title: Measuring sphere-like structures using transrectal ultrasonography.
abstract: Sphere-like structures are commonly measured for clinical or research purposes. We measured two diameters, the circumference (perimeter) and cross sectional area of 113 equine ovarian follicles in a water bath then determined the relationships between those measurements and the actual volume of fluid in the follicles. Cross-sectional area, diameter3 and area2/3 were all highly correlated with the volume of the structures and superior (p < 0.05) to diameter or perimeter as predictors of volume. As predictors of volume, there was no significant difference (p > 0.05) between cross-sectional area, diameter3, and area2/3. Because of the ease of measuring diameter, we suggest that diameter3 be used to estimate the actual size of sphere-like structures by ultrasonographic measurement. A table was generated for clinical use to show how much the largest diameter of a fluid-filled structure (follicle, cyst, hematoma, etc.) would have to increase or decrease to indicate a significant change in the volume of the structure.
authors.affiliation: Department of Health Management, Atlantic Veterinary College, Charlottetown, P E I, Canada.
authors.forename: R M
authors.initials: RM
authors.lastname: Löfstedt
authors.forename: W P
authors.initials: WP
authors.lastname: Ireland
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D005260:Female; D006736:Horses / Q000033:anatomy & histology*; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D012007:Rectum; D012044:Regression Analysis; D014463:Ultrasonography