title: The role of dual energy CT in differentiating between brain haemorrhage and contrast medium after mechanical revascularisation in acute ischaemic stroke.
abstract: OBJECTIVE
  To assess the feasibility of dual energy computed tomography (DE-CT) in intra-arterially treated acute ischaemic stroke patients to discriminate between contrast extravasation and intracerebral haemorrhage.
  
  
  METHODS
  Thirty consecutive acute ischaemic stroke patients following intra-arterial treatment were examined with DE-CT. Simultaneous imaging at 80 kV and 140 kV was employed with calculation of mixed images. Virtual unenhanced non-contrast (VNC) images and iodine overlay maps (IOM) were calculated using a dedicated brain haemorrhage algorithm. Mixed images alone, as "conventional CT", and DE-CT interpretations were evaluated and compared with follow-up CT.
  
  
  RESULTS
  Eight patients were excluded owing to a lack of follow-up or loss of data. Mixed images showed intracerebral hyperdense areas in 19/22 patients. Both haemorrhage and residual contrast material were present in 1/22. IOM suggested contrast extravasation in 18/22 patients; in 16/18 patients this was confirmed at follow-up. The positive predictive value (PPV) of mixed imaging alone was 25 %, with a negative predictive value (NPV) of 91 % and accuracy of 63 %. The PPV for detection of haemorrhage with DE-CT was 100 %, with an NPV of 89 % and accuracy improved to 89 %.
  
  
  CONCLUSIONS
  Dual energy computed tomography improves accuracy and diagnostic confidence in early differentiation between intracranial haemorrhage and contrast medium extravasation in acute stroke patients following intra-arterial revascularisation.
  
  
  CONCLUSIONS
  • Contrast material and haemorrhage have similar density on conventional 120-kV CT. • Contrast material hinders interpretation of CT in stroke patients after recanalisation. • Iodine and haemorrhage have different attenuation at lower kVs. • Dual energy CT improves accuracy in early differentiation of haemorrhage and contrast extravasation. • Early differentiation between iodine and haemorrhage helps to initiate therapy promptly.
authors.affiliation: Department of Radiology, Maastricht University Medical Centre, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: M P M
authors.initials: MP
authors.lastname: Tijssen
authors.forename: P A M
authors.initials: PA
authors.lastname: Hofman
authors.forename: A A R
authors.initials: AA
authors.lastname: Stadler
authors.forename: W
authors.initials: W
authors.lastname: van Zwam
authors.forename: R
authors.initials: R
authors.lastname: de Graaf
authors.forename: R J
authors.initials: RJ
authors.lastname: van Oostenbrugge
authors.forename: E
authors.initials: E
authors.lastname: Klotz
authors.forename: J E
authors.initials: JE
authors.lastname: Wildberger
authors.forename: A A
authors.initials: AA
authors.lastname: Postma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001921:Brain / Q000098:blood supply; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging* / Q000209:etiology; D003287:Contrast Media / Q000032:analysis; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007455:Iodine / Q000032:analysis; D008297:Male; D061185:Mechanical Thrombolysis / Q000009:adverse effects*; D008875:Middle Aged; D020521:Stroke / Q000628:therapy*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007455:Iodine