title: Three-dimensional ultrasound improves the interobserver reliability of antral follicle counts and facilitates increased clinical work flow.
abstract: OBJECTIVE
  To compare the interobserver reliability of antral follicle counts made using real-time two-dimensional (2D) ultrasound with offline counts made from stored three-dimensional (3D) data and to assess the time required for such counts.
  
  
  METHODS
  Two observers conducted transvaginal ultrasound examinations in 45 subfertile women in the early follicular phase of the menstrual cycle. Antral follicles were counted using real-time 2D ultrasound and the time taken was recorded. A 3D volume was then acquired from each ovary and stored for subsequent offline analysis using the multiplanar view. The time taken for each step was recorded and the total time was calculated. Intraclass correlation coefficients (ICC) and limits of agreement were used to assess reliability.
  
  
  RESULTS
  There was no difference in the mean antral follicle counts using real-time 2D (16.51 +/- 11.51) and 3D (16.33 +/- 12.13) ultrasound. According to ICCs, there was a significantly higher interobserver reliability for counts made using 3D (mean, 0.992; 95% CI, 0.986-0.996) compared with real-time 2D (mean, 0.961; 95% CI, 0.940-0.977) (P < 0.01) ultrasound. 3D ultrasound was also associated with narrower limits of agreement (-2.7 to + 3.1) than was 2D ultrasound (-6.9 to + 6.4). Whilst the total time taken was significantly longer for the 3D technique (239.3 +/- 71.4 s vs. 103.1 +/- 28.6 s, P < 0.001), the time required for the actual ultrasound examination was significantly less (46.4 +/- 7.4 s vs. 103.1 +/- 28.6 s, P < 0.001).
  
  
  CONCLUSIONS
  3D ultrasound significantly improves the interobserver reliability of antral follicle counts. While this is at the expense of time overall, the duration of the actual ultrasound examination and patient exposure is significantly reduced using 3D compared with real-time 2D ultrasound.
authors.affiliation: Nottingham University Research and Treatment Unit in Reproduction (NURTURE), Academic Division of Reproductive Medicine and Surgery, School of Human Development, Queen's Medical Centre, University of Nottingham, UK. k.jayaprakasan@nottingham.ac.uk
authors.forename: K
authors.initials: K
authors.lastname: Jayaprakasan
authors.forename: B K
authors.initials: BK
authors.lastname: Campbell
authors.forename: J S
authors.initials: JS
authors.lastname: Clewes
authors.forename: I R
authors.initials: IR
authors.lastname: Johnson
authors.forename: N J
authors.initials: NJ
authors.lastname: Raine-Fenning
mesh_terms: D000328:Adult; D005260:Female; D005498:Follicular Phase; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D009775:Obstetrics and Gynecology Department, Hospital / Q000458:organization & administration; D006080:Ovarian Follicle / Q000000981:diagnostic imaging*; D010053:Ovary / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography