Page 88 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
P. 88

                                Chapter 5
Inter-bone distance was scored according to the HOAMRIS without any modification of the definition using the coronal PD images. It is scaled as: 0 = normal; 1 = loss of cartilage space without bone-to-bone contact; 2 = focal complete loss of cartilage space with bone-bone contact; 3 = cartilage space loss and bone-bone contact affecting > 50% of the articulating joint area. The hrMRI cartilage score was defined in line with the MRI Osteoarthritis Knee Score (MOAKS),13 scoring both the size of any cartilage thickness loss and the size of full-thickness cartilage loss. A single cartilage score (0-3) was created based on these two items: 0 = no cartilage damage, 0.5 = Single focal cartilage defect <10% of surface area with abrupt edges, 1 = thinning of the cartilage layer > 10% of the surface area, without complete thickness loss, 2 = Global thinning of the cartilage layers with areas with (near) complete thickness loss, without direct bone-bone contact, 3 = Severe cartilage thickness loss with areas of direct bone-bone contact. The 0.5 grade has been removed from the tables in the results, as it was never scored. The cartilage was assessed on the high-resolution SPGR images. The MRI examinations for final analysis were independently read by both MS and GM. To determine intra-reader reliability, MS re-evaluated 10 randomly selected MRI examinations 4 months after the initial reading. A separate reader also measured the cartilage thickness and inter bone distance of all joints using a ruler tool. The measures were performed in the middle of the joint using the sagittal SPGR images.
Statistics
We present the mean values of both readers. Inter-reader and intra-reader reliability were calculated using percentage exact agreement (PEA), percentage close agreement (PCA), and a linear weighted kappa (κw). PEA was calculated as the percentage of joints with the exact same value by both readers. PCA was calculated as the percentage of joints with a difference of ≤ 1 between readers. Weighted kappa was interpreted as 0-0.20: poor; 0.21-0.40: fair; 0.41-0.60: moderate; 0.61-0.80: good; 0.81-1.00: very good agreement.14 The number of joints with cartilage damage and reduced inter-bone distance was calculated, and the agreement between the two features assessed in a table.
86






























































































   86   87   88   89   90