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When to expect negative diffusion-weighted images in stroke and transient ischemic attack

P N Sylaja1, Shelagh B Coutts, Andrea Krol

  • 1Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Centre, Room 1162, University of Calgary, Alberta, Canada.

Stroke
|April 19, 2008
PubMed
Abstract

Insights

A significant number of acute stroke and TIA patients initially show negative diffusion-weighted imaging (DWI). Follow-up MRI can confirm infarcts in a subset of these DWI-negative cases, particularly those with brainstem or lacunar syndromes.

Area of Science:

  • Neurology
  • Radiology
  • Neuroimaging

Background:

  • Cerebral ischemia diagnosis often relies on diffusion-weighted imaging (DWI).
  • The occurrence and predictors of DWI-negative cerebral ischemia remain unclear.
  • Understanding these cases is crucial for accurate stroke and TIA diagnosis.

Purpose of the Study:

  • To determine the frequency of DWI-negative cerebral ischemia in patients with stroke and transient ischemic attack (TIA).
  • To identify clinical factors associated with DWI-negative findings.
  • To evaluate the utility of follow-up imaging in diagnosing these cases.

Main Methods:

  • Magnetic resonance imaging (MRI) including DWI was performed on 401 patients within 24 hours of symptom onset.
  • Follow-up MRI was conducted at 30 days for all patients.
  • Clinical data and final diagnoses were analyzed.

Main Results:

  • 103 out of 401 patients (25.6%) presented with an initial negative DWI.
  • In the DWI-negative group, 23.1% of stroke patients and 3.2% of TIA patients showed infarcts on follow-up MRI.
  • Perfusion imaging detected ischemia in some DWI-negative cases, and specific syndromes (brainstem, lacunar) were more likely to be DWI-negative initially but confirmed later.

Conclusions:

  • Baseline perfusion imaging may identify ischemia in a portion of DWI-negative patients.
  • DWI-negative findings with subsequent infarct confirmation or stroke diagnosis were associated with brainstem or lacunar syndromes.
  • These findings highlight the importance of considering follow-up imaging and clinical diagnosis in DWI-negative stroke and TIA evaluations.

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