Nasal Bone Length (nasal + bone_length)

Distribution by Scientific Domains

Selected Abstracts

Fetal nasal bone length and Down syndrome during the second trimester in a Chinese population

Jeng-Hsiu Hung
Abstract Objective:, The purpose of the present study was to build a database of reference ranges of fetal nasal bone length (NBL) in a Chinese population. The accuracy rate of detecting Down syndrome was also analyzed using fetal NBL as a marker. Methods:, The control group of fetuses included 342 normal singleton pregnancies with no chromosomal or congenital anomalies. The present study was a cross-section study and the control group was used to construct percentile values of NBL from 13 to 29 gestational weeks of age. Two-dimensional ultrasonography was used for the nasal bone studies. Measurements of NBL were collected and each fetus contributed a single value to the reference sample. During the study period, 14 fetuses with Down syndrome were examined. Measurement of fetal NBL was made during amniocentesis, with gestational age ranging from 13 to 19 weeks. Results:, From 342 normal fetuses with gestational age ranging from 13 to 29 weeks, reference ranges of NBL were constructed. The reference ranges were constructed from the 100(1 , p)% reference range: , where , = 25 , exp(3.58 , 0.044 t + 0.0006 t2), with , being the fitted mean of regression model and t being gestational age (weeks). Using fetal NBL, the regression model was Pr(Down syndrome) = exp(W)/[1 + exp(W)], where W = 0.62,4.80 NBL (multiples of the median) in predicting Down syndrome. Fetal NBL was found to have a sensitivity and specificity of 0.78 and 0.78, respectively, in predicting Down syndrome in the second trimester of pregnancy. Conclusions:, Fetal NBL measurement can provide a simple and useful algorithm to predict Down syndrome during the second trimester of pregnancy. [source]

First-trimester nasal bone length in a normal Latin American population

Alexandra Casasbuenas
Abstract Objectives To report normative data of nasal bone length (NBL) in first-trimester singleton fetuses in a normal cohort of Latin American women. Methods NBL was measured during routine first-trimester sonographic examination in 1040 singleton fetuses from an unselected population. Results NBL increased linearly with advancing gestational age (GA) [NBL (mm) = , 1.10 + 0.03 GA (days), R2 = 0.21; p < 0.001]. Similarly, there was a linear relationship between the NBL and crown-lump length (CRL) [NBL (mm) = 0.41 + 0.02 CRL (mm), R2 = 0.27; p < 0.001]. The NBLs at the 50th percentile in our population were 1.5, 1.7, and 1.9 mm at 11, 12, and 13 weeks of gestation, respectively. Conclusions Whereas categorizing a nasal bone as absent or present can be subjective because of variations in echogenicity due to technique and equipment, measurement of NBL is a more objective approach to nasal bone assessment in screening for aneuploidy. Measurement of NBL in the first trimester is feasible and can be easily obtained at the time of nuchal translucency assessment. The normative data we report can provide a reference for defining nasal bone hypoplasia in the first trimester in the Latin American population. Copyright 2008 John Wiley & Sons, Ltd. [source]

Ethnic variation of fetal nasal bone length between 11,14 weeks' gestation

Fadi Collado
Abstract Objective We sought to compare the fetal nasal bone length (FNBL) between different ethnic groups at 11,14 weeks' gestation. Methods FNBL and the FNBL/CRL ratio were measured in patients undergoing first trimester ultrasound for nuchal translucency (NT) and the ethnicity of the patient was recorded under four categories: non-Hispanic White, non-Hispanic black, Hispanic, and Chinese. Results Two hundred and one patients were included in the study. Measurement of the FNBL could not be obtained in nine patients (4.5%) and foetal nasal bone was absent in one fetus. Comparing the four groups, non-Hispanic White, non-Hispanic Black, Hispanic, and Asian, there were no statistical differences in crown-rump length (61 14 mm; 68.6 15 mm; 60.2 14 mm; 62.4 8.8 mm, respectively) or the NT (1.3 0.5 mm; 1.25 0.4 mm; 1.35 1 mm; 1.4 0.4 mm, respectively). However, the FNBL (2.9 0.7 mm; 2.5 0.6 mm; 2.5 0.6 mm; 2.2 0.4 mm, respectively, p < 0.01) and the FNBL/CRL ratio (0.049 0.01, 0.045 0.01, 0.043 0.01, 0.037 0.01, respectively, p < 0.01) were both statistically different, when comparing between these groups. Conclusion If the FNBL is to be introduced into first-trimester screening, it should be adjusted for ethnicity. Copyright 2005 John Wiley & Sons, Ltd. [source]

Aspects of achondroplasia in the skulls of dwarf transgenic mice: A cephalometric study

Melissa Wadler Bloom
Abstract Achondroplasia, the most common short-limbed dwarfism in humans, results from a single nucleotide substitution in the gene for fibroblast growth factor receptor 3 (FGFR3). FGFR3 regulates bone growth in part via the mitogen-activated protein kinase pathway (MAPK). To examine the role of this pathway in chondrocyte differentiation, a transgenic mouse was generated that expresses a constitutively active mutant of MEK1 in chondrocytes and exhibits dwarfing characteristics typical of human achondroplasia, i.e., shortened axial and appendicular skeletons, mid-facial hypoplasia, and dome-shaped cranium. In this study, cephalometrics of the MEK1 mutant skulls were assessed to determine if the MEK1 mice are a good model of achondroplasia. Skull length, arc of the cranial vault, and area, maximum and minimum diameters of the brain case were measured on digitized radiographs of skulls of MEK1 and control mice. Cranial base and nasal bone length and foramen magnum diameter were measured on midsagittal micro-CT sections. Data were normalized by dividing by the cube root of each animal's weight. Transgenic mice exhibited a domed skull, deficient midface, and (relatively) prognathic mandible and had a shorter cranial base and nasal bone than the wild-type. Skull length was significantly less in transgenic mice, but cranial arc was significantly greater. The brain case was larger and more circular and minimum diameter of the brain case was significantly greater in transgenic mice. The foramen magnum was displaced anteriorly but not narrowed. MEK1 mouse cephalometrics confirm these mice as a model for achondroplasia, demonstrating that the MAP kinase signaling pathway is involved in FGF signaling in skeletal development. 2006 Wiley-Liss, Inc. [source]