A method is described for determining brain shift, such as the brain shift that occurs following a neurosurgical intervention. The method comprises taking a first image of the brain (4) of a subject, the first image showing the position of blood vessels (20) in the brain relative to a reference position (30). A second image of the brain (4), that has been acquired following an intervention on the subject is also taken. This second image has been acquired using computed tomography (CT) imaging apparatus, The second image shows the position of blood vessels (20′) in the brain relative to the reference position (30). Brain shift is then determined from the shift in position of the blood vessels in at least one region of interest (32) of the brain, with respect to the reference position (30), between the first and second images. Corresponding apparatus is also described.
