Imaging of peritoneal pseudocysts: value of MR imaging compared with sonography and CT

Peritoneal pseudocysts are created when fluid arising from the ovary is trapped by peritoneal adhesions. We studied the value of MR imaging, compared with sonography and CT, for detecting these abnormalities.

Nine women, 27 to 49 years old, who had surgically proved peritoneal pseudocysts were included in the study. All nine patients were premenopausal, and eight had a history of pelvic surgery. All patients were examined with MR imaging and sonography, and five were also examined with CT. Imaging findings were analyzed and compared with the surgical findings.

Sonograms in all nine patients showed a thick-walled cyst that contained focal echoes indicating nodules, making it difficult to differentiate these lesions from cystic ovarian tumors. In eight of the nine patients, the fluid in the pseudocysts had low signal intensity on T1-weighted MR images and high signal intensity on T2-weighted spin-echo MR images, suggesting that the fluid was serous. The pseudocyst had an irregular shape on MR images in seven patients and on CT scans in three patients. However, MR provided more information than CT did about the nature of the fluid within the pseudocyst.

Our study suggests that MR imaging is more useful than sonography and CT for determining the characteristic findings of peritoneal pseudocysts.