Pituitary macroadenomas are usually pituitary tumors larger than 1cm in diameter, which can be detected by plain scanning, and we do enhancement scanning only to delineate the tumor range more accurately. In addition, if more information is needed for clinical treatment, enhancement scanning is also needed. Pituitary microadenomas are usually very small, with a diameter of less than 1cm, and do not cause abnormal changes in the height or density of the pituitary gland, so they cannot be detected by plain scanning. Therefore, if a pituitary adenoma is suspected, CT enhancement scan should be done as much as possible. Magnetic resonance imaging (MRI) is preferred for the examination of pituitary microadenomas because of its higher resolution and lack of radiation exposure.