Definition of TIA is, patient signs and symptoms resolve by

When blood flow is quickly restored, brain tissue can recover fully and the patient's symptoms are only transient, this is called a transient ischemic attack (TIA). The definition of TIA requires that all neurologic signs and symptoms resolve within 24 h without evidence of brain infarction on brain imaging. Most TIAs last <1 h.Stroke has occurred if the neurologic signs and symptoms last for >24 h or brain infarction is demonstratedRef: Harrison 19e pg: 2559