Fig. 3.

MRA of the head without IV contrast (obtained 2 days after the initial brain CT): coronal (a) and sagittal (b) maximum intensity projection (MIP) views demonstrate diffuse narrowing and diminished flow related enhancement throughout the major branches of the anterior (yellow arrows) and posterior (purple arrows) cerebral arterial circulations and Circle of Willis (red circle). MRV of the head without IV contrast (same day): coronal (c) and sagittal (d) MIP views demonstrate absence of the major branches of the posterior superior dural venous sinuses including absence of the superior sagittal sinus (red arrows), transverse sinus (green arrows), sigmoid sinus (white arrows), and straight sinus (gray arrow).