Can cartoid stenosis be caused by trauma? is it repairable or treatable? is there an image or test that shows if the brain is getting enough blood?

Yes, but see below: Narrowing of the carotid artery can be due to stenosis secondary to atherosclerosis, but a more acute form comes from trauma due to tearing of the inner surfaces, a carotid dissection, and this is an emergency situation. A carotid duplex, a ct angio, an MRI angio can all demonstrate the block.

Not quite: Trauma can cause carotid dissection which narrows artery. Not a true stenosis. Clinical picture and radiology scans will determine if enough blood getting to brain.