate subjective image quality assessment results from observer studies with objective image quality descriptors. Objective image quality assessment was performed using two approaches:
1) evaluation of the modulation transfer function (MTF) on structures in the region-of-interest and
2) the noise power spectrum (NPS) in that same region.
The area under the MTF curve was integrated and used as an image quality metric, i.e. larger areas under the MTF curve were expected from images with good quality. By integrating the 2D-NPS, the variance of the image, i.e. of the noise, was estimated. The variance was used as another metric for determining the image quality whereas a larger variance was associated with a lower image quality.