title: A distinctive facial thermographic pattern in cluster headache--the "chai" sign.
mesh_terms: D001158:Arteries; D003027:Cluster Headache / Q000175:diagnosis*; D006801:Humans; D008881:Migraine Disorders / Q000175:diagnosis*; D009915:Orbit / Q000098:blood supply; D013817:Thermography / Q000379:methods*; D014653:Vascular Headaches / Q000175:diagnosis*