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…

Bowel Sonography is not routinely used as a primary tool for evaluation of the bowel. Nevertheless, there are many patients with nonspecific bowel-related complaints who are initially scanned with ultrasound, and in these patients attention to the intestinal structures can often identify the abnormality and direct the workup in the appropriate direction. Therefore a quick survey of the bowel is a useful undertaking in patients undergoing…

Anatomy The spleen is an intraperitoneal organ that occupies the superior, posterior, and lateral aspects of the left upper quadrant. It is normally in continuity with the diaphragm posteriorly, laterally, and superiorly. It contacts the kidney and splenic flexure inferiorly and the stomach and tail of the pancreas medially. The splenic artery arises from the celiac axis and travels along the posterior superior aspect of the…

Anatomy The pancreas is a retroperitoneal organ that develops from a large dorsal embryologic anlage and a smaller ventral anlage. The dorsal pancreatic anlage communicates by means of its central duct with the duodenum and the ventral anlage communicates with the biliary tract. During embryologic development these pancreatic anlagen rotate with the intestinal structures and ultimately fuse together so that the dorsal pancreas is located anterior…

Scrotum Sonography is the primary method used to image the scrotum. Patients undergoing sonography of the scrotum are usually examined in the supine position. A towel can be draped between the thighs to help support the scrotum. Warm gel should always be used because cold gel can elicit a cremasteric response and make it very difficult to perform a thorough examination. The anatomy relevant to the…

Anatomy Unlike the other solid abdominal organs, the kidneys have a complex internal architecture that is responsible for pro­ducing a variety of internal echogenicities. The central renal sinus is composed of fibrofatty tissue that appears echogenic on sonograms. The renal vessels and collecting system are occasionally seen as thin, anechoic, fluid-containing structures located within the echogenic tissues of the renal sinus. The lymphatics also pass through…

Anatomy The bile ducts are generally divided into the intrahepatic and extrahepatic portions. The intrahepatic ducts run in the portal triads with the portal veins and hepatic arteries. The right and left hepatic ducts are anterior to the adjacent portal veins. The peripheral intrahepatic ducts run parallel and adjacent to the hepatic arteries and portal veins, but the relative anterior and posterior relationship of the three…