Assessing myometrial invasion by endometrial carcinoma with dynamic MRI

Dynamic MRI was used to analyze patterns of contrast enhancement in muscle layers in the normal uterine body and to evaluate the depth of myometrial invasion by endometrial carcinoma.

Dynamic MRI was performed in 18 normal volunteers and 22 patients with endometrial carcinoma. Eight of the 18 normal volunteers were of reproductive age, and 10 were postmenopausal. The dynamic study was performed immediately after the bolus administration of gadopentetate dimeglumine. Twelve consecutive images, including the early phase images, were obtained during the first 2 min. The delayed phase image was obtained subsequently.

An early enhancement zone of the inner muscle layer was demonstrated in 15 normal volunteers. In all patients in whom this early enhancement zone was preserved, the tumor was confined to < 50% of the muscle layer. In the evaluation of myometrial invasion, the accuracy of dynamic MRI was 91% compared with 77% on T2-weighted images. This improvement may be attributed to greater contrast and clearer demonstration of the border between tumor and myometrium in the early phase.

We consider the disruption of the early enhancement zone of the inner muscle layer to be an important indicator of myometrial invasion.