Lacunar infarct
Lacunar infarcts are small (<15 mm) infarcts in the distal distribution of deep penetrating vessels (lenticulostriate, thalamoperforating, and pontine perforating arteries, recurrent artery of Heubner). They result from occlusion of one of the small penetrating end arteries at the base of the brain and are due to fibrinoid degeneration.
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Clinical presentation
Most lacunar infarcts are clinically silent, but repeated episodes are associated with vascular dementia. Symptomatic patients may present with lacunar stroke syndrome (LACS), one of five distinct syndromes.
Pathology
Lacunar infarcts, by definition, are caused by occlusion small penetrating end-arteries and must be smaller than 15 mm. They are thought to result primarily from in situ microatheroma formation or lipohyalinosis 2.
Pathologically, they are small holes of encephalomalacia and are traversed by a cob-web-like mesh of fibrous strands.
Radiographic features
CT
In an acute setting, lacunar infarcts appear as ill-defined hypodensities.
Chronic lesions appear as hypodense foci (similar to CSF).
MRI
In an acute setting, the following signal changes are seen:
- T1: slightly hypointense
- T2/FLAIR: hyperintense
-
DWI: restricted diffusion
- may demonstrate acute lesions not visible on other sequences
- T1C+: may enhance if acute (or early subacute)
Chronic lesions are isointense to CSF on all sequences but may demonstrate a peripheral T2/FLAIR hyperintense rim of marginal gliosis.
History and etymology
The term was penned by Charles Miller Fisher (1913-2012) 4 a Canadian neurologist, who described "lacunes" (Latin: lake) of empty fluid within the brains of stroke victims post-mortem.
Differential diagnosis
Related Radiopaedia articles
Stroke and intracranial haemorrhage
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stroke and intracranial hemorrhage
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ischemic stroke
- general discussions
- scoring and classification systems
- signs
- by region
- hemispheric infarcts
- frontal lobe infarct
- parietal lobe infarct
- temporal lobe infarct
- occipital lobe infarct
- alexia without agraphia syndrome: PCA
- cortical blindness syndrome (Anton syndrome): top of basilar or bilateral PCA
- Balint syndrome: bilateral PCA
- lacunar infarct
-
thalamic infarct
- Déjerine-Roussy syndrome (thalamic pain syndrome): thalamoperforators of PCA
- top of the basilar syndrome
- striatocapsular infarct
- cerebellar infarct
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brainstem infarct
- midbrain infarct
- Benedikt syndrome: PCA
- Claude syndrome: PCA
- Nothnagel syndrome: PCA
- Weber syndrome: PCA
- pontine infarct
- Brissaud-Sicard syndrome
- facial colliculus syndrome
- Gasperini syndrome: basilar artery or AICA
- inferior medial pontine syndrome (Foville syndrome): basilar artery
- lateral pontine syndrome (Marie-Foix syndrome): basilar artery or AICA
- locked-in syndrome: basilar artery
- Millard-Gubler syndrome: basilar artery
- Raymond syndrome: basilar artery
- medullary infarct
- Babinski-Nageotte syndrome
- hemimedullary syndrome (Reinhold syndrome)
- lateral medullary stroke syndrome (Wallenberg syndrome)
- medial medullary syndrome (Déjerine syndrome)
- midbrain infarct
- acute spinal cord ischemia syndrome
- hemispheric infarcts
- by vascular territory
- treatment options
- complications
-
intracranial hemorrhage
-
intra-axial hemorrhage
- signs and formulas
- ABC/2 (volume estimation)
- CTA spot sign
- swirl sign
- by region or type
- signs and formulas
- extra-axial hemorrhage
-
intra-axial hemorrhage
-
ischemic stroke
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