From the Guidelines
The single most important diagnostic tool for stroke is a non-contrast computed tomography (CT) scan of the brain. This recommendation is based on the 2018 guidelines for the early management of patients with acute ischemic stroke from the American Heart Association/American Stroke Association 1. The guidelines emphasize that all patients admitted to hospital with suspected acute stroke should receive brain imaging evaluation on arrival to hospital, with noncontrast CT (NCCT) being the preferred initial imaging test. NCCT is preferred due to its ability to quickly detect acute intracerebral hemorrhage (ICH) and its cost-effectiveness in guiding acute management decisions, such as the administration of antithrombotic treatment.
Key points supporting the use of NCCT include:
- Its widespread availability in emergency departments
- The speed at which it can be performed, typically within 20 minutes of arrival, which is crucial for timely treatment initiation
- Its ability to distinguish between ischemic and hemorrhagic stroke, which is essential for guiding treatment
- The lack of significant interaction between baseline CT findings (such as early ischemic changes or the hyperdense MCA sign) and the effectiveness of IV alteplase treatment, suggesting that these findings should not be used to withhold therapy in eligible patients 1.
While diffusion-weighted magnetic resonance imaging (DW-MRI) is more sensitive for detecting acute ischemic stroke, its routine use in all patients with suspected acute stroke is not considered cost-effective 1. Therefore, NCCT remains the first-line diagnostic tool for stroke due to its speed, accessibility, and critical role in guiding immediate treatment decisions.
From the Research
Diagnostic Tools for Stroke
- Non-contrast computed tomography (CT) is widely used as the initial imaging tool to evaluate stroke, due to its sensitivity for hemorrhage, rapid acquisition, and widespread availability 2, 3, 4.
- Advanced computed tomography techniques, such as CT perfusion, and stroke magnetic resonance imaging provide more information about the acute stroke patient, allowing for a more individualized approach to decision making 5, 2.
- Perfusion computed tomography (PCT) adds value to non-contrast head CT, CT angiogram, and clinical assessment in predicting outcome, and represents independent information that cannot be predicted by clinical, non-contrast CT, and CT angiogram data 6.
Importance of Imaging in Stroke Diagnosis
- Imaging is required before treating a stroke, and imaging techniques assist in diagnosis and treatment decisions 4.
- The single most important predictor of clinical outcome is recanalization status, and PCT penumbra volume is also a predictor of clinical outcome, especially when considered in conjunction with recanalization 6.
Role of Clinical Assessment
- Although clinical understanding is an important diagnostic tool, acute stroke therapy without neuroimaging is impossible 5.
- Clinical assessment, combined with imaging techniques, provides a more comprehensive understanding of the acute stroke patient, allowing for improved identification of patients with acute stroke syndromes and more sophisticated decision making 5, 2.