Imaging Manifestations of Ankle Impingement Syndromes.

Ankle impingement syndromes encompass various pathologic entities that contribute to ankle pain with limited range of motion. Although classically described in athletes, these changes can occur in individuals of all ages, often with a history of prior ankle trauma. Ankle impingement is broadly categorized as anterolateral, anterior, posterior, anteromedial, and posteromedial, depending on the area of the ankle affected. Both osseous and soft tissue abnormalities can contribute to impingement symptoms, and a combination of these is often present. Multiple imaging modalities have been evaluated in the work-up of suspected impingement, including radiography, CT, MR imaging, and ultrasound.

Postoperative Imaging of Sarcomas.

OBJECTIVE: The purpose of this article is to assist radiologists in developing an organized, systematic approach to imaging interpretation in the care of patients who have been surgically treated for sarcoma. CONCLUSION: Postoperative imaging interpretation of sarcoma can be complex and requires an organized, systematic approach that includes review of the patient's clinical and surgical history and pretreatment images to gain context for differentiating recurrence from time-dependent posttreatment changes.

CT and MR Imaging of the Postoperative Ankle and Foot.

A variety of surgical procedures exist for repair of both traumatic and degenerative osseous and soft-tissue pathologic conditions involving the foot and ankle. It is necessary for the radiologist to be familiar with these surgical procedures, so as to assess structural integrity, evaluate for complicating features, and avoid diagnostic pitfalls. Adequate interpretation of postoperative changes often requires access to surgical documentation to evaluate not only the surgery itself but the expected timeline for resolution of normal postoperative changes versus progressive disease. Appropriate use of surgical language in radiology reports is another important skill set to hone and is instrumental in providing a high-quality report to the referring surgeons. The pathophysiology of a myriad of surgical complaints, beginning from the Achilles tendon and concluding at the plantar plate, are presented, as are their common appearances at computed tomography and magnetic resonance imaging. Commonly encountered entities include Achilles tendon tear, spastic equinus, nonspastic equinus, talar dome osteochondral defect, tarsal tunnel syndrome, plantar fasciitis, pes planovalgus, pes cavovarus, peroneal tendinosis, lateral ligament complex pathology, Morton neuroma, plantar plate tear, and metatarsophalangeal joint instability. Computer-generated three-dimensional models are included with many of the procedures to provide a more global view of the surgical anatomy. Correlation with intraoperative photographs is made when available. When appropriate, discussion of postoperative complications, including entities such as infection and failure of graft integration, is presented, although a comprehensive review of postoperative complications is beyond the scope of this article. Notably absent from the current review are some common foot and ankle procedures including hallux valgus and hammertoe corrections, as these are more often evaluated radiographically than with cross-sectional imaging. ©RSNA, 2016.

Bariatric CT Imaging: Challenges and Solutions.

The obesity epidemic in the adult and pediatric populations affects all aspects of health care, including diagnostic imaging. With the increasing prevalence of obese and morbidly obese patients, bariatric computed tomographic (CT) imaging is becoming common in day-to-day radiology practice, and a basic understanding of the unique problems that bariatric patients pose to the imaging community is crucial in any setting. Because larger patients may not fit into conventional scanners, having a CT scanner with an adequate table load limit, a large gantry aperture, a large scan field of view, and a high-power generator is a prerequisite for bariatric imaging. Iterative reconstruction methods, high tube current, and high tube voltage can reduce the image noise that is frequently seen in bariatric CT images. Truncation artifacts, cropping artifacts, and ring artifacts frequently complicate the interpretation of CT images of larger patients. If recognized, these artifacts can be easily reduced by using the proper CT equipment, scan acquisition parameters, and postprocessing options. Lastly, because of complex contrast material dynamics, contrast material-enhanced studies of bariatric patients require special attention. Understanding how the rate of injection, the scan timing, and the total mass of iodine affect vascular and parenchymal enhancement will help to optimize contrast-enhanced studies in the bariatric population. This article familiarizes the reader with the challenges that are frequently encountered at CT imaging of bariatric patients, beginning with equipment selection and ending with a review of the most commonly encountered obesity-related artifacts and the technical considerations in the acquisition of contrast-enhanced images. (©)RSNA, 2016.

Magnetic Resonance Arthrography of the Wrist and Elbow.

Magnetic resonance (MR) arthrography of the wrist and elbow is useful for detecting a variety of intra-articular pathologies. MR dictations should address whether intrinsic ligament tears of the wrist are partial-thickness or full-thickness, and involve the dorsal, membranous, and/or volar components of the ligaments. With regard to elbow soft tissue pathology, partial-thickness tears of the anterior band of the ulnar collateral ligament in overhead-throwing athletes are well evaluated with MR arthrography. MR arthrography also is helpful in staging osteochondritis dissecans of the capitellum, caused by repetitive valgus impaction injury in adolescent or young adult baseball pitchers.

Imaging of ankle replacements.

Significant innovations in the field of total ankle replacement surgery have occurred since the early disappointing experiences with first-generation devices. In recent years, total ankle arthroplasties are commonly placed in patients with end-stage ankle osteoarthrosis, supplanting ankle arthrodesis as the procedure of choice at some institutions. Careful clinical and preoperative radiographic evaluation is helpful to plan concomitant ligament release, ligament reconstruction, or osteotomy. Careful attention to radiographic signs of early hardware loosening or subsidence can prompt intervention while bone loss is still minimal, and computed tomography has an adjunct role in the evaluation of periprosthetic lucency and osteolysis.