Carotid dissection with watershed infarct

Case contributed by Frank Gaillard
Diagnosis certain


Right sided weakness.

Patient Data

Age: Young adult
Gender: Female

Non contrast CT demonstrates patchy low density seen in the white matter of the left cerebral hemisphere, in a deep watershed distribution.

CT perfusion demonstrates:

  • increased mean transit time (MTT); consistent with slow flow
  • increased cerebral blood volume (CBV) in the cortex
  • decreased cerebral blood flow (CBF) in the white matter

In other words there is a ischemic penumbra (mismatch between MTT and CBF) encompassing the cortex, which has vasodilation (thus elevated CBV). 

Angiogram confirms diagnosis of left ICA dissection, seen as a tapering lumen which disappears below the base of skull. 

Patient was treated with endovascular stent placement.

Diffusion weighted imaging the next day demonstrates only patchy deep border zone restricted diffusion. Little if any cortical infarction is present.

Case Discussion

This young woman presented with a spontaneous carotid dissection and extensive watershed infarction between underperfused MCA territory on the left and ACA / PCA. The perfusion maps correctly identified an ischemic penumbra encompassing most of the cortex, which was being supplied by collaterals, encouraged by maximal vasodilatation. 

Carotid stent placement re-established cortical perfusion and saved this patient from a devastating stroke. 

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.