Fogging on T2-weighted MR after acute ischaemic stroke: how often might this occur and what are the implications?

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

"Fogging" is the temporary loss of visibility of an infarct on CT which occurs in the subacute phase at about 2 weeks after stroke. It occurs in up to 40% of medium to large infarcts on CT. It is unclear whether or how often fogging occurs on T2-weighted MR, but if it does occur, it can cause underestimation of true infarct size. This study examined the possible frequency and time scale of "fogging" on T2-weighted MR. We conducted a blinded, independent review of prospectively collected MR scans from patients with symptoms of cortical ischaemic stroke, scanned sequentially up to 7 weeks after stroke. On each scan maximum infarct area was measured, and the infarct extent and swelling were coded on a validated scale. "Fogging" was suggested by reduced infarct extent between initial and subsequent scans. In 30 patients (with 74 scans) there was some apparent "fogging" in 50% of patients between 6 and 36 days (median 10 days) after stroke. Reduction in infarct extent on T2-weighted MR which may be attributed to "fogging" occurs in a significant proportion of patients with cortical infarcts. This may lead to an underestimation of true final infarct extent. This suggests that true infarct extent on T2-weighted MR can probably only be assessed on scans obtained beyond 7 weeks after stroke.

Original languageEnglish
Pages (from-to)635-41
Number of pages7
Issue number8
Publication statusPublished - Aug 2004

Keywords / Materials (for Non-textual outputs)

  • Brain Infarction
  • Brain Ischemia
  • Cerebrovascular Circulation
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging
  • Retrospective Studies
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Time Factors


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