A method of real time determination of variations in effective diameter of cranial blood vessels, thereby to provide an indication of migraine activity, which includes determining the blood flow rate (402) to the brain of a subject; determining the intracranial blood flow rate (413) in selected blood vessels; and comparing the intracranial blood flow rate (402) with the determined blood flow rate (413) to the brain thereby to determine a change in the intracranial blood flow rate relative to the blood flow rate to the brain, indicating a corresponding change in the effective diameter of the preselected blood vessel.
NON-INVASIVE REAL TIME DIAGNOSIS OF MIGRAINE