What makes a headaches a vascular headache?

Structure involved: Tension headaches involve the muscles over the skull, and they are typically described as constant with "hat-band" like pressure. Vascular/migraine headaches involve the blood vessels in the covering over the brain, but under the skull, and they are typically on one side, throbbing, associated with light/noise intolerance, and nausea/vomiting.

Throbbing headache: By vascular headache I presume you mean a migraine headache with throbbing pain. Migraine is a constellation of features that include the headache, and other motor and sensory symptoms.

Vascular HA: A term used previously to describe headaches resulting from widening of blood vessel in brain that push on brain tissue and cause pain, to include Migraine headaches and Cluster headaches.