Value of lipid- and water-suppression MR images in distinguishing between blood and lipid within ovarian masses.

The distinction between blood and lipid in ovarian masses on MR imaging is important in the differential diagnosis of these lesions. However, this is often difficult on routine MR images because both blood and lipid within tumors can have the same signal intensity as subcutaneous fat. Accordingly, we studied the value of lipid- and water-suppression MR images in making this distinction in 16 patients (21 lesions). As proved by surgery (six patients) or laparoscopy (10 patients), there were 16 endometriomas, one hemorrhagic leiomyosarcoma, and four lipid-containing mature cystic teratomas. The signal intensity in all 17 hemorrhagic lesions was greater than that of subcutaneous fat on lipid-suppression images and less than that of fat on water-suppression images. This compared with the signal intensity of the four lesions that contained lipid, in which the signal intensity was similar to that of subcutaneous fat on both the lipid- and water-suppression images. Thus, the lipid- and water-suppression MR images allowed an accurate distinction between the two. Our experience suggests that the appearance of blood and lipid in ovarian tumors is sufficiently different on lipid- and water-suppression MR images to allow an accurate distinction between the two. The two techniques should be useful in the differential diagnosis of such lesions by MR imaging.