title: Determinants of mismatch in acute ischaemic stroke.
abstract: BACKGROUND
  Multimodal CT or MR imaging may be helpful in guiding reperfusion therapy for stroke. However, access to multimodal imaging may frequently be limited. We hypothesised that certain clinical and non-enhanced CT (NECT) findings at initial assessment can potentially predict mismatch on CT perfusion (CTP) in patients with acute ischaemic stroke.
  
  
  METHODS
  We undertook an analysis of prospectively collected clinical and imaging data of consecutive patients with anterior circulation ischaemic stroke who underwent CTP during their initial assessment. NECT was read for early ischaemic change as measured by the Alberta Stroke Program Early CT Score (ASPECTS), and for hyperdense middle cerebral artery sign (HMCAS). CTP images were evaluated for mismatch. Independent clinical and imaging predictors of a CTP mismatch were identified using stepwise logistic regression.
  
  
  RESULTS
  Of the 202 patients, 92 (46%) demonstrated a mismatch, 23 (11%) a matched deficit, and 87 (43%) no perfusion deficit. HMCAS on NECT (OR 13.65, 95% CI 6.04-30.81, p<0.001), female gender (OR 2.37, 95% CI 1.19-4.72, p = 0.015), atrial fibrillation (OR 2.05, 95% CI 1.02-4.11, p = 0.044), and absence of a history of hypertension (OR 0.46, 95% CI 0.22-0.96, p = 0.037) were independent predictors of a CTP mismatch. HMCAS had 58% sensitivity, 91% specificity, 84% positive predictive value and 72% negative predictive value.
  
  
  CONCLUSIONS
  A HMCAS on the initial NECT is associated with a high probability of mismatch in acute ischaemic stroke, and may identify patients most likely to benefit from recanalisation treatments when access to multimodal CT or MR facilities is limited.
authors: Department of Clinical Neuroscience, Institute of Psychiatry, King's College London, London, SE5 8AF, United Kingdom; Princess Royal University Hospital, South London Healthcare NHS Trust, Orpington, BR6 8ND, United Kingdom. Electronic address: laszlo.sztriha@kcl.ac.uk.
authors: Laszlo K
authors: LK
authors: Sztriha
authors: Una
authors: U
authors: Cusack
authors: Naga
authors: N
authors: Kandasamy
authors: Jozef
authors: J
authors: Jarosz
authors: Lalit
authors: L
authors: Kalra
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D011446:Prospective Studies; D011859:Radiography; D020521:Stroke / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy*; D015912:Thrombolytic Therapy
keywords: Computed tomography; Hyperdense artery sign; Ischaemic stroke; Mismatch; Perfusion; Thrombolysis