Decreased Frontal Lobe Gray Matter Perfusion in Cognitively Impaired Patients with Secondary-Progressive Multiple Sclerosis Detected by the Bookend Technique
Bibliographic record
Abstract
BACKGROUND AND PURPOSE: There is increasing evidence implicating microvascular impairment in MS pathogenesis. Perfusion imaging offers a unique opportunity to investigate the functional impact of GM pathology. We sought to quantify differences in MR imaging-based bookend-derived cerebral perfusion between cognitively impaired and nonimpaired patients with SPMS. MATERIALS AND METHODS: Patients were prospectively recruited and assessed using MR imaging and the standard cognitive battery called the Minimal Assessment of Cognitive Function in MS. Patients exhibiting impairment on ≥ 2 individual tests were classified as cognitively impaired. Healthy controls were prospectively recruited and assessed using MR imaging to validate bookend assumptions. Structural and perfusion scans were coregistered and partitioned into anatomic brain regions and tissue compartments. Clinical and radiologic characteristics were compared between patients with and without impairment to identify potential confounders. A Bonferroni adjusted P value threshold (P < .005) was used for lobar and sublobar level analyses to correct for multiple comparisons. RESULTS: Thirty-seven patients with SPMS (age 56 ± 9 years; 23 women, 14 men) and 10 age- and sex-matched healthy controls were recruited. Bookend assumptions were found to be valid in MS. GM and WM qCBV were all globally reduced in impaired patients. After adjusting for potential confounders while examining sublobar level perfusion, only GM qCBV was significantly different between cognitive groups, and this hypoperfusion localized to the bilateral medial superior frontal regions and left inferior, middle, and superior frontal regions (P < .005) of impaired patients compared with nonimpaired patients. GM qCBV accounted for 22.5% of the model variance compared with a model including only confounders (P = .0007). CONCLUSIONS: Bookend-derived GM qCBV was significantly reduced in cognitively impaired patients with SPMS in functionally relevant brain regions.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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 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".