Anatomy The liver is the largest solid organ in the normal abdomen, occupying much of the right upper quadrant. The liver is divided into eight functional segments based on vascular and biliary anatomy. The middle hepatic vein marks the division between the right and left hemiliver. The right hepatic vein divides the right hemiliver into an anterior and posterior section. The left hepatic vein divides the…
Anatomy The gallbladder is a long oval-shaped organ that is positioned beneath the liver immediately adjacent to the interlobar fissure ( Fig. 2-1 ). The fissure can be a useful landmark for locating small contracted gallbladders or gallbladders that are completely filled with stones. Likewise, the gallbladder can be used as a landmark for identifying the junction between the left and right hemiliver. The upper limit…
Ultrasonography has long been a valuable method of imaging the body with several distinct advantages over other modalities. One of the most important advantages is its lack of ionizing radiation. Sonography can provide clinically useful information without clinically significant biologic effects on the patient. This is critical in obstetrics, very important in the pediatric patient population, and becoming increasingly important in adults due to radiation dose…
How It Works A radioactive isotope (radioisotope) is an unstable form of an element that emits radiation from its nucleus as it decays. Eventually the end product is a stable, nonradioactive isotope of another element. Radioisotopes can be produced artificially (most frequently by neutron enrichment in a nuclear reactor or in a cyclotron) or may occur naturally . Naturally occurring radioisotopes include uranium and thorium. The…
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Ionizing Radiation in Radiology In the modalities of conventional radiography, CT and fluoroscopy, images are produced using ionizing radiation. Besides producing the image, this radiation can also have harmful effects if used in excess. All health care providers should understand the risks associated with radiation exposure and limit exposure when possible. Three Fates of Radiation During an Imaging Procedure Transmitted radiation is the radiation that passes…
Recognizing Adult Heart Disease From the Frontal Chest Radiograph This is a system for diagnosing cardiac disease in adults by asking a series of questions in a set fashion , the answers to which are certain fundamental observations made from the frontal chest radiograph alone. This system is PG-13. Infant hearts do not display many of the recognizable contours discussed here, so cardiovascular evaluation in infants…
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Breast imaging is the field of radiology dedicated to the detection and management of breast abnormalities, especially breast cancer. Breast cancer is second only to skin cancer as the most common cancer diagnosed in women and is the second leading cause of cancer death in women, behind lung cancer. Medicine increasingly relies on assessments of efficacy in the diagnosis and management of disease. Toward that end,…
Interventional radiology (IR), also known as vascular and interventional radiology (VIR), is a medical specialty that utilizes image-guidance (i.e., fluoroscopy, ultrasound, computed tomography [CT], or magnetic resonance imaging [MRI]) to perform minimally invasive diagnostic or therapeutic procedures. Interventional radiologists perform a wide variety of procedures that can be characterized as vascular or nonvascular and subdivided into the vascular distribution or organ system for the procedure being…
Children differ physiologically from adults and are susceptible to abnormalities in development and maturation not seen in adults. They differ in anatomy (e.g., the thymus) and are more susceptible to the harmful effects of ionizing radiation. This chapter highlights some of the more common pediatric diseases associated with imaging findings. Diseases Discussed in This Chapter Newborn respiratory distress Transient tachypnea of the newborn Neonatal respiratory distress…
Advances in neuroimaging have had a remarkable impact on the diagnosis and treatment of neurologic diseases ranging from earlier detection and treatment of stroke to a more timely diagnosis of dementia, from the rapid detection and treatment of cerebral aneurysms to the ability to diagnose multiple sclerosis after a single attack. Both CT and MRI are utilized for studying the brain and spinal cord, but MRI…
Abdominal Trauma The role of advanced imaging techniques deserves special mention in abdominal trauma. Radiology has made a significant impact on the lives of traumatized patients by distinguishing those patients who can be managed conservatively from those who need surgical or other interventions and by helping to direct the most appropriate intervention for those who need it. Box 26.1 Contrast Reactions and Renal Failure Intravenous contrast…
Trauma is the leading cause of death, hospitalization, and disability in Americans from the age of 1 year through age 45. The major imaging findings of chest trauma will be discussed in this chapter. Table 25.1 summarizes some of the traumatic injuries that are discussed in other chapters. TABLE 25.1 Other Manifestations of Trauma Injury Discussed in Pleural effusion/hemothorax Chapter 8 Aspiration Chapter 9 Fractures and…
Recognizing an Acute Fracture It seems like everyone is fascinated by an x-ray of a broken bone. Fractures are a favorite among those learning radiology, perhaps because of how common and seemingly straightforward they are. In this chapter we tell you how to recognize a fracture, describe it, name it, and avoid overlooking it. A fracture is described as a disruption in the continuity of all…
Magnetic resonance imaging , with its superior soft-tissue differentiation, is the study of choice for most diseases of the spine because of its ability to visualize and detect abnormalities in soft tissues, such as bone marrow, the spinal cord, and the intervertebral disks; its ability to display images in any plane; and the lack of exposure to radiation. But MRI has its limitations. The study remains…
Conventional Radiography, CT, and MRI in Bone Imaging Most examinations of bone start with conventional radiographs obtained with at least two views exposed at a 90-degree angle to each other (called orthogonal views ) so as to localize abnormalities better and to visualize as much of the bone as possible ( Fig. 22.1 ). Still, conventional radiographs cannot visualize the entire circumference of a tubular bone…
How MRI Works Because magnetic resonance imaging (MRI) uses the molecular composition of tissues, especially water, it is particularly sensitive to detecting soft-tissue abnormalities in much higher detail than CT scans, although the two imaging modalities are complementary. MRI produces no ionizing radiation, which is an advantage compared with CT, but MRI examinations take longer to acquire and are more expensive than CT scans. MRI uses…
In this chapter, we will discuss some additional applications of ultrasound, including vascular ultrasound, pediatric applications of ultrasound, and point-of-care ultrasound. Vascular Ultrasound Vascular ultrasound uses both B-mode (gray-scale) ultrasound and Doppler ultrasonography— a combination called duplex sonography —to display the morphologic appearance of vessels while recording the flow direction and velocity of moving blood in those vessels. Duplex sonography ensures that the direction and flow…