Crystal deposition diseases
Gout, pseudogout, hydroxyapatite (HA) or calcium pyrophosphate dihydrate (CPPD) crystal deposition diseases. May appear as a crown-like density encompassing the odontoid process (crowned-dens syndrome) 1) representing calcifications in the transverse ligament, seen best on cervical CT.
May be treated with a short course of prednisolone (e.g. 15 mg/d) followed by NSAIDs.
1)
Goto S, Umehara J, Aizawa T, Kokubun S. Crowned Dens syndrome. J Bone Joint Surg Am. 2007; 89:2732–2736