Page 42 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
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                                Chapter 2
with MRI, and cysts and BML which cannot be assessed with US. Correlations between US and clinically assessed synovitis were low, as also found in hip and knee OA studies.66 Reported reliabilities were mostly moderate to good for US and MRI, although some variability was seen in the few MRI studies for synovitis, tenosynovitis, cysts and osteophytes. Responsiveness was only evaluated in US, which demonstrated that reduction of soft tissue lesions was correlated with pain decrease. More studies should therefore focus on reliability of MRI, responsiveness of US and MRI, and comparison of US and MRI.
Bone scintigraphy seems less promising for detection and follow-up of hand OA. Scintigraphy was weakly correlated with clinical symptoms and detected less pathological joints than CR. Reliability of scintigraphy was good, but scintigraphy scores decreased over time, while the disease progressed clinically and radiographically. This responsiveness pattern is comparable to results from a systematic review about knee OA,67 and inherent to the technique. Scintigraphy shows increased uptake of bone tracers, representing osteophyte and cyst formation.68 As the new osteophytes become visible on imaging techniques showing structural damage, they will relieve stress on the joint, and scintigraphic findings will diminish.68
No studies on CT, PET or SPECT reported validity, reliability or responsiveness. However, these may be less optimal than US and MRI. Although CT is more sensitive than MRI and US for detecting erosions,69-71 it does not visualise cartilage or other soft tissues. PET and SPECT use radiopharmaceutical agents that target bone, and these imaging techniques may therefore have similar limitations as described for scintigraphy. However, this may change when cartilage-specific tracers become available.72, 73
A variety of scoring methods was used in the reviewed studies. These methods were often newly devised by the authors (based on rheumatoid arthritis literature), or not properly described. In both US and MRI literature only a single scoring method was used in multiple studies. The US method by Keen et al.40 was used in eight articles, although mostly with additions or alterations to the original method. The MRI scoring method by Haugen et al.34 has so far been used in articles by the author’s own study group, and has undergone one change in subsequent studies. As seen in knee OA,74 scoring methods can

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