Etiology The presence of extraluminal air in an acutely ill patient with abdominal pain is an ominous sign that usually indicates perforation of a hollow viscus. Common causes include gastroduodenal peptic ulcer disease, perforation of a gastrointestinal neoplasm, acute appendicitis…
Etiology Acute appendicitis results from obstruction of the appendiceal lumen from any cause (most commonly a fecalith), leading to overdistention and superinfection and, if not treated promptly, to perforation and peritonitis. Epidemiology Acute appendicitis is a common clinical concern in…
Etiology Renal calculi are typically caused by crystallization of supersaturated stone-forming materials in the urine. Calcium, in the form of calcium oxalate, calcium phosphate, and calcium urate, is the most common stone-forming material. Uric acid is the second most common…
The focus of this chapter is on positron emission tomography (PET) and PET and computed tomography (PET/CT) applications specific to the tumors arising in the gastrointestinal tract and female gynecologic organs, excluding systemic malignancies such as lymphoma and melanoma, which…
Technical Aspects Positron emission tomography and computed tomography (PET/CT) represents the successful technical combination of multidetector computed tomography (MDCT) and PET into a single scanner. PET with the fluorine-18 (18F)–labeled glucose analog fluorodeoxyglucose (FDG) provides metabolic imaging of tissues, both…
Technical Aspects Magnetic resonance imaging (MRI) has evolved significantly since its infancy, with major advances in hardware, software, coil developments, sequence development, and contrast agents. Industry and academia continue to advance the field with continued exciting emerging technologies. The discussion…
Technical Aspects Contrast agents enhance the visualization of vascular structures as well as pathologic tissues, which appear more prominent against the background of normal tissue. Development of novel contrast agents continues to be an exciting area, with new targeted agents,…
Technical Aspects The principles of magnetization and physics allow us to create images via magnetic resonance imaging (MRI) noninvasively. In this chapter, an overview is provided on how images are created, illustrating the concepts of protons, radiofrequency (RF) excitation, T1…
All radiologic contrast media available for intravascular use depend on iodine for their radiopacity. Ideally, contrast media should be inert in every respect. But unlike other therapeutic medications, contrast media are used in larger quantities and participate in numerous physiologic…
For almost 4 decades, computed tomography (CT) has made a remarkable impact on clinical practice. The rapid advances in both CT technology and software have widened the clinical utility of CT of the abdomen and pelvis. The benefits of multidetector…