Perfusion CT: is it clinically useful?

Combining perfusion CT (CTP) with CT angiography (CTA) and noncontrast CT (NCCT) provides much more information about acute stroke pathophysiology than NCCT alone. This multimodal CT approach adds only a few minutes to the standard NCCT and is more accessible and rapidly available in most centres than MRI. CTP can distinguish between infarct core and penumbra, which is not possible with NCCT alone. A small infarct core and large penumbra, plus the presence of vessel occlusion on CTA may be an ideal imaging 'target' for thrombolysis. To date, multimodal CT has predominantly been assessed in hemispheric stroke due to its limited spatial coverage. This will become less of an issue as slice coverage continues to improve with new generation CT scanners. Apart from the concepts above, more specific CTP and CTA criteria that increase (or decrease) probability of response to thrombolytic treatment are yet to be determined. Nonetheless, CTP thus has the potential to improve patient selection for thrombolysis.