Leif Østergaard

Transit time homogenization in ischemic stroke - A novel biomarker of penumbral microvascular failure?

Research output: Research - peer-reviewJournal article

DOI

  • Thorbjørn S Engedal
  • Niels Hjort
  • Kristina D Hougaard
  • Claus Z Simonsen
  • Grethe Andersen
  • Irene Klærke Mikkelsen
  • Jens K Boldsen
  • Simon F Eskildsen
  • Mikkel B Hansen
  • Hugo Angleys
  • Sune N Jespersen
  • Salvador Pedraza
    Salvador PedrazaDepartment of Radiology, Girona Biomedical Research Institute, Hospital Universitari de Girona Dr Josep Trueta, Universitat de Girona, GironaSpain
  • Tae-Hee Cho
    Tae-Hee Cho7 Department of Neurology, Hospices Civils de Lyon, Lyon, France.France
  • Joaquín Serena
    Joaquín SerenaDepartment of Neurology, Girona Biomedical Research Institute, Hospital Universitari de Girona Dr Josep Trueta, Universitat de Girona, GironaSpain
  • Susanne Siemonsen
    Susanne SiemonsenDepartment of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, HamburgGermany
  • Götz Thomalla
    Götz ThomallaDepartment of Neurology, University Medical Center Hamburg-Eppendorf, HamburgGermany
  • Norbert Nighoghossian
    Norbert NighoghossianCerebrovascular Unit, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de LyonFrance
  • Jens Fiehler
    Jens FiehlerDept. Neuroradiology, University Medical Center Hamburg-Eppendorf, HamburgGermany
  • Kim Mouridsen
  • Leif Østergaard

Cerebral ischemia causes widespread capillary no-flow in animal studies. The extent of microvascular impairment in human stroke, however, is unclear. We examined how acute intra-voxel transit time characteristics and subsequent recanalization affect tissue outcome on follow-up MRI in a historic cohort of 126 acute ischemic stroke patients. Based on perfusion-weighted MRI data, we characterized voxel-wise transit times in terms of their mean transit time (MTT), standard deviation (capillary transit time heterogeneity - CTH), and the CTH:MTT ratio (relative transit time heterogeneity), which is expected to remain constant during changes in perfusion pressure in a microvasculature consisting of passive, compliant vessels. To aid data interpretation, we also developed a computational model that relates graded microvascular failure to changes in these parameters. In perfusion-diffusion mismatch tissue, prolonged mean transit time (>5 seconds) and very low cerebral blood flow (≤6 mL/100 mL/min) was associated with high risk of infarction, largely independent of recanalization status. In the remaining mismatch region, low relative transit time heterogeneity predicted subsequent infarction if recanalization was not achieved. Our model suggested that transit time homogenization represents capillary no-flow. Consistent with this notion, low relative transit time heterogeneity values were associated with lower cerebral blood volume. We speculate that low RTH may represent a novel biomarker of penumbral microvascular failure.

Original languageEnglish
JournalJournal of Cerebral Blood Flow and Metabolism
Pages (from-to)271678X17721666
ISSN0271-678X
DOIs
StateE-pub ahead of print - 31 Jul 2017

    Research areas

  • Journal Article

See relations at Aarhus University Citationformats

ID: 115441795