Essential guide to arterial spin labelling: Review of key artifacts and applications

Arterial spin labelling (ASL) is a magnetic resonance imaging perfusion technique used to study cerebral blood flow. It differs from magnetic susceptibility-based perfusion sequences in that it does not require contrast media, but rather uses the signals emitted by pre-labelled protons. It is useful in the exploration of several different kinds of neurological pathologies including ischaemic stroke, brain tumours, dementia and epilepsy. However, it presents numerous artifacts that radiologists must be familiar with to ensure a correct interpretation of findings.