Lacunar Infarction

KEY FACTS

TERMINOLOGY

• Small, deep cerebral infarcts located in basal ganglia and

thalamus, pons, or cerebral white matter (WM), ≤ 15 mm 

IMAGING

• Commonly deep gray nuclei, especially putamen, thalamus,

caudate nuclei; internal capsule, pons

○ Other locations include deep and periventricular WM

• Range in size from microscopic to 15 mm

• Because of small size, most acute lacunar infarcts are not

seen on CTs

• Acute: T2/FLAIR increased signal

• Chronic: FLAIR central low signal with increased peripheral

signal (gliosis)

• DWI: Restricted diffusion (hyperintense) if acute/subacute

○ May show small lesions otherwise undetectable

• Prominent perivascular spaces are main imaging

differential diagnosis

PATHOLOGY

• Embolic, atheromatous, or thrombotic lesions in long,

single-penetrating-end arterioles supplying deep cerebral

gray matter

• Size of lacunar infarct depends on level of occlusion and

anatomy of affected vessel

CLINICAL ISSUES

• Many different presentations, depending on size, location,

number

• Most lacunar infarctions are clinically "silent," often subtle

neurological deficits that may go unnoticed by patient and

physician

• Typical risk factors for cerebrovascular disease:

Hypertension, diabetes, smoking history, obesity,

hypercholesterolemia, etc.

• Lacunar infarcts account for up to 25% of all strokes

• Lacunar stroke is most common stroke subtype associated

with vascular dementia

(Left) Axial graphic illustrates

numerous bilateral lacunar

infarcts within the thalami ﬉

and basal ganglia ﬊, the most

common locations. Also shown

are prominent perivascular

(Virchow-Robin) spaces ﬈, a

common normal variant.

(Right) Axial FLAIR MR shows

multiple chronic lacunar

infarcts in the periventricular

white matter ﬇ with central

hypointense encephalomalacia

and mild peripheral

hyperintense gliosis in a

patient with chronic

hypertension. Note the

hyperintensity ſt related to

chronic small vessel ischemia.

(Left) Axial DWI MR shows

focal diffusion hyperintensity

﬇ related to an acute lacunar

infarct in the pons, a common

location for lacunar infarcts.

Risk factors for lacunar

infarcts include hypertension,

diabetes, smoking history,

obesity, and

hypercholesterolemia. (Right)

Axial FLAIR MR shows a

chronic lacunar infarct in the

right thalamus ﬇ with central

encephalomalacia and mild

peripheral gliosis. The

surrounding gliosis and typical

location can help differentiate

a chronic lacunar infarct from

a perivascular space.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

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