Bone Length Ratio Research Articles

Prenasal thickness to nasal bone length ratio: effectiveness as a second or third trimester marker for Down syndrome

ObjectiveTo assess the value of the prenasal thickness to nasal bone length ratio (PT/NBL) for detecting trisomy 21 (T21) after the first trimester. MethodTwo examiners blinded to fetal T21 status retrospectively measured prenasal thickness (PT) and nasal bone length (NBL) of T21 and control fetuses at 15–36 weeks’ gestational age on two-dimensional images from all T21-screening ultrasounds from November 2010 to April 2013. ROC curve analysis and its diagnostic values determined the best cut-off value for the ratio. Interobserver reproducibility was assessed. ResultsGood quality ultrasound profile images were available for 26 fetuses with T21 compared to 91 normal fetuses. The median PT/NBL ratio was 1.28 for T21 and 0.73 for control fetuses (p<0.0001). The PT/NBL ratio performed significantly better (AUC 0.99; 95%CI 0.97–1) than either PT (0.82; 0.73–0.91) or NBL (0.91; 0.85–0.98). The optimal PT/NBL ratio cut-off was 0.98, with a sensitivity of 88.5% [76.2–100%] and a specificity of 100%. Interobserver variability was low. ConclusionThe PT/NBL ratio is a strong marker for detecting T21 in the second and third trimesters, significantly more effective than either indicator alone.

Nasal bone length, prenasal thickness, prenasal thickness-to-nasal bone length ratio and prefrontal space ratio in second- and third-trimester fetuses with Down syndrome.

To evaluate nasal bone length (NBL), prenasal thickness (PT), prenasal thickness-to-nasal bone length (PT-NBL) ratio and prefrontal space ratio (PFSR) as markers for Down syndrome in the second and third trimesters. NBL, PT, PT-NBL ratio and PFSR were measured retrospectively in stored two-dimensional images or three-dimensional volumes (corrected to the mid-sagittal plane) of fetuses with Down syndrome, which were retrieved from the digital databases of participating units. Measurements were performed on the stored images and volumes by two experienced operators, and the values obtained were compared to our previously reported normal ranges for euploid fetuses in order to assess the detection rates for Down syndrome. A total of 159 fetuses with Down syndrome were included in the analysis, six of which were excluded because of inadequate available images. Median maternal age was 36.0 years and median gestational age was 23 + 1 weeks. NBL and PT were correlated with gestational age (P < 0.001), but the PT-NBL ratio and PFSR were not. Mean NBL, PT, PT-NBL ratio and PFSR were 4.42 mm, 5.56 mm, 1.26 and 0.34, respectively. The nasal bone was absent in 23 (15.4%) cases. As a marker for Down syndrome, the PT-NBL ratio yielded the highest detection rate (86.2%), followed by PFSR (79.7%), PT (63.4%) and NBL (61.9%). All markers were abnormal in 33.6% of cases, whilst all were normal in 4.7%. At least one of the four markers was abnormal in 95.3%, and either the PT-NBL ratio or PFSR was abnormal in 93.8%. Detection rates were not related to gestational age. The PT-NBL ratio and PFSR are robust second- and third-trimester markers for Down syndrome. Both provide high detection rates and are easy to use, as the cut-off for normality is constant throughout gestation. Ltd.

Relative long bone proportions and developmental stress in a modern Thai population (919.2)

Research on relative limb proportions has revealed interesting patterns of variability with regards to environment. Since there have been few attempts to correlate variability in limb proportion with unrelated stress indicators, this study examined long bone length ratios and linear enamel hypoplasia (LEH) frequency in a modern Thai population. Inter‐limb indices were calculated for 259 adults (105 F/154 M) and compared with LEH frequency. A Spearman’s correlation coefficient analysis indicated significantly shorter relative distal limb lengths in the lower limbs of individuals with high LEH frequencies. This was strongest in females, with significant correlations in the tibia/femur (p=0.038) and the fibula/femur ratios (p=0.009) of both sides, as well as a high correlation between LEH frequency and stature. In males, only the left fibula/femur ratio (p=0.008) demonstrated a significant relationship with LEH frequencies. No correlation between stature and LEH frequency was found in males, or in the upper limbs of either sex. These findings support the claim that distal limb growth is more affected by developmental stress than proximal growth. The disparity of upper and lower limb response, in addition to the relationship between sex and observed correlations, may have significant implications for our understanding of human limb development and catch‐up growth.

Systematic review and meta‐analysis of performance of second‐trimester nasal bone assessment in detection of fetuses with Down syndrome

To review systematically the literature on diagnostic tests and performance of second-trimester sonographic assessment of nasal bone (NB) in identifying fetuses affected by Down syndrome. A search of studies involving screening tests for NB evaluation and measurements was carried out in the main international bibliographic databases (MEDLINE, EMBASE and CINAHL). Those considered to be relevant were then subjected to critical reading, following Critical Appraisal Skills Programme (CASP) criteria, by at least three independent observers. All data were extracted and tabulated by two independent investigators. A statistical synthesis of sensitivity, specificity and likelihood ratios was performed using specific software (Meta-DiSc). From an initial list of 852 articles referring to ultrasound markers for Down syndrome, 207 relevant papers were selected. Following exclusions, 21 studies were included in the quantitative synthesis. The pooled estimates of positive and negative likelihood ratios were 40.08 (95% CI, 18.10-88.76) and 0.71 (95% CI, 0.64-0.79), respectively, for absent NB and 15.15 (95% CI, 8.15-28.16) and 0.47 (95% CI, 0.34-0.64), respectively, for hypoplastic NB. No relevant differences were found between the various means of defining nasal hypoplasia (multiples of the median (MoM) or percentiles). The biparietal diameter/nasal bone length (BPD/NBL) ratio showed somewhat higher sensitivity but lower specificity with a threshold effect. NB absence or hypoplasia show high specificity and low but acceptable sensitivity in identifying fetuses with Down syndrome. Screening performance is better with NB measurements as a function of MoM or percentiles rather than as the BPD/NBL ratio. Classification of women into various risk groups for Down syndrome does not affect diagnostic performance.

Frontonasal Fold Thickness-to-Nasal Bone Length Ratio as a Prenatal Sonographic Marker for Trisomy 21 in a Low-Risk Population

Frontonasal Fold Thickness-to-Nasal Bone Length Ratio as a Prenatal Sonographic Marker for Trisomy 21 in a Low-Risk Population

Frontonasal Fold Thickness-to-Nasal Bone Length Ratio as a Prenatal Sonographic Marker for Trisomy 21 in a Low-Risk Population

To report normative data for the fetal nasal bone length (NBL), frontonasal fold (FNF) thickness, and the FNF/NBL ratio and to study their performance in the sonographic screening of trisomy 21 in a normal, unselected Latin American population. Women undergoing a routine sonographic examination between 16 and 32 weeks' gestation at a primary health care center in Santiago, Chile, were prospectively recruited for NBL and FNF thickness measurements. Pregnancies with maternal/fetal complications were subsequently excluded from analysis. Correlations between NBL, FNF thickness, and FNF/NBL ratio and gestational age were assessed with the Spearman correlation coefficient (ρ). To generate reference percentiles for NBL and FNF thickness, adjusted regression models were derived using a statistical method for calculating reference percentiles of fetal biometric parameters. A total of 1922 cases complied with entry criteria. Both the NBL and the FNF thickness increased with gestational age. However, the FNF/NBL ratio remained constant (ρ= 0.016; P = .95), with a mean value of 0.68 and 95th and 99th percentile values of 0.84 and 0.90, respectively. During the study period, all 4 fetuses with trisomy 21 diagnosed in this low-risk population had an FNF/NBL ratio above the 99th percentile, whereas only 3 had NBL below the fifth percentile, and 3 had FNF thickness above the 95th percentile. The FNF/NBL ratio is a promising marker for the sonographic screening of trisomy 21 in the low-risk population; however, further prospective studies including larger numbers of fetuses with trisomy 21 are warranted to determine the clinical value of this marker. As the NBL is dependent on the ethnicity of the population screened, determination of normative data for NBL and the FNF/NBL ratio in different ethnic populations is also recommended before including this method in the routine screening for aneuploidy.

Three-dimensional ultrasonography measurement of fetal nasal bone length during the midtrimester in Taiwanese women

ObjectiveTo evaluate the normal range of the fetal nasal bone length (NBL) in Taiwanese women using three-dimensional (3D) ultrasound, and compare the NBL of normal fetuses with Down syndrome to determine its significance in screening for trisomy 21. Materials and MethodsA total of 102 consecutive fetuses and another 7 fetuses with trisomy 21, determined by karyotyping at 15–22 weeks' gestation, were evaluated with 3D ultrasound before amniocentesis at Changhua Christian Hospital between November 2003 and April 2004. ResultsThe normal range for NBL in the second trimester in the Taiwanese population was investigated, and a linear relationship with gestational age was noted. The NBL increased with advancing gestational age (NBL in cm=0.0264×gestational age in weeks –0.042 (R2=0.2416). The median of the biparietal diameter/nasal bone length ratio had a stable value which tended to change minimally between 15 and 22 weeks of gestation. Chromosomally normal fetuses had statistically longer nasal bones than fetuses with Down syndrome (p=0.014). ConclusionWe present a reference range for 3D ultrasound measurement of the fetal NBL. A short nasal bone at 15 to 22 weeks is associated with a high risk of trisomy 21.

Prenasal thickness‐to‐nasal bone length ratio: a strong and simple second‐ and third‐trimester marker for trisomy 21

To study the ratio of prenasal thickness (PT) to nasal bone length (NBL) in normal and trisomy-21 fetuses in the second and third trimesters of pregnancy. The PT and NBL were measured retrospectively in 106 normal fetuses (in three-dimensional (3D) volumes) and in 30 fetuses with trisomy 21 (10 on two-dimensional (2D) images and 20 in 3D volumes). In normal fetuses the mean PT and NBL increased between 15 and 33 weeks' gestation from 2.3 to 6.1 mm (r = 0.85, P < 0.001) and from 3.3 to 9.6 mm (r = 0.87, P < 0.001), respectively. The PT : NBL ratio was stable throughout gestation, with a mean of 0.61 (95% CI, 0.59-0.63; r = - 0.04, P = 0.7). The 5(th) and 95(th) percentiles were 0.48 and 0.80, respectively. In trisomy-21 fetuses the mean PT and NBL increased between 14 and 34 weeks from 3.0 to 9.2 mm (r = 0.86, P < 0.001) and from 1.9 to 7.8 mm (r = 0.85, P < 0.001), respectively. The PT : NBL ratio was significantly higher than in normal fetuses (P < 0.001) but also stable throughout gestation, with a mean of 1.50 (95% CI, 1.20-1.80; r = - 0.35, P = 0.07). Twenty-three (77%) of the 30 fetuses with trisomy 21 had a PT above the 95(th) percentile and 20 (67%) had an NBL below the 5(th) percentile. All the trisomy-21 fetuses had a PT : NBL ratio above the 95(th) percentile. When the 95(th) percentile of the PT : NBL ratio was used as a cut-off value the detection and false positive rates for trisomy 21 were 100 (95% CI, 89-100)% and 5 (95% CI, 2-11)%, respectively. The positive likelihood ratio was 21.2. The PT : NBL ratio is stable in the second and third trimesters of pregnancy in both normal and trisomy-21 fetuses, but all trisomy-21 fetuses in this series had a PT : NBL ratio above the 95(th) percentile. The ratio is therefore a strong marker for trisomy 21.

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.

Second-Trimester Biparietal Diameter/Nasal Bone Length Ratio Is an Independent Predictor of Trisomy 21

The purpose of this study was to evaluate the association between the second-trimester fetal biparietal diameter/nasal bone length (BPD/NBL) ratio and trisomy 21. Thirty-one cases of trisomy 21 for which complete ultrasound images included the nasal bone were identified from the University of Washington prenatal diagnosis database and matched to 136 euploid fetuses based on maternal age, indication for referral, and gestational age. The mean NBL was shorter (mean +/- SD, 2.3+/-1.7 mm versus 3.9+/-1.2 mm; P<.001) and the BPD/NBL ratio was greater (17.7 [range, 6.2-114] versus 11.7 [range, 5.8-80]; P<.001) in the fetuses with trisomy 21. The risk of trisomy 21 increased 2.4-fold (95% confidence interval [CI], 1.7-3.4) with every 1-mm decrease in NBL and increased 1.08-fold (95% CI, 1.03-1.12) with each unit increase in the BPD/NBL ratio (P<.001). A multiple logistic regression model was constructed and included the BPD/NBL ratio, maternal indications (age>or=35 years, positive serum screening results, or both, yielding a risk of <1 per 270 for trisomy 21), and sonographic markers as covariates. The BPD/NBL ratio was found to be an independent predictor of trisomy 21 (odds ratio, 1.08; 95% CI, 1.03-1.11). An analysis of receiver operating characteristic curves revealed an improvement after the BPD/NBL ratio was added to a model containing the current second-trimester screening based on maternal age, serum screening, and sonographic markers (receiver operating characteristic curve area, mean +/-SE, 0.89+/-0.03 for the model with the BPD/NBL ratio versus 0.76+/- 0.06 without the BPD/NBL ratio; P=.009). The second-trimester BPD/NBL ratio was a significant and independent predictor of trisomy 21. An assessment of the BPD/NBL ratio may improve the diagnosis of trisomy 21 when used with current prenatal screening practices.

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.

Efficacy of absent or shortened nasal bone length for down syndrome detection in second trimester fetuses

Absent or increased biparietal diameter / nasal bone length ratio has been proposed as an ultrasound marker to identify Down syndrome in second trimester fetuses ( Bromley et al JUM 2002). We tested the utility of absent or small nasal bone length expressed as multiples of the median ( MoM) to detect Down syndrome in second trimester fetuses in our population.

Second-trimester biparietal diameter/nasal bone length ratio is not a strong postive predictor of trisomy 21

Second-trimester biparietal diameter/nasal bone length ratio is not a strong postive predictor of trisomy 21

The fibonacci sequence: Relationship to the human hand

Purpose: The motion path of the digits follows the path of an equiangular spiral in which a constant angle is formed by all radial vectors along the curve. This implies that the lengths of the metacarpals, proximal, middle, and distal phalanges approximate a Fibonacci sequence in which the ratio of any 2 consecutive numbers approaches the number 1.61803 (phi). This study tested the hypothesis that the metacarpal and phalangeal bone lengths follow the Fibonacci relationship. Methods: Standardized x-rays were taken of the hands of 100 healthy volunteers. The proximal phalanx length was subtracted from the sum of the lengths of the middle and distal phalanges and the metacarpal length was subtracted from the sum of the lengths of the middle and proximal phalanges. Confidence intervals for the quotients of the measured lengths of the adjacent bones of the hand also were used for statistical analysis. Results: Only 1 of 12 bone length ratios contained the ratio phi in the 95% confidence interval, that of the small finger metacarpal and proximal phalanx. The largest variability was seen in the small finger phalangeal relationships. Conclusion: The application of the Fibonacci sequence to the anatomy of the human hand, although previously accepted, is a relationship that is not supported mathematically. The difference between individual bone lengths as measured at the joint line and the center of rotation of the joints may explain our finding. (J Hand Surg 2003;28A:157–160. Copyright © 2003 by the American Society for Surgery of the Hand.)

Fetal Nose Bone Length

To evaluate the significance of nasal bone length in relation to the detection of Down syndrome in the second trimester. We evaluated consecutive fetuses referred to our facility between 15 and 20 weeks' gestation for sonography and amniocentesis because of an increased risk of aneuploidy. A detailed structural survey, biometric measurements, and measurement of the nasal bone were obtained at the time of amniocentesis and subsequently compared with karyotype. The characteristics of the fetuses with Down syndrome were compared with those of the euploid fetuses. A total of 239 fetuses were evaluated. Sixteen fetuses (7%) had Down syndrome, and 223 were euploid. In fetuses with Down syndrome, 6 (37%) of 16 did not have detectable nose bones, compared with 1 (0.5%) of 223 control fetuses, yielding a likelihood ratio of 83. Detectable nasal bones were seen in 10 fetuses with Down syndrome and 222 euploid fetuses. A receiver operating characteristic curve for the biparietal diameter-nasal bone length ratio showed that a value of 9 or greater detected 100% of fetuses with Down syndrome and 22% of euploid fetuses. If the ratio were 10 or greater, then 81 % fetuses with Down syndrome and 11 % of euploid fetuses would have been identified. If the ratio were 11 or greater, 69% of fetuses with Down syndrome would be identified, compared with 5% of euploid fetuses. The absence of a nasal bone is a powerful marker for Down syndrome. A short nasal bone is associated with an increased likelihood for fetal Down syndrome in a high-risk population.

Reconstruction of the predatory behaviour of the extinct marsupial thylacine (Thylacinus cynocephalus)

AbstractThe European colonists of Tasmania named the thylacine Thylacinus cynocephalus a ‘marsupial wolf’ or the ‘Tasmanian tiger’ or ‘hyena’, in reference to its resemblance to large canids and the bold stripes on its rump. The largest marsupial carnivore in historic times, it was persecuted for alleged sheep killing and became extinct before its ecology was documented. We have reconstructed the likely prey size and the hunting and killing methods of the thylacine by comparing canine tooth strength and limb bone length ratios with those of extant marsupial and placental carnivores. The thylacine was probably a pounce–pursuit predator of fairly open habitats, which killed medium‐sized prey (1–5 kg) that were small relative to its body size (15–30 kg), with a crushing, penetrating bite. The trophic niche of the thylacine was similar to that of smaller canids such as the coyote Canis latrans (rather than the wolf C. lupus), but ecomorphological convergence of the thylacine with canids was superficial. Phylogenetic constraint has resulted in unique patterns of tooth eruption, molar tooth and jaw geometry, calcaneum architecture, and perhaps FMT/running speed relationships in the Dasyuroidea.

Standards for limb bone length ratios in children.

HomeRadiologyVol. 143, No. 2 PreviousNext Standards for limb bone length ratios in children.M Robinow, W C ChumleaM Robinow, W C ChumleaM RobinowW C ChumleaPublished Online:May 1 1982https://doi.org/10.1148/radiology.143.2.7071345MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Article HistoryPublished in print: 1982 FiguresReferencesRelatedDetailsCited ByPLOS ONE, Vol. 16, No. 1Orphanet Journal of Rare Diseases, Vol. 14, No. 1International Journal of Paleopathology, Vol. 18American Journal of Medical Genetics Part A, Vol. 170, No. 8American Journal of Medical Genetics Part A, Vol. 161, No. 8Clinical Genetics, Vol. 34, No. 5Journal of Pediatric Orthopaedics, Vol. 26, No. 1Bone, Vol. 31, No. 1American Journal of Medical Genetics, Vol. 57, No. 3American Journal of Medical Genetics, Vol. 58, No. 1American Journal of Medical Genetics, Vol. 59, No. 1European Journal of Pediatrics, Vol. 154, No. 3Pediatric Radiology, Vol. 22, No. 6American Journal of Medical Genetics, Vol. 35, No. 1Forensic Science International, Vol. 46, No. 3European Journal of Pediatrics, Vol. 148, No. 7American Journal of Medical Genetics, Vol. 27, No. 1American Journal of Medical Genetics, Vol. 25, No. 2American Journal of Physical Anthropology, Vol. 70, No. 2Journal of Medical Genetics, Vol. 23, No. 4, Vol. 2American Journal of Physical Anthropology, Vol. 25, No. S3Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 143, No. 2 Metrics Altmetric Score PDF download

Effects of High-Intensity 60 Hz Fields on Bone Growth

As part of an ongoing investigation of physiologic effects of high-voltage power frequency electric fields, femora from 55 adult rats which had been conceived, born, and raised in an 80 kV/m, 60 Hz unperturbed field were excised and studied. Specimens from 49 sham-exposed animals were also characterized in this double-blind study. Parameters evaluated were body weight, wet and dry bone weights, bone length, specific gravity, and various ratios of these parameters. Results from a statistical analysis indicated that chronic field exposure enhanced growth in the long bones, causing increased length and mass.