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…
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 introduced. In 1998, the quad-slice CT scanners were introduced. In…
Elastography Principle Physicians have long used the technique of palpation in the clinical setting. The underlying principle of palpation lies in the ability to feel stiffer tissue in the background of softer tissue when pressed (palpated). Ultrasound brings this concept…
Tissue Harmonic Imaging Technical Aspects Fundamental frequency is the original frequency of the acoustic beam emitted from the transducer. Harmonic wave generation is an acoustic phenomenon. Harmonic waves are integer multiples of the fundamental frequency. The second harmonic (twice the…
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 worldwide. The principal challenge with ultrasonography is greater user-dependence than…
Fluoroscopy is a type of imaging technique in which real-time movements of body organs and radiopaque contrast material are visualized. During a fluoroscopic examination, the operator or radiologist controls the functions of radiography equipment and x-ray tubes for real-time imaging…
Technical Aspects A plain abdominal radiograph must be read with a complete knowledge of the clinical situation. The patient's history and results of the physical examination and laboratory studies are always important to evaluate an acute abdomen, which may be…