An evaluation of two software tools dedicated for an automatic analysis of the CT scanner image spatial resolution is presented in this paper. The methods evaluated consist of calculating the modulation transfer function of the CT scanners; the first uses an image of an impulse source, while the second method proposed by DROEGE uses an image of cyclic bar patterns. Two Digital Test Objects are created to this purpose. These DTOs are then blurred by doing a convolution with a two imensional Gaussian function (PSF), which has a well known FWHM. The evaluation process consists then of comparing the Fourier transform of the PSF in one hand, and the two mentioned methods in the other hand.