title: Head movement during CT brain perfusion acquisition of patients with suspected acute ischemic stroke.
abstract: OBJECTIVE
  Computed Tomography Perfusion (CTP) is a promising tool to support treatment decision for acute ischemic stroke patients. However, head movement during acquisition may limit its applicability. Information of the extent of head motion is currently lacking. Our purpose is to qualitatively and quantitatively assess the extent of head movement during acquisition.
  
  
  METHODS
  From 103 consecutive patients admitted with suspicion of acute ischemic stroke, head movement in 220 CTP datasets was qualitatively categorized by experts as none, minimal, moderate, or severe. The movement was quantified using 3D registration of CTP volume data with non-contrast CT of the same patient; yielding 6 movement parameters for each time frame. The movement categorization was correlated with National Institutes of Health Stroke Scale (NIHSS) score and baseline characteristic using multinomial logistic regression and student's t-test respectively.
  
  
  RESULTS
  Moderate and severe head movement occurred in almost 25% (25/103) of all patients with acute ischemic stroke. The registration technique quantified head movement with mean rotation angle up to 3.6° and 14°, and mean translation up to 9.1mm and 22.6mm for datasets classified as moderate and severe respectively. The rotation was predominantly in the axial plane (yaw) and the main translation was in the scan direction. There was no statistically significant association between movement classification and NIHSS score and baseline characteristics.
  
  
  CONCLUSIONS
  Moderate or severe head movement during CTP acquisition of acute stroke patients is quite common. The presented registration technique can be used to automatically quantify the movement during acquisition, which can assist identification of CTP datasets with excessive head movement.
authors.affiliation: Department of Biomedical Engineering and Physics, AMC, Amsterdam, The Netherlands. Electronic address: f.fahmi@amc.uva.nl.
authors.forename: F
authors.initials: F
authors.lastname: Fahmi
authors.forename: L F M
authors.initials: LF
authors.lastname: Beenen
authors.forename: G J
authors.initials: GJ
authors.lastname: Streekstra
authors.forename: N Y
authors.initials: NY
authors.lastname: Janssen
authors.forename: H W
authors.initials: HW
authors.lastname: de Jong
authors.forename: A
authors.initials: A
authors.lastname: Riordan
authors.forename: Y B
authors.initials: YB
authors.lastname: Roos
authors.forename: C B
authors.initials: CB
authors.lastname: Majoie
authors.forename: E
authors.initials: E
authors.lastname: Vanbavel
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000706:statistics & numerical data; D005260:Female; D019416:Head Movements; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Computed tomography; Head movements; Perfusion; Stroke