Abstract TP48: Caveats When Using the CT Perfusion Derived Cerebral Blood Volume Lesion to Help Guide Thrombolysis Treatment in Acute Ischemic Stroke
Bibliographic record
Abstract
Background: Very low CT perfusion (CTP)-derived cerebral blood volume (CBV) has shown promise in defining infarction and may also be used as a predictor of hemorrhagic transformation (HT). We sought to determine whether the CTP-CBV defect (CBVD) correlates with final infarct volume, as defined by a 3 month NCCT, and whether the CBV defect volume is associated with hemorrhagic transformation (HT). Methods: CBV defect (CBVD) volumes were outlined on all CBV functional maps using previously established CBV thresholds for infarction, CBV<1.1 ml•100g-1 and CBV<0.75 ml•100g-1 for gray and white matter, respectively. Final infarct volumes were traced on 3 month NCCT. Patients were separated into two sub-groups according to the percent truncation of the ischemic tissue TDC (ITDC) calculated at onset. A model of linear regression was used to observe whether the admission CBVD could predict final infarct volume on NCCTD. Average admission CBVD volumes for patients with hemorrhagic infarction (HI), parenchymal hematoma (PH) and no HT were calculated and compared. Results: Thirty patients were included. There were 21/30 patients (70%) whose onset CBVD volume was less than the NCCTD at 3 months; mean volume difference was 24.2 [range(1.5 to 88mL)]. Six of these patients had truncation of the ITDC at onset. There were 9 patients (30%) whose onset CBVD volume was larger than the final infarct volume from the 3 month NCCT (NCCTD); mean volume difference was -9.9mL [range(-28.5 to -0.2mL)]. Of these 9/30 patients, 8 had truncation of the ITDC at admission. For the onset CBVD versus NCCTD, the coefficients of determination (R2) were 0.56, 0.70 and 0.46 for all patients, truncation positive and truncation negative groups, respectively. 30% of patients had hyperemia at onset, defined as an increase in CBV relative to the contralateral side. HT was observed in 13/30 patients: 8 HI, 5 PH. Symptomatic intracerebral hemorrhage was found in 1 patient. Average CBVD volumes for HI, PH and non-HT groups were 15.7±17.4, 47.1±29.9 and 16.3±27.0, respectively (p > 0.05). Conclusions: The acute CBV defect remains an important diagnostic parameter for acute ischemic stroke if both truncation of the ITDC and variable perfusion states within tissue destined to infarct are taken into account.
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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 | 0.025 | 0.048 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.002 | 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".