Susceptibility-weighted MRI of extra-ovarian endometriosis: preliminary results

Extra-ovarian endometriosis (EOE) usually appears as solid masses mimicking neoplasms both clinically and radiologically. Detection of blood products within a lesion may be suggestive of its endometriotic nature. We present a descriptive study of MR imaging findings that include susceptibility-weighted imaging (SWI) for patients with EOE. Eight pathologically proven EOE (3 bowel, 2 bladder and 3 abdominal wall) were evaluated. Fat-saturated T1-weighted images (fsT1WI) and SWI were obtained using 1.5T MR imaging. Images were reviewed for the presence of signal voids on SWI and of high-intensity foci on fsT1WI. High-intensity foci reflecting subacute hemorrhage were detected in 4 of 8 lesions (50%) on fsT1WI, whereas signal voids reflecting acute to chronic hemorrhage were detected in all 8 lesions (100%) on SWI. SWI is a sensitive MRI technique which demonstrates hemorrhage of varying chronicity in patients with EOE and may improve future MRI characterization of EOE.