Gastric Stromal Tumors
Stromal tumors of the stomach are rare tumors that arise from the mesenchyma, the connective tissue and blood vessels that support an organ. The parenchyma, on the other hand, represents…
Ureteral and Kidney Stones
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…
Esophageal Imaging
Technical Aspects Anatomy The esophagus extends from the pharynx to the cardiac portion of the stomach. The length of the esophagus is approximately 25 to 30 cm, and it has cervical,…
Acute Gastrointestinal Bleeding
Etiology The causes of upper gastrointestinal bleeding include esophageal or gastric varices, Mallory-Weiss tears, gastritis, and gastric or duodenal ulcers. Common causes of lower gastrointestinal tract bleeding include colonic diverticulosis,…
Positron Emission Tomography and Computed Tomography Technique and Instrumentation
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…
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…
Advanced Magnetic Resonance Imaging Applications
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…
Principles of Computed Tomography Physics, Instrumentation, and Radiation Safety
Computed Tomography Physics In the past decade, computed tomography (CT) has undergone tremendous technical advances. In 1992, the first dual-slice CT scanner (CT Twin, formerly Elscint Technologies, Haifa, Israel) was…
Principles of Magnetic Resonance Imaging Physics
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…
Abdominal Ultrasound Imaging: Anatomy, Physics, Instrumentation, and Technique
Ultrasonography is low in cost, noninvasive, and highly portable, and it allows real-time imaging in multiple operator-controlled planes. As a result, it is the most widely used cross-sectional imaging modality…
