title: Perfusion-diffusion mismatch in MRI to indicate endovascular treatment of cerebral vasospasm after subarachnoid haemorrhage.
abstract: BACKGROUND
  Endovascular treatments such as transluminal balloon angioplasty and intra-arterial nimodipine represent rescue therapy for cerebral vasospasm (CVS) after aneurysmal subarachnoid haemorrhage (SAH). Both indication and data regarding its efficacy in the prevention of cerebral infarct are, however, inconsistent. Therefore, an MR based perfusion weighted imaging/diffusion weighted imaging (PWI/DWI) mismatch was used to indicate this treatment and to characterise its effectiveness.
  
  
  METHODS
  MRI was performed for suspicion of CVS. For quantitative evaluation, the brain was partitioned into 19 arbitrary segments of comparable volume. Segments with PWI/DWI mismatch were defined as 'segment at risk (SR)'. In these cases, MRI was followed by angiography (digital subtraction angiography (DSA)) including endovascular treatment. 48 ± 12 h after treatment, a second MRI was performed and the treatment was repeated if new or remaining SR were observed. Efficacy was classified as the percentage of reduced diameter of the proximal cerebral arteries on DSA following the treatment: mild (≥33%), moderate (34-66%) or severe (≥67%).
  
  
  RESULTS
  48 treatment cycles, each consisting of MRI, DSA and a second MRI, were performed in 25 patients. During these cycles, 95 SR were identified. The infarct rate was significantly higher in SR (37%) compared with segments without risk (4%). The infarct rate in SR was significantly reduced if mild proximal CVS could be achieved. In the case of persistent severe CVS, infarcts occurred in all SR.
  
  
  CONCLUSIONS
  The present series suggests that PWI/DWI mismatch is predictive of the development of infarct in the case of CVS. The infarct rate could, however, be improved if proximal CVS was sufficiently reduced.
authors: Department of Neurosurgery, Goethe-University, Schleusenweg, 2-16, Frankfurt/Main D-60528, Germany. h.vatter@em.uni-frankfurt.de
authors: Hartmut
authors: H
authors: Vatter
authors: Erdem
authors: E
authors: Güresir
authors: Joachim
authors: J
authors: Berkefeld
authors: Jürgen
authors: J
authors: Beck
authors: Andreas
authors: A
authors: Raabe
authors: Richard
authors: R
authors: du Mesnil de Rochemont
authors: Volker
authors: V
authors: Seifert
authors: Stefan
authors: S
authors: Weidauer
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D000800:Angioplasty, Balloon / Q000379:methods; D001921:Brain / Q000098:blood supply*; D002544:Cerebral Infarction / Q000517:prevention & control; D002560:Cerebrovascular Circulation; D004058:Diffusion; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D020301:Vasospasm, Intracranial / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*