title: Leptomeningeal collateralization in acute ischemic stroke: impact on prominent cortical veins in susceptibility-weighted imaging.
abstract: BACKGROUND
  The extent of hypoperfusion is an important prognostic factor in acute ischemic stroke. Previous studies have postulated that the extent of prominent cortical veins (PCV) on susceptibility-weighted imaging (SWI) reflects the extent of hypoperfusion. Our aim was to investigate, whether there is an association between PCV and the grade of leptomeningeal arterial collateralization in acute ischemic stroke. In addition, we analyzed the correlation between SWI and perfusion-MRI findings.
  
  
  METHODS
  33 patients with acute ischemic stroke due to a thromboembolic M1-segment occlusion underwent MRI followed by digital subtraction angiography (DSA) and were subdivided into two groups with very good to good and moderate to no leptomeningeal collaterals according to the DSA. The extent of PCV on SWI, diffusion restriction (DR) on diffusion-weighted imaging (DWI) and prolonged mean transit time (MTT) on perfusion-imaging were graded according to the Alberta Stroke Program Early CT Score (ASPECTS). The National Institutes of Health Stroke Scale (NIHSS) scores at admission and the time between symptom onset and MRI were documented.
  
  
  RESULTS
  20 patients showed very good to good and 13 patients poor to no collateralization. PCV-ASPECTS was significantly higher for cases with good leptomeningeal collaterals versus those with poor leptomeningeal collaterals (mean 4.1 versus 2.69; p=0.039). MTT-ASPECTS was significantly lower than PCV-ASPECTS in all 33 patients (mean 1.0 versus 3.5; p<0.00).
  
  
  CONCLUSIONS
  In our small study the grade of leptomeningeal collateralization correlates with the extent of PCV in SWI in acute ischemic stroke, due to the deoxyhemoglobin to oxyhemoglobin ratio. Consequently, extensive PCV correlate with poor leptomeningeal collateralization while less pronounced PCV correlate with good leptomeningeal collateralization. Further SWI is a very helpful tool in detecting tissue at risk but cannot replace PWI since MTT detects significantly more ill-perfused areas than SWI, especially in good collateralized subjects.
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland. Electronic address: rajeev.verma@insel.ch.
authors.forename: Rajeev K
authors.initials: RK
authors.lastname: Verma
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Kety
authors.initials: K
authors.lastname: Hsieh
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Pascal P
authors.initials: PP
authors.lastname: Gratz
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Schankath
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Mordasini
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Zubler
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Frauke
authors.initials: F
authors.lastname: Kellner-Weldon
authors.affiliation: Department of Neurology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Simon
authors.initials: S
authors.lastname: Jung
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schroth
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Gralla
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Marwan
authors.initials: M
authors.lastname: El-Koussy
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000473:pathology*; D002550:Cerebral Veins / Q000000981:diagnostic imaging / Q000473:pathology*; D003097:Collateral Circulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008578:Meninges / Q000098:blood supply*; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging / Q000473:pathology*
keywords: Acute ischemic stroke; Leptomeningeal collateralization; Perfusion-weighted imaging; Prominent cortical veins; Susceptibility-weighted imaging