ULTRASOUND PREDICTION OF FOLLICLE VOLUME - IS THE MEAN DIAMETER REFLECTIVE

Objective: To evaluate the relationship between 2 dimensional sonograp hic measurement of ovarian follicles and their actual volume. Design: Prospective clinical study. Setting: The in vitro fertilization (IVF) program of a University based, tertiary care hospital. Patients and in terventions: Sonographic categorization by shape, and measurement of 9 6 individual ovarian follicles immediately prior to aspiration for IVF . Each follicle was aspirated under direct ultrasound guidance and the volume recorded. The 96 follicles were visualized in a total of 14 pa tients from whom 2 to 27 oocytes were obtained. Main outcome measure: Total volume of each follicle. Results: Round and polygonal follicles exhibited a highly significant relationship between sonographically me asured mean diameter and total follicle volume. The volume of follicle s that were categorized as ellipsoid was not predicted by measurement of the longest diameter, shortest diameter or mean diameter. Conclusio n: The mean diameter of round and polygonal follicles accurately predi cts total follicular volume. However, clinical decisions in ovulation induction should be modified when the follicle shape is predominantly ellipsoid because the traditionally held belief that the sonographic m easurement of the follicular diameter correlates with the follicular v olume does not apply in those circumstances.