AVN of the lunate bone is associated with repetitive overloading/ microtrauma. Normal variants such as ulna minus or ulna plus variants are predisposing factors. Patients’ complaints may precede radiologic findings (increased bone density, reduced height, and fragmentation) by months and even years. MRI enables early diagnosis before radiographic findings are present (Trumble and Irving 1990).
In these early stages, there is signal reduction in T1-weighted and signal increase in T2-weighted FS/STIR sequences. Gadolinium uptake may be prominent, especially in T1-weighted FS sequences. With progressing disease, there is reduction flatof Gadolinium uptake and findings indicate necrosis, sclerosis, and cyst formation. This time course suggests that the initial event is stress-related edema in the bone marrow followed by fibrosis and sclerosis possibly contributing to reduced perfusion and lastly leading the way to AVN (Trumble and Irving 1990).