2023 EULAR recommendations on imaging in diagnosis and management of crystal-induced arthropathies in clinical practice.

OBJECTIVE: To formulate evidence-based recommendations and overarching principles on the use of imaging in the clinical management of crystal-induced arthropathies (CiAs). METHODS: An international task force of 25 rheumatologists, radiologists, methodologists, healthcare professionals and patient research partners from 11 countries was formed according to the EULAR standard operating procedures. Fourteen key questions on the role of imaging in the most common forms of CiA were generated. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease. Imaging modalities included conventional radiography, ultrasound, CT and MRI. Experts applied research evidence obtained from four systematic literature reviews using MEDLINE, EMBASE and CENTRAL. Task force members provided level of agreement (LoA) anonymously by using a Numerical Rating Scale from 0 to 10. RESULTS: Five overarching principles and 10 recommendations were developed encompassing 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. Overall, the LoA for the recommendations was high (8.46-9.92). CONCLUSIONS: 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.

Ultrasound imaging in crystal arthropathies: a pictorial review.

OBJECTIVE: The prevalence of crystal arthropathies in the general population is rising. The purpose of this pictorial study is to describe the sonographic elements of the most prevalent crystal arthropathies by emphasizing particular sonographic findings using illustrative images and cases while considering technical details and common pitfalls. METHODS: Using established recommendations, specialists in the fields of sonography and crystal arthropathies agreed by consensus on the unique ultrasound signs associated with each of the conditions. RESULTS: Gout, calcium pyrophosphate deposition arthropathy, and hydroxyapatite arthropathy are the three most prevalent crystal arthropathies. Today's high-resolution sonography enables reliable evaluation of the underlying crystal deposits, post-inflammatory changes, and a precise description of joint inflammation. CONCLUSIONS: High-prevalence crystal arthropathies are reliably detectable by ultrasound with current ultrasound equipment. It is necessary to have extensive ultrasound training, know specific sonographic findings, and understand all possible differential diagnoses for disorders affecting the musculoskeletal system.

Crystal arthropathies and osteoarthritis-where is the link?

Osteoarthritis (OA) is one of the leading causes of disability worldwide. As our understanding of OA progressively has moved from a purely mechanical "wear and tear" concept toward a complex multi-tissue condition in which inflammation plays a central role, the possible role of crystal-induced inflammation in OA incidence and progression may be relevant. In addition to gout, which affects 4% of the US population, basic calcium phosphate and calcium pyrophosphate deposition both may induce joint inflammation and may play a role in pain in OA. This narrative review article discusses the possible mechanisms underlying the associations between crystal-induced arthropathies and OA, and the important implications of these for clinical practice and future research.

Imaging of Crystal Disorders:: Calcium Pyrophosphate Dihydrate Crystal Deposition Disease, Calcium Hydroxyapatite Crystal Deposition Disease and Gout Pathophysiology, Imaging, and Diagnosis.

Crystal arthropathies are a group of joint disorders due to deposition of crystals in and around joints that lead to joint destruction and soft tissue masses. Clinical presentation is variable and diagnosis might be challenging. In this article the pathophysiology is addressed, the preferred deposition of crystal arthropathies and imaging findings. Case studies of calcium pyrophosphate dihydrate crystal deposition disease, hydroxyapatite crystal deposition disease, and gout are shown. Guidelines for the use of dual-energy computed tomography are given to enable the diagnosis and follow-up of gout.

Imaging of crystalline arthropathy in 2020.

Crystal-related arthropathies are the result of crystal deposition in joint and periarticular soft tissues. Identification of urate crystals is mandatory to distinguish gout from other crystalline arthropathies, including calcium pyrophosphate dihydrate and basic calcium phosphate crystal deposition diseases. ACR/EULAR classification criteria for gout included dual-energy computed tomography and ultrasound with equal impact to the final score. Different diagnostic strengths of these imaging modalities depend on disease duration and scanned anatomic site. While ultrasound has been indicated as the first-choice imaging technique, especially in the early stages of the disease, dual-energy computed tomography has shown to be highly specific, allowing the detection of crystal deposits in anatomic sites not accessible by ultrasound, such as the spine. At the spinal level, MRI findings are usually nonspecific. Finally, there is preliminary evidence that at the knee, dual-energy computed tomography may discriminate calcium pyrophosphate dihydrate from basic calcium phosphate crystal deposits.

Utility of Ultrasound and Dual Energy CT in Crystal Disease Diagnosis and Management.

PURPOSE OF REVIEW: The objective of this review is to critically discuss the latest evidence on the use of ultrasound and dual energy computed tomography (DECT) for the assessment of microcrystalline arthritis. RECENT FINDINGS: Both techniques have been included in the classification and diagnostic criteria for gout, while only ultrasound appears in the diagnostic recommendations for CPPD. Regarding the management of the diseases, there is encouraging evidence for the use of both techniques for the follow-up of gout patients, while very few or null data are available for CPPD. Ultrasound has been adequately validated for the diagnosis of CPPD, while some issues have still to be clarified regarding gout. DECT has also demonstrated to be accurate for gout diagnosis, but very few data are available regarding CPPD. Future research should aim to improve the reliability of both techniques and to create scoring systems for a more accurate follow-up of patients.

Radiological features of crystal-induced arthropathy associated with hereditary hemochromatosis with homozygous C282Y mutation. / Características radiológicas de la artropatía microcristalina asociada a hemocromatosis hereditaria con mutación homocigota C282Y.

I present a clinical case of a 64-year-old male patient with hemochromatosis (homozygous C282Y) and crystal induced arthropathy showing the most common radiological features found in this metabolic disorder and the differences that may exist when compared to other primary degenerative processes or other inflammatory pathologies.

Dual-energy CT in the differentiation of crystal depositions of the wrist: does it have added value?

OBJECTIVES: To evaluate the ability of dual-energy computed tomography (DECT) to improve diagnostic discrimination between gout and other crystal arthropathies such as calcium pyrophosphate deposition disease (CPPD) of the wrist in a clinical patient population. MATERIALS AND METHODS: This retrospective case-control study included 29 patients with either gout (case group; n = 9) or CPPD (control group; n = 20) who underwent DECT of the wrist for clinically suspected crystal arthropathy. Color-coded urate and enhanced calcium as well as virtual 120 kVe blended images were reconstructed from the DECT datasets. Two independent and blinded readers evaluated each reconstructed dataset for the presence of depositions in 17 predefined regions. Additionally, a global diagnosis was made first for 120 kVe images only, based solely on morphologic criteria, and subsequently for all reconstructed images. RESULTS: Sensitivity for the global diagnosis of gout was 1.0 (95% CI 0.63-1) for both DECT and 120 kVe images with specificities of 0.70 (95% CI 0.46-0.87) for DECT and 0.80 (95% CI 0.56-0.93) for 120 kVe images. Color-coded DECT images did not detect more depositions than monochrome standard CT images. CONCLUSION: Discrimination of crystal arthropathies of the wrist is limited using DECT and primarily relying on color-coded images. Evaluation of morphologic criteria on standard CT images is essential for accurate diagnosis.

Clinical Utility of Multi-Energy Spectral Photon-Counting Computed Tomography in Crystal Arthritis.

OBJECTIVE: To determine whether novel multi-energy spectral photon-counting computed tomography (SPCCT) imaging can detect and differentiate between monosodium urate (MSU), calcium pyrophosphate (CPP), and hydroxyapatite (HA) crystal deposits ex vivo. METHODS: A finger with a subcutaneous gouty tophus and a calcified knee meniscus excised at the time of surgery were obtained. The finger was imaged using plain x-ray, dual-energy CT (DECT), and multi-energy SPCCT. Plain x-ray and multi-energy SPCCT images of the meniscus were acquired. For validation purposes, samples of the crystals were obtained from the tophus and meniscus, and examined by polarized light microscopy and/or x-ray diffraction. As further validation, synthetic crystal suspensions of MSU, CPP, and HA were scanned using multi-energy SPCCT. RESULTS: Plain x-ray of the gouty finger revealed bone erosions with overhanging edges. DECT and multi-energy SPCCT both showed MSU crystal deposits; SPCCT was able to show finer detail. Plain x-ray of the calcified meniscus showed chondrocalcinosis consistent with CPP, while SPCCT showed and differentiated CPP and HA. CONCLUSION: Multi-energy SPCCT can not only detect, differentiate, and quantify MSU crystal deposits in a gouty finger ex vivo, but also specifically detect, identify, and quantify CPP within an osteoarthritic meniscus, and distinguish them from HA crystal deposits. There is potential for multi-energy SPCCT to become useful in the diagnosis of crystal arthropathies.

Efficacy of anakinra in acute hydroxyapatite calcification-induced joint pain: A retrospective study of 23 cases.

OBJECTIVE: Hydroxyapatite (HA) crystal calcifications in or around the joint can induce acute flares with severe pain. A previous pilot study suggested that the interleukin-1ß (IL-1ß) inhibitor anakinra was effective. The goal of this observational study was to confirm these results in a larger set of patients and to report on the long-term follow-up. METHODS: Flare was defined as acute pain for<10 days. Calcification in or around a joint (rotator cuff: 15/23 patients) was confirmed by conventional radiography and/or ultrasonography (US). Anakinra 100mg daily was administered subcutaneously for 1 to 3 consecutive days. Clinical data collected before the injection and on days 3 and 21 included pain score on a visual analog scale (VAS, 0-10cm) and C-reactive protein (CRP) level. When available, US baseline and follow-up findings were compared. Long-term follow-up data were collected from patient charts and/or after a phone call. RESULTS: 23 patients (15 males, mean [SD] age 58 [11] years) were included. Baseline mean (SD) VAS pain was 7.7 (1) cm and CRP level was elevated in half of the patients. After therapy, mean (SD) VAS pain score decreased rapidly in the first 3 days to 1.6 (1.4) cm (P<0.001) and remained stable for 3 weeks at 1.8 (2.1) cm. US assessment revealed decreased Doppler intensity but no significant change in size of calcifications. No significant side effects were noted. After long-term follow-up (median duration 24 months), half of the patients still had some chronic pain, but only 4 experienced acute relapse. CONCLUSION: This study suggests that IL-1ß inhibition may be an efficient therapeutic approach for acute HA flare, with a good safety profile.

Subclinical crystal arthropathy: a silent contributor to inflammation and functional disability in knees with osteoarthritis-an ultrasound study.

PURPOSE: This study aimed at investigating the prevalence of crystal deposits with knee osteoarthritis (OA) by ultrasonography and measure the inflammatory burden associated with crystal deposits in OA using WOMAC score. METHODS: Adult patients with primary knee OA diagnosed according to the American College of Rheumatology criteria were included. Participants were subjected to history taking, clinical examination, knee US, and plain radiography. The EULAR and the OMERACT ultrasonography definitions and scanning protocols were used. RESULTS: Fifty-three patients (44 females, 9 males) were enrolled. Mean values were 53.5 years ± 8.3 SD for age and 42.5 months ± 49.5 SD for disease duration. Crystals were detected by US in 73/106 knees (68.9%). Plain radiography revealed chondrocalcinosis in three patients. Mean values for WOMAC pain, stiffness, and disability scores were 14.38 ± 3.99, 4.93 ± 2.06, and 49.61 ± 13.06, respectively, with insignificant differences relative to presence of crystals (P > 0.05). Regression analysis revealed a 4.1-fold increase in the incidence of sonographic crystals with bursitis (OR = 4.13, CI = 1.5-11.2, p = 0.01) and a 3.2-fold increase in the incidence of sonographic crystals with synovial effusion (OR = 3.16, CI = 1.34-7.44, p = 0.01). CONCLUSION: Subclinical crystals were detected in a considerable number of patients with primary knee OA. The incidence of crystal deposits was significantly higher in patients with bursitis and knee effusion.

Advanced Imaging in the Diagnosis of Gout and Other Crystal Arthropathies.

In recent years significant advances have been made in imaging techniques. Dual-energy computed tomography has revolutionized the ability to detect and quantify gout. The key ultrasound features of gout have been defined. Magnetic resonance imaging is an excellent modality for demonstrating the extent and severity of crystal arthropathies, but the findings may be nonspecific. This article summarizes the use of advanced imaging techniques in the diagnosis and assessment of gout and other crystal arthropathies.

Computed Tomography and MR Imaging in Crystalline-Induced Arthropathies.

Crystalline-induced arthropathies impose substantial morbidity but can be challenging to diagnose, especially in early phases. The most common crystalline arthropathies are gout (monosodium urate deposition), calcium pyrophosphate dihydrate deposition, and hydroxyapatite deposition disease. Computed tomography (CT) and MR imaging provide 3-dimensional information on osseous structures, periarticular soft tissue, and tophi with superior spatial resolution. Dual-source CT (dual-energy CT [DECT]) offers the further advantage of selectively identifying crystalline deposits. CT, MR imaging, and DECT can be of value in problematic cases and can potentially be used for disease monitoring. Further research is necessary to elucidate their added value.

Conventional Radiology in Crystal Arthritis: Gout, Calcium Pyrophosphate Deposition, and Basic Calcium Phosphate Crystals.

This article reviews the main radiographic features of crystal deposition diseases. Gout is linked to monosodium urate crystals. Classic radiographic features include subcutaneous tophi, large and well-circumscribed paraarticular bone erosions, and exuberant bone hyperostosis. Calcium pyrophosphate deposition (CPPD) can involve numerous structures, such as hyaline cartilages, fibrocartilages, or tendons. CPPD arthropathy involves joints usually spared by osteoarthritis. Basic calcium phosphate deposits are periarticular or intraarticular. Periarticular calcifications are amorphous, dense, and round or oval with well-limited borders, and most are asymptomatic. When resorbing, they become cloudy and less dense with an ill-defined shape and can migrate into adjacent structures.

One year in review 2017: ultrasound in crystal arthritis.

Musculoskeletal ultrasound (MSUS) has become a relevant part of rheumatology practice and research. This imaging modality substantially allows us to optimise the management of inflammatory, degenerative and crystal-related musculoskeletal diseases. MSUS is a valuable point-of-care tool to accurately assess intra-articular and periarticular abnormalities involved in rheumatic diseases. Furthermore, MSUS is a bedside aid for guiding accurate and safe musculoskeletal diagnostic aspirations and therapeutic injections. This review provides an overview of the last year's literature on the role of MSUS in crystal arthritis.

Imaging of Inflammatory Arthritis in Adults: Status and Perspectives on the Use of Radiographs, Ultrasound, and MRI.

The term inflammatory arthritis encompasses a variety of conditions featuring synovial inflammation as a defining characteristic, with resultant local tissue damage occurring over time. These arthritides often share overlapping clinical and imaging characteristics, although the pattern of joint involvement, specific appearance of pathologic changes, and associated findings often allow imaging-based differentiation or individual arthritides.

Imaging in Gout and Other Crystal-Related Arthropathies.

In this article, the authors consider the manifestations of intraarticular and periarticular crystal deposits. Most cases of crystal deposits are asymptomatic and represent incidental findings at imaging. In symptomatic arthropathies, imaging can play an important role in the diagnosis and assessment of disease progression and the extent of crystal deposits. Conventional radiography is the most common imaging modality. But ultrasound, conventional computerized tomography (CT), dual-energy CT, and MRI play an increasing role. The authors review typical radiographic features of crystal-induced arthropathies and findings that help to differentiate them. The authors also emphasize the increasing role of complementary imaging techniques.