title: Focal hyperdense areas in endometriomas: a characteristic finding on CT.
abstract: OBJECTIVE
  To assess the value of a hyperdense focus seen on CT scans of endometrial cysts in the differential diagnosis of a lesion.
  
  
  METHODS
  The preoperative CT scans of 328 patients with 410 ovarian masses (54 patients with 62 pathologically proved endometriomas and 274 patients with 348 pathologically proved other ovarian masses) were retrospectively reviewed in a random fashion without knowledge of the pathologic findings to determine whether a hyperdense focus was visible inside a cyst.
  
  
  RESULTS
  In nine of 62 endometrial cysts (sensitivity, 15%), CT scans showed a hyperdense round or crescent-shaped focus, measuring 2 to 15 mm. This focus was located close to the inner border of the cyst in eight cases and in the central part of the cyst in one case. A hyperdense focus was not seen on CT scans of 348 other ovarian masses (specificity, 100%). An in vitro CT study of two specimens showed that this hyperdense area corresponded to a blood clot next to the inner wall of the cyst. This hyperdense area appeared as a nonspecific hyperechogenic focus on sonograms in five of nine cases and as a hypointense signal on T1- and/or T2-weighted MR images in four of five cases.
  
  
  CONCLUSIONS
  The finding on CT scans of a hyperdense focus inside an ovarian cyst is suggestive of endometrioma and should help distinguish endometrioma from other pelvic masses.
authors.affiliation: Department of Radiology, Hôtel Dieu de Paris, France.
authors.forename: J N
authors.initials: JN
authors.lastname: Buy
authors.forename: M A
authors.initials: MA
authors.lastname: Ghossain
authors.forename: A S
authors.initials: AS
authors.lastname: Mark
authors.forename: L
authors.initials: L
authors.lastname: Deligne
authors.forename: D
authors.initials: D
authors.lastname: Hugol
authors.forename: J B
authors.initials: JB
authors.lastname: Truc
authors.forename: P
authors.initials: P
authors.lastname: Poitout
authors.forename: D
authors.initials: D
authors.lastname: Vadrot
mesh_terms: D002277:Carcinoma / Q000000981:diagnostic imaging; D003287:Contrast Media; D003937:Diagnosis, Differential; D004715:Endometriosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D007483:Iothalamic Acid / Q000031:analogs & derivatives; D009373:Neoplasms, Germ Cell and Embryonal / Q000000981:diagnostic imaging; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007483:Iothalamic Acid; C002587:ioxitalamic acid