Delayed Transcranial Echo-Contrast Bolus Arrival in Unilateral Internal Carotid Artery Stenosis and Occlusion

Area of Science:

• Neurology
• Vascular Medicine
• Medical Imaging

Background:

• Internal carotid artery (ICA) occlusion or stenosis poses a risk for hemodynamic stroke.
• Assessing hemodynamic compromise in these patients is crucial for stroke prevention.
• Transcranial ultrasonography offers a potential method for evaluating intracranial hemodynamics.

Purpose of the Study:

• To describe and evaluate a transcranial Doppler (TCD) sonographic method using echo-contrast to assess hemodynamic compromise.
• To analyze differences in echo-contrast bolus arrival times between middle cerebral arteries (MCAs) in patients with ICA disease.
• To compare these findings with age-matched healthy controls.

Main Methods:

• A transcranial Doppler sonographic technique was employed, utilizing an intravenous echo-contrast bolus.
• The method analyzed the arrival time differences of the echo-contrast bolus in both MCAs.
• Patients included those with 50%-79% ICA stenosis (n=10), 80%-99% ICA stenosis (n=10), ICA occlusion (n=22), and healthy controls (n=15).

Main Results:

• Significant delays in MCA filling were observed in patients with 80%-99% ICA stenosis and ICA occlusion compared to controls.
• The degree of delay in echo-contrast bolus arrival did not correlate with vasomotor reactivity.
• This TCD method provides information on intracranial hemodynamic effects independent of established ultrasound indices.

Conclusions:

• Echo-contrast enhanced TCD sonography is a valuable tool for assessing intracranial hemodynamic compromise in patients with extracranial carotid artery disease.
• Delayed MCA filling detected by this method can indicate significant hemodynamic alterations.
• This technique offers supplementary diagnostic information for managing patients at risk of hemodynamic stroke.