The present study was designed to determine the accuracy of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) in evaluating the extent of the tumor in 36 patients with endometrial carcinoma. The CT and MRI findings were compared with the microscopic pathologic characteristics in all cases. Linear regression analysis for measurements of residual normal myometrium revealed significant positive correlations (p < 0.001) between MRI (r = 0.861) and CT (r = 0.826) findings and pathologic evaluation. Thirty-six patients were divided into two groups according to our previous CT and MRI criteria: the superficial myometrial invasion group and advanced tumor group. In MRI findings, higher incidences of deep (> or = 1/2) myometrial invasion (p < 0.001), vessel permeation (p < 0.05) and cervical involvement (p < 0.05) were observed in the advanced group. In CT findings, deep myometrial invasion (p < 0.001) was observed in the advanced group. The incidence of extrauterine extension of the tumor did not differ significantly between CT and MRI findings. The accuracy figures for cervical involvement evaluated by CT and MRI were 83% and 86%, respectively. In four of 6 patients, in whom an intact Junctional zone (j-zone) was detected by MRI, the tumor was localized in the endometrium. The remaining 2 patients had only superficial myometrial invasion histologically. In all 16 patients, in whom the j-zone was interrupted in MRI findings, myometrial invasion was confirmed pathologically.(ABSTRACT TRUNCATED AT 250 WORDS)