Magnetic resonance imaging manifestations of decidualized endometriotic cysts: comparative study with ovarian cancers associated with endometriotic cysts.

ABSTRACT

PURPOSE: The purpose of the study was to investigate the magnetic resonance imaging findings of decidualized endometriotic cysts in comparison with endometriotic cysts associated with ovarian cancers. METHODS: Eighteen decidualized endometriotic cysts and 24 ovarian cancers were retrospectively assessed on height, signal intensity of the solid component on T2- and diffusion-weighted imaging, apparent diffusion coefficient value of the solid component, size of the lesion, and signal intensity of the intracystic fluid on T1-weighted imaging. RESULTS: The heights of the solid components in the decidualized endometriotic cysts were inferior to 11.1 mm, significantly lower compared with the ovarian cancers. Similarly, decidualized tissues showed significantly higher signals on T2-weighted imaging and higher apparent diffusion coefficient values compared with ovarian cancers but not on diffusion-weighted imaging. The decidualized endometriotic cysts were also significantly smaller. Intracystic fluids showed higher signal in the decidualized endometriotic cysts compared with ovarian cancers on T1-weighted imaging. CONCLUSIONS: In pregnant subjects, the presence of endometriotic cysts with low-height solid component showing high signal intensities on T2-weighted imaging is highly indicative of decidualization.