Page 121 - Imaging of Osteoarthritis and Rheumatoid Arthritis in Hand Joints
P. 121

 In this thesis we have used radiological imaging methods to image hand osteoarthritis (OA) and rheumatoid arthritis (RA) with the following aims:
- to assess construct validity and reliability of direct cartilage imaging with magnetic resonance imaging (MRI) in hand OA.
- to asses if computed tomography (CT) has better reliability and
detection rate of thumb base OA than conventional radiography.
- to assess construct validity of low field extremity MRI in early
arthritis patients.
MRI Direct cartilage imaging.
Direct cartilage imaging with high-resolution MRI (hrMRI) in hand joints is feasible, and more accurate than indirect scoring of joint space narrowing (JSN). In chapter 4 we have shown that compared with histology, hrMRI accurately depicts the overall extent of cartilage damage. In chapter 5 we have shown that direct scoring of cartilage defects using hrMRI is certainly as reliable as JSN scoring using normal MRI, and that with hrMRI more cartilage damage was detected in hand OA (HOA) patients, and less cartilage defects were scored in healthy controls. While this does not prove that hrMRI has better sensitivity and specificity, it indicates that direct cartilage imaging with MRI is more accurate.
All the advantages of direct cartilage imaging come at a cost, as with hrMRI
only a few joints can be imaged in a single examination. Previously, direct 7 cartilage imaging of a single hand joint with hrMRI has been studied to quantify
cartilage volume 1, and was shown to be a promising technique. Technological developments since then allow us to scan a small hand joint with a similar
MRI sequence in less than one third of the scanning time, and with 4 times
smaller voxel sizes. However, as each joint needs to be scanned separately with
hrMRI, the use of hrMRI should be based on the specific research question. If
the research question focusses on other aspects of OA like synovitis, whole
hand imaging with lower resolution might be more appropriate. However, for
example, if the effects of disease-modifying osteoarthritis drugs (DMOADS)
should be assessed on all joint structures including cartilage, then hrMRI
is probably preferred. Currently, MRI for cartilage imaging in HOA is only
General discussion

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