[Computerized tomography of the pituitary gland in the diagnosis of prolactinoma: a concordance study].

BACKGROUND: The diagnostic capacity of computed tomography (CT) of the pituitary gland in the diagnosis of prolactinomas is difficult to define in terms of specificity and sensitivity since, up to the present, there is no definite diagnostic test for prolactin producing tumors. The aim of this study is to establish the consistency of CT of the hypophysis in the diagnosis of the prolactinomas based on a concordance design. METHODS: In the follow-up study of 48 patients diagnosed as affected of prolactinoma a concordance study was carried out on the blind lecture of 35 pituitary gland CT by two radiologists. RESULTS: The degree of concordance for all the diagnosis (kappa = 0.58) was greater than what might be expected by chance. The degree of concordance was also different for the different diagnosis given by the two radiologists: empty sella turcica, kappa = 0.84 (p less than 0.01); macroprolactinoma, kappa = 0.68 (p less than 0.01); microprolactinoma, kappa = 0.45 (p less than 0.01) and normal sella turcica, kappa = 0.28 (NS). CONCLUSIONS: CT of the hypophysis must be less sensitive (more false negatives) in cases of high prolactin due to microprolactinomas and less specific (more false positives) in cases of high prolactin due to a cause other than pituitary tumor, thereby making it a complementary diagnostic test to clinical evaluation and to prolactin determinations.