Nasal Bone Length Research Articles

Nasal‐bone length in euploid fetuses at 16–24 weeks' gestation by three‐dimensional ultrasound

To establish a normal range of nasal-bone length at 16-24 weeks' gestation by the use of three-dimensional (3D) ultrasound and to investigate the effect of deviations from the exact mid-sagittal plane on the measurement of nasal-bone length. We acquired 3D volumes of the fetal profile from 135 normal fetuses at 16-24 weeks' gestation. The multiplanar mode was used to obtain the exact mid-sagittal plane and to produce parasagittal and oblique views of the fetal face. Nasal-bone length was measured in each plane and the sonographic landmarks of each profile view were examined. Nasal-bone length increased with gestational age from a mean of 4.1 mm at 16 weeks to 7.1 mm at 24 weeks. There was a tendency to underestimate nasal-bone length when the measurements were taken in parasagittal planes and to overestimate the measurements when they were taken in oblique views, compared to the exact mid-sagittal plane. The mean difference in nasal-bone length from the one in the mid-sagittal plane was 0.42 and 0.63 mm for parasagittal measurements at 1 and 2 mm, respectively, from the midline, -0.08 and -0.51 mm for oblique measurements at 10 degrees and 20 degrees rotation along the z-axis and -0.69 mm for rotation of 20 degrees along the z-axis and 10 degrees along the y-axis. The vomeral bone was the only sonographic landmark defining the exact mid-sagittal plane of the face that was not visible in the parasagittal and oblique planes. Parasagittal and oblique scanning planes may produce different degrees of under- or over-estimation of nasal-bone length compared to measurements systematically taken in the exact mid-sagittal plane. Inclusion of the vomeral bone in the definition of the exact mid-sagittal plane of the face could improve the reproducibility of measurements of nasal-bone length.

Fetal facial sonographic markers for second trimester Down syndrome screening in a Thai population

Objective To assess the efficacy of using facial sonographic markers for screening fetuses in the second trimester for Down syndrome (DS) in a high-risk Thai population. Method Frontomaxillary facial angle (FMF) and nasal bone length (NBL) were measured prospectively in pregnant women at high-risk for DS who were undergoing genetic amniocentesis from November 2008 to October 2009. The receiver operator characteristic (ROC) curves were constructed to assess the screening efficacy of FMF angle and NBL. Result A total of 460 pregnant women were recruited, and a mid-sagittal facial profile was obtained for 403 fetuses. There were 386 fetuses with normal chromosomes, 10 fetuses with DS, 1 fetus with trisomy 13, and 1 fetus with trisomy 18. The remaining 5 fetuses had balanced translocation (n = 2), deletion (n = 1), and mosaic Turner (n = 2). Two different combinations of FMF angle and biparietal diameter to nasal bone length (BPD:NBL) ratio for DS screening in the second trimester achieved 50% and 90% detection rates and 4.4% and 14.0% false positive rates, respectively. Conclusion The combination of FMF angle and BPD:NBL ratio has a high sensitivity and specificity for screening for DS in the second trimester in a high-risk Thai population.

First trimester examination of fetal nasal bone in the Turkish population

The present study aims to assign the reference values for nasal bone length (NBL) screened at 11-14 weeks of pregnancy in the Turkish population, determining whether the NBLs specified for Caucasians can be validated for Turkish people. The values of NBL were investigated in a total of 415 singleton fetuses that had Turkish parents and normal neonatal outcome. Sonographic measurements of NBL were done on a transabdominal midsagittal plane at 11-14 weeks' gestation. Regression analysis was used to assess the relationship between NBL and crown-rump length (CRL). Reference values, including the 5(th), 50(th) and 95(th)percentiles, were calculated for each gestational age. The mean NBL was estimated to be 2.5 mm for 11-11 + 6/7 weeks, 2.9 mm for 12-12 + 6/7 and 3.4 mm for 13-13 + 6/7 weeks' gestation. The measurements of NBL showed a significant increase with CRL so that a linear and direct correlation was found between NBL and CRL (NBL = 0.267 + 0.043 x CRL, P < 0.001). Moreover, a significant and linear relationship was detected between NBL and gestational age (NBL = -3.858 + 0.537 x gestational age, P < 0.001). The measurement of NBL is found to be achievable in the majority of first trimester pregnancies. The reference range of NBL in normal Turkish fetuses is established so that basic data can be recorded for further studies related to NBL measurements in screening for various chromosomal abnormalities including Down syndrome within Turkish population.

Normative curves of fetal nasal bone length for the ethnic Chinese population

The purpose of this study is to determine the association between fetal nasal bone length (NBL) and gestational age (GA), biparietal diameter (BPD) and head circumference (HC) in women undergoing prenatal assessments and Down syndrome screening. Cross-sectional data were obtained from 3,003 women with singleton pregnancies who underwent a prenatal ultrasound examination at the Department of Obstetrics and Gynecology, Cheng Hsin General Hospital between August 2006 and July 2009. Statistical analyses involved linear regression. NBL with GA, BPD and HC as measured between 14(+0) and 35(+6) weeks of gestation were linearly related. Using multiple parameters (GA, BPD and HC) to estimate NBL is more accurate than using than using GA or BPD or HC alone, as indicated by the higher predictive value.

The significance of fetal maxillary length in the first trimester screening for trisomy 21

The present study aims to specify the significance of fetal maxillary length by establishing a nomogram for a Turkish population and by investigating its relationship with the ultrasonographic and biochemical parameters which are commonly used to screen trisomy 21 in the first trimester of pregnancy. The present observational study investigates 1,308 Turkish women who had 11- to 14-week-old singleton healthy pregnancies. Fetal crown-rump length (CRL), nuchal translucency (NT), nasal bone length (NBL) and maxillary length are measured by ultrasonography and maternal serum concentrations of pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (HCG) are determined. A positive and significant correlation was detected between the fetal maxillary length and gestational age (r = 0.309, P < 0.001) as was the case with fetal CRL (r = 0.357, P < 0.001) and NBL (r = 0.487, P < 0.001). Although there was a significant and positive correlation between fetal maxillary length and maternal serum PAPP-A levels (r = 0.201, P < 0.001), a significant and negative correlation was found between fetal maxillary length and the maternal serum concentrations of free beta-HCG (r = -0.238, P < 0.001). Fetal maxillary length increased in accordance with the advancing gestational age and increasing CRL. Maternal serum PAPP-A concentrations and fetal CRL and NBL were addressed as independent predictors of fetal maxillary length. The length of fetal maxillary bone is a promising biometrical parameter which can be reliably and efficiently used to screen trisomy 21 in first trimester. Fetal maxillary length is also found to correlate with gestational age, CRL, NBL and PAPP-A significantly. It would be rational to use a combination of nasal and maxillary bone length measurements in case serum concentrations of PAPP-A or beta-HCG cannot be assessed.

Nuchal fold thickness, nasal bone absence or hypoplasia, ductus venosus reversed flow and tricuspid valve regurgitation in screening for trisomies 21, 18 and 13 in the early second trimester

To investigate the performance of nuchal fold thickness, nasal bone hypoplasia, reversed flow in the ductus venosus and tricuspid valve regurgitation in the prediction of fetal aneuploidies in the early second trimester. This was a prospective study of 870 fetuses at 14 + 0 to 17 + 6 weeks of gestation, performed from 2005 to 2007. In all cases we assessed classical structural anomalies, second-trimester markers of aneuploidy including nuchal fold thickness and nasal bone length, as well as ductus venosus blood flow pattern and tricuspid valve regurgitation. The study group included 37 fetuses with trisomy 21, eight with trisomy 18 and four with trisomy 13. Nasal bone hypoplasia was the single most sensitive parameter to identify fetuses with trisomy 21. Independent from maternal age, screening by assessment of nuchal fold and nasal bone identified 64.9% of cases with trisomy 21 and 66.7% of cases with trisomy 18/13 (false-positive rate (FPR), 5.8%). By including ductus venosus and tricuspid flow evaluation, the detection rate increased to 75.7% for trisomy 21 and 83.3% for trisomy 18/13 (FPR, 10.8%). Identification of fetuses with structural abnormalities combined with assessment of all four markers under investigation raised the detection rate of trisomy 21 to 83.9% and that of trisomy 18/13 to 100%. The sensitivity of classical second-trimester markers was 62.2% for trisomy 21 and 70.6% for other autosomal aneuploidies (FPR, 11.3%). The combination of assessment of nuchal fold thickness, nasal bone hypoplasia, ductus venosus reversed flow and tricuspid regurgitation in the early second trimester is associated with a higher detection rate of autosomal trisomies compared with classical second-trimester marker screening.

Clinical decision support system for early prediction of Down syndrome fetus using sonogram images

In this paper, the segmentation and extraction of features from ultrasound second trimester fetal images have been presented for early detection of Down syndrome. The region of interest and the edges of the segmented region have been obtained using mean shift analysis and Canny operator, respectively. The prime features such as the nasal bone, the palate and the frontal bone have been segmented for estimating the nasal bone length and frontomaxillary facial angle (FMF). It is observed from the results that the rate of growth of nasal bone length is poor and the FMF angle has been found to increase above 85° for fetus with trisomy 21. This analysis may help the physician for better clinical diagnosis.

Nasal bone length in trisomy 18, triploidy and Turner syndrome analyzed on postmortem radiographs

Nasal bone length in trisomy 18, triploidy and Turner syndrome analyzed on postmortem radiographs

Study on the applicability of frontomaxillary facial angle in the first‐trimester trisomy 21 fetuses in Chinese population

To evaluate the measurement of frontomaxillary facial (FMF) angle at 11 weeks to 13 weeks, 6 days in a Chinese population and its applicability in the screening for fetal trisomy 21. In a retrospective study, the stored images for the measurement of fetal nuchal translucency (NT) thickness in a Chinese population from August 2003 to March 2007 were reviewed for the comparison of the FMF angle between 22 trisomy 21 fetuses (study group) with 220 randomly selected normal fetuses with satisfactory images (control group). No association between FMF angle and NT, nasal bone length, or fetal heart rate was shown (P > 0.05). But the FMF angle was significantly greater in the trisomy 21 fetuses (89.7 vs 82.8, P < 0.001). The intraobserver and interobserver agreement were assessed in 9.5% (n = 21) normal cases. Mean (SD) differences of two observers were -0.83 (2.69) degrees (P > 0.05). For each observer, mean (SD) differences between the two paired measurements were -0.98 (3.11) degrees and 0.93 (1.80) degrees , respectively (P > 0.05). Our results indicated that measurement of the FMF angle in the first trimester can be incorporated into the screening of trisomy 21 in the Chinese population, and its application is not affected by intraobserver and interobserver variability.

P15.11: Trends in prenasal thickness, nasal bone length and nuchal fold thickness measurements in second and third trimester Down syndrome fetuses

Objective: To analyze the methods of prenatal sonographic diagnosis of all kinds of aortic arch anomalies and to improve prenatal sonographic detection rate of aortic arch anomalies. Methods: 73 fetuses with congenital aortic arch anomalies were studied. The results from prenatal ultrasound examination, postnatal examination were compared. Results: 73 cases were with congenital aortic arch anomalies, 33 cases with malposition of aortic arch, 9 cases with normal left aortic arch with aberrant left subclavian artery, 5 cases with interruption of aortic arch, 26 cases with coarctation of aortic arch. The accuracy rate of prenatal sonographic diagnosis was 87.7%. Conclusions: Aortic arch anomalies have typical sonographic image. If we grasp typical sonographic images, we could make accurate diagnosis.

P01.11: Natural history of prenasal thickness, nasal bone length and nuchal fold in continuing Down syndrome pregnancies

P01.11: Natural history of prenasal thickness, nasal bone length and nuchal fold in continuing Down syndrome pregnancies

P02.03: First trimester measurements of nasal bone length using three-dimensional ultrasound

P02.03: First trimester measurements of nasal bone length using three-dimensional ultrasound

First‐trimester fetal nasal bone length in an ethnic Chinese population

To determine reference ranges of fetal nasal bone length (NBL) in a Chinese population and to assess the value of NBL measurement in screening for chromosomal defects in the first trimester. In this prospective study the fetal profile was examined and the fetal NBL and crown-rump length (CRL) were measured in Chinese women presenting with singleton pregnancies for first-trimester screening for aneuploidy between January 2004 and June 2007. Screening was performed on the basis of nuchal translucency (NT) measurement and maternal serum free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A levels. NBL was measured in 7543 fetuses, of which 7517 were euploid. The best fit equation for median NBL in euploid fetuses in relation to CRL was: NBL (mm) = 0.4593 + (0.0186 x CRL(mm)). The NBL for gestational age (GA, in days) was given by the equation NBL(mm) = 0.2392 + (0.0027 x GA). There was no correlation between log(10)(NBL multiples of the median (MoM)) and log(10)(NT MoM) in unaffected pregnancies (r = - 0.009; P = 0.43). Only two of the 11 cases with trisomy 21 had an NBL outside the 5(th) or 95(th) centiles of the reference range for euploid fetuses. Reference ranges for NBL in a Chinese population suitable for screening for aneuploidy between 11 and 13 + 6 weeks' gestation have been derived. The NBL in Chinese fetuses is similar to that of other ethnic groups. However, unlike the determination of presence vs. absence of the nasal bone, NBL measurement is unlikely to further improve screening for aneuploidy.

First trimester measurements of nasal bone length using three‐dimensional ultrasound

To investigate the feasibility and reproducibility of measurements of nasal bone length using a three-dimensional (3D) ultrasound in the first trimester. In a prospective study, 118 consecutive pregnant women attending for Down syndrome screening at 11-13 + 6 weeks were recruited. They had successful fetal nasal bone measurement by two-dimensional (2D) ultrasound by four operators. Three-dimensional volumes were recorded in the mid-sagittal plane of fetal profile by the fifth operator and examined using multiplanar techniques. Another independent investigator randomly compared his measurements with one of the four operators. In the subsequent 3D examination, the nasal bone length could be examined in 94 cases (79.7%). The mean difference between the 2D and 3D measurements was 0.19 mm [95% confidence interval (CI) 0.08 to 0.31] (P < 0.05). Limits of agreement were -0.73 to 1.11. The mean differences between these two observers were 0.66 mm (95% CI -0.47 to 0.86) (P < 0.05). There was significant intermethod difference between the results obtained by 2D and 3D, as well as substantial interobserver variation in 3D measurement of fetal nasal bone length in the first trimester. Independent 3D measurement of nasal bone offers no additional advantages over 2D sonography.

A Thai Reference for Normal Fetal Nasal Bone Length at 15 to 23 Weeks' Gestation

The purpose of this study was to establish a Thai reference for normal fetal nasal bone length at 15 to 23 weeks' gestation. The fetal nasal bone was measured by sonography in 295 pregnant women at 15 to 23 weeks' gestation from May to August 2005. One of the first 4 authors performed 3 measurements for each woman when the fetus was in the midsagittal plane and the nasal bone was close to a 45 degrees or 135 degrees angle to the ultrasound beam. All neonates were examined after delivery to confirm an absence of congenital abnormalities. The median nasal bone length increased by gestational age from 3.6 mm at 15 weeks to 7.3 mm at 23 weeks in a linear relationship. The fifth percentile nasal bone lengths were 2.5, 3.04, 3.28, 3.64, 4.21, 4.82, 5.69, and 6.13 mm at 15, 16, 17, 18, 19, 20, 21, and 22 weeks, respectively. The median time for measurement was 5 minutes. The nasal bone length in Thai fetuses at 15 to 23 weeks was found to be on average shorter than that in white and African American fetuses.

Lengths of the maxillary central incisor, the nasal bone, and the anterior cranial base in different skeletal malocclusions

Objective. Based on the results of previous studies of osseous structures within the frontonasal field in patients with a known malformation in the frontonasal field, the aim of the present study was to clarify whether the same structures were malformed in patients with severe skeletal malocclusions. Material and methods. Incisor, nasal, and cranial base lengths were measured on lateral radiographs of adult patients with skeletal malocclusions, including open bite (n=35), mandibular overjet (n=56), maxillary overjet (n=31), deep bite (n=19), and compared with those of a control group with neutral occlusion and normal craniofacial morphology (n=39). Two-way ANOVA tests were used to evaluate differences in lengths between groups and gender. Results. Statistically shorter maxillary central incisor length was found in the open bite group (p<0.05), the mandibular overjet group (p<0.001), and in the deep bite group (p<0.001) compared to the controls. Nasal bone length was shorter in the maxillary overjet group compared to controls (p<0.05). Conclusions. The lengths of the maxillary central incisor and nasal bone, both parameters located in the frontonasal field, are affected in different skeletal malocclusions. The present findings, especially the deviation of the upper incisor length in different skeletal malocclusions, are considered relevant for orthodontic diagnostics and treatment.

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

To report normative data of nasal bone length (NBL) in first-trimester singleton fetuses in a normal cohort of Latin American women. NBL was measured during routine first-trimester sonographic examination in 1040 singleton fetuses from an unselected population. NBL increased linearly with advancing gestational age (GA) [NBL (mm) = - 1.10 + 0.03 x GA (days), R(2) = 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 x CRL (mm), R(2) = 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. 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.

Interobserver Variability of the Measurement of Fetal Nasal Bone Length between 11 + 0 and 13 + 6 Gestation Weeks among Experienced and Inexperienced Sonographers

Examination of fetal nasal bone (NB) by ultrasound between 11 + 0 and 13 + 6 gestation weeks has been proposed as an additional tool in the detection of trisomy 21 and therefore its application and implementation are used in a broad range. The study aimed at evaluating the interobserver feasibility of the measurement of fetal nasal bone length in comparison with experienced and inexperienced sonographers. The study population was comprised of women who chose to have first trimester screening (FTS) at the Fetal Medicine Unit of the University Medical School of Hannover. Two experienced (> 400 FTS examinations, sonographer 1 and 2) and one inexperienced sonographer (95 FTS examinations, sonographer 3) were asked to measure the nasal bone length consecutively and independently of each other. Statistical analysis was performed for any differences and variations in the results. The fetal profile was examined in 220 cases. The median nasal bone length by sonographer one was 2.4 cm, sonographer two 2.4 cm and sonographer three 2 cm. The differences between the results of sonographer 1 and 3 as well 2 and 3 were statistically significant. There were no significant variations between the results of sonographer 1 and 2. There was also no significant difference in the results concerning nuchal translucency and crown-rump length among the three examiners. The uncertainty and the difficulties of an inexperienced examiner with the presenting of the nasal bone, as shown by published data sets as well as by the variability of the measurement results of this study, with all the consequences in the risk calculation and counseling show that this tool should only be implemented by experienced and quality-controlled sonographers with a minimum amount of examinations. Because of its major impact in risk calculation and the importance of the nasal bone as a sonographic marker, documentation of the sonographer's skills is mandatory for the use of the nasal bones as an additional sonographic marker in first trimester screening.

Craniofacial Morphology in Children With Operated Complete Unilateral Cleft Lip and Palate

The objective of the study was to compare the craniofacial characteristics of children with operated unilateral complete cleft lip and palate (UCLP) with those of noncleft children. Lateral and posteroanterior cephalometric radiographs of subjects with UCLP and controls who were matched for sex, age, and ethnic origin were analyzed and compared. There were a total of 21 subjects with UCLP (10 boys and 11 girls) from the Orthodontic Department of Selcuk University and 15 controls (7 boys and 8 girls) from the Orthodontic Department of Ankara University. The nasal bone length in the group with cleft did not differ significantly from that in the control group. Subjects with UCLP included in the study appeared to have shorter faces, smaller mandibulae, greater lateral orbital width, and smaller sella turcicae compared with controls. Unilateral cleft lip and palate affects the intracranial morphology as well as dentofacial structures.

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

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. 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. 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: Y +/- Zp x square root sigma 2, where Y = 25 - exp(3.58 - 0.044 x t + 0.0006 x t2), with Y 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 x 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. Fetal NBL measurement can provide a simple and useful algorithm to predict Down syndrome during the second trimester of pregnancy.