Stands for transient ischemic attack. Sometimes called mini strokes. They mimic stroke symptoms but resolve quickly and may be precursors to strokes: https://www.mayoclinic.org/diseases-conditions/transient-ischemic-attack/symptoms-causes/syc-20355679

Mini-strokes, in simple terms. My left hand started feeling tingly and numb and sort of floppy. I had that a few times, so I had some brain scans. I fairly quickly went back on HU.