Arthritis Rheumatol. 2022 Sep 19. doi: 10.1002/art.42368. Online ahead of print.
ABSTRACT
OBJECTIVES: To assess the reliability and diagnostic accuracy of new radiographic definitions for calcium pyrophosphate deposition (CPPD) identification, developed by an international multidisciplinary working group.
METHODS: Patients with knee osteoarthritis scheduled for knee replacement were enrolled. Two radiologists and two rheumatologists assessed twice the images for presence/absence of CPPD on menisci, hyaline cartilage, tendons, joint capsule, synovial membrane, using the new definitions. In case of disagreement, a consensus decision was taken and considered for the assessment of diagnostic performance. Histological examination of specimens under compensated polarized light microscopy was the reference standard. Prevalence-adjusted bias-adjusted kappa (PABAK) was used to assess the reliability. Diagnostic performance statistics were calculated.
RESULTS: Sixty-seven participants were enrolled for the reliability study. The inter-observer reliability was substantial in most of the assessed structures when considering all 4 readers (kappa range 0.59 – 0.90), substantial to almost perfect among radiologists (kappa range 0.70-0.91), and moderate to almost perfect among rheumatologists (kappa range 0.46 – 0.88). The intra-observer reliability was substantial to almost perfect for all the observers (kappa range 0.70 – 1). Fifty-one patients were enrolled for the accuracy study. Radiography demonstrated to be specific for CPPD (92%), but sensitivity remained low in all sites and in the overall diagnosis (54%).
CONCLUSION: The new imaging definitions of CPPD are highly specific against the gold standard of histological diagnosis; when described findings are present these definitions allow for a definite diagnosis of CPPD, rather than other calcium-containing crystal depositions; instead a negative finding does not exclude the diagnosis.
PMID:36122187 | DOI:10.1002/art.42368
