Assessment of Myometrial Invasion at the Invasion Site of an Endometrial Carcinoma by Ultrasonography Along with an Intrauterine Catheter

Objectives: To evaluate by transvaginal ultrasonography (TVU) the thickness of the intact myometrium at the presumed tumor‐origin site and to establish criteria for a half myometrial invasion. Methods: A total of 19 successive patients with endometrial cancer who were treated between January 1, 1997, and January 31, 1998, participated in this study. TVU mode B with and without the use of an intrauterine silicon catheter was performed. Results: Using a catheter, the origin site was correctly detected in 15 cases (79%). The best criterion for half myometrial invasion was a 6‐mm thickness of the intact myometrium at the origin site. The sensitivity/specificity/accuracy of TVU with the use of a catheter in cases with the correct estimated origin site, were 1.00/0.67/0.86 for myometrial invasion < 1/2, and 0.67/1.00/0.86 for myometrial invasion < 1/2. Conclusion: It is of value to use 6‐mm as the criterion for the thickness of the intact myometrium at the estimated tumor‐origin site in connection with TVU with the use of a catheter for preoperatively assessing half myometrial invasion.