MicroemboliMESOMEGANCT07172165
A Multicenter Study to Optimize Microembolic Signal Classification Based on Double--Blind Multiparametric Assessment by Human Experts Using an Universal Graphical Interface [MESOMEGA]
An observational study of Microemboli and Stroke, run by Universidade do Porto at 1 site in Portugal.
Trial summary
Microembolic signals (MES) is a powerful predictor of future embolic events. This study aims to develop and validate a accurate model of classification of MES obtained by transcranial Doppler. monitoring of However, MES detection is technically demanding and requires expert interpretation. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Microemboli, Stroke, Transcranial Doppler Ultrasound
- What is being tested?
- Expert double-blind evaluation
- How many people
- 850 participants
- Where
- 1 sitePortugal
- Study dates
- 15 May 2025to 15 Mar 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Clips of Transcranial Doppler monitoring either MES or non-MES high intensity transient signals (e.g. artifacts, speckle).
Who may be able to join
- MES of presumed solid form or non-MES high intensity transient signals
- Obtained from on a human subject with age equal to or more than 18years old
- Obtained from proximal middle cerebral artery (M1 segment)
- Clip with 20 seconds duration with clearly event of interest marked using TCDPlayer
- With an overall background spectrum of reasonable quality to be analyzed
Who cannot join
- MES in gaseous form
- Use of ultrasound contrast agent or agitated saline in the previous 24 hours
- Obtained from patients with mechanical valve
- Obtained from patient during any cardiac surgery or endovascular procedure1
- Obtained from patient with recent severe trauma
- Clips with multiples inseparable MES (e.g. curtain)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Microembolic signals (MES) is a powerful predictor of future embolic events. This study aims to develop and validate a accurate model of classification of MES obtained by transcranial Doppler. monitoring of However, MES detection is technically demanding and requires expert interpretation. By providing a reproducible framework for MES interpretation, this work aims to facilitate MES integration into future clinical trials and decision-making.
Read the detailed description
Rationale
The presence of microembolic signals (MES) is a powerful predictor of future embolic events. However, MES detection is technically demanding and requires expert interpretation.
Aim We aim to develop and validate a supervised prediction model for MES classification using features extracted from transcranial Doppler (TCD) signals. The model is intended to support expert consensus and enhance classification concordance by utilizing standardized, pre-specified signal features.
Sample size estimates Sample size was estimated using the pmsampsize R package. Based on five predictors, a 1:1 proportion of MES in final dataset, a maximum Nagelkerke R² of 0.75, a shrinkage factor of 90% (to minimize overfitting), and a mean absolute error in predicted probabilities ≤ 0.05, the required sample size is 850 clips. The calculations included an 80:20 training/testing split and a 10% dropout rate.
Methods and Design The "Multicenter Study to Optimize Microembolic Signal Classification Based on Double-blind Multiparametric Assessment by Human Experts Using a Universal Graphical Interface" (MESOMEGA trial) is a prospective, randomized, double-blind, diagnostic validation study. All members of World Organization of Neurosonology, their national affiliated societies, and worldwide TCD users in the medical community will be invited to submit TCD monitoring 20-second clips of presumed solid MES or non-MES high-intensity transient signals recorded using a 2 MHz transducer from the proximal middle cerebral artery. Exclusion criteria include inseparable multiple MES (e.g., curtain) or any gaseous embolic form. Each clip will be independently assessed by two randomly allocated experts. Expert reading will be using TCDPlayer and will be blinded to clinical data, source information, and other assessments. They will manually annotate six predefined signal features: characteristic audible signal increase, characteristic wave-like of raw Doppler signals, Emboli-to-Background Ratio, Emboli-to-Mirror Ratio, signal duration, and average velocity of maximum intensity. Analysis will be completed within 90 days. A supervised decision tree model will be developed on the training dataset and validation set. Performance will be assessed using stratified k-fold cross-validation, reporting accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Following model development, a Delphi consensus process will be used to evaluate and validate model outputs, aiming for expert agreement on model acceptability and readiness for clinical application. The study will be conducted under appropriate ethical approval and in accordance with international report standards. The study will be conducted under ethical guidelines and approval.
Study Outcomes The primary outcome is the classification of clips as MES or non-MES, using expert consensus as ground truth. The model will aim for ≥ 90% classification accuracy. Secondary outcomes include model performance without auditory parameter, interrater concordance and variability, and Delphi consensus strength.
Discussion This study will assess the performance of a supervised decision tree model for MES classification and benchmark it against prior MES detection approaches. By providing a reproducible framework for MES interpretation, this work aims to facilitate MES integration into future clinical trials and decision-making.
- Conditions
- Microemboli, Stroke, Transcranial Doppler Ultrasound
- Being tested
- Expert double-blind evaluation
- Keywords
- microembolic signals (MES), decision tree, stroke, microemboli, transcranial Doppler, diagnostic standard, prediction model
- Medical subject headings
- Stroke
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Expert double-blind evaluationDiagnostic test
Expert reading will be using TCDPlayer and will be blinded to clinical data, source information, and other assessments. They will manually annotate six predefined signal features: characteristic audible signal increase, characteristic wave-like of raw Doppler signals, Emboli-to-Background Ratio, Emboli-to-Mirror Ratio, signal duration, and average velocity of maximum intensity. Analysis will be completed within 90 days.
| Study group | Role | What they receive |
|---|---|---|
| Transcranial Doppler clips database | Clips of MES and non-MES events. Each clip will be 20 seconds (-10 and +10 seconds in reference to the marked event). The data presented will not be modified from its original form. The final database that will be used for expert evaluation will include the necessary clips and proportions to ensure maximum reproducibility and generalization of the data. Clips will be obtained from at least 3 different types or brands of TCD machines. A single machine cannot be the source of more than 50% of the final data set. MES will be from a variety of sources including patients with atherosclerotic disease, cardioembolic stroke, or embolic stroke of unknown source. Receives: Diagnostic Test: Expert double-blind evaluation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Classification of each signal as MES or Non-MES
A MES or non-MES will be considered as such the two experts agree. If the two experts do not agree, a special board (RA, WM) will decide on classification. "Recordings that remain undetermined, or those classified as undetermined by both experts, will be excluded from the primary analysis of this study. All experts will be blinded to each other, any identification tag or clinical information. We will include five predictors in the primary analysis which are: the presence of characteristic audible signal increase, characteristic wave-like raw Doppler signals, the Emboli-to-Background Ratio (EBR), Emboli-to-mirror-ratio (EMR), time length and average velocity of maximum intensity. The calculation and definition of each predictor is detailed in table 3 and in supplemental information (Proposal for a systematic analysis and reporting of microembolic signal detection of the Microembolic Signal Detection Working Groups of the World Organization of Neurosonology).
Measured: From enrollment until December of 2026
Secondary outcomes (4)
Trimmed version of the model
To compare the model performance with and without auditory parameter To compare the subgroups of exclude MES vs non-MES how model performance
Measured: From enrollment until December of 2026
Model with extra-features
To compare the model performance with and without a derived Embolus Distance parameter as calculated by the formula: Embolus Distance (mm) = Time length x average velocity of maximum intensity
Measured: From enrollment until December of 2026
Inter-expert variability in feature extraction.
Measured: From enrollment until December of 2026
Delphi process
Strength of the Delphi process
Measured: From enrollment until December of 2026
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2025
- Study start15 May 2025
- Primary completion15 Dec 2025 (estimated)
- Study completion15 Mar 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (10)Papers the sponsor has linked to this study.
- Other trials for MicroemboliStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 850 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidade do Porto
- Sponsor type
- University, hospital or other
- Collaborators
- Sound Vascular Neurology, RISE-Heatlh, CRU-RISE, University of Ostrava, Maastricht University Medical Center, Justus-Liebig University Gießen Medical Center, University of Bern, Centro Hospitalar De São João, E.P.E., Houston Methodist DeBakey Heart & Vascular Center
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07172165
- Sponsor's protocol ID
- MESOMEGA
- Acronym
- MESOMEGA
- Status last verified
- May 2025
- First submitted
- 27 Jun 2025
- Last updated
- 10 Dec 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Publication of protocol and associate report sheets
Publications
Collins GS, Moons KGM, Dhiman P, Riley RD, Beam AL, Van Calster B, Ghassemi M, Liu X, Reitsma JB, van Smeden M, Boulesteix AL, Camaradou JC, Celi LA, Denaxas S, Denniston AK, Glocker B, Golub RM, Harvey H, Heinze G, Hoffman MM, Kengne AP, Lam E, Lee N, Loder EW, Maier-Hein L, Mateen BA, McCradden MD, Oakden-Rayner L, Ordish J, Parnell R, Rose S, Singh K, Wynants L, Logullo P. TRIPOD+AI statement: updated guidance for reporting clinical prediction models that use regression or machine learning methods. BMJ. 2024 Apr 16;385:e078378. doi: 10.1136/bmj-2023-078378.
PubMed 38626948Riley RD, Ensor J, Snell KIE, Harrell FE Jr, Martin GP, Reitsma JB, Moons KGM, Collins G, van Smeden M. Calculating the sample size required for developing a clinical prediction model. BMJ. 2020 Mar 18;368:m441. doi: 10.1136/bmj.m441. No abstract available.
PubMed 32188600Wong KS, Chen C, Fu J, Chang HM, Suwanwela NC, Huang YN, Han Z, Tan KS, Ratanakorn D, Chollate P, Zhao Y, Koh A, Hao Q, Markus HS; CLAIR study investigators. Clopidogrel plus aspirin versus aspirin alone for reducing embolisation in patients with acute symptomatic cerebral or carotid artery stenosis (CLAIR study): a randomised, open-label, blinded-endpoint trial. Lancet Neurol. 2010 May;9(5):489-97. doi: 10.1016/S1474-4422(10)70060-0. Epub 2010 Mar 22.
PubMed 20335070Markus HS, Droste DW, Kaps M, Larrue V, Lees KR, Siebler M, Ringelstein EB. Dual antiplatelet therapy with clopidogrel and aspirin in symptomatic carotid stenosis evaluated using doppler embolic signal detection: the Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic Carotid Stenosis (CARESS) trial. Circulation. 2005 May 3;111(17):2233-40. doi: 10.1161/01.CIR.0000163561.90680.1C. Epub 2005 Apr 25.
PubMed 15851601Castro P, Ferreira J, Malojcic B, Bazadona D, Baracchini C, Pieroni A, Skoloudik D, Azevedo E, Kaps M. Detection of microemboli in patients with acute ischaemic stroke and atrial fibrillation suggests poor functional outcome. Eur Stroke J. 2024 Jun;9(2):409-417. doi: 10.1177/23969873231220508. Epub 2023 Dec 27.
PubMed 38149620Das AS, Regenhardt RW, LaRose S, Monk AD, Castro PM, Sheriff FG, Sorond FA, Vaitkevicius H. Microembolic Signals Detected by Transcranial Doppler Predict Future Stroke and Poor Outcomes. J Neuroimaging. 2020 Nov;30(6):882-889. doi: 10.1111/jon.12749. Epub 2020 Jul 10.
PubMed 32648610Sheriff F, Diz-Lopes M, Khawaja A, Sorond F, Tan CO, Azevedo E, Franceschini MA, Vaitkevicius H, Li K, Monk AD, Michaud SL, Feske SK, Castro P. Microemboli After Successful Thrombectomy Do Not Affect Outcome but Predict New Embolic Events. Stroke. 2020 Jan;51(1):154-161. doi: 10.1161/STROKEAHA.119.025856. Epub 2019 Dec 4.
PubMed 31795906Padayachee TS, Parsons S, Theobold R, Linley J, Gosling RG, Deverall PB. The detection of microemboli in the middle cerebral artery during cardiopulmonary bypass: a transcranial Doppler ultrasound investigation using membrane and bubble oxygenators. Ann Thorac Surg. 1987 Sep;44(3):298-302. doi: 10.1016/s0003-4975(10)62077-2.
PubMed 2957966Farina F, Palmieri A, Favaretto S, Viaro F, Cester G, Causin F, Baracchini C. Prognostic Role of Microembolic Signals After Endovascular Treatment in Anterior Circulation Ischemic Stroke Patients. World Neurosurg. 2018 Feb;110:e882-e889. doi: 10.1016/j.wneu.2017.11.120. Epub 2017 Nov 28.
PubMed 29191539Spencer MP, Thomas GI, Nicholls SC, Sauvage LR. Detection of middle cerebral artery emboli during carotid endarterectomy using transcranial Doppler ultrasonography. Stroke. 1990 Mar;21(3):415-23. doi: 10.1161/01.str.21.3.415.
PubMed 2408197
Study at a glance
From the registry record, last updated by the sponsor on 10 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Multicenter Study to Optimize Microembolic Signal Classification Based on Double--Blind Multiparametric Assessment by Human Experts Using an Universal Graphical Interface [MESOMEGA]
- ClinicalTrials.gov ID
- NCT07172165
- Acronym / sponsor ID
- MESOMEGA / MESOMEGA
- Conditions
- Microemboli, Stroke, Transcranial Doppler Ultrasound
- Keywords
- microembolic signals (MES), decision tree, stroke, microemboli, transcranial Doppler, diagnostic standard, prediction model
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 850 participants (estimated)
- Lead sponsor
- Universidade do PortoUniversity, hospital or other
- Collaborators
- Sound Vascular Neurology, RISE-Heatlh, CRU-RISE, University of Ostrava, Maastricht University Medical Center, Justus-Liebig University Gießen Medical Center, University of Bern, Centro Hospitalar De São João, E.P.E., Houston Methodist DeBakey Heart & Vascular Center
- Study start
- 15 May 2025 (actual)
- Primary completion
- 15 Dec 2025 (estimated)
- Study completion
- 15 Mar 2026 (estimated)
- First posted
- 15 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Microembolic signals (MES) is a powerful predictor of future embolic events. This study aims to develop and validate a accurate model of classification of MES obtained by transcranial Doppler. monitoring of However, MES detection is technically demanding and requires expert interpretation. By providing a reproducible framework for MES interpretation, this work aims to facilitate MES integration into future clinical trials and decision-making.
Detailed description
Rationale
The presence of microembolic signals (MES) is a powerful predictor of future embolic events. However, MES detection is technically demanding and requires expert interpretation.
Aim We aim to develop and validate a supervised prediction model for MES classification using features extracted from transcranial Doppler (TCD) signals. The model is intended to support expert consensus and enhance classification concordance by utilizing standardized, pre-specified signal features.
Sample size estimates Sample size was estimated using the pmsampsize R package. Based on five predictors, a 1:1 proportion of MES in final dataset, a maximum Nagelkerke R² of 0.75, a shrinkage factor of 90% (to minimize overfitting), and a mean absolute error in predicted probabilities ≤ 0.05, the required sample size is 850 clips. The calculations included an 80:20 training/testing split and a 10% dropout rate.
Methods and Design The "Multicenter Study to Optimize Microembolic Signal Classification Based on Double-blind Multiparametric Assessment by Human Experts Using a Universal Graphical Interface" (MESOMEGA trial) is a prospective, randomized, double-blind, diagnostic validation study. All members of World Organization of Neurosonology, their national affiliated societies, and worldwide TCD users in the medical community will be invited to submit TCD monitoring 20-second clips of presumed solid MES or non-MES high-intensity transient signals recorded using a 2 MHz transducer from the proximal middle cerebral artery. Exclusion criteria include inseparable multiple MES (e.g., curtain) or any gaseous embolic form. Each clip will be independently assessed by two randomly allocated experts. Expert reading will be using TCDPlayer and will be blinded to clinical data, source information, and other assessments. They will manually annotate six predefined signal features: characteristic audible signal increase, characteristic wave-like of raw Doppler signals, Emboli-to-Background Ratio, Emboli-to-Mirror Ratio, signal duration, and average velocity of maximum intensity. Analysis will be completed within 90 days. A supervised decision tree model will be developed on the training dataset and validation set. Performance will be assessed using stratified k-fold cross-validation, reporting accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Following model development, a Delphi consensus process will be used to evaluate and validate model outputs, aiming for expert agreement on model acceptability and readiness for clinical application. The study will be conducted under appropriate ethical approval and in accordance with international report standards. The study will be conducted under ethical guidelines and approval.
Study Outcomes The primary outcome is the classification of clips as MES or non-MES, using expert consensus as ground truth. The model will aim for ≥ 90% classification accuracy. Secondary outcomes include model performance without auditory parameter, interrater concordance and variability, and Delphi consensus strength.
Discussion This study will assess the performance of a supervised decision tree model for MES classification and benchmark it against prior MES detection approaches. By providing a reproducible framework for MES interpretation, this work aims to facilitate MES integration into future clinical trials and decision-making.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Transcranial Doppler clips database | – | Diagnostic Test: Expert double-blind evaluationClips of MES and non-MES events. Each clip will be 20 seconds (-10 and +10 seconds in reference to the marked event). The data presented will not be modified from its original form. The final database that will be used for expert evaluation will include the necessary clips and proportions to ensure maximum reproducibility and generalization of the data. Clips will be obtained from at least 3 different types or brands of TCD machines. A single machine cannot be the source of more than 50% of the final data set. MES will be from a variety of sources including patients with atherosclerotic disease, cardioembolic stroke, or embolic stroke of unknown source. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Clips of Transcranial Doppler monitoring either MES or non-MES high intensity transient signals (e.g. artifacts, speckle).
Key inclusion criteria (5 listed)
- MES of presumed solid form or non-MES high intensity transient signals
- Obtained from on a human subject with age equal to or more than 18years old
- Obtained from proximal middle cerebral artery (M1 segment)
- Clip with 20 seconds duration with clearly event of interest marked using TCDPlayer
- With an overall background spectrum of reasonable quality to be analyzed
Key exclusion criteria (6 listed)
- MES in gaseous form
- Use of ultrasound contrast agent or agitated saline in the previous 24 hours
- Obtained from patients with mechanical valve
- Obtained from patient during any cardiac surgery or endovascular procedure1
- Obtained from patient with recent severe trauma
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Expert double-blind evaluationExpert reading will be using TCDPlayer and will be blinded to clinical data, source information, and other assessments. They will manually annotate six predefined signal features: characteristic audible signal increase, characteristic wave-like of raw Doppler signals, Emboli-to-Background Ratio, Emboli-to-Mirror Ratio, signal duration, and average velocity of maximum intensity. Analysis will be completed within 90 days. | Diagnostic test | Transcranial Doppler clips database |
Primary outcome
Classification of each signal as MES or Non-MES
Time frame: From enrollment until December of 2026
A MES or non-MES will be considered as such the two experts agree. If the two experts do not agree, a special board (RA, WM) will decide on classification. "Recordings that remain undetermined, or those classified as undetermined by both experts, will be excluded from the primary analysis of this study. All experts will be blinded to each other, any identification tag or clinical information. We will include five predictors in the primary analysis which are: the presence of characteristic audible signal increase, characteristic wave-like raw Doppler signals, the Emboli-to-Background Ratio (EBR), Emboli-to-mirror-ratio (EMR), time length and average velocity of maximum intensity. The calculation and definition of each predictor is detailed in table 3 and in supplemental information (Proposal for a systematic analysis and reporting of microembolic signal detection of the Microembolic Signal Detection Working Groups of the World Organization of Neurosonology).
4 secondary outcomes
Trimmed version of the model
Time frame: From enrollment until December of 2026
Model with extra-features
Time frame: From enrollment until December of 2026
Inter-expert variability in feature extraction.
Time frame: From enrollment until December of 2026
Delphi process
Time frame: From enrollment until December of 2026
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Dec 2025.
- Results publication: PubMed 38626948Collins GS, Moons KGM, Dhiman P, Riley RD, Beam AL, Van Calster B, Ghassemi M, Liu X, Reitsma JB, van Smeden M, Boulesteix AL, Camaradou JC, Celi LA, Denaxas S, Denniston AK, Glocker B, Golub RM, Harvey H, Heinze G, Hoffman MM, Kengne AP, Lam E, Lee N, Loder EW, Maier-Hein L, Mateen BA, McCradden MD, Oakden-Rayner L, Ordish J, Parnell R, Rose S, Singh K, Wynants L, Logullo P. TRIPOD+AI statement: updated guidance for reporting clinical prediction models that use regression or machine learning methods. BMJ. 2024 Apr 16;385:e078378. doi: 10.1136/bmj-2023-078378.
- Results publication: PubMed 32188600Riley RD, Ensor J, Snell KIE, Harrell FE Jr, Martin GP, Reitsma JB, Moons KGM, Collins G, van Smeden M. Calculating the sample size required for developing a clinical prediction model. BMJ. 2020 Mar 18;368:m441. doi: 10.1136/bmj.m441. No abstract available.
- Results publication: PubMed 20335070Wong KS, Chen C, Fu J, Chang HM, Suwanwela NC, Huang YN, Han Z, Tan KS, Ratanakorn D, Chollate P, Zhao Y, Koh A, Hao Q, Markus HS; CLAIR study investigators. Clopidogrel plus aspirin versus aspirin alone for reducing embolisation in patients with acute symptomatic cerebral or carotid artery stenosis (CLAIR study): a randomised, open-label, blinded-endpoint trial. Lancet Neurol. 2010 May;9(5):489-97. doi: 10.1016/S1474-4422(10)70060-0. Epub 2010 Mar 22.
- Results publication: PubMed 15851601Markus HS, Droste DW, Kaps M, Larrue V, Lees KR, Siebler M, Ringelstein EB. Dual antiplatelet therapy with clopidogrel and aspirin in symptomatic carotid stenosis evaluated using doppler embolic signal detection: the Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic Carotid Stenosis (CARESS) trial. Circulation. 2005 May 3;111(17):2233-40. doi: 10.1161/01.CIR.0000163561.90680.1C. Epub 2005 Apr 25.
- Results publication: PubMed 38149620Castro P, Ferreira J, Malojcic B, Bazadona D, Baracchini C, Pieroni A, Skoloudik D, Azevedo E, Kaps M. Detection of microemboli in patients with acute ischaemic stroke and atrial fibrillation suggests poor functional outcome. Eur Stroke J. 2024 Jun;9(2):409-417. doi: 10.1177/23969873231220508. Epub 2023 Dec 27.
- Results publication: PubMed 32648610Das AS, Regenhardt RW, LaRose S, Monk AD, Castro PM, Sheriff FG, Sorond FA, Vaitkevicius H. Microembolic Signals Detected by Transcranial Doppler Predict Future Stroke and Poor Outcomes. J Neuroimaging. 2020 Nov;30(6):882-889. doi: 10.1111/jon.12749. Epub 2020 Jul 10.
- Results publication: PubMed 31795906Sheriff F, Diz-Lopes M, Khawaja A, Sorond F, Tan CO, Azevedo E, Franceschini MA, Vaitkevicius H, Li K, Monk AD, Michaud SL, Feske SK, Castro P. Microemboli After Successful Thrombectomy Do Not Affect Outcome but Predict New Embolic Events. Stroke. 2020 Jan;51(1):154-161. doi: 10.1161/STROKEAHA.119.025856. Epub 2019 Dec 4.
- Results publication: PubMed 2957966Padayachee TS, Parsons S, Theobold R, Linley J, Gosling RG, Deverall PB. The detection of microemboli in the middle cerebral artery during cardiopulmonary bypass: a transcranial Doppler ultrasound investigation using membrane and bubble oxygenators. Ann Thorac Surg. 1987 Sep;44(3):298-302. doi: 10.1016/s0003-4975(10)62077-2.
- Results publication: PubMed 29191539Farina F, Palmieri A, Favaretto S, Viaro F, Cester G, Causin F, Baracchini C. Prognostic Role of Microembolic Signals After Endovascular Treatment in Anterior Circulation Ischemic Stroke Patients. World Neurosurg. 2018 Feb;110:e882-e889. doi: 10.1016/j.wneu.2017.11.120. Epub 2017 Nov 28.
- Results publication: PubMed 2408197Spencer MP, Thomas GI, Nicholls SC, Sauvage LR. Detection of middle cerebral artery emboli during carotid endarterectomy using transcranial Doppler ultrasonography. Stroke. 1990 Mar;21(3):415-23. doi: 10.1161/01.str.21.3.415.
- Individual participant dataSharing planned: Yes. Publication of protocol and associate report sheets
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Microemboli and Stroke, run by Universidade do Porto at 1 site in Portugal.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 10 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Portugal. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Classification of each signal as MES or Non-MES (time frame: From enrollment until December of 2026). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07172165, which also lists 10 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Dec 2025.