Regional T1:T2 Ratios are Higher in Alzheimer’s Disease than Healthy Controls and Cerebral Amyloid Angiopathy Patients
Bibliographic record
Abstract
Cerebral amyloid angiopathy (CAA) is a small vessel disease with b-amyloid accumulation in the walls of cerebral vessels. The ratio of T1-weighted to T2-weighted magnetic resonance images (T1:T2ratio) has been shown to improve sensitivity of detecting changes in signal intensity associated with myelin content in both gray and white matter (WM) and b-amyloid accumulation in gray matter (GM). In this exploratory study, we compared regional T1:T2ratios between control (CTRL), CAA, and AD groups to determine if regional T1:T2ratios are higher in CAA. Cross-sectional data from an ongoing longitudinal cohort study (Functional Assessment of Vascular Reactivity: FAVR) were analyzed. CAA participants were diagnosed according to the Boston criteria. 3D T1-weighted and 2D T2-weighted images were bias corrected, skull stripped, and co-registered to the MNI152 template prior to calculating the ratio images. Linear mixed effects models were used to compare mean T1:T2ratios between groups and gray brain regions adjusting for age and sex, using Tukey’s method to adjust for multiple post-hoc comparisons across 3 groups and 56 regions. Data for 62 CTRL, 48 CAA and 24 AD participants were analyzed. No differences in regional T1:T2ratios were detected between CTRL and CAA (p>0.05 for all comparisons). However, AD had higher T1:T2ratios than CTRL and CAA in the anterior temporal fusiform, posterior temporal fusiform, putamen, and thalamus. AD also had higher T1:T2ratios than CTRL in the lingual cortex and temporal occipital fusiform cortex. T1:T2ratios in both cortical and subcortical gray matter regions were higher in AD than CTRL and CAA. Similar T1:T2ratios in CTRL and CAA may be a consequence of b- amyloid localization to the cerebral blood vessels rather than senile plaques, and/or lower concentration of b-amyloid than in AD.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".