Dynamic computed tomography for the diagnosis of pituitary microadenoma, 2

The purpose of this paper is to establish the diagnostic criteria on microadenoma by dynamic CT. Dynamic CT was studied in 19 patients with hormone-secreting microadenomas. There were 10 prolactin-secreting, 5 growth-hormone-secreting, and 4 adrenocorticotropic-hormone-secreting adenomas. The following diagnostic criteria on microadenomas were concluded by analyzing dynamic CT on 19 microadenomas, in which histology, location and extension of the tumor were verified by surgery and postoperative CT. The tuft distorted and displaced indicates a mass effect mainly in the opposite side. The mid-situated tuft with a disproportionately small size compared with a size of the anterior lobe indicates a mass effect mainly in the midportion. The area, into which a high density at the tuft definitely spreads, presents the normal anterior lobe. The area, in which less increase in density than the former area is observed, indicates an abnormal mass. In the time-density curve, the former area represents the vascular pattern or the hypervascular extravasation pattern, while the latter area represents extravasation of contrast material in a hypovascular tissue. Only eight microadenomas were presented as a less enhanced mass. The rest of the cases exhibited adenomas isodense to the normal pituitary gland. Dynamic CT was useful particularly in the diagnosis of isodense adenomas. (author)