Thunderclap headache is a typical presentation, and may be associated with convexal SAH as in this case.  More commonly there is no SAH.  MRA may be of poor quality or targetted to the circle of Willis, and may miss the stenoses.  Angiography is typically positive in the distal branches - follow up imaging with 3T MRA +/- contrast typically shows complete resolution of vessel findings. Clinical and imaging findings distinguish this syndrome from PACNS and post aneurysmsal SAH related vsaospasm.