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Updated: Jul 1, 2026
Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
[Transcranial Doppler test for evaluation of cerebral artery embolism--microemboli detection]
Insights
Transcranial Doppler (TCD) effectively detects microembolic signals (MES) in one-third of ischemic cerebrovascular diseases, aiding in identifying stroke causes. This method helps determine if embolism sources are local or cardiac, crucial for risk assessment.
Area of Science:
- Neurology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Approximately one-third of ischemic cerebrovascular diseases exhibit embolic properties.
- Cerebral emboli, originating from various sources, can occlude cerebral arterioles, leading to transient ischemic attack (TIA) or stroke.
- Microemboli detection is critical for understanding stroke pathogenesis and risk.
Purpose of the Study:
- To evaluate the utility of transcranial Doppler (TCD) for detecting microembolic signals (MES).
- To assess the diagnostic value of TCD in identifying the source of cerebral embolism.
- To determine the prevalence of MES in patients with cerebrovascular diseases.
Main Methods:
- Bilateral monitoring of the middle cerebral arteries (MCA) using transcranial Doppler (TCD).
- Continuous recording and analysis of microembolic signals (MES) with computer-assisted replay.
- Correlation of MES detection with potential embolic sources (e.g., carotid artery, cardiac conditions).
Main Results:
- Microembolic signals (MES) were detected in 23 out of 78 investigated patients (28.7%).
- Unilateral MES detection suggested ipsilateral carotid artery sources.
- Bilateral MES detection indicated a cardiogenic source of embolism.
Conclusions:
- Transcranial Doppler (TCD) is a valuable tool for detecting microembolic signals (MES).
- TCD aids in differentiating between carotid and cardiogenic sources of cerebral embolism.
- The findings support the use of TCD in evaluating stroke pathogenesis and risk assessment.
Abstract:
About one third of ischaemic cerebrovascular diseases have embolic properties. Because of that, transcranial Doppler (TCD) test for detection of microembolic signals (MES), as the only one method for detection of microemboli, is a very important test for the evaluation of cerebral artery embolism. Cerebral emboli are particles of thrombus or atheromatous plaque, platelet aggregates, lipid or air particles in cerebral circulation, which can occlude arterioles and cause ischaemic transient attack (TIA) or stroke. Most frequently, they derive from exulcerated plaques of the carotid bifurcation or the aortic arch, from the atrial thrombus, prosthetic heart valves, as well as during carotid endarterectomy, arterial stent, aortocoronary by-pass. For MES detection, bilateral monitoring of a. cerebri mediae (ACM) is performed with each probe held in place over a temporal bone. MES are represented as brightly coloured embolic tracks as they pass through the insonated arteries. A computer hard disk provides continuous recording that is replayed for counting embolic signals. Colour intensity or acoustic range indicate the size and structure of MES. MES in the range of one ACM indicate the source of embolism on the ipsilateral carotid artery, while the bilateral detection of MES suggests a cardiogenic source. Indications for TCD detection of MES are the evaluation of pathogenesis and risk for embolic stroke or TIA and assessing the source of embolism. We started applying this method at the Institute of Neurology in Belgrade 2 years ago. We have investigated 78 patients till today and detected MES in 23 patients (28.7%). The Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology, 2004, considers that TCD is probably useful for detection of cerebral MES in various cardiovascular and cerebrovascular disorders and procedures.
