Intrauterine sonographic measurement of embryonic brain vesicle.

Our purpose was to evaluate embryonic brain vesicle measurements using intrauterine sonography in early first-trimester pregnancy. Fifty-one women about to undergo therapeutic abortion from 7-9.9 weeks gestational age were studied with a specially developed flexible catheter-based high-resolution real-time miniature (2.4 mm in outer diameter) ultrasound transducer (20 MHz). Length, width and height of telencephalon, diencephalon, mesencephalon and rhombencephalon were measured. The normal range of embryonic brain vesicle measurements for each day of pregnancy was determined. Curvilinear relationships were found between the menstrual age and telencephalon height (r(2) = 71.2%), diencephalon length (r(2) = 39. 6%), width (r(2) = 39.4%) and height (r(2) = 48.3%) and mesencephalon length (r(2) = 59.0%) respectively. Linear relationships were found between the menstrual age and telencephalon width (r(2) = 41.4%), mesencephalon height (r(2) = 58.7%) and rhombencephalon length (r(2) = 44.9%), width (r(2) = 56.8%) and height (r(2) = 35.5%) respectively. Telencephalon length and mesencephalon width were constant throughout menstrual age. These results suggest that intrauterine sonography provides accurate embryonic brain measurements in utero. Moreover, intrauterine sonography may become an important modality in future embryological research and in detection of embryonic brain developmental disorders in early first-trimester pregnancy.