EULAR has released the first evidence-based recommendations that go beyond gout to cover the use of imaging in the clinical management of other common crystal-induced arthropathies (CiAs).

Published in the Annals of the Rheumatic Diseases (link here), the guidance comprises five overarching principles and 10 recommendations on the role of imaging modalities such as conventional radiography, ultrasound, CT and MRI. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease.

The EULAR international task force comprised rheumatologists such as Professor Nicola Dalbeth of Auckland University, as well as radiologists, and other healthcare professionals. They address the role of imaging in various aspects of patient management: making a diagnosis of CiA, monitoring inflammation and damage, predicting outcome, response to treatment, guided interventions and patient education.

The principles state that CiA can be characterised by intermittent, acute episodes of inflammation – but they can also follow a chronic disease course with or without flares.

They include the caveat that while imaging provides useful information on crystal deposition, inflammation,  and structural damage, 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.

The 10 recommendations are:

1. When performing imaging in crystal-induced arthropathies, both symptomatic areas and disease-specific target sites (ie, MTP1 joint in gout, knee and wrist in CPPD, shoulder in BCPD) should be considered.
2. In the diagnostic assessment of gout, ultrasound and DECT are both recommended imaging modalities.
3. When characteristic features of monosodium urate crystal deposition on ultrasound (ie, double contour sign or tophi) or on DECT are identified, synovial fluid analysis is not needed to confirm a diagnosis of gout.
4. In the diagnostic assessment of CPPD, conventional radiography and ultrasound (or CT if axial involvement is suspected) are recommended imaging modalities.
5. In the diagnostic assessment of BCPD, imaging is necessary; conventional radiography or ultrasound is the recommended modality.
6. In gout, ultrasound and DECT can be used to monitor crystal deposition and in case of ultrasound, also inflammation. Both modalities provide additional information on top of clinical and biochemical assessment. In case ultrasound/DECT are not available, conventional radiography can be used to assess structural damage due to gout. The decision on when to repeat imaging depends on the clinical circumstances.
7. In CPPD and BCPD, serial imaging is not recommended, unless there is an unexpected change in clinical characteristics.
8. In gout, assessing the amount of monosodium urate crystal deposition by ultrasound or DECT may be used to predict future flares.
9. If synovial fluid analysis is required in the assessment of crystal-induced arthropathies, ultrasound guidance should be used in cases where aspiration based on anatomical landmarks is challenging.
10. Showing and explaining imaging findings of CiAs to people with such conditions may help them understand their condition and improve treatment adherence in gout.

“These are the first recommendations that encompass the major forms of CiA and guide the use of common imaging modalities in this disease group in clinical practice,” the task force writing group said.

“While previous guidelines on gout and CPPD disease developed by EULAR include imaging, mainly as a diagnostic tool, the purpose of the current recommendations is to guide physicians including rheumatologists, orthopaedic surgeons, radiologists, specialists in physical medicine and rehabilitation or sports medicine as well as general practitioners in applying imaging techniques for all common CiAs and encompass the full spectrum of imaging in clinical practice, namely in diagnosis, monitoring disease activity and prediction of outcome and treatment response.”

They concluded that : “ …these practical recommendations, developed by a panel of international experts in the field, will allow clinicians, not only rheumatologists, but also orthopaedic surgeons, and commonly general practitioners, who deal with CiAs to guide the decision-making process in daily clinical practice using the most appropriate techniques, thereby improving patient care in this disease group.”