title: Ultrasound image attributes of human ovarian dominant follicles during natural and oral contraceptive cycles.
abstract: BACKGROUND
  Computer-assisted analyses were used to examine ultrasound image attributes of human dominant ovarian follicles that developed during natural and oral contraceptive (OC) cycles. We hypothesized that image attributes of natural cycle follicles would quantitatively differ from those in OC cycles and that OC cycle follicles would possess image attributes indicative of atresia.
  
  
  METHODS
  Dominant ovarian follicles of 18 clinically normal women were compared using transvaginal ultrasonography for the 7 days before ovulation during a natural cycle (n = 9) or the 7 days before peak estradiol in women using OC (n = 11). Follicles were analyzed using region and line techniques designed to compare the image attributes numerical pixel value (NPV), pixel heterogeneity (PH) and area under the curve (AUC).
  
  
  RESULTS
  NPV was higher in OC cycle follicles with region analysis and tended to be higher with line analysis (p = 0.005 and p = 0.06, respectively). No differences were observed in two other image attributes (AUC and PH), measured with either technique, between natural and OC cycle follicles.
  
  
  CONCLUSIONS
  The increased NPV value of OC cycle follicles and lack of differences in PH and AUC values between natural cycle and OC cycle follicles did not support the hypothesis that OC cycle follicles would show ultrasonographically detectable signs of atresia. Image attributes observed in OC cycle follicles were not clearly indicative of atresia nor were they large enough to preclude preovulatory physiologic status in OC cycle follicles.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. birtch@erato.usask.ca
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Birtch
authors.forename: Angela R
authors.initials: AR
authors.lastname: Baerwald
authors.forename: Olufemi A
authors.initials: OA
authors.lastname: Olatunbosun
authors.forename: Roger A
authors.initials: RA
authors.lastname: Pierson
mesh_terms: D000328:Adult; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D005496:Follicular Atresia / Q000187:drug effects*; D005498:Follicular Phase / Q000502:physiology; D006801:Humans; D006080:Ovarian Follicle / Q000000981:diagnostic imaging* / Q000254:growth & development; D012189:Retrospective Studies; D014463:Ultrasonography
chemical_list: D003276:Contraceptives, Oral