Cerebral arteriovenous malformation

Case contributed by Ian Bickle
Diagnosis certain

Presentation

Long history of a cerebral AVM. Unspecified non surgical treatment overseas. Rare cognitive decline in recent weeks.

Patient Data

Age: 25 years
Gender: Male

Day 1 ( as an outpatient )

ct

Extensive area of irregular dense calcification with metallic artifact in the left occipitotemporoparietal region associated with surrounding gliosis representing the area of known arteriovenous malformation.

VP shunt is seen in situ with its tip in the anterior horn of the left lateral ventricle.

Low attenuation in the periventricular white matter.

Day 7 ( as an outpatient )

mri

Right parietal V-P shunt.

Huge left parieto-occipital arteriovenous malformation measuring 6.5 cm with significant surrounding gliosis. Flow-voids in keeping with partial calcification of the AVM.

The arterial feeders arise from an enlarged left posterior cerebral artery, enlarged pericallosal artery and smaller caliber vessels from the posterior branch of the left middle cerebral artery.

The draining vein measures 7 mm going directly into the straight sinus.

Huge number of dilated surface veins, best appreciated on SWI images.

Large number of dilated veins anterior to the pons and brainstem and extending into the intradural, perimedullary space from C2-T1.

Additional 2.2 cm ''mesh'' of smaller cortical vessels in the right parietal lobe at the site of the V-P shunt insertion.

No hydrocephalus. High T2 signal in the periventricular white matter of the frontal horns.

Acute Rt sided HA & reduced...

ct

Acute Rt sided HA & reduced GCS Day 14. Admitted to hospital.

Extensive area of irregular dense calcification with metallic artifact in the left occipito- temporoparietal region associated with surrounding gliosis representing the area of known arterio-venous malformation.

VP shunt is seen in situ with its tip in the anterior horn of the left lateral ventricle.

A focal cortical hemorrhage has developed in the right parietal lobe at the site of entry of the VP shunt.

Low attenuation in the periventricular white matter, more pronounced than on the index CT scan.

Case Discussion

Cerebral arteriovenous malformations (CAVM's) are a common form of cerebral vascular malformation and are composed of a nidus of vessels through which arteriovenous shunting occurs. They tend to be solitary in the vast majority of cases (>95%). The origin of arteriovenous malformations remains uncertain, although they are thought to be congenital.

The Spetzler-Martin AVM grading system allocates points for various features of intracranial AVM's to give a score between 1 and 5.  This case represents the extreme end of the scale - a grade 5 AVM.

Catheter angiography was performed following this acute bleed - the nature of the AVM on MRI was confirmed:

  1. huge left parieto-occipital AVM
  2. smaller right cortical parietal vascular lesion – this appears separate adjacent to the VP shunt entry point. This subsequently bled.
  3. distended cortical veins and periventricular appearances are suggestive of cerebral venous hypertension, and perhaps responsible for the patient's decline prior to the cortical hemorrhage.

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