Radiographics : a review publication of the Radiological Society of North America, Inc
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The temporomandibular joint (TMJ) is a common site of complaint. Clicking sounds and pain are indicators of a frequent condition called internal derangement, most often affecting females. As a general term, internal derangement describes a structural abnormality within an articulation. ⋯ The authors elucidate joint anatomy, correlating cadaveric specimen and anatomic slices with conventional and cross-sectional imaging studies. TMJ biomechanics are illustrated with schematics and animations, and an overview of imaging strategies and techniques is presented. Common abnormalities are described and illustrated, and a brief discussion of therapeutic options is included.
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Review Case Reports
Multisection CT evaluation of the reoperative cardiac surgery patient.
Development of electrocardiographically (ECG) gated multisection computed tomography (CT) has had a significant, immediate impact in cardiovascular imaging. The capabilities of this new technique have become particularly important in the preoperative assessment of the cardiac surgery patient. Cardiac surgery in the 21st century has become increasingly complex because of an aging population needing multiple procedures. ⋯ Proximity of the aorta, pulmonary artery, and native coronary arteries to the sternum is an important potential cause of morbidity and mortality, and it can be preoperatively assessed with multisection CT. The advancement of ECG gating has enabled accurate assessment of the coronary arteries, which is particularly important in the preoperative identification of congenital and acquired abnormalities. With continued advances, ECG-gated multisection CT will play an increasingly important role in the evaluation of patients with cardiovascular disease.
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Techniques of Doppler ultrasonography (US) have been available to clinicians for nearly 40 years. The Doppler effect as developed by sound propagation in human tissues and with the velocities observed for the human vasculature produces shifts in the frequencies of returning echo signals. These signals can be processed in a manner that allows the observer to determine the condition of the blood flow. ⋯ The algorithms used are complex, but increasingly powerful microelectronics have made these methods a reality at a reasonable cost. Users of Doppler US techniques must be aware of the complicated aspects of flow in the body, especially with regard to detection of disease in the human vasculature. The continuing development of US equipment aims to provide a greater understanding of hemodynamics and the relationship between blood flow and various disease processes.
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Foreign bodies are uncommon, but they are important and interesting. Foreign bodies may be ingested, inserted into a body cavity, or deposited into the body by a traumatic or iatrogenic injury. Most ingested foreign bodies pass through the gastrointestinal tract without a problem. ⋯ Metallic objects, except aluminum, are opaque, and most animal bones and all glass foreign bodies are opaque on radiographs. Most plastic and wooden foreign bodies (cactus thorns, splinters) and most fish bones are not opaque on radiographs. All patients should be thoroughly screened for foreign bodies before undergoing a magnetic resonance imaging study.
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Emergency radiologic evaluation of the pediatric cervical spine can be challenging because of the confusing appearance of synchondroses, normal anatomic variants, and injuries that are unique to children. Cervical spine injuries in children are usually seen in the upper cervical region owing to the unique biomechanics and anatomy of the pediatric cervical spine. ⋯ Familiarity with anatomic variants is also important for correct image interpretation. These variants include pseudosubluxation, absence of cervical lordosis, wedging of the C3 vertebra, widening of the predental space, prevertebral soft-tissue widening, intervertebral widening, and "pseudo-Jefferson fracture." In addition, familiarity with mechanisms of injury and appropriate imaging modalities will aid in the correct interpretation of radiologic images of the pediatric cervical spine.