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Doppler Sonography of the Brain in Children

Summary of Key Points Transcranial Doppler (TCD) can be performed, with or without imaging. Four windows are available after closure of the anterior fontanelle—temporal, orbital, transforaminal, and submandibular. Physiologic variables including age, gender, hematocrit, viscosity, carbon dioxide, temperature, blood pressure, and mental or motor activity can impact flow velocity. There are several established clinical applications for TCD and many potential applications for the assessment of cerebral…

Duplex Sonography of the Neonatal and Infant Brain

Summary of Key Points Duplex sonography is a valuable, functional addition to anatomic sonography of the pediatric brain. Various quantitative metrics can be extracted from the flow curves, including peak systolic, end-diastolic flow velocity, time average maximum mean blood flow velocity, and resistive index. The quantitative markers may be influenced or altered by mechanical ventilation, patent ductus arteriosus, extracorporeal membrane oxygenation (ECMO), arteriovenous shunting, and pathologies…

Neonatal and Infant Brain Imaging

Summary of Key Points Brain ultrasound of premature infants is best performed for germinal matrix hemorrhage and hydrocephalus at 10 to 14 days of life and for cystic periventricular leukomalacia at 30 days of life. The best time to assess for white matter injury of prematurity is at term-equivalent age. Cerebellar hemorrhage is missed if mastoid views of the posterior fossa are not obtained. High-resolution images…

Cervical Ultrasound and Preterm Birth

Summary of Key Points There is a significant association between cervix length and the risk of preterm birth. A cervical length of more than 3 cm has a high negative predictive value for delivery at less than 34 weeks' gestation. The most reliable method of documenting cervical length is transvaginal ultrasound. The single most reliable parameter for cervical assessment is a short cervical length. The earlier in…

Fetal Measurements: Normal and Abnormal Fetal Growth and Assessment of Fetal Well-Being

Summary of Key Points Accurate assignment of gestational age to a pregnancy is important for several reasons, including timing of screening tests for aneuploidy, monitoring fetal growth and diagnosing growth disturbances, and scheduling of delivery by elective induction or cesarean. If a woman has more than one sonogram during her pregnancy, the pregnancy should not be redated after the first scan; instead, the gestational age at…

Fetal Hydrops

Summary of Key Points Hydrops is defined as an abnormal accumulation of interstitial fluid in at least two body cavities (pleural, peritoneal, or pericardial) or one body cavity in association with anasarca (generalized massive edema). Placentomegaly and polyhydramnios are common findings in cases of hydrops but are not needed for the diagnosis. Hydrops represents a terminal stage for many conditions, the vast majority of which are…

The Fetal Musculoskeletal System

Summary of Key Points Two-dimensional ultrasound is the primary imaging modality for the majority of musculoskeletal disorders. When a fetal musculoskeletal dysplasia is suspected on ultrasound, referral to a center with expertise may be helpful. A main role of ultrasound is to determine if the condition is likely lethal; it is important to use multiple parameters to make this determination. After delivery or pregnancy termination, a…

The Fetal Urogenital Tract

Summary of Key Points Evaluation of amniotic fluid volume (subjective assessment combined with semiquantitative methods such as maximum vertical pocket or amniotic fluid index) provides important information about some maternal and fetal conditions, as well as placental function. Sonographic findings suspicious of renal cystic disease include cysts, renal hyperechogenicity, and/or large kidneys. Whenever renal cystic disease is suspected, it is useful to perform a renal ultrasound…

The Fetal Gastrointestinal Tract and Abdominal Wall

Summary of Key Points The gastrointestinal (GI) tract and abdominal wall anomalies are diverse. Although they may occur in isolation, many are associated with syndromic or karyotype abnormalities; thus it is important to search for associated anomalies. Familiarity with normal development is needed to recognize the varying appearances during gestation of structures such as the abdominal wall with physiologic midgut herniation, the identification of the gallbladder…

The Fetal Heart

Summary of Key Points Moderate to severe congenital heart disease (CHD) occurs in approximately 6 per 1000 live births. The incidence of CHD is much higher in the fetal population, estimated to be at least 15 per 1000. The incidence of CHD is higher with positive family history, monochorionic twins, and in vitro fertilization. Most fetuses with CHD have no known risk factors. Fetal echocardiography is…

The Fetal Chest

Summary of Key Points Normal fetal lungs appear homogeneously echogenic on ultrasound surrounding the heart with a cardiothoracic ratio that remains constant through the second and third trimesters. Pulmonary hypoplasia can be primary or secondary and unilateral or bilateral. Congenital pulmonary airway malformations (CPAMs) are a spectrum of disorders that include bronchopulmonary malformation, hybrid lesions (CPAM and sequestration), and congenital lobar overinflation/bronchial atresia. A large fetal…

The Fetal Spine

Summary of Key Points Neural tube defects (NTDs) are a common congenital anomaly with clinically important associated morbidity and mortality rates. Most open NTDs will have associated intracranial abnormalities, most commonly Chiari II malformation, detected by sonography. Although much less common, closed NTDs are less likely to have associated intracranial abnormalities and require careful examination of the spine for detection. Other spinal abnormalities such as scoliosis,…

The Fetal Brain

Summary of Key Points Protocol-based ultrasound carefully performed by a knowledgeable and experienced examiner following established guidelines is very sensitive in evaluating the central nervous system (CNS). Ventriculomegaly can be due to many underlying conditions, including obstruction, destruction, and dysmorphism, or a combination. In cases of brain abnormalities in which additional morphologic or functional information is needed beyond that available with ultrasound, magnetic resonance imaging can…

The Fetal Face and Neck

Summary Key Points Ear and eye anomalies often accompany abnormalities of the skull and face. Abnormalities of fetal head size and shape may be associated with various syndromes and chromosomal anomalies. Hypoplastic or absent nasal bone may be seen in fetuses with trisomy 21. Cleft lip may be associated with cleft palate, and detailed description of the cleft is important to accurately counsel parents, predict postnatal…

Multifetal Pregnancy

Summary of Key Points Multifetal pregnancies have higher rates of perinatal morbidity and mortality than singletons. Chorionicity is the major determining feature for the inherent unique complications faced by multiple gestations. Fetal growth differences and congenital malformations are increased in all types of multiple gestations. In monochorionic twins with a single demise, there is a high risk of severe cerebral and other injuries in the survivor.…

Chromosomal Abnormalities

Summary of Key Points Screening for aneuploidy using the nuchal translucency (NT) measurement should be performed by a credentialed provider participating in an ongoing quality-monitoring program. In chromosomally normal fetuses with an increased NT, normal anatomy and no identifiable genetic syndromes, there does not appear to be a higher risk of developmental delay than in the general population. A “marker” identified during a second-trimester sonogram should…

The First Trimester

Summary of Key Points First-trimester development follows a predictable pattern on first-trimester ultrasound. Some ultrasound findings are definitive for early pregnancy failure, whereas others are suggestive and require follow-up. Ultrasound is vital in the diagnosis of ectopic pregnancy in typical and atypical locations. Gestational trophoblastic disease is composed of four entities, and ultrasound is helpful in their diagnosis and management. The first trimester of pregnancy is…

Bioeffects and Safety of Ultrasound in Obstetrics

Summary of Key Points Obstetric ultrasound should only be performed with a clear indication, with calibrated machines, and by proficient professionals. Know the specific machine being used (what causes increase in output power). Keep the examination as short as possible and use the lowest possible output power but compatible with arriving at the correct diagnosis (as low as reasonably achievable [ALARA] principle). Keep track of the…

Overview of Obstetric Imaging

Summary of Key Points Ultrasound allows for accurate prediction of gestational age. The appropriate training and skills are necessary for safely performing and accurately interpreting obstetric ultrasound There are many options for screening pregnant women, most of which include ultrasound. Routine obstetric ultrasound has specific recommended views that allow for depiction of many, but not all, fetal anomalies. Three-dimensional ultrasound, fetal Doppler examinations, and fetal magnetic…