title: Volume assessment of the normal female cervix with MR imaging: comparison of the segmentation technique and two geometric formula.
abstract: OBJECTIVE
  The purpose of this study was to determine the volume of the normal female cervix and to determine the geometric formula that yields the best estimate.
  
  
  METHODS
  Magnetic resonance images of the pelvis in 30 young women were reviewed retrospectively. The volume of the cervix was estimated by using the formulas for an ellipse and a cylinder. Manual labeling and segmentation of the cervix were also performed, and the volume was calculated on the basis of the number and size of the voxels. Comparison of these methods was then performed by using a two-tailed Student t test.
  
  
  RESULTS
  No statistically significant difference was found (P = .7) between the volume calculated with the segmentation technique (25.3 mL) and that estimated with the formula for a cylinder (24.8 mL). A statistically significant difference (P < .05) was found between the volume calculated with the segmentation technique and that estimated with the formula for an ellipse (16.4 mL).
  
  
  CONCLUSIONS
  The normal volume of the cervix in this population of young women was approximately 25 mL. The volume of the cervix should be estimated with the formula for a cylinder.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: H
authors.initials: H
authors.lastname: Dumanli
authors.forename: J R
authors.initials: JR
authors.lastname: Fielding
authors.forename: D T
authors.initials: DT
authors.lastname: Gering
authors.forename: R
authors.initials: R
authors.lastname: Kikinis
mesh_terms: D000328:Adult; D002584:Cervix Uteri / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012016:Reference Values; D012189:Retrospective Studies