Value of magnetic resonance imaging in predicting efficacy of GnRH analogue treatment for uterine leiomyoma

BACKGROUND: Estimating pharmacological efficacy is important when selecting conservative treatment of uterine leiomyoma. Hence, the ability of magneti c resonance (MR) imaging to predict gonadotrophin-releasing hormone (GnRH) analogue efficacy was investigated. METHODS: A total of 85 lesions was stud ied in 40 patients who were clinically diagnosed as having uterine leiomyom a and treated with GnRH analogue for 24 weeks. To evaluate changes in lesio n size, T2-weighted and gadopentetate-dimeglumine (Gd-DTPA)-enhanced, T1-we ighted MR images were obtained within 2 weeks before, and immediately after termination of, GnRH analogue treatment. RESULTS: An average 46.3% size re duction was observed in 45 lesions (52.9%); these were seen as low signal i ntensity on T2-weighted images and enhanced by Gd-DTPA. Also, an average 44 .7% size reduction was observed in lesions enhanced by Gd-DTPA, irrespectiv e of signal intensity findings on T2-weighted images. The average size redu ction of unenhanced lesions was only 17.8%, and significantly different fro m enhanced lesions (P<0.001). The prediction of efficacy was difficult in t hose lesions not enhanced. CONCLUSIONS: It is considered that evaluation of MR signal intensities, and the presence or absence of Gd-DTPA enhancement, would predict treatment efficacy before GnRH analogue administration.