Figure 1
TC de la base del cráneo
A CT of the skull base exhibits an absent of left carotid canal. The right carotid canal (arrow) is normal.
Unilateral agenesis of the internal carotid artery
SectionHead & neck imaging
Case TypeAnatomy and Functional Imaging
AuthorsBasekim CC, Ozturk E, Kizilkaya E
Connected authors
32 years, male
Clinical History
We present an internal carotid artery anomaly in an asymptomatic patient.
Imaging Findings
The patient presented with headache. Physical examination was within normal limits. Computed tomography (CT) images revealed ethmoidal sinusitis which was the probable cause of headache and an absent
left carotid canal (Fig 1). Cervical digital subtraction angiography (DSA) showed absence of the left internal carotid artery (ICA); where as the right one was normal (Fig 2). Three dimensional (3D)
magnetic resonance angiography (MRA) showed the left ICA was absent, the left posterior communicating artery (PCoA) and A1 segment of the right anterior cerebral artery (ACA) was enlarged, A1 segment
of the left ACA and right PCoA were absent (Fig 3).
Discussion
Absence of the ICA is a very rare anomaly of the embryonic development. Absence may be referred to agenesis which is with absence of the carotid canal or aplasia which the carotid canal is present.
The left-right distribution is about 3:1. This entity rarely occurs bilaterally. Most of the cases with unilateral agenesis are asymptomatic because of the extensive collateral supply to the
intracranial arteries from the contralateral ICA and the vertebrobasilar system via the circle of Willis. Three types of collateral circulation were described. The first type is termed the
“fetal” type. This is the most common type and it was similar with our case. In this particular type, anterior and posterior communicating arteries of the affected side are patent, and
these arteries reconstitute the anterior and middle cerebral artery circulations. In the second type which is called the “adult” type, both the anterior and middle cerebral arteries are
supplied by a patent anterior communicating artery. In the third type, an intercavernous vessel arising from the contralateral internal carotid artery supplies most of the cavernous and the
supraclinoid portion of the vessel. This is the least common type. The frequent association between agenesis of the ICA and the intracranial aneurysm has been reported. Hemodynamic stress in the
collateral arteries could be the origin of the aneurysm development. For this reason, demonstration of the intracranial vessels is important. DSA and/or MRA can be use for this screening.
Differential Diagnosis List
AGENESIS OF THE INTERNAL CAROTID ARTERY
Final Diagnosis
AGENESIS OF THE INTERNAL CAROTID ARTERY
References
[1] Cali RL, Bare R, Rama K. Bilateral internal carotid artery agenesis: a case study and review of the literature. Surgery 1993; 113 Feb (2): 227-233. (PMID: 8430372)
[2] Iaccarino V, Tedeschi E, Brunetti A, Soricelli A, Salvatore M. Congenital agenesis/aplasia of the internal carotid arteries: MRA and SPECT findings. J Comput Assist Tomogr 1995 Nov-Dec;19(6):987-90. (PMID: 8537538)
[3] Midkiff RB, Boykin MW, McFarland DR, Bauman JA. Agenesis of the internal carotid artery with intercavernous anastomosis AJNR 1995; 16(Jun):1356-1359. (PMID: 7677040)
[4] Quint DJ, Silbergleit R, Young WC. Absence of the carotid canals at skull base CT. Radiology 1992 Feb;182(2):477-81. (PMID: 1732967)
[5] Takahashi S, Higano S, Kurihara N, Shirane R, Asai R, Kadoyama S, Sakamoto K. Congenital absence and aberrant course of the internal carotid artery. Eur Radiol 1996;6(5):650-4. (PMID: 8934129)
Case information
| URL: | https://eurorad.org/case/3488 |
| DOI: | 10.1594/EURORAD/CASE.3488 |
| ISSN: | 1563-4086 |
Figure 3
Angio-RM imagen axial
a. Non-reconstructed MRA image demonstrates absence of the left ICA,
b. 3-D reconstructed MRA image demonstrates absence of the left ICA, absence of the A1 segment of the left ACA, and absence of the right PCoA. Left PCoA (arrow) and A1 segment of the right ACA (arrow head) are enlarged.
a. Non-reconstructed MRA image demonstrates absence of the left ICA,
b. 3-D reconstructed MRA image demonstrates absence of the left ICA, absence of the A1 segment of the left ACA, and absence of the right PCoA. Left PCoA (arrow) and A1 segment of the right ACA (arrow head) are enlarged.
TC de la base del cráneo
A CT of the skull base exhibits an absent of left carotid canal. The right carotid canal (arrow) is normal.
Angio-RM imagen axial
a. Non-reconstructed MRA image demonstrates absence of the left ICA,
b. 3-D reconstructed MRA image demonstrates absence of the left ICA, absence of the A1 segment of the left ACA, and absence of the right PCoA. Left PCoA (arrow) and A1 segment of the right ACA (arrow head) are enlarged.
a. Non-reconstructed MRA image demonstrates absence of the left ICA,
b. 3-D reconstructed MRA image demonstrates absence of the left ICA, absence of the A1 segment of the left ACA, and absence of the right PCoA. Left PCoA (arrow) and A1 segment of the right ACA (arrow head) are enlarged.