P2‐013: A direct comparison of ventricular volumes derived from 1.5 Tesla and 3.0 Tesla MRI in 115 ADNI participants
Bibliographic record
Abstract
Ventricular enlargement measured from T1-weighted magnetic resonance images (MRI) is an indirect measure of Alzheimer disease (AD) progression. Most MRI volumetric studies have assessed structural change derived from 1.5 Tesla MRI. However, 3.0 Tesla scanners are becoming prevalent, and there are few studies assessing potential differences in volumetry between field strengths. More than 25% of ADNI subjects undergo both 1.5 Tesla and 3.0 Tesla MRI. Objectives: to compare the sensitivity of ventricular measures derived from both 1.5 Tesla and 3.0 Tesla MRI in the same subjects. Baseline and 12-month data were obtained from the Alzheimer Disease Neuroimaging Initiative (ADNI), including 42 normal controls (NC), 53 subjects with mild cognitive impairment (MCI) and 20 subjects with AD (mean age =76 years in each group). Baseline and 12-month processed 3D T1-weighted MP-RAGE MRI, and corresponding, demographic measures were collected. Ventricular volume was computed using a semi-automated region-growing algorithm (Cedara Software). Intra-class correlation coefficients (ICCs) were computed to assess differences between 1.5 Tesla and 3.0 Tesla data for cross-sectional and longitudinal measures. A one-way ANOVA was used for group-wise comparisons between NEC, MCI and AD groups for baseline and longitudinal ventricular measures. Ventricular volumes measured from 1.5 Tesla (mean ±SD: NEC=31.5 ±11.2cm, MCI=51.6 ±23.9cm, AD= 48.8 ±26.5cm) were smaller (p<0.001) than ventricular volumes derived from 3.0 Tesla MRI (NEC= 32.8 ±11.2cm, MCI=53.8 ±24.2cm, AD=49.8 ±29.4cm) at baseline (ICC=0.99, p<0.0001). Ventricular enlargement was similar for measures derived from 1.5 Tesla MRI (mean ± SD = 2.6 ± 2.8 cm) and 3.0 Tesla MRI (mean ± SD = 2.5 ±3.3 cm) when collapsing across groups (ICC=0.75, p<0.0001). For both field strengths the AD and MCI groups had significantly greater ventricular enlargement after 12 months than the NC group (p<0.01). These data demonstrate similar sensitivities for 1.5 Tesla and 3.0 Tesla derived ventricular measures. Baseline comparisons reveal high reproducibility between field strengths, with a slightly larger ventricular volume for 3.0 Tesla measures. Nevertheless, ventricular enlargement computed from 3.0 and 1.5 Tesla MRI demonstrated comparable group-wise discrimination.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".