title: Assessment of thrombus in acute middle cerebral artery occlusion using thin-slice nonenhanced Computed Tomography reconstructions.
abstract: OBJECTIVE
  We sought to evaluate how accurately length and volume of thrombotic clots occluding cerebral arteries of patients with acute ischemic stroke can be assessed from nonenhanced CT (NECT) scans reconstructed with different slice widths.
  
  
  METHODS
  NECT image data of 58 patients with acute ischemic stroke with vascular occlusion proven by CT angiography were reconstructed with slice widths of 1.25 mm, 2.5 mm, 3.75 mm, and 5 mm. Thrombus lengths and volumes were quantified based on these NECT images by detecting and segmenting intra-arterial hyperdensities. The results were compared with reference values of thrombus length and volume obtained from CT angiography images using Bland-Altman analysis and predefined levels or tolerance to find NECT slice thicknesses that allow for sufficiently accurate thrombus quantification.
  
  
  RESULTS
  Thrombus length can be measured with high accuracy using the hyperdense middle cerebral artery sign detected in NECT images with slice thicknesses of 1.25 mm and 2.5 mm. We found mean deviations from the reference values and limits of agreement of -0.1 mm+/-0.6 mm with slice widths of 1.25 mm and 0.1 mm+/-0.7 mm for slice widths of 2.5 mm. Thrombus length measurements in NECT images with higher slice width and all evaluated thrombus volume measurements exhibited severe dependence on the level and did not match the accuracy criteria.
  
  
  CONCLUSIONS
  The length of the hyperdense middle cerebral artery sign as detected on thin-slice NECT reconstructions in patients with acute ischemic stroke can be used to quantify thrombotic burden accurately. Thus, it might qualify as a new diagnostic parameter in acute stroke management that indicates and quantifies the extent of vascular obliteration.
authors.affiliation: Department of Neuroradiology, UKS-H, Campus Kiel, Kiel, Germany. c.riedel@neurorad.uni-kiel.de
authors.forename: Christian H
authors.initials: CH
authors.lastname: Riedel
authors.forename: Ulf
authors.initials: U
authors.lastname: Jensen
authors.forename: Axel
authors.initials: A
authors.lastname: Rohr
authors.forename: Marc
authors.initials: M
authors.lastname: Tietke
authors.forename: Karsten
authors.initials: K
authors.lastname: Alfke
authors.forename: Stephan
authors.initials: S
authors.lastname: Ulmer
authors.forename: Olav
authors.initials: O
authors.lastname: Jansen
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*