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Case Reports
. 2024 Sep 2;20(1):87-93.
doi: 10.14797/mdcvj.1417. eCollection 2024.

Internal Carotid Artery Hypoplasia Misidentified as Internal Carotid Artery Dissection

Esther Collado  1 , Adam Bardoczi  1 , Alan B Lumsden  1 , Zsolt Garami  1
Affiliations
Case Reports

Internal Carotid Artery Hypoplasia Misidentified as Internal Carotid Artery Dissection

Esther Collado et al. Methodist Debakey Cardiovasc J. .

Abstract

Agenesis or hypoplasia of the internal carotid artery (ICA) may easily be confused with dissection or occlusion. We report a case of a 24-year-old female with complaint of acute left-hand hypoesthesia and a history of occasional intermittent numbness of her right hand with myoclonic jerking. Because previous imaging studies over 2 years were interpreted as occlusion of the left ICA secondary to carotid dissection, the treating physician had prescribed anticoagulant therapy. During transcranial Doppler (TCD) examination, the spectral waveform was unexpectedly normal, prompting a repeat review of all imaging due to the TCD results. Magnetic resonance angiography (MRA) revealed the same "flame-like" appearance of the ICA origin. Late-phase digital subtraction angiography showed a small caliber cervical ICA (occluded at the skull base). Computed tomography demonstrated absence of the carotid canal, confirming an absent intracranial portion of the ICA and establishing a correct diagnosis of left internal carotid hypoplasia. Vascular ultrasound and TCD examinations are noninvasive and inexpensive tools that can improve the interpretation and understanding of the clinical significance of other "static" radiographic tests (MRA, digital subtraction angiography ). An accurate diagnosis is essential to avoid risky, aggressive treatment, such as anticoagulation for an "absent" dissection.

Keywords: agenesis; hypoplasia; internal carotid artery (ICA); transcranial Doppler; vascular ultrasound.

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Conflict of interest statement

The authors have no competing interests to declare.

Figures

(A) Right common carotid artery (CCA); (B) left CCA; (C) left internal carotid
Figure 1
(A) Normal waveforms and velocity in the right common carotid artery (CCA); (B) small left CCA suggesting abnormal development; (C) proximal left internal carotid artery displaying “flame-like” appearance.
Absent left ICA with good cross-filling via contralateral anterior cerebral artery
Figure 2
Absent left internal carotid artery with good cross-filling via contralateral anterior cerebral artery.
TCD of MCAs and unexpectedly normal left MCA waveform
Figure 3
Transcranial Doppler image of the left and right middle cerebral arteries (MCA). Unexpectedly normal left MCA waveform. ICA: internal carotid artery; TCD: transcranial Doppler
Ultrasound and digital subtraction angiography demonstrate “flame-like” left ICA
Figure 4
(A, B) Ultrasound and digital subtraction angiography demonstrating a tapered, “flame-like” left internal carotid artery. (C) Illustration of the anatomical configuration.
CT demonstrates absent carotid canal at base of skull on left
Figure 5
Computed tomography demonstrating absent carotid canal at the base of the skull on the left.
See this image and copyright information in PMC

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