Computed Tomography Assessment of Acute Ischemic Stroke

Computed tomography (CT) remains the cornerstone of acute ischemic stroke evaluation due to its rapid acquisition, widespread availability and ability to guide time-sensitive reperfusion therapies. Non-contrast CT (NCCT) provides the first assessment of parenchymal hypodensity and early ischemic signs, while CT angiography (CTA) identifies vessel occlusions and collateral status. CT perfusion (CTP) extends this assessment by mapping cerebral blood flow, blood volume and mean transit time to distinguish irreversibly injured core tissue from potentially salvageable penumbra. The Alberta Stroke Program Early CT Score (ASPECTS) offers a standardised semiquantitative method to estimate early infarct extent on NCCT, CTP and diffusion MRI. Recent advances in automated scoring algorithms and machine-learning models aim to reduce interobserver variability, accelerate decision-making and expand access to expert-level interpretation in resource-limited settings. In contemporary practice, integration of dynamic perfusion parameters and deep learning-driven image analysis enhances patient selection for intravenous thrombolysis and mechanical thrombectomy, ultimately improving functional outcomes on a global scale.

Research from Nature Portfolio

Recent studies have developed a convolutional deep learning model trained on matched NCCT and diffusion MRI scans to detect and delineate early acute infarcts within three to six hours of symptom onset. The model achieved sensitivities of 96–97% and specificities of 72–99% for infarcts above clinically relevant volume thresholds, substantially outperforming expert neuroradiologists in acute detection. Volume estimates from the model exhibited exceptionally high correlation with diffusion-weighted imaging (R² > 0.98), demonstrating potential for automated triage in hyperacute stroke pathways and optimisation of thrombectomy candidacy.

Computed Tomography Assessment of Acute Ischemic Stroke publication trend

The graph below shows the total number of articles in computed tomography assessment of acute ischemic stroke across all publications each year (not limited to Nature Index journals).

Technical terms

Non-contrast CT: Tomographic imaging obtained without intravenous contrast to detect early ischaemic hypoattenuation and exclude haemorrhage.

CT perfusion (CTP): Dynamic imaging technique that measures cerebral blood flow, blood volume and transit time to differentiate core infarct from penumbra.

Alberta Stroke Program Early CT Score (ASPECTS): A ten-point semiquantitative scoring system assessing early ischaemic changes in defined middle cerebral artery regions.

Ischaemic core: Brain tissue irreversibly damaged by prolonged blood flow reduction, identified on perfusion maps or diffusion imaging.

Ischaemic penumbra: Hypoperfused yet potentially salvageable brain tissue surrounding the core, targeted for reperfusion therapies.

References

1. Automated ASPECTS Segmentation and Scoring Tool: a Method Tailored for a Colombian Telestroke Network. Journal of Imaging Informatics in Medicine (2024).
2. Head CT deep learning model is highly accurate for early infarct estimation. Scientific Reports (2023).
3. A Critical Review of Alberta Stroke Program Early CT Score for Evaluation of Acute Stroke Imaging. Frontiers in Neurology (2017).
4. Automated ASPECTS in Acute Ischemic Stroke: A Comparative Analysis with CT Perfusion. American Journal of Neuroradiology (2019).