ISUOG Practice Guidelines (updated): performance of 11–14‐week ultrasound scan

• DOI: 10.1002/uog.26106
• Publication Date: 2023-01-03T13:54:46Z
• Authors: C. M. Bilardo; R. Chaoui; J. A. Hyett; K. O. Kagan; J. N. Karim; A. T. Papageorghiou; L. C. Poon; L. J. Salomon; A. Syngelaki; K. H. Nicolaides
• Keywords: 570; Pregnancy; 610; Humans; 600; Female; 530; Ultrasonography, Prenatal; Ultrasonography

The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) is a scientific organization that encourages sound clinical practice high-quality teaching research related to diagnostic imaging women's healthcare. ISUOG Clinical Standards Committee (CSC) has remit develop Practice Guidelines Consensus Statements as educational recommendations provide healthcare practitioners with consensus-based approach, from experts, for imaging. They are intended reflect what considered by be the best at time which they issued. Although made every effort ensure accurate when issued, neither nor any its employees or members accepts liability consequences inaccurate misleading data, opinions statements issued CSC. CSC documents not establish legal standard care, because interpretation evidence underpins may influenced individual circumstances, local protocol available resources. Approved can distributed freely permission ([email protected]). Performing routine first-trimester ultrasound examination 11 + 0 14 weeks' gestation value confirming viability plurality, pregnancy dating, screening aneuploidies, identification major structural anomalies preterm pre-eclampsia. This document aims guidance performing, planning perform, scans weeks. Details grades recommendation levels used given Appendix 1. In general, main goal scan information will facilitate delivery optimized antenatal ensuring possible outcomes mother fetus. early pregnancy, it important confirm viability, gestational age accurately, determine number fetuses and, presence multiple assess chorionicity amnionicity. Towards end first trimester, also offers an opportunity detect fetal abnormalities systems offer aneuploidy screening, measure nuchal translucency (NT) thickness. However, many malformations later detected even appropriate equipment most experienced hands. If earlier been done, advisable estimated between gestation, this provides achieve aforementioned aims, i.e. viable if requested, evaluate anatomy risk aneuploidy1-18. Before starting examination, provider should counsel woman/couple regarding potential benefits limitations (GOOD PRACTICE POINT). Individuals who perform obstetric routinely have specialized training pregnant women An report produced electronic and/or paper (see Appendices 2 3 examples). stored locally accordance protocol, woman referring There no indications use B-mode M-mode prenatal ultrasonography harmful during due their limited acoustic output20, 21. scanning lowest power output obtain according ALARA (As Low As Reasonably Achievable) principle Doppler is, however, associated greater energy therefore, there more bioeffects, especially applied small region interest embryonic period before gestation20, 22, 23. From weeks, spectral Doppler, color flow imaging, other modalities certain indications, such aneuploidies cardiac anomalies. When performing ultrasound, displayed thermal index (TI) ≤ 1.0 exposure kept short (usually longer than 5–10 min). Scanning maternal uterine arteries (UtA) point trimester unlikely safety implications long embryo/fetus lies outside beam22. These represent international benchmark scan, but consideration must protocols medical practice. cannot completed these Guidelines, reasons this. repeat refer case another practitioner. done soon possible, minimize unnecessary patient anxiety delay achieving desired goals initial Determination amnionicity testing management multifetal pregnancies. Chorionicity determined characterization reliable24, 25. Once accomplished, further including timing frequency examinations, planned health resources guidelines26 defined heartbeat, achieved easily using ultrasound. Fetal activity identified 2D heartbeat heard Doppler. heart rate, recorded, measured either assessed over cycles Cardiac typically visible 5–6 gestation. Heart rate increases up 10 (mean, 171 bpm) then decreases through 156 bpm)27. tachy- bradycardia indicative abnormality28, 29. normal range, reassessed examination. demonstrated, intrauterine nature pregnancy. sac bounded completely myometrium. sweep covering entire uterus integrity breached located Cesarean section scar on ‘Assessment complications’) rudimentary horn. specific charts assessing biometry38. Systematic measurement cephalic, abdominal femoral biometry enables documentation essential anatomical landmarks, measurements reveal expression serious pathologies. cut-off values follow-up procedures decided protocols, order avoid excessive false-positive findings examinations. Crown–rump length (CRL) part transabdominally transvaginally (Figure 1a). performed, following criteria, fetus oriented horizontally screen so line crown rump about 90° beam. neutral position (i.e. flexed hyperextended). image magnified fill width screen. Calipers placed points rump, need visualized clearly30, 31. CRL estimate all cases except pregnancies conceived in-vitro fertilization32, 33. taken, based best-quality 45 84 mm. A different published significant variations reported age34. older still widely, recommended recent, international, prescriptive charts35, take into account improvements machine quality aim statistical bias36, 37. (and calculated age) reference define where NT, UtA pulsatility (PI) biochemical markers free β-human chorionic gonadotropin (β-hCG), pregnancy-associated plasma protein-A (PAPP-A) placental growth factor (PlGF) lie relation range. reduced affected trisomy 18 triploidy, care taken ‘normalize’ changing dates obvious Particular attention paid smaller expected measurement. Biparietal diameter (BPD) head circumference largest symmetrical axial view 1b). Two techniques BPD described, placing calipers outer-to-inner (leading edge) outer-to-outer, perpendicular midline falx. Measurements methodology nomogram employed. adjusted CRL38 (AC) transverse (TAD) useful myelomeningocele39-42 holoprosencephaly43. AC abdomen level stomach 1c), outer surface skin line. It directly ellipse linear measurements, usually anteroposterior (APAD) TAD. To APAD, borders body outline, posterior aspect (skin spine) anterior wall. TAD, across widest point. formula: = π (APAD TAD)/2 1.57 TAD). advantage record shows place. Femur long-axis plane femur 1d). ossified diaphysis, clearly visible. ensures sonographer checks development lower limbs severe skeletal anomalies44. Successful detection dependent skill set sonographers sonologists prevalence population. Some sonographic features abnormality described only relatively recently, yet clear how population screening. We therefore describe two presenting both checklist ‘minimum requirements’ basic survey (Table 1) advanced ‘best practice’ comprehensive detailed 2). currently describing economic benefit abnormalities. Axial head: Calcification cranium Contour/shape (with bony defects) brain halves separated interhemispheric falx Choroid plexuses almost filling lateral ventricles two- thirds (butterfly sign) Sagittal neck: Confirm whether thickness < 95th percentile four-chamber view: inside chest regular rhythm Stomach Intact wall sagittal Bladder dilated two-thirds Thalami Brainstem Cerebral peduncles aqueduct Sylvius Intracranial (fourth ventricle) Cisterna magna Forehead Bilateral orbits Nasal bone Maxilla Retronasal triangle Upper lip Mandible Nuchal No jugular cysts neck Shape thoracic Lung fields Diaphragmatic continuity present Establish situs Position: intrathoracic axis left (30–60°) Size: one-third space Four-chamber distinct grayscale diastole Left ventricular outflow tract Three-vessel-and-trachea Absence tricuspid regurgitation/antegrade ductus venosus A-wave pulsed-wave Stomach: upper Bladder: normally filled pelvis (longitudinal 7 mm) Abdominal wall: intact umbilical cord insertion bordering bladder Kidneys: bilateral three segments movement Lower Size texture normal, without cystic appearance Location cervix previous Cord placenta Amniotic fluid volume membrane chorion dissociated physiologically 0-week assessment NT. Whilst cell-free (cf) DNA highly effective means common test identify defects, extensive range rarer chromosomal Identification support invasive rather non-invasive approach aneuploidy48-50. Several cases45 absence minimum patients Most occur categorized being ‘low risk’ traditional (history-based) approaches Effective relies whole predefined groups only. Demonstration weeks reassurance women. Early anomaly allows genetic diagnosis parental counseling decision-making. Detailed high-resolution transabdominal transvaginal transducers. Both required complete systematic organs adequate needs scheduled assessment. While mandatory, better resolution anatomy, increased mass index, fibroids retroverted uterus. Within 3-week interval, doubles size (CRL, 45–84 mm). Visualization details around 13 studies shown adoption standardized increase gestation46, 47, 51, 52. gain experience ‘best-practice’ review allow higher proportion wider include Overview fetus, overview 2a). appear slightly echogenic, uniform, homogeneous echotexture, large lacunae 2b). subchorionic hematoma assessed. Prediction final location internal cervical os challenging subject reporting low-lying placenta. history section, careful could help abnormal discussed complications’. uterus, fibroids, amniotic bands synechiae evaluated. membranes. change rarely observed so, unlike second-trimester hint membranes often well surrounding fused chorion. bleeding, blood clot retroamniotic space. documented 2c). Head brain. Examination central nervous system combination midsagittal planes. visualize ossification skull symmetry developing structures. Cranial cerebral dominated asymmetric echogenic choroid 2d). hemispheres fissure mantle very thin appreciated anteriorly, lining fluid-filled 2e). within thalami fossa Sylvius, fourth ventricle future cisterna structures 2f). head/face intracranial brainstem open neural tube defects 2g). face. face plane, complemented coronal plane. several anatomic regions face, forehead, nasal bone, maxilla, mandible mouth Different facial angles (e.g. maxillary gap, superimposed-line proposed clefts confirmation planes53, 54. attempt eyes interorbital distance retronasal triangle, demonstrating maxilla 2h 2i). ‘absent’ hypoplastic 50–60% 21 additional marker improve efficacy ultrasound-based Neck. Sonographic NT 1e), independent aneuploidy. Increased while cfDNA mostly aneuploidies. method reviewed Guidelines. Other discrete collections seen sides lymph sacs hygroma. 40% death55, 56. Thorax heart. cavity lungs evaluated 2j). ribs, lungs, assessed, pointing (the 30–60°)57, 58. homogeneously sign pleural effusion. axial, sagittal/parasagittal noting intra-abdominal liver. reliably combining Color helps separate exclude atrioventricular valve regurgitation 2k). great vessels three-vessel-and-trachea demonstrates presence, vessels, relationship direction flow, along ductal aortic arches, enabling ruling out complex affecting 2l). Multicenter rates planes addition Doppler59. content. echolucent pelvis. side abdomen, together levocardia, visceral 2m). kidneys paraspinal bean-shaped, structures, typical hypoechoic renal 2r). By 12 median round structure longitudinal mm 2p 2q). after 2n). Physiologic midgut herniation differentiated omphalocele gastroschisis. Umbilical cord. umbilicus noted. Brief evaluation paravesical helpful 2o). Single artery (SUA) does constitute anomaly, congenital restriction. Care cause parents SUA detected, found scan. yet, consensus impact outcome. Placental stage Spine. spine examined, view, vertebral alignment 2s). Vertebral bodies signs suspicious spina bifida found60. Limbs. Presence orientation hands feet noted 2t 2u). Genitalia. Evaluation external genitalia sex upon genital tubercle Role three-dimensional (3D) four-dimensional (4D) 3D 4D evaluation. hands, methods abnormalities, multiplanar reconstruction selected tests generally aneuploidies: combined (includes risks derived history, serum biochemistry); (also known (NIPT) (NIPS)). Combined trisomies, comprise approximately 50% aberrations identifiable prenatally array-based genomic diagnose Turner syndrome. extended microdeletions microduplications. conditions carried provider. clinicians calculate trisomies 21, 13, algorithm Medicine Foundation61, 62. combines a-priori age, β-hCG PAPP-A63, 64. altered multiplying likelihood ratio each factors. Likelihood ratios comparing distributions chromosomally populations. cross margins. Three (on images) correct, technique Nicolaides65. calculation, essential. restricting performance trained personnel agree undergo continuous process assurance compares measures recognized standard. quality-assurance programs run nationally; others participate internationally (www.fetalmedicine.org). First-trimester improved PAPP-A. national guidelines recommend 13. show patterns up- down-regulation individualized Recently, data demonstrated low concentrations PlGF suggesting incorporated already pre-eclampsia complications’). bone. described. Delayed ‘hypoplastic’ ‘absence the’ powerful absent euploid consequently dichotomized variable positive negative ratios66-69. potentially improvement specificity whilst maintaining high sensitivity69. same includes tip nose rectangular shape palate anteriorly. Posterior it, centrally brain, translucent diencephalon identified. below bridge nose, immediately above itself 1e)67. above, deemed absent. Ductus 1f). Fetuses likely