Advanced Imaging of Arthritis

Imaging has always had an important role to play in the diagnosis and management of both inflammatory arthritis and osteoarthritis. In recent years, advanced imaging techniques, in particular MRI and ultrasound, have been applied to the investigation of these conditions. This issue of Seminars in Musculoskeletal Radiology examines these techniques and the role they play. It is a pleasure to be able to highlight the field of MRI and ultrasound in imaging arthritis because many publications in this field occur in the rheumatologic literature and may not be familiar to radiologists. Contributors to this issue include both radiologists and rheumatologists, which in itself emphasizes the close relationship between the two fields.

Changes in the management of inflammatory arthritis has been one of the driving forces behind the increased use of advanced imaging techniques in inflammatory arthritis, in particular the growing use of powerful biological therapies early in the disease process. The first article in this issue is by Lesley Kay, a rheumatologist who offers an illuminating personal perspective on the changes in the way rheumatology is practiced today, with particular reference to rheumatoid arthritis.

This sets the scene for the next group of articles that look specifically at ultrasound and MRI in the field of inflammatory arthritis. We contributed an article on the technique and role of ultrasound in this field coauthored by radiologists and a rheumatologist with a particular interest in the use of musculoskeletal ultrasound. A companion article by Richard Hodgson and colleagues reviews the technical aspects of MRI imaging of peripheral arthritis. It includes a discussion of protocols and pitfalls and also introduces some of the novel techniques now being applied to MRI of inflammatory arthritis. Recent years have seen rheumatologic applications for whole-body MRI emerge, and the current applications for this technique are reviewed in an article by Sabine Weckbach from Munich, who has significant expertise in this field.

MRI has now found a mainstream role in the diagnosis and management of axial disease in spondyloarthritis and is ideally suited for this purpose. However, there are several challenges for the radiologist both in technique and interpretation. The Edmonton group in Canada under the direction of Robert Lambert has been at the forefront of this field. They have contributed an excellent article addressing these issues.

Mikkel Østergaard, a rheumatologist practicing in Denmark, has a particular interest in imaging techniques in rheumatology. In his review he pulls together the themes of the preceding articles, highlighting the position of the different imaging modalities in the diagnostic pathway from a rheumatologist's perspective and the evidence for their use.

The next two articles look at advanced imaging techniques in osteoarthritis. Ultrasound and MRI remain predominantly research tools in this field, but they have contributed considerably to providing information about the nature of osteoarthritis and its causes. This is an area reviewed by David Hunter and colleagues from Sydney, again providing input from both radiology and rheumatology coauthors. Three radiologists from Boston, Massachusetts, and Augsburg, Germany, with particular expertise in MRI of osteoarthritis and its quantification, contributed the final article. There has been recent interest in how osteoarthritis might be defined on MRI, which these authors address along with the techniques and pitfalls for imaging osteoarthritis with MRI.

We would like to thank the editors for giving us the opportunity to serve as guest editors. We also extend our thanks and appreciation to all the authors in this issue for their excellent contributions.