Cortical watershed infarcts

Case contribution: Dr. Raja Rizal Azman 


  • A 41-year old  man with a history of  diabetes and hypertension
  • Presents with a one week history of worsening right sided upper and lower limb weakness and a single episode of facial twitching.
  • Examination revealed a right sided upper and lower limb weakness with increased tone and brisk reflexes.

Imaging findings:

  • Unenhanced CTof the brain at the level of the corona radiata (A) and the centrum semiovale (B)
  • There are ill defined hypodensities affecting the grey and white matter at the left frontal lobe at the left MCA/ACA borderzone and the left parietal lobe at the MCA/PCA bordezone.

Diagnosis: Cortical watershed infarcts


  • Watershed infarcts occur at the borderzone of two vascular territories and represent up to 10% of infarcts.
  • They can be classified into internal or cortical watershed infarcts.
  • Internal watershed infarcts are thought to be secondary to haemodynamic compromise and have a risk of recurrent stroke with higher mortality and morbidity whereas cortical infarcts are more related to emboli and are associated with a more benign course.
Figure showing the cortical (blue triangles) and internal (red ovals) vascular border zones where watershed infarcts occur.


Author: radhianahassan