Page 90 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints

Chapter 5
Table 2. Reliability of cartilage scores
Inter-reader reliability
Inter bone distance (n=233) High-res cartilage score (n=234)
Intra-reader reliability
Inter bone distance (n=36) High-res cartilage score (n=39)
PEA (%)
73 75
83 77
PCA (%)
97 95
97 100
κw (95% CI)
0.39 (0.27-0.51) 0.59 (0.53-0.66)
0.59 (0.32-0.86) 0.62 (0.42-0.82)
n = number of assessed joints; PEA, percentage exact agreement; PCA, percentage close agreement; κw, linearly weighted kappa; CI, Confidence interval
According to the hrMRI cartilage score 64/81 PIP and 21/81MCP joints had cartilage damage, including 27 PIP and 5 MCP joints with areas of full-thickness loss. Compared to the inter bone distance score, with hrMRI an additional 33 joints were scored as abnormal in OA patients, and 8 less joints in healthy controls were scored as abnormal (Table 3).
Table 3. Reclassification table of inter bone distance to the high-resolution cartilage score
Joints of hand OA patients (n=161)
Normal inter bone distance
Loss of cartilage space without bone-bone contact Focal complete loss with bone-bone contact Bone-bone contact >50%
Joints of healthy controls (n=71)
Normal inter bone distance
Loss of cartilage space without bone-bone contact Focal complete loss with bone-bone contact Bone-bone contact >50%
No Thinning cartilage of cartilage damage layer >10%
of surface area, without complete loss
77 19 7 19 0 1 0 0
59 1 9 1 1 0 0 0
Thinning of cartilage with areas with complete cartilage loss Without bone-bone contact
14 15 4 0
0 0 0 0
Severe cartilage loss including areas with direct bone-bone contact
0 2 2 0
0 0 0 0
n= number of assessed joints. Presented values are means of the two readers (rounded down).
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