Abstract W P246: Diagnostic Value of Lobar Hemorrhages for Cerebral Amyloid Angiopathy in Hospital and Community-based Individuals: A Pathological Correlation Study
Bibliographic record
Abstract
Objectives: To determine and compare the accuracy of the Boston criteria for the diagnosis of cerebral amyloid angiopathy (CAA) applied to: 1) a large hospital-based cohort; 2) a cohort of community-dwelling individuals. Methods: Among patients seen at a single academic medical center and participants enrolled in the Framingham Heart Study (FHS) we identified all individuals having had brain MRI (including hemosiderin-specific sequences) and pathological assessment of CAA at age ≥55. CAA was defined as Vonsattel degree ≥2, except in non-autopsy studies, where any vascular amloyid deposition was considered diagnostic of CAA. We excluded cases with: 1) non-lobar ICH; 2) alternative clinical diagnosis for the lobar hemorrhage/es; 3) CAA-negative studies based on small brain biopsy samples (greater diameter <1 cm) or clot evacuations with none or rare vessels identified; 4) autopsy studies not grading CAA. We determined sensitivity and specificity of “possible CAA” (1 lobar hemorrhage) and “probable CAA” (>1 strictly lobar hemorrhage) in both cohorts. Results: The study included 143 cases: 96 from the hospital cohort (mean age at time of MRI 74.1±8.2 years, 47.9% women, 47.9% autopsy studies, 54.2% cases with any lobar microbleed, 44.8% with any lobar ICH) and 47 from FHS (mean age at time of MRI 83.4±10.9 years, 48.9% women, 100% autopsy studies, 17% cases with any lobar microbleed, no lobar ICH cases). Hospital cohort: CAA prevalence was 72.6%. Specificity/sensitivity of “possible CAA” and “probable CAA” were 78.2%/33.3% and 92%/57.7%. Community cohort: CAA prevalence was 47%. Specificity/sensitivity of “probable CAA” were 88%/3%. Discussion: Specificity of detection of multiple lobar hemorrhages on MRI (“probable CAA”) for moderate-severe CAA is similarly high in both hospital and community cohorts. This increases the opportunity to identify individuals with CAA for observational studies and emerging anti-amyloid therapeutic trials. In view of its poor sensitivity, “probable CAA” diagnosis represents an inadequate screening tool for exclusion of CAA in both populations.
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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 | 0.001 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".