Vasospasm

KEY FACTS

TERMINOLOGY

• Reversible stenosis of intracranial arteries

• Common with aneurysmal subarachnoid hemorrhage (SAH)

• Caused by exposure to blood breakdown products

○ Contraction of vascular smooth muscle

○ Histological changes in vessel wall

IMAGING

• General features (CTA/MRA/DSA)

○ Typically occurs 4-14 days after SAH

○ Smooth, relatively long segmental stenoses

○ Seen as arterial luminal irregularity/undulations

○ Multiple arteries, usually > 1 vascular territory

• CT perfusion

○ ↑ time to peak, ↑ mean transit time

○ ↓ cerebral blood flow in areas of hypoperfusion

• Transcranial Doppler shows ↑ mean flow velocity

TOP DIFFERENTIAL DIAGNOSES

• Non-SAH causes of vasospasm

○ Meningitis

○ Acute hypertensive encephalopathy (PRES)

○ Reversible cerebral vasoconstriction syndrome

○ Migraine headache

• Vasculitis

• Atherosclerosis

CLINICAL ISSUES

• Delayed ischemic neurological deficit

○ ~ 1 week after SAH is typical

• Management

○ "Triple H" therapy to prevent/treat vasospasm after SAH

– Induced hypertension

– Hypervolemia

– Hemodilution

○ Endovascular (chemical or balloon angioplasty)

(Left) Autopsied case of

ruptured middle cerebral

artery (MCA) aneurysm ﬊

with subarachnoid

hemorrhage (SAH) in a patient

who survived several days

shows severe vasospasm of

the parent MCA ﬈. (Right)

Axial NECT in a 43-year-old

man in the ER with "worst

headache of life" shows

diffuse SAH ſt in the basal

cisterns, especially in the left

sylvian fissure.

(Left) CTA in the same patient

shows a lobulated aneurysm

﬇ at the left distal internal

carotid artery bifurcation.

(Right) Four days after

emergency clipping of the

aneurysm, the patient became

drowsy and developed rightsided weakness. AP DSA of the

left internal carotid artery

shows mass effect, vasospasm

﬈, seen here as narrowing of

the proximal anterior cerebral

artery and MCA. The patient

responded well to intraarterial

infusion of verapamil.

Trauma, and Stroke

Brain: Pathology-Based Diagnoses: Malformations,

85