Diffusion weighted MRI imaging and MES detection in the assessment of stroke origin
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Updated: Jul 14, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Dirk W Droste1, Jan Knapp, Michael Freund
1Department of Neurology, University of Münster, Germany. droste2@uni-muenster.de
Objectives:
This study compares the additional benefit of diffusion-weighted MRI (DWI) and microembolus detection by transcranial Doppler ultrasonography (TCD) in the assessment of stroke etiology.
Methods:
Fifty-five acute anterior circulation stroke or TIA patients were investigated by both cranial DWI and bilateral TCD of the middle cerebral arteries (1 hour).
Results:
In one of the 13 patients without acute ischemic lesions visualized on DWI, microembolic signal (MES) detection was positive. However, in 33 out of 44 patients without MES, DWI revealed at least one lesion. In two patients with unilateral territorial infarction and otherwise normal cardiovascular work-up, bilateral MES were found thus localizing the embolic source into the aortic arch or the heart. In a further patient with a dissection, the occurrence of contralateral MES raised doubts on a dissection to be the cause of the infarct.
Discussion:
There is a contribution of both techniques to the understanding of stroke etiology. The impact of DWI is, however, superior to that of MES detection. Longer TCD recording times may diminish this discrepancy.
Insights
Diffusion-weighted MRI (DWI) and transcranial Doppler ultrasonography (TCD) both aid in stroke etiology assessment. DWI provides superior diagnostic impact for stroke, though longer TCD monitoring may reduce the difference.
Area of Science:
- Neurology
- Radiology
- Vascular Ultrasound
Background:
- Stroke etiology assessment is crucial for effective treatment and prevention.
- Diffusion-weighted MRI (DWI) and transcranial Doppler ultrasonography (TCD) are advanced neuroimaging techniques.
- Microemboli detection by TCD (MES) can indicate potential embolic sources.
Purpose of the Study:
- To compare the additional diagnostic value of DWI and TCD-based microembolus detection (MES) in determining stroke etiology.
- To evaluate the complementary roles of these neuroimaging modalities in acute stroke patients.
Main Methods:
- Fifty-five patients with acute anterior circulation stroke or transient ischemic attack (TIA) underwent cranial DWI.
- Bilateral TCD of the middle cerebral arteries was performed for microembolic signal (MES) detection within 1 hour.
Main Results:
- DWI identified ischemic lesions in 33 of 44 patients without MES.
- MES was detected in 1 patient with normal DWI findings, suggesting its utility in specific cases.
- Bilateral MES localized embolic sources to the heart or aortic arch in two patients, and raised questions about dissection etiology in another.
Conclusions:
- Both DWI and TCD-based MES detection contribute to understanding stroke etiology.
- DWI demonstrates a superior impact in identifying stroke-related lesions compared to MES detection.
- Extended TCD recording durations may potentially decrease the observed discrepancy between the two methods.
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