Monitoring therapy with a gonadotropin-releasing hormone analog: utility of MR imaging.

The utility of magnetic resonance (MR) imaging in assessing response to therapy with a gonadotropin-releasing hormone (GnRH) analog was assessed in 19 women with uterine leiomyomas and 19 women with endometriosis. There was a significant reduction in individual fibroid volumes at 3 months (P less than .05) and at 6 months (P less than .005) in the drug group, whereas there was no significant change in the placebo group. Vessel conspicuity significantly decreased at 3 months (P less than .02) and at 6 months (P less than .01) in the drug group but not in the placebo group. In the patients with endometriosis, there was a significant decrease (P less than .0006) in the number of endometriomas visualized. Significant changes were also noted in the pelvis in women who were receiving the GnRH analog. After 6 months of therapy, the identifiability of the ovaries was significantly poorer (P less than .05). The authors conclude that the utility of conservative therapy with a GnRH analog can be quantitatively assessed with MR imaging.