Imaging of the Elbow

Many practices are increasingly being asked to do advanced imaging of the elbow. The elbow is a fairly complex joint and has some features that can make it challenging to image. In this issue of Seminars in Musculoskeletal Radiology we present several articles that we hope will make you more comfortable performing elbow imaging.

Radiologists are asked to image the elbow for several reasons, including chronic pain, acute trauma, and overuse or sports-related injuries. One of the difficulties with elbow imaging is that the best imaging modality often depends on the type of elbow injury and the specific question being asked. Even within a single modality, how the examination is performed may be affected by the indication. For example, radiographs are the main examination for imaging acute elbow trauma, but a radial head/capitellar view is often added in adult patients because it shows nondisplaced radial head fractures better than the standard two views.

Computed tomography (CT) is helpful for imaging complex intra-articular fractures and helps the surgeon with presurgical planning. One of the challenges with CT is that the arm is usually not aligned straight and neutral in the gantry. Because most technologists do not perform elbow CT examinations very frequently, creating two-dimensional reformatted images in the appropriate sagittal and coronal planes can be confusing.

Magnetic resonance (MR) imaging of the elbow can also be complex. Most centers do not have a dedicated elbow coil, so a decision has to be made whether to image the patient with their arm overhead or at the side. We prefer imaging the patient prone in the so-called “mighty dog” position with the extended elbow in a knee coil, but this position can be uncomfortable and lead to motion artifact. We also choose among several elbow protocols depending on what we are looking for, and therefore the image sequences are different, for example, for a capitellar osteochondritis than for a biceps tendon tear. Finally, most radiologists are less familiar with elbow MR anatomy than for other joints where the MR volume is much higher such as the knee.

Many practices are seeing an increase in musculoskeletal ultrasound (US), a cost-effective modality for performing focused examinations of the elbow tendons, ligaments, and nerves. New techniques, including US-guided platelet-rich plasma injections for lateral epicondylitis or ulnar collateral ligament partial tears, are an alternative to surgery and can reduce the athlete's time away from sport.

This issue of Seminars in Musculoskeletal Radiology contains a collection of excellent articles focusing on various aspects of elbow imaging, written by an esteemed group of experts in the field. The journal kicks off with a review of normal anatomy and variants written by Scott Tomsick and Brian Petersen from the University of Colorado. Humberto Rosas and Kenneth Lee from the University of Wisconsin then discuss acute elbow trauma, including fractures and dislocations. Hugue Ouellette, Bill Palmer, Martin Torriani, and Miriam Bredella from Harvard Medical School and Massachusetts General Hospital present MR imaging of the adult throwing athlete, including MR imaging of ulnar collateral ligament tears. Richard Kijowski and Mike Tuite review the unique features of pediatric throwing injuries. Matthew Frick and Naveen Murthy from the Mayo Clinic discuss muscle and tendon injuries, and Thomas Hash and Eric Bogner from the Hospital for Special Surgery and Weill Cornell Medical College review nerve impingement syndromes. Finally, musculoskeletal ultrasound experts Kenneth Lee and Humberto Rosas from the University of Wisconsin, and Joseph Craig from Wayne State University Medical School/Henry Ford Hospital present a tutorial on both diagnostic elbow ultrasound and using ultrasound for image-guided injections.

We hope that you enjoy reading this issue of Seminars in Musculoskeletal Radiology, and we are confident you will find the articles both interesting and educational.