Diagnosis of calcium pyrophosphate crystal deposition disease by ultrasonography: how many and which sites should be scanned?

Cipolletta, Edoardo; Moscioni, Erica; Sirotti, Silvia; Di Battista, Jacopo; Abhishek, Abhishek; Rozza, Davide; Zanetti, Anna; Carrara, Greta; Scirè, Carlo Alberto; Grassi, Walter; Filippou, Georgios; Filippucci, Emilio

Abstract

Objective

To develop the optimal US scanning protocol for the diagnosis of CPPD disease.

Methods

In this cross-sectional study, consecutive patients with a crystal-proven diagnosis of CPPD disease, and age-, sex-matched disease controls and with a negative synovial fluid analysis were prospectively enrolled in two Italian Institutions. Four rheumatologists, blinded to patients’ clinical details, performed US examinations using a standardised scanning protocol including 20 joints (shoulders, elbows, wrists, metacarpophalangeal joints from 2nd to 5th fingers, hips, knees, ankles). CPPD was identified as presence/absence, according to the OMERACT definitions. Reduced US scanning protocols were developed by selecting the most informative joints to be imaged by US using the LASSO technique. Patients were randomly divided into training and validation sets. Their diagnostic accuracy was tested comparing the area under the ROC curves.

Results

204 participants were enrolled: 102 with CPPD disease and 102 disease controls [age (mean±standard deviation) 71.3 ± 12.0 vs 71.1 ± 13.5 years, female: 62.8% vs 57.8%].

The median number of joints with US evidence of CPPD was 5 (IQR: 4–7) and 0 (IQR: 0–1) in patients with CPPD disease and controls, respectively (p< 0 01).

The detection of CPPD in ≥ 2 joints using a reduced scanning protocol (bilateral assessment of knees, wrists, and hips) showed a sensitivity of 96.7% (95%CI: 82.8–99.9) and a specificity of 100 (95%CI: 88.8–100.0) for the diagnosis of CPPD disease and had good feasibility [(mean±standard deviation) 12.5 ± 5.3 min].

Conclusion

Bilateral US assessment of knees, wrists, and hips had excellent accuracy and good feasibility for the diagnosis of CPPD disease.

• Journal Article Type: Article
• Acceptance Date: Oct 5, 2023
• Online Publication Date: Oct 26, 2023
• Publication Date: Oct 26, 2023
• Deposit Date: Oct 30, 2023
• Publicly Available Date: Oct 30, 2023
• Journal: Rheumatology
• Print ISSN: 1462-0324
• Electronic ISSN: 1462-0332
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1093/rheumatology/kead565
• Keywords: chondrocalcinosis, CPPD, ultrasound, crystal arthritis, diagnostic accuracy
• Public URL: https://nottingham-repository.worktribe.com/output/26539058
• Publisher URL: https://academic.oup.com/rheumatology/advance-article/doi/10.1093/rheumatology/kead565/7330416