Abstract
The management of acute ischemic stroke has witnessed a paradigm change in the last
few years with the advent of mechanical thrombectomy. Imaging plays a key role in
evaluation and patient selection. Computed tomography (CT) forms the workhorse in
most centers due to its widespread availability and quick performance, though magnetic
resonance imaging (MRI) can also be adopted as a reasonable alternative. The key role
of imaging is to rule out hemorrhage and other stroke mimics while at the same time
establish early signs of ischemia and provide detailed information of cervicocranial
vasculature and salvageable brain parenchyma; all in the shortest timeframe. Key imaging
predictors of good clinical outcomes are good Alberta stroke protocol early CT score
(ASPECTS) (greater than 6) and collateral scores. Selection of patients beyond the
standard window period of 6 to 8 hours has become possible by tissue perfusion imaging
with some recent trials demonstrating the utility of thrombectomy even up to 24 hours.
Quick MRI-based protocols are being devised to achieve similar information as on CT
with no adverse effects related to radiation and contrast effects. Research is underway
to decipher the intricacies of blood flow in the brain through more sophisticated
imaging methods in attempt to increase the base for mechanical thrombectomy, which
will benefit more number of patients.
Keywords
ischemic stroke - mechanical thrombectomy - computed tomography - MRI - cervicocranial
vasculature - salvage brain parenchyma
