I am being treated for cluster headache for the past month. Taking Neurontin, 600mg TID. Have had a CT in the ER, it was clear. Had an MRI W/O contrast, normal except for a couple cysts in my sinuses. Tried to have a head/neck CT w/contrast today but was told no because my creatinine is 1.7. (I did a donor nephrectomy 5 years ago...) My GFR is 64, creatinine clearaince 96, and no protein.) The purpose of the CT was to rule out a possible carotid artery fissure, as well as study the circulation in the brain and neck. Are there any observable symptoms for a carotid artery fissure? My name is John Hart, email YYYY@YYYY .