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Updated: Jul 3, 2026

A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Diffusion-negative MRI in acute ischemic stroke: a case report
Rahul Rathakrishnan1, Vijay K Sharma, Bernard Pl Chan
1Division of Neurology, Department of Medicine, National University Hospital, Singapore. drvijay@singnet.com.sg.
Background:
Diffusion-weighted magnetic resonance imaging is a very sensitive tool for the early diagnosis of acute ischemic stroke. This is employed in some stroke centers as the primary screening tool to select patients eligible for thrombolysis.
Methods:
We present the case of a 49-years old Chinese man whose diffusion-weighted magnetic resonance imaging performed 12 hours of symptom onset was negative.
Results:
Although the initial diffusion-weighted magnetic resonance imaging was negative, the imaging repeated after 4 days despite static neurological symptoms and signs, could demonstrate an acute medullary infarction.
Conclusion:
Diffusion-weighted imaging may not be100% sensitive in very early stages, especially in posterior circulation strokes. Our case serves as a reminder that clinical assessment still retains priority until a diagnostic modality offering 100% sensitivity and specificity is discovered.
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