IMAGES IN NEUROLOGY

Isolated Posterior Cerebral Artery Infarction
Caused by Carotid Artery Dissection

A

45- YEAR - OLD MAN
with a history of
smoking experienced
sudden onset of loss
of vision on his left
side and transitory left hemiparesis.
There was no history of recent
trauma. Examination showed mild
left hemiparesis and hypoesthesia, and
left homonymous hemianopsia. Cranial computed tomographic imaging
findings at admission were normal.
Magnetic resonance imaging demonstrated a right occipital lobe infarction in the territory of the right posterior cerebral artery (PCA) (Figure,
A and B). Transcranial Doppler
sonography demonstrated collateral
blood supply to the right hemisphere via the anterior communicating artery and no flow on the right carotid siphon or right PCA. Magnetic
resonance angiographic imaging
showed occlusion of both the right internal carotid artery (ICA) and the
second portion of the right PCA (P2).
There was also asymmetry of the
proximal portion (P1) of the PCAs
with a hypoplastic right P1, suggesting that the right occipital lobe was
originally supplied by the right ICA
(fetal pattern) (Figure, D). Digital subtraction angiography showed a coneshaped complete occlusion of the
right ICA, highly suggestive of dissection (Figure, C). Posterior cerebral artery infarct related to emboli-

zation from ICA dissection, associated
with a persistent fetal configuration
of the right PCA, was diagnosed. The
patient was treated with anticoagulation therapy.
COMMENT
Dissection of the ICA is a frequent
cause of stroke in young adults.1 Posterior cerebral artery infarcts represent 5% to 10% of all strokes. Embolism from a cardiac or undetermined
source accounts for up to half of the
cases.2 The PCA territory is supplied
exclusively via the ICA in 11% of
hemispheres, and in 46% of hemispheres the ICA might contribute via
a patent posterior communicating artery.3 In these cases, ICA disease can
cause occipital lobe infarction. However, isolated PCA infarct secondary
to ICA dissection is very rare, probably because the middle cerebral arteryarisesasthelargerterminalbranch
of the ICA, being the branch mainly
affected by embolism. The diagnosis
of PCA infarct due to ICA dissection
should be considered, especially in
young patients or in those with head
or neck trauma and normal vertebrobasilar circulation studies.
Daniel de H. Christoph, MD
Fabiana Souza-Lima, MD
Mario A. da C. Saporta, MD
Gabriel R. de Freitas, MD, PhD

(REPRINTED) ARCH NEUROL / VOL 66 (NO. 8), AUG 2009
1034

Correspondence: Dr de Freitas, Rua
Mário Pederneiras 55, 206-1, Rio de
Janeiro, RJ, Brazil CEP 22261-020
(grdefreitas@gmail.com).
Author Contributions: Study concept and design: Christoph and de
Freitas. Acquisition of data: Christoph and de Freitas. Analysis and
interpretation of data: Christoph,
Souza-Lima, Saporta, and de Freitas. Drafting of the manuscript: Christoph and de Freitas. Critical revision of the manuscript for important
intellectual content: Christoph,
Souza-Lima, Saporta, and de Freitas. Administrative, technical, and material support: Christoph and de Freitas. Study supervision: de Freitas.
Financial Disclosure: None reported.

REFERENCES
1. Benninger DH, Georgiadis D, Kremer C, Studer A,
Nedeltchev K, Baumgartner RW. Mechanism of ischemic infarct in spontaneous carotid dissection.
Stroke. 2004;35(2):482-485.
2. Brandt T, Steinke W, Thie A, Pessin MS, Caplan LR.
Posterior cerebral artery territory infarcts: clinical features, infarct topography, causes and outcome: multicenter results and a review of the literature. Cerebrovasc Dis. 2000;10:179-182.
3. Jongen JC, Franke CL, Soeterboek AA, Versteege CW,
Ramos LM, van Gijn J. Blood supply of the posterior cerebral artery by the carotid system on
angiograms. J Neurol. 2002;249(4):455-460.

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A

B

C

D

Figure. Magnetic resonance imaging (MRI), digital subtraction angiography, and magnetic resonance angiogram of a 45-year-old man with isolated posterior
cerebral artery (PCA) infarction caused by carotid artery dissection. Right PCA infarct is demonstrated by MRI (diffusion-weighted imaging [A] and T2-weighted
sequences [B]). Digital subtraction angiography shows a tapered occlusion of the right internal carotid artery (ICA) compatible with dissection (C, arrow).
D, Magnetic resonance angiogram reveals an asymmetry of the proximal portion (P1) of the PCAs, with a hypoplastic right P1, suggesting that the right occipital
lobe was originally supplied by the right ICA.

(REPRINTED) ARCH NEUROL / VOL 66 (NO. 8), AUG 2009
1035

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©2009 American Medical Association. All rights reserved.
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