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'Fogging' resulting in normal MRI 3 weeks after ischaemic stroke
Philip Choi1, Velandai Srikanth, Thanh Phan
1Department of Neurosciences, Monash Medical Centre, Melbourne, Australia. philip.choi@gmx.com
BMJ Case Reports
|June 14, 2012
Summary
Acute stroke diagnosis can be challenging as brain imaging may not show immediate changes. Magnetic resonance imaging (MRI) may not detect ischemic stroke in the subacute phase, highlighting the importance of clinical evaluation.
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Computed tomography (CT) of the brain is frequently normal in acute stroke cases.
- Magnetic resonance imaging (MRI) is a sensitive tool for detecting ischemic changes, but findings can be delayed.
- Stroke diagnosis relies heavily on clinical presentation, especially when initial imaging is inconclusive.
Observation:
- A 69-year-old male presented with acute right hemiparesis after 26 hours.
- Initial CT brain scan revealed no abnormalities.
- Follow-up MRI scans showed abnormalities only 11 weeks post-stroke; initial scans at 3 weeks were normal.
Findings:
- Ischemic stroke may not be visible on MRI in the subacute phase.
- The 'invisibility' of infarct on MRI can occur despite clinical symptoms of stroke.
- Delayed detection of ischemic changes on MRI is possible, emphasizing the temporal aspect of imaging.
Implications:
- Clinical diagnosis of stroke remains crucial, especially when imaging is negative or equivocal.
- Interpretation of MRI in suspected stroke requires careful consideration of the time elapsed since symptom onset.
- This case underscores the potential for 'invisible' infarcts on MRI during the subacute period of ischemic stroke.
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