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ERROR: type should be string, got "https://profreg.medscape.com/px/getpracticeprofile.do?method=getProfessionalProfile&urlCache=aHR0cHM6Ly9lbWVkaWNpbmUubWVkc2NhcGUuY29tL2FydGljbGUvNDAyODYzLW92ZXJ2aWV3\nDrugs & Diseases > Radiology\nPrenatal Imaging Findings in Down Syndrome\nAuthor: Badar Bin Bilal Shafi, MBBS, MRCP, FRCR, CCT, EBIR; Chief Editor: Eugene C Lin, MD more...\nSections Prenatal Imaging Findings in Down Syndrome\nPractice Essentials\nDown syndrome, also called trisomy 21, is a congenital disorder caused by the presence of an extra 21st chromosome. Frequency is about 1 per 800 live births, and each year about 6000 children are born with Down syndrome. Although the clinical presentation of Down syndrome can vary, it is associated with a number of major disorders, including learning disabilities, congential heart defects, duodenal atresia (ie, part of the small intestines is not developed), seizures, childhood leukemia, and early-onset Alzheimer disease. Approximately 50% of children with Down syndrome are born with a heart defect, most often a hole between the sides of the heart. In addition, Hirschsprung disease (congenital aganglionic megacolon), which can cause intestinal obstruction, occurs more frequently in children with Down syndrome than it does in other children. [1, 2]\nThe diagnosis of Down syndrome is based on fetal karyotype analyzed predominantly on fetal cells from amniotic fluid sampled by amniocentesis or chronic villus sampling (CVS). Diagnostic tests are invasive and resource-intensive, and because the fetal-placental unit is invaded, these tests pose risks of pain, infection, bleeding, fetal scarring, and fetal loss. Due to the risk of fetal loss inherent to these invasive techniques, they are not offered routinely to all women. Screening consists in targeting patients with an increased risk of chromosomal abnormalities for whom diagnostic testing is then considered.\nScreening tests are noninvasive and generally painless studies performed to estimate the risk of a fetus having Down syndrome. These tests do not give a definitive answer as to whether a baby has Down syndrome, but they are used to help parents and clinicians decide whether diagnostic tests are warranted.\nRadiologic screening tests include nuchal translucency testing and detailed ultrasonography. Ultrasound-guided transabdominal or transvaginal interventions include amniocentesis with chorionic villus sampling (CVS), percutaneous umbilical blood sampling (PUBS), and termination of pregnancy. [3, 4, 5]\nOther conditions that should be considered are trisomy 18; trisomy G syndrome; 49,XXXXY chromosome and other high-order multiple X chromosomes; Zellweger syndrome; chromosome 21, mosaic 21 syndrome; and chromosome 21, translocation 21 syndrome. If diagnostic tests yield positive results and parents decide to continue the pregnancy, fetal echocardiography should be performed at 20 weeks' gestation to detect serious cardiac malformations. Ultrasonography should be performed at 28-32 weeks' gestation.\nAccording to the American College of Obstetricians and Gynecologists, all women should be offered screening for aneuploidy before 20 weeks' gestation, and all pregnant women, regardless of their age, should have the option of diagnostic testing. [1]\nUltrasonography is the imaging modality mainstay of prenatal screening and diagnosis of Down syndrome, and it is often used in combination with biochemical tests. Second-trimester ultrasonography helps detect 60-91% cases of Down syndrome, depending on the criteria used. The addition of color Doppler imaging to gray-scale ultrasonography increases the sensitivity for detection of cardiac malformations, which include atrioventricular septal defect (AVSD), abnormalities of the outflow tract, mitral and tricuspid regurgitation, and right-to-left disproportion of the cardiac chamber. [6, 7, 8, 9, 10, 11, 12]\nUltrasonographic markers include thickness of the nuchal fold, cardiac abnormalities, duodenal atresia, shortened femur, shortened humerus, renal pyelectasis, absence of the nasal bone, a hyperechogenic bowel, and a choroid plexus cyst. An echogenic intracardiac focus has also been identified as a soft marker. None of these markers are specific, and false-positive rates have been reported.\nStructural anomalies, cardiac abnormalities, a nuchal fold 6 mm or thicker, bowel echogenicity, choroid plexus cysts, and renal pyelectasis have been studied. With the exception of bowel echogenicity and choroid plexus cysts, the ultrasonographic markers have been found to be more common in fetuses with trisomy 21 than in euploid fetuses. Cardiac anomalies, other structural anomalies, and a nuchal fold 6 mm or thicker were independent predictors of trisomy 21.\nEvidence suggests that the careful combination of accurately performed noninvasive ultrasonography and maternal blood testing, eventually followed by a quantitative fluorescent polymerase chain reaction (QF-PCR), should reduce the need for conventional chromosomal analysis, which is relatively time consuming.\nA Cochrane Database Review evaluated 22 studies and a total of 32 test combinations formed from 8 different tests and maternal age. The 8 tests included first-trimester nuchal translucency (NT) and the serum markers AFP, uE3, total hCG, free βhCG, inhibin A, PAPP‐A, and ADAM 12. A test strategy involving maternal age and a combination of first-trimester NT and PAPP‐A and second-trimester total hCG, uE3, AFP and Inhibin A outperformed other test combinations. [6] Another meta-analysis of first-trimester ultrasound screening tests investigated 11 ultrasound markers and 12 serum markers and found that the test strategies that combined ultrasound markers with serum markers (especially PAPP‐A and free βhCG) and maternal age provided better results than those consisting only of ultrasound markers (with or without maternal age), except nasal bone. [7]\nThe genetic ultrasonogram scoring index\nIn a proposed a scoring system for the detection of Down syndrome, [13] the importance of the clustering of markers forms the basis of the scoring index, such that individual markers are assigned point values based on their sensitivity and specificity in the detection of Down syndrome. The points acquired by each fetus are tabulated into a final score. One study proposed the following scoring system: nuchal fold = 2; major structural defect = 2; and short femur, short humerus, and pyelectasis = 1 each. Selecting fetuses with a score of 2 or more identified 26/32 (81%) Down syndrome fetuses, 9/9 (100%) trisomy-18 fetuses, and 2/2 (100%) trisomy-13 fetuses, but only 26/588 (4.4%) normal fetuses were identified by this scoring system. For a 1/250 risk group, using the ultrasonographic score of 2 resulted in a positive predictive value of 6.87% for Down syndrome and 7.25% for all 3 trisomies. [14]\nLimitations of techniques\nFirst-trimester combined screening at 11 weeks' gestation for Down syndrome is better than second-trimester quadruple screening. [10, 11] However, at 13 weeks, the results are similar to those of second-trimester quadruple screening. Rates of detecting Down syndrome are high with both stepwise, sequential screening and fully integrated screening, with low rates of false-positive results.\nThe choice of screening strategy should be between the integrated test, first-trimester combined test, quadruple test, and nuchal translucency measurement, depending on how much service providers are willing to pay, the total budget available, and values on safety. Screening based on maternal age, the second-trimester double test, and the first-trimester serum test is less effective, less safe, and more costly than the integrated test, first-trimester combined test, quadruple test, and nuchal translucency measurement.\nOne study showed that integrated serum screening was the most cost-effective screening strategy for Down syndrome. [12] First-trimester combined screening was found to be the most cost-effective strategy if the cost of nuchal translucency was less than $57 or if a genetic ultrasonogram was included in the second-trimester strategies. [15]\n(The image below is that of a fetus with Down syndrome.)\nPrenatal ultrasonogram in a fetus at 21 weeks and 1 day of gestation shows shortening of the femur length to 27 mm. This indicates a deficit of 3 weeks in the estimated gestation based on the femoral length.\nView Media Gallery\nNuchal translucency testing\nNuchal translucency (NT) testing is performed between 11 and 14 weeks of pregnancy and involves the use of ultrasonography to measure the clear space in the folds of tissue behind a developing fetus's neck. In fetuses with Down syndrome and other chromosomal abnormalities, fluid tends to accumulate in this location, making the space appear enlarged. Increased nuchal translucency refers to a measurement greater than 3 mm. This finding does not mean that the fetus has a chromosomal abnormality but, rather, indicates that the risks of some genetic disorders and birth defects, including Down syndrome, are increased. This measurement, taken together with the mother's age and the fetus's gestational age, can be used to calculate the odds that the fetus has Down syndrome. With nuchal translucency testing, Down syndrome is correctly detected in about 80% of cases. When performed with a maternal blood test, its accuracy may be improved. [16, 17, 18]\n(See the images below.)\nAxial prenatal ultrasonogram of a fetal head demonstrates nuchal thickening and translucency (arrow).\nLongitudinal prenatal ultrasonogram shows nuchal thickening (arrow).\nUltrasonography is the mainstay of prenatal screening and diagnosis of Down syndrome, and it is often used in combination with biochemical tests. Second-trimester ultrasonography helps detect 60-91% cases of Down syndrome, depending on the criteria used. The addition of color Doppler imaging to gray-scale ultrasonography increases the sensitivity for detection of cardiac malformations, which include atrioventricular septal defect (AVSD), abnormalities of the outflow tract, mitral and tricuspid regurgitation, and right-to-left disproportion of the cardiac chamber. [3, 19, 16, 20, 21, 22]\nGeneral ultrasonographic markers\nThe most common sonographic marker is an elevated nuchal translucency (NT). NT testing is performed between 11 and 14 weeks of pregnancy and involves the use of ultrasonography to measure the clear space in the folds of tissue behind a developing baby's neck. In fetuses with Down syndrome and other chromosomal abnormalities, fluid tends to accumulate in this location, making the space appear enlarged. Increased nuchal translucency refers to a measurement greater than 3 mm. This finding does not mean that the fetus has a chromosomal abnormality but, rather, indicates that the risks of some genetic disorders and birth defects, including Down syndrome, are increased. This measurement, taken together with the mother's age and the fetus's gestational age, can be used to calculate the odds that the baby has Down syndrome. With nuchal translucency testing, Down syndrome is correctly detected in about 80% of cases. When performed with a maternal blood test, its accuracy may be improved. [16, 17]\nSecond-trimester ultrasound findings, termed \"soft markers\" because they may be transient, may nclude cardiac abnormalities, duodenal atresia, absent nasal bone, shortened femur, shortened humerus, pyelectasis or hydronephrosis, echogenic bowel, cardiac echogenic chorda tendineae (“golf ball”), and choroid plexus cysts (CPC, which is related more to trisomy 18). [23] An echogenic intracardiac focus (EIF) has also been identified as a second-trimester soft marker. [24] None of these markers are specific, and false-positive rates have been reported.\nThe absence of a nasal bone is a powerful marker for Down syndrome. A short nasal bone is associated with an increased likelihood of fetal Down syndrome in a high-risk population. The ratio of prenasal thickness to nasal bone length (PT/NBL) has been found to be a valuable first-trimester screening marker for Down syndrome. [21, 22, 25]\nAxial prenatal ultrasonogram of the head shows a choroid plexus cyst (arrow) in the lateral ventricle.\nAxial prenatal ultrasonogram of the abdomen obtained at the level of the kidneys demonstrates bilateral renal pyelectasis (arrows).\nCoronal prenatal ultrasonogram of the abdomen shows bilateral renal pyelectasis (arrows).\nPelvic and cerebral diameters\nAlthough the diameters of the pelvis and the cerebrum are individually statistically significant as markers of trisomy 21, the combination of transcerebellar diameter (TCD) and frontothalamic distance (FTD) measurements may be superior to the measurement of either parameter alone.\nPatients with Down syndrome have a large mean iliac angle and a shortened mean iliac length. The most pronounced differences are at the middle sacral level. This observation suggests that the middle sacral level may be the optimal level for measuring the iliac angle and length during prenatal ultrasonography. [22]\nThe iliac angle is significantly greater in second-trimester fetuses with trisomy 21 than in euploid fetuses. The iliac angle varies with the axial level, with the widest angle being at the most superior level. Evidence supports the measurement of the iliac angle at the most superior level as a potential marker for Down syndrome on prenatal ultrasonography.\nMeasurements of the axial iliac angle on standardized 3-dimensional multiplanar views of the pelvis are reliable and can be used to identify some fetuses at increased risk for trisomy 21.\nIn the second trimester, the nasal bones are present in most fetuses with trisomy 21. These fetuses have a characteristic midfacial anthropometry.\nBest ultrasonographic markers to detect trisomy 21 in the second trimester\nStructural anomalies, cardiac abnormalities, a nuchal fold 6 mm or thicker, bowel echogenicity, choroid plexus cysts (see the first image below), and renal pyelectasis (see the second and third images below) have been studied. With the exception of bowel echogenicity and choroid plexus cysts, the ultrasonographic markers have been found to be more common in fetuses with trisomy 21 than in euploid fetuses. Cardiac anomalies, other structural anomalies, and a nuchal fold 6 mm or thicker were the only independent predictors of trisomy 21. When any of the ultrasonographic markers significant in univariate analysis are considered, the false-positive rate is reported to be 5.3%, and the sensitivity is reported to be 59.1%. When any of the predictors from multivariate analysis are present, the false-positive rate has been reported as 3.1%, and the sensitivity 54.5%. Because of the considerable overlap of ultrasonographic markers in fetuses with trisomy 21, use of markers that are not independent predictors increases the false-positive rate without a gain in sensitivity. [8, 9, 11, 12, 16, 20, 23, 24]\n[Guideline] Practice Bulletin No. 163 Summary: Screening for Fetal Aneuploidy. Obstet Gynecol. 2016 May. 127 (5):979-81. [Medline].\nCanfield MA, Honein MA, Yuskiv N, Xing J, Mai CT, Collins JS, et al. National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999-2001. Birth Defects Res A Clin Mol Teratol. 2006 Nov. 76 (11):747-56. [Medline].\nCole R, Jones G. Testing times: do new prenatal tests signal the end of Down syndrome?. N Z Med J. 2013 Mar 1. 126(1370):96-102. [Medline].\nSmith M, Visootsak J. Noninvasive screening tools for Down syndrome: a review. Int J Womens Health. 2013. 5:125-31. [Medline]. [Full Text].\nWald NJ, Kennard A, Hackshaw A, McGuire A. Antenatal screening for Down syndrome. J Med Screen. 1997. 4(4):181-246.\nAlldred SK, Takwoingi Y, Guo B, Pennant M, Deeks JJ, Neilson JP, et al. First and second trimester serum tests with and without first trimester ultrasound tests for Down's syndrome screening. Cochrane Database Syst Rev. 2017 Mar 15. 3:CD012599. [Medline]. [Full Text].\nAlldred SK, Takwoingi Y, Guo B, Pennant M, Deeks JJ, Neilson JP, et al. First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening. Cochrane Database Syst Rev. 2017 Mar 15. 3:CD012600. [Medline]. [Full Text].\nOfferdal K, Blaas HG, Eik-Nes SH. Prenatal detection of trisomy 21 by second-trimester ultrasound examination and maternal age in a non-selected population of 49 314 births in Norway. Ultrasound Obstet Gynecol. 2008 Sep. 32(4):493-500. [Medline].\nOdibo AO, Ghidini A. Role of the second-trimester 'genetic sonogram' for Down syndrome screen in the era of first-trimester screening and noninvasive prenatal testing. Prenat Diagn. 2014 Jun. 34 (6):511-7. [Medline].\nMalone FD, Canick JA, Ball RH, Nyberg DA, Comstock CH, Bukowski R. First-trimester or second-trimester screening, or both, for Down's syndrome. N Engl J Med. 2005 Nov 10. 353(19):2001-11. [Medline].\nSmith-Bindman R, Hosmer W, Feldstein VA, Deeks JJ, Goldberg JD. Second-trimester ultrasound to detect fetuses with Down syndrome: a meta-analysis. JAMA. 2001 Feb 28. 285(8):1044-55. [Medline].\nGilbert RE, Augood C, Gupta R, Ades AE, Logan S, Sculpher M. Screening for Down's syndrome: effects, safety, and cost effectiveness of first and second trimester strategies. BMJ. 2001 Aug 25. 323(7310):423-5. [Medline].\nBromley B, Benacerraf BR. The Genetic Sonogram Scoring Index. Semin Perinatol. 2003 Apr. 27(2):124-9. [Medline].\nHamdaoui N, Lesieur E, Mancini J, Dabadie A, Bourderionnet V, Pico H, et al. Herman score in prenatal screening for Down syndrome: Can a junior assess a senior?. Diagn Interv Imaging. 2017 Feb. 98 (2):155-160. [Medline]. [Full Text].\nOdibo AO, Stamilio DM, Nelson DB, Sehdev HM, Macones GA. A cost-effectiveness analysis of prenatal screening strategies for Down syndrome. Obstet Gynecol. 2005 Sep. 106(3):562-8. [Medline].\nCicero S, Spencer K, Avgidou K, Faiola S, Nicolaides KH. 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. Prenat Diagn. 2005 Nov. 25(11):977-83. [Medline].\nMonni G, Zoppi MA, Ibba RM, Floris M, Manca F, Axiana C. Nuchal translucency and nasal bone for trisomy 21 screening: single center experience. Croat Med J. 2005 Oct. 46 (5):786-91. [Medline].\nTekesin I. The diagnostic value of a detailed first trimester anomaly scan in fetuses with increased nuchal translucency thickness. J Perinat Med. 2019 Feb 25. 47 (2):241-246. [Medline].\nFang YM, Benn P, Egan JF. Use of the genetic sonogram in the United States in 2001 and 2007. J Ultrasound Med. 2008 Nov. 27(11):1543-8. [Medline].\nGrijseels EW, Cohen-Overbeek TE, van Scheltema PN, Groenenberg IA, Schoonderwaldt EM, Steegers EA, et al. [Sonomarkers: subtle ultrasound findings in the 20-week ultrasound examination, which have a low association with some chromosomal and non-chromosomal abnormalities in the fetus]. Ned Tijdschr Geneeskd. 2008 Oct 11. 152(41):2225-31. [Medline].\nVos FI, De Jong-Pleij EA, Bakker M, Tromp E, Pajkrt E, Kagan KO, et al. 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. Ultrasound Obstet Gynecol. 2015 Feb. 45 (2):211-6. [Medline].\nAlphonse J, Cox J, Clarke JL, Schluter PJ, McLennan A. Frontomaxillary facial angle measurement in trisomy 21 and euploid fetuses: two- and three-dimensional assessment during routine first trimester screening. Fetal Diagn Ther. 2014. 36 (3):183-9. [Medline].\nBronshtein E, Solt I, Bronshtein M, Gover A, Wolman I, Blumenfeld Z. Detection Rate and Sonographic Signs of Trisomy 21 Fetuses at 14-17 Weeks of Gestation. Isr Med Assoc J. 2017 Jan. 19 (1):8-12. [Medline]. [Full Text].\nLorente AMR, Moreno-Cid M, Rodríguez MJ, Bueno G, Tenías JM, Román C, et al. Meta-analysis of validity of echogenic intracardiac foci for calculating the risk of Down syndrome in the second trimester of pregnancy. Taiwan J Obstet Gynecol. 2017 Feb. 56 (1):16-22. [Medline]. [Full Text].\nManegold-Brauer G, Maymon R, Shor S, Cuckle H, Gembruch U, Geipel A. Down's syndrome screening at 11-14 weeks' gestation using prenasal thickness and nasal bone length. Arch Gynecol Obstet. 2019 Feb 9. [Medline].\nShamshirsaz AA, Ravangard SF, Turner G, Borgida A, Janicki MB, Campbell WA, et al. Efficacy of the genetic sonogram in a stepwise sequential protocol for down syndrome screening. J Ultrasound Med. 2013 Sep. 32(9):1607-13. [Medline].\nAbdominal chorionic villus sampling (CVS).\nVaginal chorionic villus sampling (CVS).\nAmniocentesis.\nContributor Information and Disclosures\nBadar Bin Bilal Shafi, MBBS, MRCP, FRCR, CCT, EBIR Consultant Interventional Radiologist, South Mersey Vascular Centre and Countess of Chester Hospital, UK\nBadar Bin Bilal Shafi, MBBS, MRCP, FRCR, CCT, EBIR is a member of the following medical societies: Radiological Society of North America, Royal College of Physicians, Royal College of Radiologists, Society of Interventional Radiology, Cardiovascular and Interventional Radiological Society of Europe, British Society of Interventional Radiology\nDisclosure: Nothing to disclose.\nCoauthor(s)\nMusa Kaleem, MBBS, FRCR, MRCP Consultant Pediatric Radiologist, Central Manchester University Hospitals NHS Foundation Trust (Royal Manchester Children's Hospital); Honorary Lecturer, University of Liverpool Faculty of Medicine, UK\nMusa Kaleem, MBBS, FRCR, MRCP is a member of the following medical societies: Radiological Society of North America, Royal College of Radiologists, Royal College of Paediatrics and Child Health\nSuhaib Bin Bilal Hafi, MBBS Core Trainee 1 (CT1) Psychiatry, Greater Manchester West Mental Health NHS Foundation Trust, UK\nR H Bilal, MBBS, MRCS Specialist Registrar in Cardiothoracic Surgery, North West Cardiothoracic Rotation, UK\nR H Bilal, MBBS, MRCS is a member of the following medical societies: British Medical Association\nSpecialty Editor Board\nBernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand\nKaren L Reuter, MD, FACR Professor, Department of Radiology, Lahey Clinic Medical Center\nKaren L Reuter, MD, FACR is a member of the following medical societies: American Association for Women Radiologists, American College of Radiology, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, Radiological Society of North America\nEugene C Lin, MD Attending Radiologist, Teaching Coordinator for Cardiac Imaging, Radiology Residency Program, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine\nEugene C Lin, MD is a member of the following medical societies: American College of Nuclear Medicine, American College of Radiology, Radiological Society of North America, Society of Nuclear Medicine and Molecular Imaging\nThe authors extend their sincere thanks to Mrs Helen Lee, ultrasonographer, Liverpool Women's NHS Trust and Royal Liverpool Children's NHS Trust, for her help in compiling prenatal sonograms for this article.\nPrint this section\nPrint the entire contents of\nPrint the entire contents of article\nencoded search term (Prenatal Imaging Findings in Down Syndrome) and Prenatal Imaging Findings in Down Syndrome\nWhat to Read Next on Medscape\nRelated Conditions and Diseases\nPrenatal Diagnosis and Fetal Therapy\nDiGeorge Syndrome\nPrenatal Diagnosis for Congenital Malformations and Genetic Disorders\nFast Five Quiz: Do You Know the Zika Virus Guidelines?\nPatau Syndrome\nMedscape Consult\nNo U.S. Labs Follow All Guidelines for 'Cell-Free' Prenatal Testing\nAnalytical and Clinical Performance Evaluation of the Elecsys HIV Combi PT Assay on the Cobas e 602 Analyzer for the Diagnosis of Human Immunodeficiency Virus\nA Devastating Surge in Congenital Syphilis: How Can We Stop It?\nGrowth Disorders: 10 Cases of a Developing Problem\nAccording to Obstetrician / Gynecologists\nPhysician Moms With Babies Escorted From ACOG Meeting Hall\nWorld's First Vagina Museum in London to Tackle Taboos\nPhysical Activity: The Real Magic Bullet\nFDA Pulls Vaginal Mesh Products for Prolapse Off the Market\n2002 936318-overview Diseases & Conditions\nDiseases & Conditions Prenatal Diagnosis and Fetal Therapy\n2001 /viewarticle/914202 Article\nArticle Coding Consults Correctly\nDiseases & Conditions DiGeorge Syndrome\n2001 /viewarticle/913415 News\nNews Prevalence of Perinatal Depression Significantly Underestimated?\nNeed a Curbside Consult? 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