Perfusion abnormalities in subchondral bone associated with marrow edema, osteoarthritis, and avascular necrosis
Bone marrow edema is seen in osteoarthritis, avascular necrosis, and other clinical conditions including the bone marrow edema syndrome. Bone marrow edema is associated with bone pain and may be related to the pathophysiology of osteoarthritis. Our hypothesis is that bone marrow edema is associated with a reduction in perfusion in subchondral bone, which contributes to focal and segmental bone necrosis and cartilage breakdown. We further hypothesize that altered fluid dynamics in subchondral bone comprise part of the physicochemical environment to which osteocytes are highly sensitive and alter their cytokine expression profile in response to changes in fluid flow, pressure, and oxygen gradients. We have used contrast-enhanced magnetic resonance imaging with Gd-DTPA to characterize changes in subchondral bone perfusion in two relevant and related models-the Dunkin-Hartley guinea pig model of osteoarthritis and human bone marrow edema associated with osteoarthritis and avascular necrosis. Pharmacokinetic modeling was used to extract dynamic parameters of perfusion. Representative time-intensity curves are derived, which characterize normal bone and bone with marrow edema. Dynamic contrast-enhanced magnetic resonance imaging may be a useful tool for the early diagnosis of bone perfusion abnormalities and may be used to characterize marrow edema associated with a number of clinical conditions. This technique may also shed light on the pathophysiology of subchondral perfusion in osteoarthritis and avascular necrosis.