Objective: To compare the accuracy of transvaginal sonography and magnetic rezonance imaging (MRI) in determining the depth of myometrial invasion in proven cases of endometrial cancer. Design: A prospective study. Setting: Department of Obstetrics and Gynecology, Department of Medical Genetics and Fetal Medicine, Department of Radiology, University Hospital, Olomouc. Methods: Fifty five patients diagnosed as having FIGO stage I endometrial carcinoma were evaluated preoperatively by transvaginal ultrasound; 44 cases of the same group were also evaluated by magnetic resonance imaging (MRI). The degree of invasion evaluated by transvaginal sonography and by MRI was compared to the pathological specimens. Results: Transvaginal sonography was successful in evaluating myometrial invasion in 44 of 55 cases (accuracy 80%, sensitivity 80%, specificity 88%, positive predictive value 77%, negative predictive value 87%). Evaluation with MRI was accurate in 37 of 44 cases (accuracy 84%, sensitivity 84%, specificity 91%, positive predictive value 81%, negative predictive value 91%). Conclusion: Although MRI is superior to transvaginal sonography in evaluating myometrial invasion, it is expensive and time consuming, and would not be suitable as a screening test for depth of invasion. On the other hand, transvaginal sonography is relatively low-cost technique, which can be easily performed and repeated. However, it requires more operator experience than MRI in order to achieve high accuracy.

        Key words: magnetic resonance imaging, ultrasound, endometrial cancer, myometrial invasion