title: Use of enhanced T2 star-weighted angiography (ESWAN) and R2* values to distinguish ovarian cysts due to endometriosis from other causes.
abstract: OBJECTIVE
  To evaluate the feasibility of enhanced T2 star-weighted angiography (ESWAN) in differentiating endometrial from non-endometrial cysts.
  
  
  METHODS
  Forty-nine patients with 60 histopathologically proven ovarian cystic lesions underwent pelvic MRI including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), liver acquisition with volume acceleration, and ESWAN. Ovarian cystic lesions were divided into endometrial cysts (group 1; n = 28), pyosalpinx and hydrosalpinx (group 2; n = 13), and ovarian cystic and cystic-solid tumors (group 3; n = 19). R2* (effective transverse relaxation rate) values were measured and pairwise comparison of the R2* values among the three groups was made using Kruskal-Wallis test. Receiver operating characteristic curves were used to calculate cutoff values and performance of R2* values for distinguishing among groups. T1WI signal intensity and R2* value were also compared using area under curve values.
  
  
  RESULTS
  R2* values for group 1 were statistically higher than groups 2 and 3 (15.37, 1.40, and 1.79 Hz, respectively; P < 0.001). The cutoff value for R2* was 7.43 Hz with a sensitivity, specificity, PPV, NPV, and accuracy of 96.43, 87.50, 87.10, 96.55, and 91.67%, respectively. There was no significant difference between the R2* value and T1WI in diagnosing endometrial cysts.
  
  
  CONCLUSIONS
  The R2* value provides an effective way to discriminate endometrial cysts from other ovarian cystic lesions.
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Dalian Medical University, No.222 Zhongshan Road, Xigang District, Dalian, 116011, Liaoning, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Song
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Sun
authors.forename: He-Qing
authors.initials: HQ
authors.lastname: Wang
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wei
authors.forename: Jing-Hong
authors.initials: JH
authors.lastname: Liu
authors.forename: Shi-Feng
authors.initials: SF
authors.lastname: Tian
authors.forename: Zi-Bin
authors.initials: ZB
authors.lastname: Tong
authors.forename: Ai-Lian
authors.initials: AL
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D004715:Endometriosis / Q000150:complications* / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010048:Ovarian Cysts / Q000209:etiology* / Q000473:pathology*; D010053:Ovary / Q000473:pathology; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media