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The Pancreas

Summary of Key Points Knowledge of a few key scanning techniques will optimize imaging of the entire pancreas. Understanding of the embryologic development, normal anatomy, and anatomic variants of the pancreas aids in detection and characterization of disease. Ultrasound plays an important role in assessment of acute and chronic pancreatitis, allowing for detection of gallstones, bile duct dilation, and guiding aspiration and drainage when needed. Computed…

The Biliary Tree and Gallbladder

Summary of Key Points Ultrasound should be the first imaging modality used in the evaluation of the patients with potential disease of the biliary tree. Awareness of various scanning techniques and use of harmonic and compound imaging improve visualization of various diseases affecting the biliary tree. Stones in the intrahepatic and extrahepatic biliary tree can be easily overlooked; familiarity with their appearance and a high index…

The Spleen

Summary of Key Points Ultrasound can be used to diagnose or exclude splenic abnormalities, but computed tomography and/or magnetic resonance imaging may be needed in indeterminate cases. There is no single upper limit of normal for spleen size, since size varies with patient sex, weight, and height. Use of a strict 12-cm upper limit of normal for the spleen will lead to overdiagnosis of splenomegaly. The…

The Liver

Summary of Key Points The liver is an ideal organ for sonographic evaluation based on its large size, homogeneous parenchyma, and location high in the abdomen with access provided from both a subcostal and an intercostal approach. Standard ultrasound with real-time gray-scale morphologic assessment and Doppler evaluation of the liver vasculature is augmented by newer techniques of contrast-enhanced ultrasound and elastography. Fatty liver is considered an…

Contrast Agents for Ultrasound

Summary of Key Points After more than 20 years of development and a somewhat hesitant start, microbubbles have finally come of age as a contrast agent for ultrasound. The principal requirements for an ultrasound contrast agent are that it should be easily introducible into the vascular system, be stable for the duration of the diagnostic examination, have low toxicity, and modify one or more acoustic properties…

Biologic Effects and Safety

Summary of Key Points Clinical ultrasound has been found to be an effective imaging modality with an excellent safety profile when used appropriately. Ultrasound can produce physical effects, which should be understood as part of the benefit-versus-risk assessment as with any medical procedure. The thermal index (TI) and mechanical index (MI) provide feedback to the user and should be minimized while obtaining the requisite medical benefit…

Physics of Ultrasound

Summary of Key Points Quality imaging requires an understanding of basic acoustic principles. Image interpretation requires recognition and understanding of common artifacts. Special modes of operation, including harmonic imaging, compounding, elastography, and Doppler, expand the capabilities of conventional gray-scale imaging. Knowledge of mechanical and thermal bioeffects of ultrasound is necessary for prudent use. High-intensity focused ultrasound has potential therapeutic applications. All diagnostic ultrasound applications are based…

Classic Signs and Findings in Musculoskeletal Radiology

Condition Absent in posterior dislocation of the shoulder Name of Sign Half-moon sign Description The medial humeral head normally overlaps the posterior glenoid rim on a standard anteroposterior (AP) shoulder radiograph in external rotation, an appearance resembling a half-moon. When a patient has a posterior shoulder dislocation, there is often no overlap (rim sign). Reference Schild H, Muller HA, Klose K: The halfmoon sign. Australas Radiol…

Diseases with Names

A few examples of these are shown here, and the full listing is available online. A Aarskog Syndrome Aarskog syndrome is an extremely rare genetic disorder marked by stunted growth that may not become obvious until the child is about 3 years of age, and also by broad facial abnormalities, musculoskeletal and genital anomalies, and mild mental retardation. Aarskog D. A familial syndrome of short stature…

Fractures with Names

Abstract In general, an eponym can be considered the proper name of the first person or persons describing an anatomical structure, a classification system, a disease, a fracture, a surgical technique, an instrument, and so on. It is believed that the use of eponyms tends to cause confusion and should be avoided. A clear example of this is the Colles fracture, a name applied to many…

Orthopedic Devices

Abstract Plates and Screws Blade Plate and Screws Indications: subtrochanteric and supracondylar femoral fractures ( Fig. 1 ) as well as femoral osteotomies Angled plate configuration Reconstruction Plate Indications: pelvic ( Fig. 2 ) and calcaneal ( Fig. 3 ) fractures Malleable plate that can be appropriately sized and configured for stabilization of fractures with complex bony surfaces Buttress Plate and Screws Also known as periarticular…

Measurements Most Frequently Used in Orthopedic Imaging

Abstract Measuring distances and angles is an important task in daily orthopedic practice. Radiologic measurements are the key to diagnosing certain injuries and defining their prognosis, and they often have a decisive impact on treatment. Radiologic measurements can be used in orthopedics to diagnose certain injuries or to assess progression in some diseases, in particular chronic ones. After a fracture, measurements are useful to quantify displacement…

Ultrasound Procedures

Abstract Indications Ultrasound guidance is the optimum technique for placing needles into soft tissue structures when they are well visualized using this imaging method. In broad terms, ultrasound is used for injections and biopsies, but both the structures to be punctured and those that must be avoided should be visible. Ultrasound imaging has particularly good resolution within the first 5 to 10 cm of soft tissue. Sound…

Percutaneous Intradiskal Therapies

Abstract Percutaneous intradiskal therapies are currently used in the treatment of two distinct medical problems: chronic low back pain and the herniated nucleus pulposus–related radicular syndrome (sciatica). Both conditions lead to substantial medical and economic losses, with low back pain being the major cause of disability in the United States for patients less than 45 years of age. The prevalence of low back pain in the…

Vertebroplasty and Kyphoplasty

Abstract Vertebroplasty was first described by Herve Deramond and his colleagues from Amiens, France, in 1987. They were faced with a patient with an aggressive, destructive, but otherwise benign hemangioma of a C2 vertebral body. There seemed to be no surgical option, and they elected to perform an experimental procedure placing a needle via a transoral route and injecting methylmethacrylate under image-intensifier control. It became apparent…

Discography

Abstract Indications Discography is a diagnostic tool for the diagnosis of cervical, thoracic, or lumbar radicular or referral pain. Although the use of discography as the first-line diagnostic examination is not indicated, it is usually recommended when conservative treatment or noninvasive diagnostic tools fail to establish a reasonable outcome. It is reserved for suspicious abnormalities seen on other tests and when severe symptoms are propelling the…

Spinal Injections

Indications Epidural pain injections are useful in the patient with a wide variety of disorders that could generate back pain, including extruded and bulging disks; foraminal and lateral recess stenoses with nerve compression from facet osteoarthritis, capsular hypertrophy, synovial cyst formation, and scar production; spondylolysis with spondylolisthesis; and congenital and/or acquired central canal stenosis. In addition to these mechanical abnormalities, chemical irritation of the nerves can…

Tumor Ablation

Techniques Chemical Ablation with Sclerosing Agents Sclerosing agents act by diffusion into cells and cause immediate dehydration of cytoplasm with subsequent necrosis followed by fibrosis. By entering into the circulation, these agents induce necrosis of endothelial cells and platelet aggregation, causing thrombosis. Radiofrequency Ablation In radiofrequency ablation (RFA), an RF probe is positioned in the patient. The probe is usually monopolar, and large grounding pads are…

Percutaneous Biopsy of the Spine

Percutaneous biopsy of the spine is an effective, reliable, safe, and rapid procedure that can be easily performed in comparison with open biopsy. It may be performed at a lower cost than surgery. This procedure has become routine and is indicated in many cases. Indications Bone Metastases A suspicion of bone metastasis represents the principal indication for percutaneous biopsy of the spine. It is especially helpful…

Percutaneous Biopsy of the Appendicular Skeleton

Percutaneous biopsy of the appendicular skeletal lesion is a minimally invasive, safe, and inexpensive procedure compared with open biopsy. Therefore, this procedure is indicated in many cases. Indications Bone Metastases A suspicion of bone metastasis is the main indication for percutaneous biopsy of skeletal lesions. This procedure is particularly helpful in patients with no known primary bone tumor who present with multiple lesions consistent with metastases…