Page 125 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
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 inflammatory arthralgia, establishing the presence of arthritis is important, as this may have immediate implications for diagnosis and treatment. If clinical examination remains unsure, imaging plays a role in detecting subclinical synovitis. Ultrasound remains the first choice, and only in cases with negative ultrasound and remaining clinical suspicion for arthritis, MRI may play a role because of its higher sensitivity and specificity, when clinically relevant. For research purposes, e.g. in clinical trials the higher sensitivity of high field MRI, including its higher sensitivity to detect erosions and ability to detect BME, is a good reason to prefer above US.
Limitations of performed studies
There are a few limitations of the performed studies which should be taken into consideration.
A first limitation is that selection bias may be present in some of our studies.
Selection bias is an error which can occur if the studied sample was not a
good random sample of the targeted population. In chapter 6, patients with
arthritis were only eligible for participation if they did not yet start treatment.
This probably has led to some selection bias, as some patients with severe
symptoms, and therefore with more possible imaging findings on MRI and
US, had to start treatment before both MRI scans could be performed. We will
therefore have imaged a subpopulation of patients with overall lower disease
activity. If we extrapolate our findings to the general population of patients 7 with inflammatory hand complaints, the sensitivity of ultrasound and low field
MRI may be higher. In our OA studies in chapter 4 and 5, we studied hrMRI of cartilage in two vastly different subpopulations of patients with hand OA. In chapter 4 patients with severe CMC1 OA were imaged, while in chapter 5, generally patients with mild to moderate finger OA were imaged. We expect the validity results of chapter 4 to be generalizable to chapter 5, but we cannot be certain.
As a second limitation, radiological imaging will always be subject to some information bias. Information bias occurs due to systematic errors in measurement, which may then lead to misclassification. In radiology this can
General discussion

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