Arterial Spin Labeling in Cerebral Perfusion Imaging

Arterial Spin Labeling (ASL) is a non-invasive magnetic resonance imaging technique that employs magnetically labelled arterial blood water as an endogenous tracer to map cerebral blood flow (CBF). By inverting the magnetisation of inflowing arterial spins upstream of the imaging slab and acquiring control images without inversion, quantitative perfusion maps can be derived through subtraction and modelling of the labelled and control signals. ASL offers absolute CBF quantification without contrast agents, making it especially attractive for repeated measurements, paediatric and renal-insufficient populations. Developments in labelling schemes—such as pulsed, continuous and pseudo-continuous ASL—and multi-delay acquisitions have enhanced temporal resolution and accuracy by accounting for arterial transit time. Clinically, ASL has found applications in cerebrovascular disease assessment, dementia diagnostics, tumour perfusion evaluation and functional neuroimaging. Advances in vessel-selective labelling permit collateral flow mapping, while integration with high-field scanners and time-encoded strategies is expanding dynamic perfusion assessment. ASL’s ability to characterise regional hypoperfusion and hyperperfusion patterns underpins its growing role in diagnosis, therapy monitoring and physiological research.

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Arterial Spin Labeling in Cerebral Perfusion Imaging publication trend

The graph below shows the total number of articles in arterial spin labeling in cerebral perfusion imaging across all publications each year (not limited to Nature Index journals).

Technical terms

Arterial Spin Labeling (ASL): An MRI technique using magnetically labelled arterial blood water to quantify cerebral blood flow.

Cerebral Blood Flow (CBF): The volume of blood passing through a given mass of brain tissue per unit time, usually expressed in mL/100 g/min.

Pseudo-Continuous ASL (pCASL): A labelling scheme that mimics continuous inversion of arterial spins using a train of radiofrequency pulses, balancing labelling efficiency and hardware requirements.

Arterial Transit Time (ATT): The delay between labelling arterial spins and their arrival in the imaging region, critical for accurate CBF quantification.

Diffusion-Prepared pCASL (DP-pCASL): A hybrid method combining diffusion preparation with pCASL to estimate water exchange across the blood–brain barrier in addition to perfusion.

Blood–Brain Barrier (BBB): The selective vascular interface that regulates passage of molecules between the circulatory system and the brain’s extracellular fluid.

References

1. Dobutamine-induced alternations in cerebral blood flow of healthy adults: a 3D pseudocontinuous arterial spin labeling study. BMC Medicine (2023).
2. Age-related decline in blood-brain barrier function is more pronounced in males than females in parietal and temporal regions. eLife (2024).
3. A neuroradiologist’s guide to arterial spin labeling MRI in clinical practice. Neuroradiology (2015).
4. Arterial Spin-Labeling in Routine Clinical Practice, Part 1: Technique and Artifacts. American Journal of Neuroradiology (2008).
5. Arterial Spin Labeling (ASL) fMRI: Advantages, Theoretical Constrains and Experimental Challenges in Neurosciences. International Journal of Biomedical Imaging (2012).
6. Advances in arterial spin labelling MRI methods for measuring perfusion and collateral flow. Cerebrovascular and Brain Metabolism Reviews (2017).
7. Cerebral Blood Flow Quantification Using Vessel-Encoded Arterial Spin Labeling. Cerebrovascular and Brain Metabolism Reviews (2013).
8. Arterial Transit Time Mapping Obtained by Pulsed Continuous 3D ASL Imaging with Multiple Post-Label Delay Acquisitions: Comparative Study with PET-CBF in Patients with Chronic Occlusive Cerebrovascular Disease. PLOS ONE (2016).