Arterial Spin Labeling Applications in Acute Ischemic Stroke

Arterial Spin Labeling (ASL) has emerged as a pivotal non-invasive MRI technique for quantifying cerebral perfusion in the context of acute ischaemic stroke. By magnetically labelling inflowing arterial blood water, ASL provides absolute measures of cerebral blood flow (CBF) without the need for exogenous contrast agents. In acute stroke settings, ASL can delineate ischaemic core, penumbral regions and post-recanalisation perfusion patterns with high reproducibility. Recent methodological advances, including multi-delay ASL protocols, enable correction for arterial transit time and more precise mapping of hypoperfusion and hyperperfusion in both infarcted and salvaged tissue. Clinically, ASL-derived perfusion biomarkers are proving valuable for predicting early neurological outcome, guiding blood pressure management after reperfusion therapies and stratifying patients at risk of reperfusion-related complications. The technique’s non-invasive nature, repeatability and compatibility with standard clinical scanners underscore its potential to inform personalised stroke management and therapeutic decision-making on a global scale.

Research from Nature Portfolio

Recent studies employing ASL after endovascular thrombectomy have defined distinct perfusion phenotypes based on the spatial extent of hyperperfusion. Patients exhibiting global hyperperfusion—characterised by increased CBF in more than half of the affected vascular territory—demonstrate larger infarct volumes and poorer 90-day functional outcomes compared with those showing focal or no hyperperfusion. This classification underscores the prognostic significance of post-recanalisation perfusion patterns and supports the integration of ASL into post-procedural imaging workflows to tailor follow-up care and haemodynamic management.

Arterial Spin Labeling Applications in Acute Ischemic Stroke publication trend

The graph below shows the total number of articles in arterial spin labeling applications in acute ischemic stroke across all publications each year (not limited to Nature Index journals).

Technical terms

Arterial Spin Labeling (ASL): An MRI technique that uses magnetically labelled arterial blood water as an endogenous tracer to non-invasively measure cerebral blood flow.

Cerebral Blood Flow (CBF): The volume of blood delivered to a specified mass of brain tissue per unit time, typically expressed in mL/100 g/min.

Ischaemic Core: The region of brain tissue with critically reduced perfusion that has undergone irreversible infarction.

Penumbra: The surround of the ischaemic core where perfusion is compromised but tissue remains viable and potentially salvageable.

Hyperperfusion: A state of increased regional CBF above baseline following reperfusion therapy, which may be global or focal in distribution.

Hypoperfusion: A reduction in regional CBF below normal baseline levels, indicating continued ischaemia and risk of infarct growth.

Endovascular Thrombectomy (EVT): A mechanical intervention to remove occlusive thrombi and restore arterial circulation in acute ischaemic stroke.

Post-Labeling Delay (PLD): The interval between arterial blood labelling and image acquisition in ASL sequences, affecting transit time correction.

References

1. Implications of Post-recanalization Perfusion Deficit After Acute Ischemic Stroke: a Scoping Review of Clinical and Preclinical Imaging Studies. Translational Stroke Research (2023).
2. Cerebral blood flow quantification with multi-delay arterial spin labeling in ischemic stroke and the association with early neurological outcome. NeuroImage Clinical (2023).
3. Global hyperperfusion after successful endovascular thrombectomy is linked to worse outcome in acute ischemic stroke. Scientific Reports (2024).
4. Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy. Translational Stroke Research (2021).