The adnexa are composed of the ovaries, fallopian tubes, blood vessels, and supporting tissues such as the broad ligaments. The ovaries are a key component of the pelvic ultrasound examination, but it is also important to assess the surrounding tissues. The broad ligaments and fallopian tubes are not routinely identified sonographically unless they are thickened, dilated, or surrounded by fluid. Normal Ovary General Concepts The ovaries…

Ultrasound is the modality of choice for the initial imaging assessment of the female pelvis in most settings. This chapter focuses on the sonographic evaluation of the pelvis, with particular attention to the uterus. Chapter 24 covers the ultrasound examination of the ovaries and adnexa. Transabdominal and Transvaginal Ultrasound Transabdominal (TA) and transvaginal (TV) ultrasound are the most commonly used approaches for performing pelvic ultrasound. The…

Aneuploidy refers to an abnormal number of chromosomes that is not an exact multiple of the haploid number of chromosomes for the species (23 in humans). Humans normally have a diploid karyotype, with two complete chromosome sets, for a total of 46 chromosomes. Most aneuploid fetuses have either a single extra chromosome (trisomy) or a single missing chromosome (monosomy). The term aneuploidy is occasionally more broadly…

Ultrasound plays an important role in the assessment of women carrying multiple gestations. Sonography is used to evaluate the number of gestations; characterize the type of twinning; assess fetal anatomy, growth, and complications; and guide diagnostic and therapeutic interventions. As a group, multiple gestation pregnancies are at increased risk for complications (e.g., growth restriction, preterm delivery, velamentous umbilical cord insertion, and congenital anomalies) compared with singleton…

Placenta Evaluation of the placenta, umbilical cord, and cervix is an important component of the second and third trimester obstetrical ultrasound examination. Ultrasound facilitates assessment of placental location and appearance, relationship of the placenta to the cervix, umbilical cord insertion, umbilical cord coiling and vessel number, and cervical length. Normal Placenta The placenta is visualized by the end of the first trimester, when it is depicted…

The standard obstetrical ultrasound examination delineated in the ACR-ACOG-AIUM-SRU Practice Parameter for the Performance of Obstetrical Ultrasound incorporates imaging of the fetal musculoskeletal system, including the femur length (FL); the calvarium during measurement of the biparietal diameter and head circumference; and the spine, legs, and arms. When a skeletal abnormality is suspected, more detailed views and additional measurements are obtained as appropriate. Musculoskeletal Abnormalities Head and…

The standard second and third trimester fetal ultrasound examination includes evaluation of the kidneys, urinary bladder, and amniotic fluid volume. A significant abnormality of both kidneys or of the urinary bladder can result in oligohydramnios. Cyclical changes in the size of the urinary bladder suggest that at least one kidney is producing urine. The normal fetal ureters are not typically identified, although when dilated, the ureters…

The standard obstetrical ultrasound examination delineated in the ACR-ACOG-AIUM-SRU Practice Parameter for the Performance of Obstetrical Ultrasound incorporates imaging of the fetal gastrointestinal system, including the stomach (presence, size, and situs) and umbilical cord insertion site into the fetal abdomen. Abdominal circumference or average abdominal diameter should be determined at the skin line on a true transverse view at the level of the junction of the…

The practice guideline for the standard obstetrical ultra­sound examination identifies the four-chamber, left ventricular outflow tract (LVOT), and right ventricular outflow tract (RVOT) views as the minimum components in evaluation of the heart. Additional views are incorporated during dedicated fetal echocardiography and when an abnormality is sus­pected. Video clips are useful in documenting cardiac findings, facilitating assessment of cardiac motion. Doppler analysis is beneficial in detecting…

Central nervous system (CNS) abnormalities are among the most common congenital anomalies. A systematic evaluation of the head and spine should be performed to include, at a minimum, the following structures listed in the practice guideline for the standard obstetrical ultrasound examination: the lateral cerebral ventricles, the choroid plexus, the midline falx, the cavum septi pellucidi, the cerebellum, the cisterna magna, the upper lip, and the…

Ultrasound is the most widely used imaging test in early pregnancy. Confirmation of a live intrauterine pregnancy requires sonographic identification of an intrauterine gestational sac with an embryo exhibiting cardiac activity. Other disorders such as failed intrauterine pregnancy, ectopic pregnancy, gestational trophoblastic disease, pelvic inflammatory disease, and endometriosis may complicate the ultrasound examination. The ultrasound examination is best interpreted in conjunction with the result of a…

The sonographic evaluation of the fetus includes assessments that extend beyond simple evaluation of fetal anatomy. Fetal well-being can be evaluated using surveillance methods such as fetal size and growth, Doppler waveform analysis, and the biophysical profile (BPP). In combination with the clinical findings, these tests help predict when fetuses are compromised and facilitate management decisions such as the timing of delivery. Amniotic Fluid Volume General…

Practice Guidelines: Overview This chapter reviews the components of the standard obstetrical (OB) ultrasound examination, as delineated in the ACR-ACOG-AIUM-SRU Practice Parameter for the Performance of Obstetrical Ultrasound. The practice parameter was developed through the collaboration of the American College of Radiology (ACR), American College of Obstetrics and Gynecology (ACOG), American Institute of Ultrasound in Medicine (AIUM), and the Society of Radiologists in Ultrasound (SRU). The…

Tendons A number of superficial structures in the extremities are well suited for sonographic imaging. This is especially true of tendons. The interfaces between internal tendon fibers produce strong specular reflections when the sound reflects off the tendon at 90 degrees. The result is referred to as a fibrillar pattern and consists of closely spaced, parallel, bright linear reflections ( Fig. 11-1 ). When imaged at…

Thyroid Normal Anatomy The normal thyroid gland is located in the anterior inferior neck. It is divided into two lobes resting on either side of the trachea. The lobes are connected at their lower third by a thin isthmus that crosses anterior to the trachea ( Fig. 10-1 ). Immediately anterior to the thyroid are the thin strap muscles (sternohyoid, sternothyroid, and omohyoid). Lateral to the…