Noninvasive blood–brain barrier integrity mapping in patients with high‐grade glioma and metastasis by multi–echo time–encoded arterial spin labeling
Bibliographic record
Abstract
Abstract Purpose In brain tumors, disruption of the blood–brain barrier (BBB) indicates malignancy. Clinical assessment is qualitative; quantitative evaluation is feasible using the K 2 leakage parameter from dynamic susceptibility contrast MRI. However, contrast agent–based techniques are limited in patients with renal dysfunction and insensitive to subtle impairments. Assessing water transport times across the BBB ( T ex ) by multi‐echo arterial spin labeling promises to detect BBB impairments noninvasively and potentially more sensitively. We hypothesized that reduced T ex indicates impaired BBB. Furthermore, we assumed higher sensitivity for T ex than dynamic susceptibility contrast–based K 2 , because arterial spin labeling uses water as a freely diffusible tracer. Methods We acquired 3T MRI data from 28 patients with intraparenchymal brain tumors (World Health Organization Grade 3 & 4 gliomas [ n = 17] or metastases [ n = 11]) and 17 age‐matched healthy controls. The protocol included multi‐echo and single‐echo Hadamard‐encoded arterial spin labeling, dynamic susceptibility contrast, and conventional clinical imaging. T ex was calculated using a T 2 ‐dependent multi‐compartment model. Areas of contrast‐enhancing tissue, edema, and normal‐appearing tissue were automatically segmented, and parameter values were compared across volumes of interest and between patients and healthy controls. Results T ex was significantly reduced (−20.3%) in contrast‐enhancing tissue compared with normal‐appearing gray matter and correlated well with | K 2 | ( r = −0.347). Compared with healthy controls, T ex was significantly lower in tumor patients' normal‐appearing gray matter ( T ex,tumor = 0.141 ± 0.032 s vs. T ex,HC = 0.172 ± 0.036 s) and normal‐appearing white matter ( T ex,tumor = 0.116 ± 0.015 vs. T ex,HC = 0.127 ± 0.017 s), whereas | K 2 | did not differ significantly. Receiver operating characteristic analysis showed a larger area under the curve for T ex (0.784) than K 2 (0.604). Conclusion T ex is sensitive to pathophysiologically impaired BBB. It agrees with contrast agent–based K 2 in contrast‐enhancing tissue and indicates sensitivity to subtle leakage.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".