Three-dimensional ultrasound imaging of the fetal skull and face

To assess the types and numbers of cases, gestational age at specific prenatal diagnosis and diagnostic accuracy of the diagnosis of skeletal dysplasias in a prenatal population from a single tertiary center. This was a retrospective database review of type, prenatal and definitive postnatal diagnoses and gestational age at specific prenatal diagnosis of all cases of skeletal dysplasias from a mixed referral and screening population between 1985 and 2007. Prenatal diagnoses were grouped into 'correct ultrasound diagnosis' (complete concordance with postnatal pediatric or pathological findings) or 'partially correct ultrasound diagnosis' (skeletal dysplasias found postnatally to be a different one from that diagnosed prenatally). We included 178 fetuses in this study, of which 176 had a prenatal ultrasound diagnosis of 'skeletal dysplasia'. In 160 cases the prenatal diagnosis of a skeletal dysplasia was confirmed; two cases with skeletal dysplasias identified postnatally had not been diagnosed prenatally, giving 162 fetuses with skeletal dysplasias in total. There were 23 different classifiable types of skeletal dysplasia. The specific diagnoses based on prenatal ultrasound examination alone were correct in 110/162 (67.9%) cases and partially correct in 50/162 (30.9%) cases, (160/162 overall, 98.8%). In 16 cases, skeletal dysplasia was diagnosed prenatally, but was not confirmed postnatally (n = 12 false positives) or the case was lost to follow-up (n = 4). The following skeletal dysplasias were recorded: thanatophoric dysplasia (35 diagnosed correctly prenatally of 40 overall), osteogenesis imperfecta (lethal and non-lethal, 31/35), short-rib dysplasias (5/10), chondroectodermal dysplasia Ellis-van Creveld (4/9), achondroplasia (7/9), achondrogenesis (7/8), campomelic dysplasia (6/8), asphyxiating thoracic dysplasia Jeune (3/7), hypochondrogenesis (1/6), diastrophic dysplasia (2/5), chondrodysplasia punctata (2/2), hypophosphatasia (0/2) as well as a further 7/21 cases with rare or unclassifiable skeletal dysplasias. Prenatal diagnosis of skeletal dysplasias can present a considerable diagnostic challenge. However, a meticulous sonographic examination yields high overall detection. In the two most common disorders, thanatophoric dysplasia and osteogenesis imperfecta (25% and 22% of all cases, respectively), typical sonomorphology accounts for the high rates of completely correct prenatal diagnosis (88% and 89%, respectively) at the first diagnostic examination.

To define parameters that enable the objective diagnosis of anomalies of the position and/or size of the fetal mandible in utero.

Prenatal diagnosis of trisomy 21 requires an invasive test in women regarded as being at high risk after screening. At present there are four screening tests, and for a 5% false-positive rate, the sensitivities are about 30% for maternal age alone, 60-70% for maternal age and second-trimester maternal serum biochemical testing, 75% for maternal age and first-trimester fetal nuchal translucency scanning, and 85% for maternal age with fetal nuchal translucency and maternal serum biochemistry at 11-14 weeks. In this study, we examined the possible improvement in screening for trisomy 21 by examining the fetal nasal bone with ultrasound at 11-14 weeks of gestation. We did an ultrasound examination of the fetal profile in 701 fetuses at 11-14 weeks' gestation immediately before karyotyping for a possible chromosomal abnormality detected by maternal age and fetal nuchal translucency screening. The presence or absence of a nasal bone was noted. The fetal profile was successfully examined in all cases. The nasal bone was absent in 43 of 59 (73%) trisomy 21 fetuses and in three of 603 (0.5%) chromosomally normal fetuses. The likelihood ratio for trisomy 21 was 146 (95% CI 50-434) for absent nasal bone and 0.27 (0.18-0.40) for present nasal bone. In screening for trisomy 21, by a combination of maternal age and fetal nuchal translucency, we estimated that inclusion of examination of the fetal profile for the presence or absence of nasal bone could increase the sensitivity to 85% and decrease the false-positive rate to about 1%. In screening for trisomy 21, examination of the fetal nasal bone could result in major reduction in the need for invasive testing and a substantial increase in sensitivity.