The imaging of brain haemodynamics and its applications are generating growing interest. By providing quantitative measurements of cerebral blood flow (CBF) and cerebral blood volume (CBV), dynamic perfusion computed tomography (p-CT) allows visualisation of cerebral autoregulation mechanisms and represents a fast, available and reliable imaging option for assessing cerebral perfusion. Thanks to its feasibility in emergency settings, p-CT is considered most useful, in combination with CT angiography, in acute ischaemic patients, as it is able to provide a fast and noninvasive assessment of cerebral perfusion impairment. In addition, p-CT can play a diagnostic role in other types of cerebrovascular disease to assess functional reserve, and in intracranial neoplasms, where it has a role in diagnosis, grading, biopsy guidance, and follow-up during treatment. This article illustrates the principles, technique and clinical applications of p-CT cerebral perfusion studies.