7T Sodium MRI of healthy and osteoarthritic cartilage of the knee

Osteoarthritis (OA) is a prevalent and disabling disease of the cartilage of
the articular joints. Reliable indicators do not exist to diagnose or monitor
changes of OA.
Furthermore, there is no therapy available to cure OA or to slow the
progression of the disease.
The gold standard at this moment is the radiograph that can show OA, however
this is at a late
stage of the disease where the damage to the cartilage is irreversible.
Reliable biomarkers are necessary
for fundamental OA research and for the development and monitoring the effect
of new treatments.

A strong candidate biomarker is sodium magnetic resonance imaging (MRI). Sodium
is a building block of cartilage and is strongly linked to proteoglycan (PG)
structures that determine the quality of cartilage. Changes in PG and
subsequent "swelling" of cartilage are indicators of early OA. Using the
high-field 7T MRI of the C.J. Gorter centre in the Radiology Department of the
LUMC we can measure the sodium signal of cartilage in vivo.

Goal of this study is to determine if high-field sodium-MRI can be used as:
1) a sensitive, in vivo, and non-invasive biomarker to diagnose OA in an early
stage and 2) as a method to follow the progression of OA and to monitor the
effect of new treatments.

This research is a feasibility study to determine the possibility to use in
vivo sodium-MRI of articular cartilage as a biomarker of OA and cartilage
quality. The study was funded by the Dutch Reumafonds and is a
"serendipity-project", indicating that is is a pilot study for which not much
experimental work has been done but for which a theoretical basis exists.

The cartilage of patients who are undergoing knee prosthesis surgery due to OA
will be analyzed with a biohistochemical sodium analysis such that pre-surgery
sodium-MRI can be compared with post-operative ex vivo sodium concentration. By
doing so, sodium-MRI can be directly related to a gold standard.

In addition to the patients a series of healthy volunteers (i.e. OA
symptom-free) will be scanned using the same imaging protocol to determine a
normal curve of sodium concentration in relation to age. Early detection of OA
could be possible by comparing suspected patients to this curve.

Study participants will be in the 7T MRI scanner for a maximum duration of 60
minutes. After 30 minutes the knee coil will be placed around the other knee.
The risk of this study is equal to the normal, low, risk of 7T MRI. It is
important that the participants are screened for contra-indications for 7T MRI.
There is no contrast agent administered, the participants have to tasks to
perform other than to move as little as possible during scanning. The
participant can listen to music during scanning.