Biparietal Diameter and Your Pregnancy Ultrasound - Verywell Family Unable to process the form. 1.44). ICD 10 code for Maternal care for other (suspected) fetal abnormality and damage, not applicable or unspecified. >> FIGURE 1.46: Coronal views of the vertebral column. FIGURE 1.25: Both lower extremities visible at 13 to 14 weeks gestation. Dolichocephaly is diagnosed when the skull has a cephalic index less than 75 on the scale. Optimal timing of the first trimester scan involves some compromise. 137 (1): 83-5. You may have fears about the future, and you may not know how to handle what is happening in the here and now. It can also be used to localize the DV in a right parasagittal section, allowing pulse wave assessment of this vessel for aneuploidy and cardiac screening. This slit-like structure is filled with CSF and is hypoechoic in its ultrasound appearance (see Fig. As the transducer is moved caudally, the orbits can be identified. Marley Hall is a writer and fact-checker who is certified in clinical and translational research. Babies' skull bones contain spaces in between them that are filled with a flexible substance called sutures. Dolichocephaly is a term used to describe a tall, narrow head. Dolichocephaly - ULTRASOUNDPAEDIA Dolichocephaly can develop in an otherwise normal developing skull when a baby spends too much time in certain positions. /SMask /None>> The fetus is also larger and more developed, making the detection of anomalies easier.6073 In some jurisdictions, the anomaly scan is performed earlier (e.g., at 18 to 20 weeks gestation) in view of the legal restrictions related to interruption of pregnancy if there are abnormal findings. Scaphocephaly, results from premature closure of the sagittal suture, so that lateral growth of the skull is prevented whilst anteroposterior growth continues, producing a narrow and elongated cranium. If thats the case for you, you may have a lot of questions about this condition, what it means for your baby, and what treatment options are available. FIGURE 1.31: Anterior coronal view of the brain at 24 weeks gestation. For unknown reasons, the rate of survival is higher in females than in males, leading to a female predominance among live-born trisomy 18 infants. If the baby's head circumference is much smaller than the average head circumference for their age group or the week of pregnancy, he/she is said to have microcephaly. Standard fetal biometry includes the following measurements: biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL).7580 Other measurements that are commonly performed as a part of a routine examination in some centers are the humerus length (HL) and the transcerebellar diameter (TCD).81,82 The correct manner in which each of these measurements should be obtained is described in the individual sections below. FIGURE 1.9: Midcoronal view of the head at 12 to 13 weeks gestation. 4) Likus W, Bajor G, Gruszczyska K, et al. Here are some the AAP recommends you try at home: Caring for a baby with any sort of abnormality can be stressful. Finally, the suboccipitobregmatic view is also used as a standardized view for nuchal fold measurement. Although these 2 terms have been used interchangeably by many, dolichocephaly refers to an elongated head without associated biparietal narrowing and is caused by positioning. Can craniosynostosis correct itself? Brachycephalic vs Dolichocephalic - What's the difference? /Height 60 But what happens if your babys head is more severely misshapen? The inferior (temporal) horns run through the area of the temporal lobe and are difficult to identify unless they are enlarged. PDF I - Revised Ghent criteria for the diagnosis of Marfan - Orphanet Color Doppler may be used to look for the renal arteries. However, fetal position, reduction in amniotic fluid volume, and increased bony ossification often make the third trimester examination more challenging. You can find out more about our use, change your default settings, and withdraw your consent at any time with effect for the future by visiting Cookies Settings, which can also be found in the footer of the site. B: Axial view in a plane slightly caudal to A, where the cavum septi pellucidi (solid arrow) and cavum septi vergae (open arrow) are seen as two separate structures. ADVERTISEMENT: Supporters see fewer/no ads. Acrocephaly - ULTRASOUNDPAEDIA The issue of fetal biometry is discussed in this chapter only to illustrate the proper technique rather than clinical applicability. In utero death occurs in more than 95% of fetuses with this chromosome anomaly. The most common defects are a cephalocele or an encephalocele. 1.1).47 This finding is considered normal until the early portion 12th week of gestation and should not be mistaken for an omphalocele. 1110 d - 37 cp, choroid plexus; arrow, third ventricle. Systematic evaluation is needed to accurately distinguish between a viable intrauterine pregnancy, a miscarriage, or an ectopic pregnancy. Cookies collect information about your preferences and your devices and are used to make the site work as you expect it to, to understand how you interact with the site, and to show advertisements that are targeted to your interests. Several national and international bodies have described standards for imaging in the first, second, and third trimester of pregnancy. The normal range for CI is 0.74 to 0.83. Note the relatively prominent adrenal glands (a), which need to be kept in mind in order not to mistake them for the kidneys. The whole length of the vertebral column can be seen in both a coronal and in a sagittal section, and the ossification centers should be spaced evenly in these views. FIGURE 1.10: Coronal view of the fetal face. Nuchal translucency measurement is typically increased in fetuses affected by chromosomal abnormality. Note that CVA will be symmetric in symmetric brachy-, and dolichocephaly. Even though this view is primarily designed to evaluate the posterior fossa and the back of the fetal head, it also offers a good view of the CSP, thalami, and the midbrain as well as their anatomic relationship (Fig. Both hands are commonly held in front of the chest or fetal face, and the legs are generally flexed at the hip at this gestation. It is obtained by multiplying the maximum width of the head by 100 and dividing that number by the entire length of the head. However, it should be kept in mind that since the vessels are very small, only small adjustments of the transducer can affect their visualization (Fig. no financial relationships to ineligible companies to disclose. Absence of the nasal bone is associated with an increased risk of trisomy 21.55 Similarly, the intracranial anatomy of the posterior fossa can be examined and used to screen for spina bifida in this view.12 The methodology for assessment of these features as well as the overall utility of the 11 to 13+6 week scan is discussed in detail in Chapter 8. It is bounded by the corpus callosum anteriorly and superiorly, the fornix posteriorly, and the anterior commissure inferiorly. Prenatal dolichocephaly: sign of trouble? -A variant of Miller-Dieker It needs to be kept in mind that the shape of the lateral ventricle is 3D complex; unless it is enlarged, it is difficult to visualize in its entirety in a single ultrasound plane. s^Xmj{4BM+o2Lo_Y0 It can change according to various situations such as In the axial view, this defect translates into flattening of the cerebellar hemispheres with an anterior bend (so-called banana sign) and obliteration of the CM.84,85,9799 Finally, since most cephaloceles and encephaloceles are located in the occipital region of the skull, examination of the posterior fossa must also include a careful evaluation of the calvarium in that region.100, The formation of the cerebellar hemispheres and the connecting vermis continues throughout the first half of the pregnancy. 4 0 obj 1.48). 1 synonym for dolichocephaly: dolichocephalism. This is often recommended when a babys head does not reach a healthy shape by the time they are 5 to 6 months old. As a normal variant, the CSV can be unusually large and visible in this section. A Diagnosis of Microcephaly refers to some babies having a small head when measured by ultrasound during pregnancy, and with a tape measure around the head after birth. A@h%F( *>`%1* nc13l>{|Yww=~ q2v7 `OKq2xP[rp2"%#0uTF ;WS+' Reference article, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-15495, View Yuranga Weerakkody's current disclosures, View Munyi Ambrose Ithiga's current disclosures, see full revision history and disclosures, 1. Merz E, Bahlmann F. Ultrasound in obstetrics and gynecology. The fetal echocardiogra showed an increase in postvalvular flow and altered pulmonary venous return. J4Wr~]RF+J7j_A@]5%"po!Y*i| $JC]l The kidneys are generally difficult to see owing to their small size and echogenicity, which is similar to that of the small bowel. FIGURE 1.11: Transverse view of the lower neck at 12 to 13 weeks gestation. Con transductor linear de 7,5 Mhz se visualiza imagen nodular con eco-patrn mixto ( contenido solido-liquido ), se localiza en lbulo derecho . FIGURE 1.4: Sagittal view of an 11- to 12-week fetus. In order to assess the symmetry of the two halves of the brain, regardless of the level of the axial view, care should be taken to keep the falx cerebri truly in the midline. FIGURE 1.26: Upper extremity at 12 to 13 weeks gestation. On this page: Article: Epidemiology Pathology These are due to subarachnoid trabeculae and represent a normal finding.103105. Asterisk, center of the circle of Willis; notched arrow, cerebellum. Therefore, in the standard axial section at the level of the BPD, usually it is only the CSP that is visible. Scaphocephaly (also known as dolichocephaly) is the most common form of craniosynostosis, where premature closure of the sagittal sutureresults in an impediment to the lateral growth of the skull while anteroposterior growth continues, producing a classic elongated, yet narrow, skull. It begins as infolding of the cerebral cortex at the lateral edge of the cerebrum located initially in the anterior half of the distance between the occiput and the forehead. Solid arrow, medulla oblongata; open arrow, pons; asterisk, cisterna magna; c, cerebellum. Anyone had this and how did it turn out? Fetal feet can also be identified, though evaluating the number of toes may be difficult because of their small size (Fig. 4,f~Z]\1aHZ9Lx40!?-v*oTf+*i;/F@l#C5b[4I.uf B,\ux+~G39EzF^}gsR8v.jnS$6p-,b$1F3{o V W'4C8)3j|jO 7w&p5=Rj [BD,11X1vHd+/H3$S)`"A 1@"2FIcD]9Rt52D[ The Radiology Assistant : Craniosynostosis 1.5). A: Section demonstrating all three types of ossification centers in the same view. It can also be helpful to get in touch with other parents who have been through similar experiences through an online or in-person support group. The calvarium should be systematically examined to ensure that it is intact. In contrast to other craniosynostoses, there is near normal IQ and no hydrocephalus. Objective: Cephalic index less than 76% Subjective: Apparently increased antero-posterior length of the head compared to width Comments: Cephalic index is the ratio of head width expressed as a percentage of head length. Calipers, CRL measurement. The breech head and its ultrasound significance - PubMed 1010 << Anterior cerebral (open arrow) and pericallosal (solid arrow) arteries with some of their branches are demonstrated using color Doppler. Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. If your babys skull looks elongated, they may be diagnosed with a condition called dolichocephaly (also known as scaphocephaly). Scientific World Journal. h, fetal head. However, the presence of multiple vertebral ossification centers does obscure it to a variable degree, especially later in gestation. Head ultrasound was normal except marked dolicocephaly, head circumference between -1 and -2 SD, and suspected delay of sulcation. The effect of 3D/4D . It is measured with the cursor placed on the outer edge to the outer edge of the cranial bone. A specialist must fit molding helmets. They invariably resolve spontaneously and do not represent a true pathologic entity. Measurement according to standardized methodology allows individualized levels of risk for trisomy 21, 18, and 13 to be calculated. The temporal horn extends from the atrium in an inferior and anterior direction. Gray DL, Songster GS, Parvin CA et-al. "They are purely cosmetic, and the majority do not require surgery. Fetal measurements are concordant with dates, apart from BPD below 5th centile reflecting dolichocephaly. A thin line of hair along the fetal back (arrows) is seen. 2. Color Doppler is used to demonstrate the renal arteries (solid arrows) in A, which can become nondetectable with only a slight adjustment of the transducer, as in B. FIGURE 1.47: Sagittal view of the spine in mid-second trimester demonstrating its normal curvature. Psychological problems such as poor self-esteem and depression can also occur as the child gets older. Please note the increased amount of extra-axial fluid, which is normal early in gestation. We evaluated dolichocephaly, the name associated with a nonsynostotic cause to be a physiological variant having no prognostic value, to that of a similar synostotic or secondary to a. In these conditions, the skull is also easily compressible, which can be demonstrated by applying gentle pressure with the ultrasound transducer. Asterisks, corpus callosum; open arrow, cavum septi pellucidi; chevron, cavum septi vergae; solid arrow, fourth ventricle; c, cerebellum; cm, cisterna magna. Dolichocephaly - National Institutes of Health FIGURE 1.20: Coronal view of the abdomen at the level of the kidneys (open arrows) in a 12- to 13-week fetus. Turri-, acro- and oxy-cephaly are associated with a cephalic index of 80 or more. 1.8). Wendy Wisner is a lactation consultant and writer covering maternal/child health, parenting, general health and wellness, and mental health. At the time the article was created Yuranga Weerakkody had no recorded disclosures. 2. Head length is measured between the glabella (the most prominent point on the . This is due to ossification of the skull, which casts an acoustic shadow over the proximal portion of the fetal brain. In the coronal view, the two lateral points of ossification can be visualized cleanly, and by moving the probe anteriorly, ossification of the vertebral body can be brought into view. The body and the anterior horn of the lateral ventricle radiate anteriorly, superiorly, and laterally from the atrium. Dolichocephaly is a mild cranial deformity in which the head has become disproportionately long and narrow, due to mechanical forces associated with breech positioning in utero. These positions are used to protect premature babies' healthincluding decreasing their risk of reflux, apnea, and bradycardiabut unfortunately can result in dolichocephaly. The face, specifically lips and nose, are best examined in sagittal section (see Fig. The fetus is in a neutral position and occupies the majority of the image. The use of obstetric ultrasound in the antenatal diagnosis of . The images can provide valuable information for diagnosing and directing treatment for a variety of diseases and conditions. Lyndsey Garbi, MD, is a pediatrician who is double board-certified in pediatrics and neonatology. endobj Dolichocephaly anyone? - Hot Topics | Forums | What to Expect There is a tendency of the ankles to turn inward, making the diagnosis of clubfoot in the first trimester challenging. Causes. Treatment is often with a cranioplasty. The cerebral cortex is a hypoechoic structure, which is fairly thin and difficult to visualize at early gestations. 1. Ideally, the surgery takes place in the early months of life for optimal results. If a cerebellar defect or ventriculomegaly is suspected, the fourth ventricle should be evaluated. Prenatal ultrasound diagnosis of fetal craniosynostosis Remember that any concerns you may have are valid. a, atria. A CI, which is below 0.74, connotes a relatively flat head (dolichocephaly), while a CI above 0.83 describes a relatively round head (brachycephaly).83 Dolichocephaly is not uncommon and is often seen in fetuses that are in a persistently breech presentation or in association with chronic oligohydramnios. The yolk sac becomes visible within the gestational sac by the midportion of the 6th gestational week, corresponding to an MSD of approximately 10 mm. 1.36). 1.2). In the axial section, the three ossification centers are in a triangular arrangement. American Academy of Pediatrics. Thank you, {{form.email}}, for signing up. 1.24). Note that this is a neonatal image to show the anatomy in its entirety. Using 3D ultrasound (Figs. FIGURE 1.50: Superficial coronal view along the fetal back in the third trimester. cp, choroid plexus; thick solid arrow, frontal horn; open arrow, body of the lateral ventricle; chevron, trigone; thin solid arrow, portion of the occipital horn; notched arrow, inferior (temporal) horn. /Type /XObject Discrepancy of ultrasound biometric parameters of the head (HC - head Features of this skull deformation (dolichocephaly, a prominent occiput with a suboccipital shelf, an elongated face and a parallel-sided head) constitute the 'breech head'. 1.43). Cephalic index. B,&uT>|Z'%,B!yZ~ayZpStTON"vl4sEJ{"=9#/j4UM. My 20 week ultrasound also recvealed abnormal head dimensions and cephalic index of 69. A skeletal survey is best performed by utilizing both axial and transverse sections. The caliper-determined occipitofrontal/biparietal diameter ratio (OFD/BPD) in these newborn infants was consistently above 1 . Color Doppler may be used to help define the cord insertion and the number of arteries in the cord (Fig. Even though operculization of the insula begins at approximately 14 weeks gestation, on ultrasound, this process does not become evident until approximately 19 weeks gestation. SCAPHOCEPHALY / DOLICOCEPHALY (boat or canoe head) Premature closure of sagittal suture. /Filter /FlateDecode As the spine is curved, it is common to be able to visualize the vertebral bodies at some levels and the arches at other levels in the same view (Fig. It can also be seen in conditions where the skull is poorly ossified such as certain types of osteogenesis imperfecta and hypophosphatasia. There is no direct communication between the ventricular system and CSPV; it is diffusion across the thin septi pellucidi that allows CSF to enter this space. Prominent pulsations can be seen at the bottom of the depression, which represents the Sylvian segment of the middle cerebral artery (Fig. Chevron, falx cerebri; cp, cerebral peduncles. The cephalic index (CI) is a ratio/value calculated using two fetal biometric parameters which are the occipitofrontal diameter (OFD) and the biparietal diameter (BPD). << D4?n*uU5[ \lGi'X!fS+yUCDKu\e T\DO[bTq2FiTPiePL \GC?h3s$t_*pWiKBi\$3WGbln In addition to the bifrontal scalloping of the cranium described earlier, open spine defects are accompanied by the Chiari Type II malformation (herniation of the cerebellar tonsils through the foramen magnum and downward displacement of the cerebellar vermis). It can change according to various situations such as, The usual range is variable depending on various sources and different demographic groups. /ColorSpace /DeviceRGB The normal range is 76-80.9%. The occipital horns project posteriorly. 1 0 obj It may be associated with craniosynostosis of the sagittal suture; it may be commonly seen in the premature infant and is more frequently a normal variant. 2008;27:503515. Dolichocephaly is a long keel-shaped skull with prominent forehead and occiput. FIGURE 1.32: Midcoronal view of the brain at 24 weeks gestation. The uterus should then be scanned in cross section, from left to right and from top to bottom, determining the number of fetuses that are present and defining the lie of the fetus. (PDF) New Screening Tool for Aortic Root Dilation in Children with Dolichocephaly - understanding 'breech head' molding Most ultrasound machines can produce this calculation automatically at any obstetric scan with minimal programming. 1.28).8 Doppler examination involves higher power levels and consequently should generally be avoided during the embryonic period (10 weeks menstrual gestational age) unless the benefits clearly outweigh the risks. The approach to the anatomical survey is essentially the same in both the second and the third trimesters. Open arrow, vertebral body ossification center. Some anomalies may be more readily detectable with the fetus in a different position and others (e.g., duodenal atresia, X-linked aqueductal stenosis, certain skeletal dysplasias, and fetal tumors) generally only become apparent after the mid-second trimester examination. Both the femur and the humerus can be identified and measured (Figs. 7 0 obj The conus medullaris can be identified as the place where the spinal cord comes to its end point (Fig. In humans, the anterior-posterior diameter (length) of the dolichocephaly head is more than the transverse diameter (width). "iM.1,O`jpW}&kG3k}-:(Ht-%mV(uJ]J5/qBS(w$|a>=*>3aPtP4(Ey=:tS{FB[@}XtVu/Zj0LMD6iBQ~eg- b28|0@WY6>!Q*D&;&\C4jK)wlrgGDu+^QR'[nV=MC@ C6?jFBE[T-lQ @-9,~\(?KMq9_pJ^(3EGR6S/^+rv7y~ The shape of the skull may be abnormal in association with a number of specific fetal anomalies. Returning to an axial section, the anterior abdominal wall and cord insertion are evaluated (Fig. If one or more sutures close early, it will cause the skull to expand in the direction of the sutures that remain open, which can result in an abnormal head shape. ADVERTISEMENT: Supporters see fewer/no ads. The accuracy of CRL measurement decreases with gestational age. A complete examination of the uterine contents in pregnancy includes much more than evaluation of the fetal anatomy; the remaining issues will be discussed in later chapters. Early fusing of the joints (sutures) between the bony plates that form an infant's skull keeps the brain . This involves evaluation of the vertebrae and the contents of the spinal canal. FIGURE 1.7: Transverse views of a fetal head at 12 weeks gestation demonstrating hindbrain appearance at various levels in descending order. The posterior fossa anomalies are one area where a fetal MRI may be especially helpful in arriving at the correct diagnosis. FIGURE 1.18: Transverse view of the abdomen at the level of the kidneys (arrows) at 12 weeks gestation (A) and at 13 weeks gestation (B). Please note the difference in the texture of the surface of the cortex, with absent sulci and gyri at 22 weeks gestation (A) and well-developed pattern of sulci and gyri at term (B). Orphanet: Trisomy 18 Craniosynostosis is a birth defect in which the bones of the baby's skull fuse together prematurely before the brain has fully developed. In this view, an upper lip seen extending beyond the tip of the nose raises the possibility of cleft lip and palate. Cephalic index - Wikipedia FIGURE 1.2: Embryo at 6.5 weeks gestation. The transvaginal approach should be used in all circumstances where a viable intrauterine pregnancy is not obvious on transabdominal assessment. Sometimes casually referred to as "NICUcephaly," some cases of dolichocephaly affect premature babies who have spent some time in the NICU. Assessment of the central nervous system is not complete without detailed examination of the fetal spine. Quiste Tiroides. Exposure Criteria for Medical Ultrasound, II: Criteria Based on All Known Mechanisms. Occasionally, the third ventricle can be detected in a midcoronal section of the head (Fig. The CSPV begins to close in the third trimester, a process that is completed in infancy. 1.49). anyone have a baby with this condition? The posterior fossa undergoes rapid change during the late first trimester, and by 13 to 14 weeks the cerebellum begins to assume a shape resembling that seen in the mid-second trimester (Fig. ; C]pb FIGURE 1.15: Transverse view of the abdomen at 13 weeks gestation at the level of the abdominal circumference. Absence of an ossified calvarium in association with abnormal intracranial anatomy is consistent with exencephaly/anencephaly sequence. Normal Fetal Ultrasound Survey | Radiology Key Brachycephaly as dened by a BPD/OFD ratio > 0.85 was diagnosed in one case. When you visit the site, Dotdash Meredith and its partners may store or retrieve information on your browser, mostly in the form of cookies. Scaphocephaly, or sagittal craniosynostosis, is a type of cephalic disorder which occurs when there is a premature fusion of the sagittal suture.Premature closure results in limited lateral expansion of the skull resulting in a characteristic long, narrow head. As operculization progresses, the depression is roofed over by the temporal lobe. Other causes may include: Craniosynostosis (kray-nee-o-sin-os-TOE-sis). FIGURE 1.49: Sagittal view of the lumbar spinal cord (solid arrow) ending in the conus medullaris (notched arrow) in late second trimester. 1.27). Examination of the cerebral cortex focuses on ruling out any space occupying lesions, either cystic or solid in nature. FIGURE 1.24: Fetal foot (arrow) with all five toes visible (12 to 13 weeks gestation). Additionally, the bodies of the lateral ventricle and their continuation, the frontal horns, are domed in shape in the sagittal section; therefore, their appearance differs significantly when viewed in various axial planes. Dolichocephalic Head June 11, 2019 | by Emily1082 My 19 week ultrasound suggests that the baby has a dolichocephalic head. Z@N 1.20).56,57. Isolated enlargement of the fourth ventricle is unlikely to occur and is of limited clinical significance. Coronal sections add very little information to the axial ones, but depending on the position of the fetus, this approach may provide the clearest view. In the mid-second trimester, bifrontal scalloping occurs in >95% of open neural tube defects resulting in a lemon-shaped calvarium seen in the axial section.84,85 The occipital portion of the skull is typically flattened in trisomy 18, while the frontal and parietal portions of the skull gently slope toward one another anteriorly, creating a strawberry shape in axial view. In a midsagittal section, the CSPV is arched in shape. CARTA, Human Uniqueness Compared to "Great Apes": Absolute Difference Dolichocephaly seems a Materials and methods Ultrasound examinations were performed prospectively at the Department of Obstetrics and Gynecology and at the Department of Medical Genetics and Fetal Medicine at Palack University Teaching Hospital in Olomouc. A: Arrow, developing aqueduct of Sylvius; bs, brain stem. Every attempt should be made to visualize both cerebellar hemispheres to allow a comparison of their size and echotexture. In some cases, the dolichocephaly resolves by the time the baby goes home, but in other cases, it remains, and babies are discharged from the hospital with dolichocephaly. Dolichocephaly (or positional scaphocephaly) is defined as a boat-shaped or elongated anterior-posterior axis as a result of skull flattening during side-to-side head positioning of infants during hospitalization. 1.9). However, unlike the CSP, a thin echogenic line can be seen between the two fornices, which helps to differentiate between the two entities (Fig. The process of cortical maturation can be most easily observed in the insula. A small angle, which is essentially parallel to the longitudinal axis of the fetus, indicates a female gender, whereas an angle measuring 30 or more suggests a male gender (Figs. Regardless of the approach used, the fetus needs to be assessed in all planes: Longitudinal, axial, and coronal. The CSP and its posterior extension, the cavum septi vergae (CSV), are seen as a continuous hypoechoic structure located in the midline. . Confirm that the fetal heart is beating. Examination of the CSPV in the sagittal section will help to elucidate the diagnosis (see Fig. . Dolichocephaly = CI <76%; 5. The index is calculated from measurement of the diameters of the skull. Microcephaly - International Society of Ultrasound in Obstetrics and