Enlarged perivascular space and fusiform MCA aneursym

Case contribution: Dr Radhiana Hassan


  • An 82 years old lady
  • UnderlyingDM, HPT, hyperlipidaemia,
  • Presented with incoherent speech and lower limb weakness.
  • Clinical examination shows GCS E4V4M6, power lower limbs 3/5.
  • Fluctuation in GCS is due to metabolic disorders (acute CKD with urea 23 and metabolic acidosis)
  • Improve during hospitalization
CT scan brain non-contrast in axial plane soft tissue window

CT scan findings:

  • There is dilatation of lateral, third and fourth ventricles
  • Widening of CSF spaces seen, more prominent at frontotemporal region.
  • No crowding of vertex. Callosal angle is normal.
  • Left MCA appears dilated (red arrow)
  • A few areas of lacunar infarctions are also seen
MRI brain in axial and coronal T2-weigthed images
MRI of brain in axial planes, T1, T2 and FLAIR sequences

MRI findings:

  • MRI better demonstrate the fusiform dilatation of left distal ICA extending to MCA (red arrows)
  • No saccular aneurysm is seen
  • The are numerous T1-hypointense, T2-hyperintense and FLAIR suppressed lesions in both basal ganglia with almost symmetrical distributions (blue arrows). This is in keeping with dilated perivascular spaces.
  • No acute infarction seen
  • Generalised cerebral atrophy with leukoariosis are also seen

Diagnosis: Fusiform MCA aneurysm with dilated perivascular space and cerebral atrophy


  • Dilated perivascular spaces (PVS) is seen as cluster of variable-sized fluid-filled spaces similar to CSF signal intensity
  • Most common site for PVS is basal ganglia.
  • Other location includes midbrain, deep white matter, subinsular cortex, thalami and corpus callosum, dentate nuclei
  • Fusiform aneurysm of intracranial vessels are usually caused by atherosclerotic disease. It comprises 3-13% of intracranial aneurysms. Most cases are treated conservatively.
Author: radhianahassan