Susceptibility weighted imaging: a pictorial review.

Susceptibility weighted imaging (SWI) is a valuable technique in the evaluation of a wide variety of intracranial pathologies. SWI is a gradient echo sequence utilising both phase and magnitude data to achieve exquisite sensitivity to tissue magnetic susceptibility effects. Normal SWI appearances and common artefacts are illustrated. Examples of SWI in common intracranial pathologies such as subarachnoid, intraventricular and intraparenchymal haemorrhage, intra-axial and extra-axial tumours, pyogenic and non-pyogenic infections, trauma, neurodegenerative diseases and vascular disease including aneurysms, vascular malformations are illustrated and discussed. This pictorial essay will enable radiologists to recognise the normal, artefactual and common intracranial pathological appearances of SWI.