Inverted grayscale in hand X-rays in patients with rheumatoid arthritis: A pilot study

Objective:

To test the evaluability of inverted grayscale (IGS), a digital editing method on plain X-ray images, in diagnosing rheumatoid arthritis (RA).

Methods:

Standard and IGS views of X-rays of 15 patients who were randomly selected among patients with RA or suspected inflammatory arthropathy who applied to our outpatient clinic consecutively between June 2020 and September 2022, were evaluated by 3 rheumatology specialists with at least 2 years of rheumatology experience. The presence of findings of RA and osteoarthritis (OA) and how confident they were in their decisions were assessed. The evaluations of the rheumatologists were compared with the evaluation of the radiologist, and the inter-rater agreement was calculated with the Cohen Kappa (CK) test. Inter-rater agreement according to the coefficient of variation obtained with the CK test was defined as; <0.20: no agreement, 0.21-0.40: poor agreement, 0.41-0.60: moderate agreement, 0.61-0.80: good agreement, 0.80-1: excellent agreement.

Results:

In evaluating images of patients with RA, a low-moderate agreement was found between the raters. While the agreement level of less experienced specialists for IGS and standard view differed, the agreement level of the more experienced rheumatologist was similar for TGT and standard views. The Likert scale score, which expresses how confident the evaluators are in their decisions, was high for all researchers.

Conclusion:

IGS is a method that rheumatologists can easily evaluate. However, large-scale studies are needed to evaluate the additional contribution of IGS in detecting RA findings, especially by less experienced specialists.