Diagnosis of stroke with advanced CT and MR imaging.

There have been important advances in stroke imaging, including CT perfusion imaging, xenon-CT, CT angiography, MR diffusion imaging, MR perfusion imaging, MR angiography and haemorrhage-sensitive gradient echo MR sequences. The technical principles and clinical applications of these methods are explained. An emphasis is made on the diagnosis of hyperacute cerebral ischaemia and issues surrounding the differentiation of reversible from irreversible ischaemic damage with modern imaging modalities, which has implications for thrombolytic therapy. This is followed by an overview of the role of imaging in patients with chronic stroke and transient ischaemic attack. In these patients, the diagnostic contribution of MRI in detecting the underlying pathology and the assessment of cerebrovascular reserve with perfusion imaging from an important part in the secondary prevention of stroke.