Proton magnetic resonance imaging in ischemic cerebrovascular disease.

Proton magnetic resonance imaging (MRI) using a 0.6- or 1.5-Tesla superconductive magnet was compared with high-resolution computed tomography (CT) in 60 patients with transient ischemic attacks (TIAs) or brain infarction. MRI showed focal parenchymal changes in 84% of patients with TIAs, whereas CT showed similar changes in 42%. The sensitivity of MRI was also greater in patients with infarcts, but the difference between CT and MRI was not as great. Infarcts were usually better delineated by MRI regardless of location. However, MRI failed to reveal cortical infarcts that were clearly seen on contrast-enhanced CT scans and was unable to clearly distinguish subacute from chronic hemorrhagic infarcts. MRI changes were best detected with T2-weighted images and usually appeared as multiple areas of increased signal intensity in the subcortical and periventricular white matter. MRI changes often could not be correlated with the clinical history and neurological findings; identical changes have been seen in patients with no history of cerebrovascular disease.