How long does a brain aneurysm take to develop? i had a head mri 9 years ago and it was normal. i have a vein on my left temple that is close to the surface that often throbs.

Basics: Aneurisms are thought to originate from weak areas in blood vessels that are present for an undetermined period of time. Some become symptomatic in kids & some in adulthood. If you did not have a blood vessel study done specifically I don't know that a simple mri would identify such an area. Veins do not throb. What you are feeling is a normal artery in that position.