Harvard Health Letter

By the way, doctor: Can four MRIs "miss" my TIAs?

Can four MRIs "miss" my TIAs?

Q. Is it possible to have one or more TIAs in the past four years and not have them show up in four MRIs?

A. Transient ischemic attacks (TIAs) are symptomatically small strokes. Like a major stroke, a TIA occurs when a part of the brain suddenly fails to get an adequate supply of blood. The most common cause is blockage of an artery, usually by a piece of atherosclerotic plaque in one of the brain's main arteries that has broken off and gotten stuck "downstream." TIAs are also caused by blood clots that originate in the heart, travel to the brain, and become lodged in a small artery there.

By definition, the symptoms of a TIA last less than 24 hours, in contrast to the symptoms of a stroke, which last longer — and are often permanent. Common TIA symptoms include sudden weakness in an arm or leg on one side of the body, dimness or loss of vision in one eye, dizziness (usually with other symptoms), and difficulty speaking or understanding what other people are saying.

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