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Carotid pseudostring sign from vasa vasorum collaterals
J Scott Kriegshauser1, Maitray D Patel, Kent D Nelson
1Department of Radiology, Mayo Clinic, Scottsdale, Arizona 85259, USA. skriegshauser@mayo.edu
Summary
Internal carotid artery occlusion can mimic a narrow vessel on Doppler imaging due to vasa vasorum collaterals, a finding termed the "pseudostring sign." This sign indicates potential misdiagnosis and inappropriate surgical intervention.
Area of Science:
- Vascular Imaging
- Cerebrovascular Disease
- Diagnostic Radiology
Background:
- Internal carotid artery (ICA) occlusion is a significant cause of ischemic stroke.
- Accurate diagnosis is crucial for appropriate patient management, including surgical intervention considerations.
- Collateral circulation plays a vital role in maintaining cerebral perfusion in cases of arterial stenosis or occlusion.
Observation:
- This study describes two cases of internal carotid artery occlusion.
- Color Doppler imaging revealed a narrow, string-like internal carotid artery.
- Spectral Doppler showed normal flow characteristics (velocity < 125 cm/s, normal waveform).
Findings:
- The "pseudostring sign" is characterized by color Doppler imaging showing a narrow, tortuous internal carotid artery with normal spectral Doppler features.
- Advanced imaging (MRA, conventional angiography) confirmed proximal ICA occlusion with collateral flow via vasa vasorum.
- Vasa vasorum provided distal reconstitution of the lumen, mimicking a patent but narrowed vessel.
Implications:
- The "pseudostring sign" on Doppler imaging may lead to misinterpretation as significant stenosis rather than occlusion.
- Patients presenting with the pseudostring sign should not undergo carotid endarterectomy based solely on Doppler findings.
- Further investigation with advanced imaging is recommended to confirm the diagnosis and guide treatment decisions.