Diffusion-negative acute ischemic stroke

Case contributed by Dr Mohamed Saber


Acute right-sided weakness, aphasia and , disturbed level of consciousness. Known as diabetic and hypertensive.

Patient Data

Age: 70 years
Gender: Male

Initial MRI


No definite areas of restricted diffusion in the DWI and ADC.

Small vessel disease is noted in the FLAIR sequence.

Follow up after 18 hours


Left frontal parasagittal patchy area of diffusion restriction along left anterior cerebral artery territory elicits high signal in DWI and low signal in ADC.

Case Discussion

Here is a rare case of negative diffusion in an acute ischemic stroke of the left anterior cerebral artery territory. It is very uncommon for the MRI diffusion to fail to detect acute ischemia.

Posterior fossa strokes, small strokes especially of the brain stem as well as hyperacute ischemia may be missed or underestimated in the MRI diffusion 1.

The radiologists should be aware of this condition and consider the clinical suspicion of acute ischemic stroke even with negative initial MRI diffusion. Using a description like (no detected areas of diffusion restriction) could be more reasonable in the radiology report than (no acute cerebral infarction). 

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