Computed Tomography Perfusion Techniques in Acute Ischemic Stroke

Computed tomography perfusion (CTP) has emerged as a pivotal tool in the acute assessment of ischaemic stroke by enabling rapid quantification of cerebral haemodynamics. By administering an iodinated contrast bolus and acquiring serial images, CTP generates parametric maps of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). These maps distinguish the irreversibly injured core from the potentially salvageable penumbra, thus guiding reperfusion therapy decisions. Advances in post-processing algorithms—such as delay-insensitive deconvolution methods—have enhanced robustness against tracer arrival delays and reduced artefacts. Whole-brain coverage scanners now capture spatio-temporal dynamics across both hemispheres, improving the detection of distal perfusion deficits. Recent integration of machine-learning frameworks has further refined noise suppression and automated region segmentation, shortening analysis times and minimising user dependence. Collectively, these developments strengthen the clinical utility of CTP as a global standard for early stroke triage, offering reproducible biomarkers for infarct core estimation, penumbral volume delineation and prediction of functional outcome.

Research from Nature Portfolio

Threshold determination on baseline whole-brain perfusion maps has been refined to standardise core and penumbra identification. Delay time≥3 s most accurately delineates penumbral tissue, while a relative CBF≤30 % within that delay interval defines the ischaemic core. These optimised thresholds yield high agreement with follow-up imaging and support the mismatch concept to select patients for thrombolysis or thrombectomy. By establishing interoperable perfusion criteria, this work underpins multicentre trials and harmonises patient selection protocols worldwide.

Computed Tomography Perfusion Techniques in Acute Ischemic Stroke publication trend

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

Technical terms

CT perfusion (CTP): Dynamic imaging technique that measures passage of contrast through cerebral vessels to quantify tissue perfusion.

Cerebral blood flow (CBF): Volume of blood passing through a given amount of brain tissue per unit time, typically expressed in mL/100 g/min.

Cerebral blood volume (CBV): Total volume of blood within a specified brain region, reported in mL/100 g.

Mean transit time (MTT): Average time taken by blood to traverse the cerebral microvasculature, calculated as CBV divided by CBF.

Delay time (Tmax): Time to maximum residue function, indicating contrast arrival delay relative to an arterial input.

Ischaemic core: Brain region with critically reduced perfusion, representing irreversibly damaged tissue.

Penumbra: Surrounding zone of hypoperfused but potentially salvageable tissue at risk of progression to infarction.

References

1. Defining Core and Penumbra in Ischemic Stroke: A Voxel- and Volume-Based Analysis of Whole Brain CT Perfusion. Scientific Reports (2016).
2. Spatio-temporal physics-informed learning: A novel approach to CT perfusion analysis in acute ischemic stroke. Medical Image Analysis (2023).
3. Perfusion parameter map generation from TOF-MRA in stroke using generative adversarial networks. NeuroImage (2024).
4. Assessment of a Bayesian Vitrea CT Perfusion Analysis to Predict Final Infarct and Penumbra Volumes in Patients with Acute Ischemic Stroke: A Comparison with RAPID. American Journal of Neuroradiology (2020).