Abstract T P31: Microembolus (MES) Detection by TCD in Acute Stroke Service
Bibliographic record
Abstract
Background and purpose: One of the main applications of TCD in acute stroke is microembolic signal (MES) detection. Both Spectral display and M-mode can be used to detect MES using validated criteria published previously. MES is reported to be an independent risk factor for stroke. Our study’s aim is to evaluate the yield of TCD MES in an acute stroke service and if this correlate with stroke’s mechanism and recurrence of stroke. Methods: We did analysis of all stroke and TIA patients who were evaluated in the University of Alberta Hospital between jan2006- July 2013. The clinical information was collected from charts and TCD studies for MES detection were reviewed by Neurologists certified by American Society of Neuroimaging using validated criteria. All cases had bilateral TCD monitoring of MCA /ACA or PCA vessels. The positive emboli on spectrogram was defined based on the consensus criteria and the M mode one based on our previous published criteria. Positive MES TCD monitoring was defined by the presence of ≥1 MES on either hemisphere. RESULTS: 49 /455 patients(10.7%) were MES positive. Mean age was 54.7(StD ±20), Gender: 33/49( 67.3%)were male, Median duration of monitoring was 50minutes( interquartile range 27.5-60), the indication was TIA in 16/49( 32.7%) acute ischemic stroke in 32/49(65.3%) subarachnoid hemorrhage in 1/49(2%), 36/49( 73.5%) presented with motor weakness 4/49( 8.2%) with isolated vision disturbances, 45/49(91.9%) patients had anterior circulation related symptoms, whereas 4/49(8.2%) had posterior circulation related symptoms,17/49(34.7%) showed acute infarct on imaging 6/49(12.2%) showed both acute and chronic infarcts and 3/49(6.1%) showed chronic infarcts only, 12/49(24.5%) showed infarcts in multiple vessels territories, TOAST: 20/49(40.8%) had large vessel atherosclerosis(LVA), 14/49(28.6%)had cardioembolic(CE) cause, 8/49(16.3%) had other determined etiology and 7/49(14.3%) had cryptogenic stroke, 7/49(14.3%) had recurrent stroke and 1/49(2%) had recurrent TIA. Total no of MES in anterior circulation were 324. CONCLUSION: Our study showed that 1 out of every 10 patients with acute ischemic stroke or TIA showed positive micro embolic signal on TCD monitoring. The high yield was mainly seen in LVA and CE stroke.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".