Premium
Prospective Study of Intracranial Translucency and the Posterior Brain in Normal Fetuses at the 11‐ to 13‐Week Scan
Author(s) -
Fong Katherine W.,
Dengler Jana,
Toi Ants,
Menezes Ravi J.,
Karimzad Yasser,
Okun Nanette
Publication year - 2014
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/ultra.33.8.1373
Subject(s) - medicine , fetus , prospective cohort study , pregnancy , surgery , genetics , biology
Objectives To evaluate the ability of sonographers to prospectively identify intracranial translucency and posterior brain structures at 11 to 13 weeks and to evaluate measurement reproducibility of brain stem and brain stem–occipital bone diameters on stored images. Methods After specific training for intracranial translucency visualization, 10 nonphysician sonographers prospectively identified intracranial translucency at the 11‐ to 13‐week scan, noting whether intracranial translucency was present, absent, or uncertain. If absent/uncertain, they documented the reason as spina bifida or an inadequate image (with reasons for the inadequate image). Measurements of brain stem and brain stem–occipital bone diameters were performed on stored images. Fifty randomly selected cases were reviewed for intraobserver and interobserver variability. Results In 313 singleton pregnancies, the posterior brain including intracranial translucency was evaluated; 293 (93.6%) had known pregnancy outcomes. None had open spina bifida, but 7 had chromosomal or congenital abnormalities. In the remaining 286 normal fetuses, intracranial translucency was seen in 275 (96%) and uncertain in 11 (4%), due to inadequate images (top 3 reasons were fetal position [n = 8], obesity [n = 5], and retroverted uterus [n = 4]). Fetal position and gestational age were significantly associated with intracranial translucency visualization ( P < .05). Intraobserver and interobserver agreement rates were moderate for measurements of brain stem diameter (intraclass correlation coefficients, 0.59 and 0.57) and substantial for brain stem–occipital bone diameter (intraclass correlation coefficients, 0.76 and 0.61). Bland‐Altman analysis revealed negligible intraobserver and interobserver differences in brain stem and brain stem–occipital bone diameter measurements. Conclusions Intracranial translucency can be prospectively identified by trained sonographers in 96% of normal fetuses at 11 to 13 weeks. Measurements of brain stem and brain stem–occipital bone diameters are reproducible.