Transcript Artery of Percheron Infarct: Clinical and Radiological

Unusual Brain Lesion
with a Usual Cause
Ryan Frederiksen MD, Sean Snodgress MD,
Benjamin Kianmahd MSIV
Department of Radiology
Santa Barbara Cottage Hospital
Clinical History: Patient A
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36 year old right handed male with no prior
medical history
Found unresponsive at gas station
No history of drug abuse, trauma,
hypertension, hypercoaguable state or
significant family history
Physical Exam: GCS 8
Labs: within normal limits except for BS > 500
Imaging: Patient A
Initial Head CT Day 1:
Normal.
Imaging: Patient A
MRI DWI
MRI ADC
MRI Day 2:
Bilateral thalamic infarcts.
Imaging: Patient A
Head CTA Day 2:
Bilateral thalamic infarcts;
CTA portion was normal.
Imaging: Patient A
Head CT Day 3:
Hemorrhagic thalamic infarcts.
Clinical History: Patient B
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85 year old male with history of
hypertension and GERD
Presented to PMD with 5 day history of
ataxia and double vision
Physical Exam: leftward ataxic gait,
bilateral horizontal nystagmus, no focal
sensory or motor deficits
Labs: LDL 151
Imaging: Patient B
MRI DWI
MRI FLAIR
MRI Day 5 of Symptoms:
Bilateral thalamic infarcts.
What’s the diagnosis?
Bilateral Thalamic Infarcts
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Broad differential diagnosis
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Venous occlusion: vein of Galen, straight
sinus, bilateral internal cerebral veins
Diffuse astrocytoma
ADEM
Arterial ischemia: artery of Percheron
Discussion: Background
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These two cases demonstrate an
anatomic variant
Occlusion of the artery of Percheron
results in a characteristic pattern of infarct
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Infarct of the bilateral paramedian thalamus
with or without midbrain involvement
Discussion: Background
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The thalamus’ blood supply is usually
supplied by:
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multiple perforator vessesls originating from
the posterior communicating artery
the P1 and P2 segments of the posterior
cerebral arteries
Discussion: Background
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The anterior region is supplied by
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The paramedian region is supplied by
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the paramedian (thalamoperforating) arteries which originate
from the P1 segment of the posterior cerebral artery
The inferolateral region is supplied by
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the polar (thalamotuberal) arteries, arising from the posterior
communicating artery
the thalamogeniculate arteries which arise from the P2 segment
of the posterior cerebral artery
The posterior region is supplied by
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the posterior choroidal arteries, which originate from the P2
segment of the posterior cerebral artery.
Discussion: Background
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The paramedian arteries supplying the
thalamus and midbrain exhibit the greatest
amount of variability
According to Percheron, there are three
variations
This exhibit focuses on a specific anatomic
variant of the paramedian arteries, known
as the Artery of Percheron
Discussion: Paramedian Thalamic Blood Supply
Variations
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A. Many perforating arteries from the P1 segment of the PCA; the most
common
B. A single artery from the P1 segment; the artery of Perheron
C. An arcade of perforating arteries from both PCAs
Discussion: Artery of Percheron
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A single dominant
thalamoperforating
artery supplying
the bilateral medial
thalami with
variable
contribution to the
rostral midbrain
Discussion
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Common physical exam findings
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Oculomotor palsy (76% of patients)
Mild gait ataxia (67%)
Deficits of attention (63%)
Fluency and error control (59%)
Learning and memory (67%)
Behavior (67%)
Discussion
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One retrospective study identified four
patterns of artery of Percheron infarcts
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Bilateral paramedian thalamic with midbrain (43%)
Bilateral paramedian thalamic without midbrain (38%)
Bilateral paramedian thalamic with anterior thalamus
and midbrain (14%)
Bilateral paramedian thalamic with anterior thalamus
without midbrain (5%)
Conclusion
The artery of Percheron is one of the few
examples where a cerebral blood vessel
supplies structures on both sides of the
midline!
References
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Lazzaro NA, et al. Artery of Percheron
infarction: imaging patterns and clinical
spectrum. AJNR Am J Neuroradiol. 2010
Aug;31(7):1283-9. Epub 2010 Mar 18.
Matheus MG, et al. Imaging of acute bilateral
paramedian thalamic and mesencephalic
infarcts. AJNR Am J Neuroradiol. 2003 NovDec;24(10):2005-8.
Mujeeb, S, et al. Symmetric bilateral thalamic
infarcts: a rare complication of cardiac
catheterization. The Internet Journal of
Cardiology. 2009 Vol 7; No 1.