Recommendations for imaging in crystal-induced arthropathies

Crystal-induced arthropathies (CiA) are caused by crystal deposits in a person's joints and associated tissues. The most frequent forms of these very common conditions be caused by three different types of crystals: monosodium urate (MSU), calcium pyrophosphate (CPP), and basic calcium phosphate (BCP).

Each of these types of crystals causes different types of CiA, with different symptoms and treatments. For example, MSU is the type of crystal responsible for gout. Imaging techniques are often used to help diagnose CiA, but choosing which to use can be challenging. The right imaging technique may depend on people's unique symptoms, stage and manifestation of their disease—but is also influenced by concerns around radiation exposure, cost, and local availability.

To help optimize clinical management, EULAR has drafted new recommendations for the use of imaging in diagnosis and management of CiA. A special taskforce—made up of rheumatologists, radiologists, methodologists, health care professionals, and patient research partners—collected evidence from four systematic literature reviews.

The new work, published in the February issue of the Annals of the Rheumatic Diseases, includes five overarching principles and 10 recommendations. The principles stress that CiA are can be characterized by intermittent, acute episodes of inflammation—but they can also follow a chronic disease course with or without flares.

Imaging provides useful information on crystal deposition, inflammation, and structural damage. However, abnormalities on imaging may not be related to clinical symptoms, and patient information including medical history, laboratory results, and physical examination are always the most relevant to be taken into account. Finally, imaging in CiA should be performed and interpreted by trained health care professionals.

The individual recommendations focus on the role of imaging in CiA diagnosis, as well as in the long-term monitoring of inflammation and damage—but also in predicting outcomes and response to treatment, guided interventions, and patient education.

Much research is still needed in CiA, but EULAR hopes these new recommendations will provide practical support for clinicians who deal with CiA, and help guide decisions around imaging techniques to use. This includes rheumatologists, orthopaedic surgeons, and general practitioners, as well as radiologists. Implementation of the recommendations should help to improve care for people with CiA.