[en] X-ray computed microtomography (microCT) is a powerful nondestructive and noninvasive technique for 2D and 3D structure analyses. However, the parameters used in the image acquisition process have a direct influence on the qualitative and quantitative results, such as porosity, and on the characterization of samples, such as carbonate rocks, due to the spatial resolution of the image. The aim of this study is to determine the influence of these parameters on the results through tests in which these parameters are changed in different scenarios and system characterizations. In addition, with the optimum parameters, the whole sample image was acquired for characterization and compared to the homogeneity and representativeness of one part of the sample. The results demonstrate that the pixel size and detector matrix are the main parameters that influence the spatial resolution and that the use of additional filters for better image quality is essential. Microtomography is considered an excellent technique for rock characterization by using the best image spatial resolution possible.