Absent Nasal Bone Research Articles

Evaluating the Efficiency of Using Second-Trimester Nasal Bone Hypoplasia as a Single or a Combined Marker for Fetal Aneuploidy

Although second-trimester nasal bone (NB) hypoplasia has been associated with fetal aneuploidy, its role as a single marker is still uncertain. Our objective was to evaluate the efficiency of NB hypoplasia as an independent marker for fetal aneuploidy. This was a prospective cohort study of women undergoing an anatomic survey between 16 and 22 weeks' gestation. The fetal NB and other markers of fetal aneuploidy, including nuchal fold, femur and humeral lengths, choroid plexus cysts, major fetal anomalies, echogenic bowel, pyelectasis, and hypoplastic fifth digits, were evaluated. Nasal bone hypoplasia was defined either as an absent NB or by a ratio of the biparietal diameter to NB. Fetuses or infants with fetal aneuploidy were compared with those without for the presence of NB hypoplasia either as a single marker or in the presence of other markers for aneuploidy. Of 2885 women evaluated, NB measurements were obtained in 2465 (85%). There were 35 (1.4%) cases with fetal aneuploidy. The sensitivity and specificity of a single NB in detecting Down syndrome varied from 23% to 64% and 57% to 99%, respectively, depending on the definition of NB hypoplasia used. There was an improvement in the efficiency of using the NB when combined with other markers, with sensitivity and specificity increasing from 59% to 82% and 74% to 87%, respectively. Nasal bone hypoplasia is a marker for fetal aneuploidy. The combination of the NB with other makers was associated with an improvement in detection of fetal aneuploidy.

Second‐Trimester Diagnosis of Cri du Chat (5p–) Syndrome Following Sonographic Depiction of an Absent Fetal Nasal Bone

A high association between trisomy 21 and absence of the nasal bone at first-trimester sonography (11-14 weeks' gestation) has been established. 1-3 The presence or absence of the nasal bone was found to be independent of other maternal or fetal variables and thus may be added to other sonographic markers for prenatal detection of trisomy 21. 3 Bromley et al, 4 later Bunduki et al, 5 and others 6 confirmed a mid-second-trimester (15-22 weeks' gestation) association of an absent or hypoplastic nasal bone and trisomy 21. In addition, an absent nasal bone at the 11- to 14-week sonographic scan has been associated with other fetal aneuploidies. 7,8 Cicero et al 7 reported an absent nasal bone in 161 (66.9%) of 242 fetuses with trisomy 21, 48 (57.1%) of 84 fetuses with trisomy 18, 7 (31.8%) of 22 fetuses with trisomy 13, 3 (8.8%) of 34 fetuses with 45,XO, and 4 (8.3%) of 48 fetuses with other aneuploidy defects (XXX, XXY, XYY, and triploidy). The association of an absent or hypoplastic nasal bone and aneuploidies other than trisomy 21 was confirmed by Odibo et al 8 We report a case in which sonographic depiction of an absent nasal bone at 20 weeks' gestation led to amniocentesis and the detection of a fetus with cri du chat (5p-) syndrome.

Avaliação ultra-sonográfica do osso nasal fetal: evolução das medidas ao longo da gestação

PURPOSE: the absence of fetal nasal bone is correlated with trisomy 21. Although a hypoplastic nasal bone is also correlated with trisomy 21, there is no clear definition of this term in the literature. Our objective was to establish the reference values for fetal nasal bone size throughout gestation in a local population in Brazil. METHODS: it is a cross-sectional study on 902 fetuses at 10 to 39 weeks of gestation. After having excluded fetal malformations and maternal diseases which are known to interfere with fetal growth, 625 fetuses were selected. We obtained a mid-sagittal view of the fetal profile by holding the ultrasound bean at an angle of 45o or 135o. The nasal bone size mean was calculated by using polynomial regression. The Anderson-Darling test proved the normal distribution of the measurements (p>0.05). RESULTS: of the 625 fetuses, 88.3% were from single gestations and 11.7% from multiple ones. There was a direct correlation between fetal nasal bone size and gestational age. The variability of nasal bone size became larger as gestational age increased. Minimal length of 1.0 and 4.7 mm in the first and second trimesters, respectively, were found. CONCLUSIONS: there is a direct correlation between fetal nasal bone size and gestational age. This correlation is valid either for a single gestation or a multiple one. These measurements of the fetal nasal bone will allow us to use them as a screening test for cromosomal abnormalities. This is a useful study if we consider the large miscegenation of the Brazilian population. However, further systematic and standardized approach to study the fetal nasal bone is needed to establish its real value in fetuses once classified as at high or low risk for aneuploidies.

First-trimester nuchal translucency, nasal bones, and trisomy 21 in selected and unselected populations

The purpose of this study was to assess the role of fetal nasal bones evaluation in first-trimester screening for trisomy 21 in selected and unselected pregnancies. Visualization of the nasal bones was attempted in women attending for routine nuchal translucency screening (unselected population, n = 7116, 12 cases of trisomy 21), as well as in high-risk pregnancies referred to our tertiary care center (selected population, n = 510, 23 cases of trisomy 21). The sensitivity, specificity, positive and negative predictive value of absent nasal bones for trisomy 21 were 16.7%, 97.3%, 1.1%, 99.8% and 47.6%, 95.3%, 33.3%, 97.4% in the unselected and selected population, respectively. At logistic regression analysis including nuchal translucency and nasal bones findings, the latter resulted to be an independent predictor of trisomy 21 in the selected but not in the unselected population. First-trimester nasal bones assessment for trisomy 21 screening has a very different performance in selected and unselected pregnancies.

Additional Performance of Nasal Bone in First Trimester Screening

To evaluate and compare the screening performance for fetal trisomy 21 in the first trimester of pregnancy either with or without inclusion of fetal nasal bone using two separate risk-algorithms of the Fetal Medicine Foundation London (FMF). This study included 3174 patients self-referred to our tertiary level prenatal centre for first trimester screening at 11-14 weeks of gestation between December 1, 2002 and November 30, 2004. Fetal risk for trisomy 21 was calculated using either the old FMF-algorithm including maternal age, nuchal translucency (NT), free ss-human chorionic gonadotropin (hCG), pregnancy-associated plasma protein-A (PAPP-A) or the new FMF-algorithm using additionally the presence or absence of fetal nasal bone (NB). All ultrasonographers were certified for measurement of nuchal translucency and nasal bone by the Fetal Medicine Foundation Germany. The detection rate for a fixed risk cut-off (1:300) and a fixed false-positive rate (5 %) was calculated for ultrasound (single NT or NT and NB), serum biochemistry, maternal age and the combination of these components. Pregnancy outcome was obtained in 2973 (93.6 %) cases. Nasal bone was absent in 5 of 18 (27.8 %) cases with fetal trisomy 21 and in 2 of 2961 (0.1 %) normal cases. The estimated risks for trisomy 21 based on maternal age, fetal ultrasound and maternal serum free ss-hCG and PAPP-A was 1 in 300 or greater in (old algorithm without NB/new algorithm including NB) 5.5 % (179 of 2961) and 2.8 % (97 of 2961) normal pregnancies and in 94.4 % (17 of 18) and 77.8 % (14 of 18) of those with trisomy 21. For a fixed false-positive rate of 5 % the respective detection rates of screening for fetal Down's syndrome by maternal age and serum free ss-hCG and PAAP-A, maternal age and fetal ultrasound and by maternal age, fetal ultrasound and maternal serum biochemistry were (old algorithm without NB/new algorithm including NB) 72.2 %/66.7 %, 83.3 %/77.8 % and 88.9 %/83.3 %, respectively. Our data show no additional performance of including presence or absence of fetal nasal bone in calculation of risk for fetal Down's syndrome between 11 and 14 weeks of gestation. Individual risk-orientated two-stage screening could be an alternative approach for integration of additional ultrasound markers in first trimester screening.

Ultrasonographic evaluation of fetal nasal bone in a low-risk population at 11–13 + 6 gestational weeks

To evaluate the utility of determining the presence/absence of nasal bone in a low-risk fetal population. Prospective study of the presence/absence of nasal bone among 1800 consecutive unselected fetuses, with complete follow-up of results. An adequate sonographic evaluation of nasal bone was obtained in 1682 (93.44%) of the fetuses. Nasal bone was considered absent in 19 (1.06%) of 1790 fetuses with a normal karyotype and in 2 (28.57%) of the seven recorded cases of Down syndrome (DS). The overall first-trimester sensitivity for DS to the absence of nasal bone was two of the six cases (33.3%) and the false-positive rate was 1.13%. The positive predictive value for DS of the absence of nasal bone was 2/21 (9.52%). In a low-risk population, the evaluation of the presence/absence of nasal bone in DS screening during the first trimester has a low sensitivity. First-trimester assessment of the nasal bone in population screening may play a lesser role than in the re-evaluation of high-risk pregnancies.

Prenatal ultrasound diagnosis of Down syndrome. After major malformations, soft markers, nuchal translucency and skeletal signs, a new vascular sign?

Prenatal ultrasound diagnosis of Down syndrome. After major malformations, soft markers, nuchal translucency and skeletal signs, a new vascular sign?

Isolated Congenital Absence of the Nasal Bones and Aesthetic SurgicalCorrection: Managing and Case Report

A rare case of isolated congenital bone agenesis in a young woman referred to the authors for aesthetic correction of the dorsum profile is described. There are no descriptions of surgical treatment for this isolated facial defect in the literature. After a complete and accurate diagnostic study, a rhinoplasty was performed with a good result and without complications during a 2-year follow-up period. To explain this congenital malformation, several hypotheses were examined, such as bony resorption and embryologic bony development syndromes. This report describes the possibility of intervention in the case of nasal bone absence and shows how risks of structural instability can be avoided with an accurate preoperative study and a careful surgical approach.

Visualización y validación del hueso nasal y la translucencia nucal como marcadores ecográficos de aneuploidías

Objective To assess the value of assessment of fetal nasal bone and nuchal translucency as chromosomal markers in early pregnancy. Subjects and methods We performed an observational cross-sectional study in 434 pregnant women with 466 fetuses. To evaluate the presence or absence of nuchal translucency and nasal bone, ultrasound scans performed between weeks 11 and 14 respectively were studied. Results In 60 (12.9%) fetuses, the presence or absence of the nasal bone could not be confirmed. Fetal nasal bone had a sensitivity of 0% and a specificity of 97.5% with poor positive and negative likelihood ratios. Nuchal translucency had a sensitivity of 100% and a specificity of 98.7%, with excellent likelihood ratios. Conclusions More precise methodology is required for the systematic application of nasal bone assessment as a marker of trisomy 21. Nasal bone should be considered together with maternal age, nuchal translucency and blood test to increase the accuracy of screening.

Congenital Arhinia: A Case Report and Functional Evaluation

Congenital arhinia is rare clinical entity. An unusual case of congenital arhinia with no surgical treatment is presented. Case report. A 9-year-old with congenital arhinia was referred for treatment of otitis media with effusion. In addition to his undergoing imaging studies since birth, various functional evaluations regarding the nose were performed. Furthermore, the pathogenesis of arhinia is discussed. The imaging workup revealed the absence of nasal bones, the nasal septum, and turbinates, hypoxia of the maxilla, and a high-arched palate. Furthermore, magnetic resonance imaging clearly demonstrated the absence of olfactory bulbs and tracts, resulting in no response with olfactometry. Among the examinations performed, chromosomal analysis, polysomnography, and an intelligence test produced normal results. In the hearing assessment, he had a slight conductive hearing loss. A phonetic examination revealed the typical pattern of rhinophonia clausa. This study presents congenital arhinia associated with facial anomalies. Because there was no life-threatening complications and normal psychomotor development, the patient could not only be followed up long-term but could also have his nose functionally evaluated. It is highly likely that this case might have been the result of the failure of medial and lateral nasal processes to grow, which was the underlying pathogenesis.

Assessment of the gap between the fetal nasal bones at 11 to 13 + 6 weeks of gestation by three‐dimensional ultrasound

To detect the presence of a gap between the fetal nasal bones at 11 to 13 + 6 weeks of gestation and to verify if this gap could lead to the erroneous diagnosis of absent nasal bone. Three-dimensional (3D) ultrasound was used to assess the fetal nose in 450 singleton pregnancies, immediately after two-dimensional (2D) evaluation of the nasal bones and screening for chromosomal defects by a combination of maternal age and the measurement of fetal nuchal translucency at 11 to 13 + 6 (median, 12) weeks of gestation. A 3D volume of the fetal face was acquired and then analyzed using the multiplanar mode. A sequence of transverse views was used to confirm the presence or absence of the nasal bones and when they were present any visible gap between them was measured. A perfectly mid-sagittal plane was then examined to determine if the nasal bone was visible or not. In 421/450 (93.6%) cases the nasal bone was present during 2D ultrasound. Using the multiplanar mode of 3D ultrasound, in 83/421 (19.7%) fetuses a gap between the nasal bones could be demonstrated and in 36/83 (43.4%) cases the nasal bone was found to be absent in the perfect mid-sagittal view. In 29/450 (6.4%) cases the nasal bones were absent during the 2D scan. In the 3D assessment there was absence of both bones in 25/29 (86.2%) cases and absence of one of the two bones in 4/29 (13.8%) cases. Chorionic villus sampling demonstrated that the fetal karyotype was normal in 404 and abnormal in 46 cases, including 31 cases of trisomy 21. There was absence of one or both nasal bones in three (0.7%) of the chromosomally normal fetuses, in 19 (61.3%) with trisomy 21 and in seven (46.7%) with other chromosomal defects. At 11 to 13 + 6 weeks of gestation there is a gap between the nasal bones in about 20% of fetuses, and in about 40% of these cases in the perfect mid-sagittal plane the nasal bone may erroneously be considered to be absent.

First-trimester screening for trisomy-21 using a simplified method to assess the presence or absence of the fetal nasal bone

To determine the benefit of including nasal bone assessment in addition to standard first-trimester markers (nuchal translucency, free beta human chorionic gonadotropin and pregnancy-associated plasma protein A) as a screening test for Down syndrome, using a strict criterion for classification of nasal bone absence. Nasal bone assessment was conducted in 2411 patients with crown-rump length between 45 and 84 mm, including 15 patients with Down syndrome. A patient was considered to have an absent nasal bone only if there was no evidence of present nasal bone. Unlike other studies, nasal bone was classified as present when there was evidence of a thin echogenic line under the skin. Simulation studies were conducted to assess the detection rate and false-positive rate of a combined first-trimester screening protocol including nasal bone assessment. There were 9 of 2396 (0.4%) unaffected cases with absent nasal bone (95% confidence interval 0.2%, 0.7%) and 8 of 15 (53.3%) Down syndrome cases (95% confidence interval 26.6%, 78.7%). Using a 1 in 250 risk cut-off, the detection rate of standard first-trimester screening was 87%, with a false-positive rate of 4.3%. Incorporating nasal bone measurement improved the detection rate of Down syndrome to 90% and reduced the false-positive rate to 2.5%. The use of a strict criterion to determine nasal bone absence leads to fewer cases classified as absent and may simplify the implementation of nasal bone as a marker for first-trimester screening, resulting in lower false-positives and higher detection, compared with other current screening protocols.

Ultrasound and fetal diagnosis

The purpose of this review is to highlight publications from the last year that have advanced the use of ultrasound in obstetrics. Anatomic examination of the fetus in the first trimester has been emphasized because it allows for early diagnosis of many conditions. The prevalence of absent nasal bone, a marker for trisomy 21, in euploid fetuses depends on ethnicity. Nasal bone hypoplasia is another marker for Down syndrome. Studies on genetic screening in the first trimester have involved various serum analytes, adjustments in timing and calculations, use in multiple gestations, and the association of extreme measurements with adverse outcomes. A first-trimester integrated screening approach, which incorporates nuchal translucency, nasal bone, crown-rump length, pregnancy-associated plasma protein-A, and free beta-human chorionic gonadotropin, has the potential to maximize detection rates of Down syndrome and trisomy 18 and minimizes the screen-positive rate. The value of combining first and second-trimester results in sequential, contingent, or integrated screening protocols has been assessed. Isolated mild ventriculomegaly (10-12 mm) may prove to be a normal variant, and the role of 'soft' ultrasound markers in genetic counseling continues to be debated. Anomaly or high-risk status detection in the second trimester has been enhanced by the use of Doppler, 3D/4D ultrasound, and magnetic resonance imaging. Imaging techniques have been critical in the development of screening methods for Down syndrome or trisomy 18 and for euploid fetuses at high risk for adverse outcomes.

Maternal serum biochemistry at 11-13+6 weeks in relation to the presence or absence of the fetal nasal bone on ultrasonography in chromosomally abnormal fetuses: an updated analysis of integrated ultrasound and biochemical screening

Screening for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free beta-hCG and pregnancy associated plasma protein-A (PAPP-A) at 11-13(+6) weeks of gestation is associated with a detection rate of 90%, for a false-positive rate of 5%. Recent evidence suggests that in about 70% of fetuses with trisomy 21 the nasal bone is not visible at the 11-13(+6) week scan and that the frequency of absence of nasal bone differs in different ethnic groups. In addition, there is a relationship between absent nasal bone and nuchal translucency thickness. In a preliminary study we showed that while PAPP-A levels were lower and free beta-hCG levels were higher in trisomy 21 fetuses with an absent nasal bone, this difference was not statistically different. In fetuses with trisomy 13 and trisomy 18, there is also a high (57 and 67%) incidence of an absent nasal bone. The aim of this present study was to extend our examination of whether the level of maternal serum biochemical markers is independent of the presence or absence of the nasal bone in cases with trisomy 21 and to ascertain if any differences exist in cases with trisomies 13 and 18. This study data comprised 100 trisomy 21 singleton pregnancies at 11-13(+6) weeks of gestation from our previous study and an additional 42 cases analysed as part of routine OSCAR screening. A total of 34 cases with trisomy 18 and 12 cases with trisomy 13 were also available. Ultrasound examination was carried out for measurement of fetal NT and assessment of the presence or absence of the fetal nasal bone. Maternal serum free beta-hCG and PAPP-A were measured using the Kryptor rapid random access immunoassay analyser (Brahms Diagnostica AG, Berlin). The distribution of maternal serum free beta-hCG and PAPP-A in chromosomally abnormal fetuses with absent and present nasal bone was examined. The nasal bone was absent in 29 and present in 13 of the new trisomy 21 cases and in 98 (69%) and 44 respectively in the combined series. For the trisomy 18 cases, the nasal bone was absent in 19 (55.9%) cases and in 3 (25%) of cases of trisomy 13. There were no significant differences in median maternal age, median gestational age, NT delta, free beta-hCG MoM and PAPP-A MoM in trisomy 21 fetuses with and without a visible nasal bone, and similarly for those with trisomies 13 or 18. For a false-positive rate of 5%, it was estimated that screening with the four markers in combination with maternal age would be associated with a detection rate of 96% of cases with trisomy 21. For a false-positive rate of 0.5%, the detection rate was 88%. There is no relationship between an absent fetal nasal bone and the levels of maternal serum PAPP-A or free beta-hCG in cases with trisomies 13, 18 or 21. An integrated sonographic and biochemical test at 11-13(+6) weeks can potentially identify about 88% of trisomy 21 fetuses for a false-positive rate of 0.5%.

Fetal nasal bone: Review of first trimester findings

In 1866, Langdon Down included in his observation of individuals with the syndrome that would come to bear his name the following statements: ‘‘The nose is small. The face is flat and broad, and destitute of prominence’’ [1]. The prenatal diagnosis involves an invasive procedure, which carries a 1% risk of fetal loss [2]. Since every woman has a risk of this form of aneuploidy, extensive research has been done to identify markers that would identify fetuses at risk of having this condition. The phenotypic appearance of a small nose, which may range from a complete absence of the nasal bone to diminished nasal bone length, has been seen during the prenatal period. There is a hope that the evaluation of the fetal nasal bone (NB) can add to our armamentarium and allow us to increase our sensitivity for detecting Down syndrome (trisomy 21) and ultimately limit the number of women who need an invasive procedure. It has now become possible to delineate the risk of trisomy 21 based on an evaluation of NB between 11 and 14 weeks [3–5]. The association between the absent NB seen on ultrasound and trisomy 21 was observed in a review of videotape recordings of first-trimester ultrasounds of three fetuses with trisomy 21 which showed absence of or small NB 2/3 fetuses [6]. Afterwards, in a prospective study of 701 fetuses, absent NB was found in 43/59 (73%) fetuses with trisomy 21, compared to 21/603 (0.5%) euploid fetuses. This association between trisomy 21 and absent NB was seen in a smaller study where the nasal bone was absent in 3/5 (60%) fetuses with trisomy 21 compared to 1/175 (0.6%) fetuses with normal chromosomes [7]. Larger studies came out later that demonstrated the effectiveness of using the absent nasal bone in the first trimester. A study of 5525 fetuses found absent NB in 70% of trisomy 21 fetuses compared with 0.5% of fetuses with normal fetuses [8]. In their latest assessment of the absent fetal nasal bone in a multiethnic population of 3788, Cicero et al. found an absent nasal bone in 161/242 (66.9%) of trisomy 21 fetuses compared to 93/3358 (2.3%) of fetuses

Fetal nasal bone and trisomy 21 in the second trimester

To assess the feasibility of measuring nasal bone length in the second trimester of pregnancy and to confirm if fetal nasal bone absence or hypoplasia is a marker for Down syndrome. Fetal nasal bone assessment was performed in 439 consecutive singleton pregnancies at high risk of Down syndrome between 15 and 21 weeks. All ultrasound examinations were performed transabdominally by five skilled sonographers. If the nasal bone was present, its length was measured. The biparietal diameter: nasal bone length ratio (BPD/NBL) was also calculated. Nasal bone assessment was successfully achieved in all fetuses. The nasal bone was absent in 2(0.47%) of the 417 unaffected fetuses and in 10(55.5%) of the 18 fetuses with trisomy 21. Of the 8 Down syndrome cases with a nasal bone present, 4 had nasal bone hypoplasia and 4 had a normal nasal bone. BPD/NBL was 9 or greater in 7 of the 8 fetuses affected by trisomy 21 with nasal bone present and in 86 (20.6%) of the 417 normal fetuses; it was 10 or greater in 5 of the 8 (62.5%) fetuses affected by trisomy 21 and in 41 of the 417 (9.8%) euploid fetuses. Nasal bone absence is a marker for Down syndrome in the second trimester of pregnancy. Inclusion of nasal bone length into the second-trimester screening protocol could potentially obviate the false-negative cases from other screening tests. The measurement of nasal bone length in the second trimester seems to provide additional benefits beyond the assessment of the presence or absence of the nasal bone.

Three‐dimensional ultrasound with maximal mode rendering: a novel technique for the diagnosis of bilateral or unilateral absence or hypoplasia of nasal bones in second‐trimester screening for Down syndrome

Three-dimensional (3D) ultrasound of the fetal face with maximal mode rendering allows accurate visualization of the bony face and the distinct demonstration of both nasal bones in second-trimester fetuses. The aim of this study was to analyze the feasibility of assessing nasal bones spatially on prenatal ultrasound in second- and third-trimester fetuses with present and absent nasal bones. The faces of 38 fetuses between 17 and 33 weeks' gestation were examined with 3D ultrasound and volumes were stored for offline evaluation. Eighteen fetuses had normal karyotype and an apparently normal nasal bone on 2D ultrasound; these were examined to standardize the 3D rendering technique. Twenty fetuses had trisomy 21. In all 18 healthy fetuses both nasal bones could be demonstrated on 3D ultrasound. Nine of the 20 Down syndrome fetuses had a hypoplastic or absent nasal bone on two-dimensional ultrasound. On 3D ultrasound three of the nine had discrepant findings between left and right nasal bones with evidence of absence of one side, and hypoplasia (n = 2) or normal length (n = 1) of the other. Unilateral absence or hypoplasia of nasal bones is an important and new observation in fetuses with Down syndrome. This differentiation is best demonstrated on 3D ultrasound with maximal mode rendering. This observation of unilaterality of findings could explain some discrepant findings on absence of nasal bones on two-dimensional ultrasound but their "presence" on lateral postmortem radiographs.

Phenotypic Characteristics of Absent and Hypoplastic Nasal Bones in Fetuses With Down Syndrome

To determine the frequency and clinical significance of bilateral and unilateral hypoplastic nasal bones for the detection of Down syndrome by 3-dimensional ultrasonography. Thirty-seven volumes of the fetal skull from fetuses with Down syndrome and 37 from fetuses without abnormalities were analyzed by 1 investigator blinded to fetal karyotype. The maximum intensity projection algorithm was used to reconstruct nasal bones. Ossification patterns were identified in anteroposterior and profile views. Sensitivity, false-positive rates (FPRs), and likelihood ratios (LRs) for detection of Down syndrome were calculated. After exclusions (coronal acquisition [n = 11], hand in front of the face [n = 4], poor imaging [n = 2], incomplete follow-up [n = 2], and anomalies detected after delivery [n = 2]), 53 volumes were analyzed (26 fetuses with Down syndrome and 27 without abnormalities; median gestational age, 21 6/7 weeks [interquartile range, 19 6/7-25 2/7 weeks]). Rendered profile views revealed absent nasal bones in 18.9% (10 of 53) of the fetuses, and, among these, 90% (9 of 10) had Down syndrome (sensitivity, 34.6% [9 of 26]; FPR, 3.7% [1 of 27]; LR, 9.3 [95% confidence interval (CI), 1.3-68.7]). Three ossification patterns were identified in anteroposterior views: (1) normally developed, (2) delayed ossification, and (3) absent nasal bones. Sensitivity, FPR, and LR of absent nasal bones for detecting Down syndrome were 34.6% (9 of 26), 3.7% (1 of 27), and 9.0 (95% CI, 1.3-68.7), respectively. Sensitivity, FPR, and LR of delayed ossification for detecting Down syndrome were 42.3% (11 of 26), 22% (6 of 27), and 1.83 (95% CI, 0.8-4.4). Absence of nasal bones is associated with the highest risk of Down syndrome. Delayed ossification is associated with a lower risk of Down syndrome than absent nasal bones. These ossification patterns may be indistinguishable on 2-dimensional ultrasonography.

First-Trimester Nasal Bone Evaluation for Aneuploidy in the General Population

To evaluate the role of fetal nasal bone imaging at 10 3/7 to 13 6/7 weeks as a screening tool for aneuploidy, in a prospective multicenter trial. Unselected patients from the general population with viable singleton pregnancies at 10 3/7 to 13 6/7 weeks were recruited at 15 U.S. centers. All had screening with nuchal translucency (NT) ultrasound by specially trained sonographers. In the last 8 months of this trial, first trimester nasal bone evaluation was added to the screening protocol. Nasal bones were described as present, absent, or unable to determine. A total of 38,189 patients completed first trimester NT screening, of whom 6,324 also underwent nasal bone sonography. An acceptable nasal image was obtained in 4,801 cases (76%), with nasal bones described as present in 4,779 (99.5%), and absent in 22 (0.5%). There were 11 identified cases of trisomy-21 in the population of 6,324 patients. In 9 of the 11 cases (82%) the nasal bones were described as present, and 2 cases were described as unable to determine. The only other aneuploidies were 2 cases of trisomy-18, in 1 of which the nasal bones were described as absent, and in 1 present. Absence of nasal bones had sensitivity for aneuploidy of 7.7%, false-positive rate 0.3%, and positive predictive value 4.5%. First-trimester nasal bone evaluation was not a useful test for population screening for trisomy-21 and added little to first-trimester NT screening. The difficulty in performing first-trimester nasal bone sonography consistently, in the general population setting, will significantly limit the usefulness of this aneuploidy screening technique.

Transcutaneous electrical nerve stimulation: Intervention for pain and disability associated with ultrasonography

AND DISABILITY ASSOCIATED WITH ULTRASONOGRAPHY NORA DOYLE, MILDRED M. RAMIREZ, MICHAEL GARDNER, JOAN M. MASTROBATTISTA, University of Texas Health Science Center at Houston, Obstetrics, Gynecology, and Reproductive Sciences, Houston, Texas, Baylor College of Medicine, Obstetrics and Gynecology, Houston, Texas OBJECTIVE: The incidence of musculoskeletal injuries (MSI) among sonographers and sonologists is increasing with resultant lost work days having a significant negative impact on the delivery of ultrasound services. Transcutaneous electrical nerve stimulation (TENS) is used clinically by a variety of health care professionals for pain reduction. Mechanism of action is supported by the gate control pain theory and release of endogenous opioids. We sought to evaluate the efficacy and practicality of using a TENS unit by obstetrical sonographers in the workplace. STUDY DESIGN: Baseline demographic information, ergonomics survey and Upper Extremity Function Scale (Pransky) (UES) was obtained from all participants (n = 8) prior to device application. TENS unit was used by participants during a normal work day with subject control of intensity and duration. Post use information was then collected. RESULTS: Participants were female, age 25-57, with mean BMI 26.2 for the group. Ethnicity was 6 white and 2 Hispanic. All engaged in regular physical activity and reported good to excellent health. All performed ultrasounds 5 days/ week with >30 scans/week with no interventions currently being used at work. All were right hand dominant and scanned using their right hand. All reported wearing comfortable shoes and adjusting patient bed height when possible, with no other ergonomic interventions used. All reported pain after becoming a sonographer, with 2 missing work because of the pain. Satisfaction with using the TENS during work for relief of pain symptoms was high with all 8 saying they would use it again and 6 saying they would recommend it to others. CONCLUSION: Repetitive use injuries are a growing concern in sonographers and sonologists. TENS is a low cost, noninvasive modality that is easy to apply with few contraindications. Our study suggests it can sensibly be used in the workplace to relieve pain symptoms associated with performance of ultrasound. 648 ULTRASONOGRAPHIC MEASUREMENT OF FETAL NASAL BONE IN THE KOREAN POPULATION AT THE FIRST AND SECOND TRIMESTER EUI JUNG, HYE-SUNG WON, JUNG-SUN KIM, JAE-YOON SHIM, PIL RYANG LEE, AHM KIM, Asan Medical Center, University of Ulsan, Obstetrics and Gynecology, Seoul, South Korea, Asan Medical Center, University of Ulsan, Pathology, Seoul, South Korea OBJECTIVE: To establish the reference range of fetal nasal bone length(NBL) at the 1st and 2nd trimester in the Korean population and to determine the accuracy of prenatal NBL by postmortem examination including radiographs and autopsy. STUDY DESIGN: A total of 404 consecutive ultrasound examinations were performed at 11-14 weeks of gestation for nuchal translucency and nasal bone measurement and 820 consecutive fetuses underwent ultrasound examination at 18-26 weeks of gestation in Asan Medical Center. And the association between chromosomal abnormality and nasal bone absence or hypoplasia(smaller than 2.5th percentile) was analysed. Twenty-two fetuses with congenital anomaly or intrauterine death had undergone sonographic measurement of NBL before termination of pregnancy and were examined by radiographs and autopsy following termination. RESULTS: At the 1st trimester, the visualization of fetal profile was obtained in 398 fetuses (98.5%), and linear regression was performed. The incidence of nasal bone absence was 3/398 (0.75%). One fetus had T.21, one with T.18 and the other was acrania with euploidy. At the 2nd trimester, fetal profile was successfully examined in 818 fetuses(99.8%) and the NBL increased linearly with gestation. During this period, 6 fetuses with chromosomal abnormality (including 2 T.21) were detected and only one fetus with T.21 had hypoplastic nasal bone. Hypoplastic nasal bones was seen in 14/812 (1.7%) chromosomally normal fetuses. NBL measured by ultrasound was similar to that confirmed by autopsy and longer than by postmortem radiograph. CONCLUSION: We present the normal range of NBL at the 1st and 2nd trimester and their linear relationship with CRL and gestational age. Although numerically limited, our experience shows that the NBL in the 2nd trimester in Korean seems to be shorter than that of Caucasian and similar to Chinese. So different normal ranges for different races are required, and relative percentile is more reliable than absolute value. And the accuracy of the NBL measured by ultrasonography was confirmed by postmortem autopsy.