[Clinical application of magnetic resonance imaging (MRI) in uterine disease]

We investigated the value of MRI in investigating uterine anatomy and disease. 1. Normal uterus: The signal intensity and endometrial thickness changed during the menstrual cycle. Endometrial thickness in the secretory phase was 12.8 +/- 3.6 mm, significantly greater than in the proliferative phase (5.4 +/- 0.7 mm, p less than 0.01). In contrast, endometrial thickness was reduced in postmenopausal women (4.1 +/- 0.9 mm) and was never over 6 mm. 2. Uterine disease: a. T2-weighted images were useful in differentiating leiomyoma and adenomyosis. Leiomyomas appeared as well-circumscribed nodules with sharp margins, while adenomyosis was seen as a low signal intensity area with an irregular border extending beneath the endometrium. b. In endometrial carcinoma, endometrial thickening with a high signal intensity was a characteristic of T2-weighted images, the maximal thickness being 16.5 +/- 6.9 mm. Moreover, endometrial carcinomas invading over 1/3 of the myometrium showed the following features: (1) The ratio of maximal endometrial thickness to uterine cross sectional diameter was over 50%. (2) The minimal myometrial thickness was under 5.0 mm. (3) The minimal to maximal myometrial thickness ratio was under 50%. Furthermore, cervical extension could be detected in all cases of endometrial carcinoma extending to the myometrium in T2-weighted images.