Neurovascular Cases

What’s the diagnosis?

There is acute intracranial hemorrhage within the left basal ganglia with intraventricular extension. The CT angiogram shows severe stenosis of the bilateral internal carotid arteries at the communicating segment with prominent lenticulostriate collateral vessels. Arteriography shows advanced moymoya disease without any obvious or treatable associated vascular lesions, such as prominent microaneurysms.

There is also an incidental interhemispheric mass, most likely a meningioma.

On these left internal carotid artery injections, notice the advanced moyamoya vasculature about the terminus segment of the vessel. There is cross filling through the anterior communicating artery to the contralateral middle cerebral artery as well.

On these right internal carotid artery injections, notice the advanced moyamoya vasculature about the terminus segment of the vessel.

On this right external artery injection note the trans-osseous collaterals that have developed from the superficial temporal artery through the bony skull and into the right intracranial circulation.

On this left vertebral artery injection, note the extensive leptomeningeal collateral flow that has developed from the posterior cerebral artery to the anterior cerebral artery.

Background

  • Moyamoya disease is an odd, progressive disease of the intracranial circulation where the internal carotid arteries gradually occlude. To compensate, new collateral blood flow pathways form.
  • Abnormal, small-caliber networks of “moyamoya” vessels, such as dilated lenticulostriate and choroidal arteries, form at the base of the brain. (Flow through these tiny vessels at the base of the brain are responsible for the angiographic puff of smoke appearance.)
  • Collateral pathways route blood from the external carotid artery circulation to the intracranial circulation as well.
  • Unlike moyamoya disease that presents in children with ischemic events, moyamoya that presents in older adults is commonly hemorrhagic. Chronic hemodynamic stress to the small-caliber moyamoya vessels → development of microaneurysms that may rupture. Hemorrhage about these vessels is typically located in the thalamus, basal ganglia, and ventricular system.

What's your treatment plan?

  • If intraventricular hemorrhage causes obstructive hydrocephalus, then a ventriculostomy catheter should be placed.
  • Unfortunately, many older patients with hemorrhagic moyamoya disease suffer significant neurological morbidity.
  • In patients who mount a recovery after their initial hemorrhage, it seems that revascularization surgeries that augment external carotid-to-intracranial collateral flow pathways help to reduce the occurrence of recurrent intracranial hemorrhage.
  • Revascularization strategies include indirect bypass surgery, such as encephalo-duro-arterio-synangiosis (EDAS) and direct bypass surgery, such as superficial temporal artery-to-middle cerebral artery bypass.

Advanced moyamoya disease that presents in middle-aged and older adults with hemorrhage is a debilitating chronic disease. If patients mount a recovery from their initial bleeding event, then surgical revascularization should be considered to reduce the occurrence of further ischemic and hemorrhagic events.