Contrast-detail assessment of computed tomography scanners.

The design and construction of contrast-detail detectability phantoms for the assessment of the imaging performance of CT scanners are described. These phantoms have been employed to undertake a series of measurements on a number of different machines. The results are expressed in terms of object contrast which is consistent with the conventional definition of radiological contrast. For one particular scanner, the imaging performance of a number of image reconstruction and post-processing filters has been investigated. The results indicate that there was no observed energy dependence of contrast-detail detectability once differences in technique factors and attenuation were taken into account. A similar conclusion was drawn from the results of a set of measurements made to examine the effect on detectability of additional filtration.