Headache and visual symptoms in two patients with MRI alterations in posterior cerebral artery territory.

Posterior cerebral artery (PCA) territory infarcts account for only 5-10% of all infarcts in stroke registries. Moreover, the clinical features and etiology of such infarcts have not been studied as extensively as those in other vascular territories.We describe two patients with recurrent episodes of visual symptoms and headache due to probable transitory PCA vasospasm. MR angiography in the acute phase revealed incomplete visualization of PCA, conventional MRI showed mild T2 signal alterations and MR perfusion showed the presence of marked hypoperfusion in the same regions. Diffusion weighted MR images were normal. All these findings resolved after therapy. These cases suggest that reversible signal alterations associated with reversible vessel and perfusion abnormalities may be observed in patients with visual symptoms and headache. Normal DWI-MR may help distinguish these patients from those affected by non-reversible ischemic attacks.