Page 55 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints

were five cases with STT OA and 17 cases without STT OA. The disagreement
in the remaining seven cases was caused by different judgements of JSN in
three cases, osteophyte presence in one case, cyst presence in one case, and
a combination of these factors in two cases. Percentage agreement for CMC1
JSN was slightly lower with CT than with radiography. Interestingly, with radiography the disagreement between the readers was about the absence or
presence of JSN, while on CT the readers mostly agreed that there was JSN,
but disagreed about the severity of the JSN. Reliability of CT for the detection
of erosions was lower than that of radiography. In almost all disconcordant 3 erosions cases were cysts detected in the same joint by both readers.
Table 1. Inter-reader reliability on joint level for CT and CR. ICC ICC
%Agreement CT
100
67
90
80
73
90
90
76
72
38
82
62
86
%Agreement CR
80
70
67
83
83
100
76
69
76
79
90
93
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CMC1
STT
presence of OA
Joint space narrowing Osteophytes Subchondral sclerosis Bone Cyst
Erosion
Subluxation
presence of OA
Joint space narrowing Osteophytes Subchondral sclerosis Bone cyst
Erosion
CT CR 1.00 0.15 0.76 0.70 0.87 0.66
* 0.67 0.48 0.37
* * 0.65 0.62
0.80 0.45 0.81 0.41 0.69 0.53
* 0.70 0.77 0.52 0.24 *
0.86 0.63
Eaton Stage
CMC1 = first carpometacarpal joint, STT = scapho-trapezio-trapezoidal joint, CT = computed tomography, CR = conventional radiography, ICC = intraclass correlation coefficient, OA = osteoarthritis, * = incalculable
Each reader individually detected more OA in both joints with CT than with CR (Tables 2 and 3). Reader 1 detected three cases of CMC1 OA and 12 cases of STT OA with CT which he did not detect with radiography. Reader 2 detected three cases of CMC1 OA and five cases of STT OA which he did not detect with radiography. In only one case was STT OA detected with radiography and not with CT by one of the readers. In this case the JSN in the STT joint was scored as definite on radiography and doubtful on CT. Two examples of patients in whom STT OA was only detected with CT are shown in Figures 1 and 2.
CT for detection of thumb base OA
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