title: Asymmetrically hypointense veins on T2*w imaging and susceptibility-weighted imaging in ischemic stroke.
abstract: OBJECTIVE
  To review the literature on the assessment of venous vessels to estimate the penumbra on T2*w imaging and susceptibility-weighted imaging (SWI).
  
  
  METHODS
  Literature that reported on the assessment of penumbra by T2*w imaging or SWI and used a validation method was included. PubMed and relevant stroke and magnetic resonance imaging (MRI) related conference abstracts were searched. Abstracts that had overlapping content with full text articles were excluded. The retrieved literature was scanned for further relevant references. Only clinical literature published in English was considered, patients with Moya-Moya syndrome were disregarded. Data is given as cumulative absolute and relative values, ranges are given where appropriate.
  
  
  RESULTS
  Forty-three publications including 1145 patients could be identified. T2*w imaging was used in 16 publications (627 patients), SWI in 26 publications (453 patients). Only one publication used both (65 patients). The cumulative presence of hypointense vessel sign was 54% (range 32%-100%) for T2* (668 patients) and 81% (range 34%-100%) for SWI (334 patients). There was rare mentioning of interrater agreement (6 publications, 210 patients) and reliability (1 publication, 20 patients) but the numbers reported ranged from good to excellent. In most publications (n = 22) perfusion MRI was used as a validation method (617 patients). More patients were scanned in the subacute than in the acute phase (596 patients vs 320 patients). Clinical outcome was reported in 13 publications (521 patients) but was not consistent.
  
  
  CONCLUSIONS
  The low presence of vessels signs on T2*w imaging makes SWI much more promising. More research is needed to obtain formal validation and quantification.
authors.affiliation: Ulf Jensen-Kondering, Institute of Neuroradiology, University of Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Jensen-Kondering
authors.forename: Ruwen
authors.initials: R
authors.lastname: Böhm
keywords: Acute ischemic stroke; Oxygen extraction fraction; Penumbra; Susceptibility-weighted imaging; T2*