Presentation

46M who presented with left hemiplegia

Diagnosis

• Acute embolic infarcts

Key Findings

• Large area of cortical restricted diffusion in the right posterior frontal lobe with associated T2/FLAIR signal hyperintensity involving the precentral gyrus
• Several punctate scattered bilateral supratentorial and infratentorial foci of restricted diffusion with involvement of both hemispheres, the left caudate, and the bilateral cerebellar hemispheres

Incidental findings

• Right frontal and anterior ethmoidal sinus opacification.

Discussion

• Bilateral supratentorial and posterior fossa acute infarcts with restricted diffusion consistent with embolic etiology. Don't let satisfaction of search stop you from completing your search pattern. If you just discussed the large right cortical lesion you may conclude this was a MCA territory pathology, and miss the other smaller/more subtle infarcts.
• There was no hemorrhage in these lesions. The GRE/SWI sequences can be most useful to detect subtle cases of hemorrhagic transformation. Look for hypo-intense blooming that can have variable T1/T2 signal depending on the age of the blood products.
• Whenever you see an infarct, try to associate it with a specific vascular territory. Whenever there are multiple infarcts than span multiple vascular territories, think about the possibility of a central/embolic etiology.
• Remember that MRI can be useful in the staging of infarcts. This can have consequences for clinical decision making and possible mechanical thrombectomy.
• For our case the areas of concern were hypointense on ADC, and hyperintense on DWI, T2 and FLAIR, compatible with an acute timeframe

Further reading

• An excellent review of vascular territories is provided here: https://radiologyassistant.nl/neuroradiology/brain-ischemia/vascular-territories
• Become familiar with the staging of infarcts as outlined in this review: https://radiologyassistant.nl/neuroradiology/brain-ischemia/imaging-in-acute-stroke.
• Although no blood products were seen in this case, hemorrhagic transformation can be an important finding on the GRE/SWI images as described above. The T1/T2 signal of blood is variable and can be remembered by several ridiculous mnemonics: https://radiopaedia.org/articles/ageing-blood-on-mri-mnemonic?lang=us