Acute Stroke Imaging: Current Trends

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