Chronic Cerebral Infarction

KEY FACTS

IMAGING

• Volume loss with gliosis along affected margins

• Classic: Wedge-shaped area of encephalomalacia

• Territorial infarction

○ Involves brain supplied by major cerebral artery

• Watershed infarction

○ Involves brain between main vascular territories

• Lacunar infarction(s)

○ Most common in basal ganglia/thalami, deep white

matter

TOP DIFFERENTIAL DIAGNOSES

• Porencephalic cyst

• Arachnoid cyst

• Postsurgical/posttraumatic encephalomalacia

• Low-attenuating tumors

PATHOLOGY

• Volume loss, gliosis are pathological hallmarks

CLINICAL ISSUES

• Elderly patient with typical risk factors

• Focal neurologic deficit

○ Varies depending on size, location of cerebral infarction

• Stroke severity most consistent predictor of 30-day

mortality after stroke

• Lacunar stroke most common stroke subtype associated

with vascular dementia

DIAGNOSTIC CHECKLIST

• Evaluate for associated acute infarcts in same or different

vascular territory

• Evaluate for underlying cause

○ CTA/MRA of extra-/intracranial vasculature

○ If negative, consider cardiac source

• Evaluate for risk factors

(Left) Axial graphic shows

chronic infarct involving the

posterior left middle cerebral

artery (MCA) territory. Infarct

is lined with gliotic WM. Small

lacunar infarctions and

atrophy also depicted. (Right)

Axial gross pathology,

sectioned through the

midventricular level, shows a

chronic left MCA infarct with

encephalomalacia in the

classic MCA vascular

distribution ﬈. Note the

adjacent WM gliosis ﬊ and

the mild compensatory

enlargement of the left lateral

ventricle ﬉. (Courtesy R.

Hewlett, MD.)

(Left) Axial NECT scan 2 days

after large territorial

infarction in the left MCA

territory shows wedge-shaped

hypodensity ſt involving both

cortex, WM, and basal ganglia.

Moderate mass effect is

present, with subfalcine

herniation of the lateral

ventricles. (Right) Follow-up

scan 2 months later shows

findings of chronic infarct. The

mass effect has resolved

completely, and there is frank

encephalomalacia in the left

MCA territory ſt. The left

lateral ventricle shows

compensatory enlargement

﬇.

Trauma, and Stroke

Brain: Pathology-Based Diagnoses: Malformations,

99

Multiple Embolic Cerebral Infarctions

KEY FACTS

TERMINOLOGY

• Infarcts in multiple arterial distributions from embolic

source, often cardiac origin

IMAGING

• Best imaging clue: DWI restriction in multiple vascular

distributions

• NECT: Multiple regions of low attenuation, loss of graywhite differentiation

• T2/FLAIR: Multiple supratentorial and infratentorial regions

of hyperintensity, often in vascular distribution

○ May be of different ages

• Embolic infarcts tend to involve terminal cortical branches,

producing wedge-shaped infarcts

• Cardiac echocardiography may show valve vegetations,

intracardiac filling defect, or atrial or ventricular septal

defect

• Best imaging tool: MR with DWI, FLAIR, T1WI C+

TOP DIFFERENTIAL DIAGNOSES

• Hypotensive cerebral infarction

• Multiple sclerosis

• Parenchymal metastases

• Vasculitis

CLINICAL ISSUES

• Multiple focal neurologic complaints not conforming to

singular vascular distribution

• Peripheral signs of emboli, such as splinter hemorrhages or

paradoxical emboli

• Cardiac source most common etiology of multiple embolic

infarcts

○ May be septic or benign

• Carotid artery disease may cause multiple embolic infarct, if

associated with variant posterior cerebral artery origin

• Cardiac and vascular evaluation → treat underlying disease

(Left) Axial DTI trace image

shows multiple regions of

diffusion hyperintensity ſt

related to acute middle

cerebral artery (MCA)

distribution ischemia in

bilateral hemispheres in a

patient with embolic disease

from a cardiac source. (Right)

Axial FLAIR MR shows

bilateral chronic MCA

distribution ischemia ﬇

related to untreated atrial

fibrillation. Note the areas of

encephalomalacia ſt with

surrounding gliosis st, typical

of chronic ischemia.

(Left) Axial DTI trace shows

acute ischemia in the left

hemisphere in multiple

vascular distributions. Note

the involvement of the

recurrent artery of Heubner

from the ACA distribution

(head of caudate) ﬇, as well

as the MCA ſt and PCA st

territories, in this patient with

severe internal carotid artery

atherosclerotic disease and a

fetal origin PCA. (Right) Axial

T1 C+ FS MR shows multiple

foci of enhancement ﬇ in

bilateral hemispheres related

to septic emboli in a patient

with cardiac valve

vegetations.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

100