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A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
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A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia

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Microembolic signals within 24 hours of stroke onset and diffusion-weighted MRI abnormalities

Makoto Nakajima1, Kazumi Kimura, Atsuko Shimode

  • 1Cerebrovascular Division, Department of Medicine, National Cardiovascular Center, Osaka, Japan. rosainakazima@ybb.ne.jp

Cerebrovascular Diseases (Basel, Switzerland)
|January 3, 2007
PubMed
Abstract

Insights

Microembolic signals (MES) detected by transcranial Doppler sonography (TCD) in acute stroke patients are associated with small cortical and subcortical lesions seen on diffusion-weighted magnetic resonance imaging (DWI). This finding clarifies the clinical relevance of MES in acute ischemic stroke.

Area of Science:

  • Neurology
  • Medical Imaging
  • Cardiovascular Research

Background:

  • The clinical significance of microembolic signals (MES) detected via transcranial Doppler sonography (TCD) in acute stroke patients is not well-established.
  • This prospective study investigates the correlation between MES and diffusion-weighted magnetic resonance imaging (DWI) findings in acute stroke.

Purpose of the Study:

  • To analyze the relationship between microembolic signals (MES) detected by TCD and acute ischemic lesions identified by DWI.
  • To determine the clinical relevance of MES in the context of acute stroke imaging.

Main Methods:

  • Transcranial Doppler sonography (TCD) was used to detect MES within 24 hours of stroke onset.
  • Diffusion-weighted magnetic resonance imaging (DWI) was performed within 7 days to identify and characterize acute ischemic lesions.
  • MES were assessed from Doppler waves in the middle cerebral artery contralateral to neurological deficits, and lesions were classified by size and location.

Main Results:

  • Out of 37 patients, 12 vessels (MES-positive group) showed MES, while 27 vessels (MES-negative group) did not.
  • No significant clinical differences were found between the MES-positive and MES-negative groups.
  • The MES-positive group had a significantly higher number of small lesions (p=0.02) and a higher incidence of cortical (p=0.002) and superficial perforator infarcts (p=0.02) compared to the MES-negative group.

Conclusions:

  • Microembolic signals (MES) detected by TCD during the acute phase of ischemic stroke are associated with the presence of small cortical and subcortical lesions.
  • These findings suggest that MES may be indicative of small infarcts detectable by DWI in acute stroke.

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