After being driven mad with phantom smells, and weird dizzy episodes, my doctor ordered an MRI of the brain. Since I couldn't tolerate the claustrophobia in the tunnel, she special ordered that I be anesthetized for the procedure. I got through it fine and even better the neurologist who interpreted the results said that my brain is presenting as if it were twenty years younger than the rest of me! Since there is a history of Parkinson's and strokes in my family, this made me very happy. The dizzy spells where due to inner ear issues.
(Still don't know where those phantom smells are coming from, though!)