TIA, or transient ischemic attack, is a "mini stroke" that occurs when a blood clot blocks an artery for a short time. The only difference between a stroke and TIA is that with TIA the blockage is transient (temporary). TIA symptoms occur rapidly and last a relatively short time. Unlike a stroke, when a TIA is over, there's no permanent injury to the brain. There's no way to tell if symptoms of a stroke will lead to a TIA or a major stroke. It's important to call 9-1-1 immediately for any stroke symptoms.