Dr sridhar role of CT and CT perfusion in evaluation of stro

Role of CT in Acute Stroke Dr PG Sridhar Sr Consultant Epidemiology • Third most common cause of death world wide • Age adjusted prevalence rate of stroke in India  250350/100,000* • Age adjusted prevalence rate of stroke in Bangalore  262/100,000** • Estimated *Neurologystroke Asia 2006;related 11 : – death 1.2 % of the total 2004;23:261–268 deaths* **Neuroepidemiology Stroke • Infarction 85% – – – – Cerebral atherothrombosis 30-40% Cardiogenic embolism 20-25% Penetrating artery disease (lacune) 20% Other unusual causes 5% • Hemorrhage 15% • In India, ratio of cerebral infarct to hemorrhage is estimated to be 2.21* *Neurology Asia 2006; 11 : – “Time is Brain” “Time is Brain” National Institute of Neurological Diseases and Stroke trial (NINDS) 3Hrs (N Engl J Med 1995;333:1581-7.) European Cooperative Acute Stroke Study III (ECASS III) (Stroke 2009;40:2262-2263 ) 4.5 Hrs Goals of Acute Stroke Imaging • Parenchyma: Assess early signs of acute stroke and rule out hemorrhage • Pipes: Assess extracranial and intracranial circulation for evidence of intravascular thrombus • Perfusion : Assess cerebral blood volume, cerebral blood flow, and mean transit time • Penumbra : Assess tissue at risk of dying if ischemia continues without recanalization of intravascular thrombus Rowley HA AJNR 2001;22:599–601 • Non contrast CT • CT perfusion • CT angiogram • Other emerging imaging techniques Unenhanced CT • R/o hemorrhage • Insular ribbon sign • obscuration of the lentiform nucleus • Cerebral swelling • Dense vessel sign (MCA or MCA dot sign) Intracranial Hemorrhage obscuration of the lentiform nucleus May be seen on CT images within hours after the onset of a Stroke CT PERFUSION Wintermark M, Stroke 2006;37:979–985 Penumbra CBF CBV Oligemia survival >60% of normal >80% of normal Oligemia infarction 30-60% of normal 60-80% of normal infarction