Abstract 15584: Magnetic Resonance Imaging Reveals Decreased Oxygen Delivery and Consumption in Human Fetuses with Congenital Heart Disease
Bibliographic record
Abstract
Introduction: Animal models suggest chronic hypoxia in utero results in down regulation of brain metabolism, impairing brain growth and development. A new approach to assessing fetal hemodynamics with phase contrast (PC) MRI and T2 mapping offers the means to assess the impact of congenital heart disease (CHD) on cerebral oxygen delivery (DO2) and consumption (VO2). Hypothesis: Fetuses with CHD might have reduced cerebral DO2 and VO2 with associated reductions in brain size. Methods: 28 normal fetuses and 23 fetuses with CHD with either single ventricle (SV) or biventricular physiology (BV) underwent MRI close to term. Assuming a hemoglobin concentration of 15g/dL, we calculated oxygen delivery (DO2) = umbilical vein flow (Q UV ) х UV oxygen content, where oxygen content = oxygen saturation of hemoglobin [HbO2] х 1.36 х [Hb]. We calculated fetal oxygen consumption (VO2) as Q UV х AV[[Unable to Display Character: ∆]]O2, where AV[[Unable to Display Character: ∆]]O2 is the arterio-venous difference in oxygen content between the UV and umbilical artery. Cerebral DO2 and VO2 were similarly measured using aortic and superior vena cava oxygen content and flow. Fetal brain volume was measured by segmenting a 3D steady state free precession acquisition of the fetal brain. Normal and CHD fetal VO2 and DO2 and cerebral VO2 and DO2 were compared using a Student’s t -test. The correlation between brain size and hemodynamic parameters was examined using Pearson’s Correlation. Results: The combined ventricular output (CVO; p =0.0003), Q UV ( p =0.0007) were reduced in fetuses with SV (n=6) compared with normals and fetuses with BV hearts (n=17) ( p =0.02), while UV T2 was lower in CHD fetuses ( p =0.0001). This resulted in mean reductions of >25% in fetal VO2 and DO2 in SV and BV CHD fetuses compared to normals ( p p =0.01). In fetuses with brain sizes below the mean, brain size correlated with cerebral VO2 ( r =0.58, p =0.01). Conclusions: This study provides evidence of a potential hemodynamic cause for the delayed brain growth and development that has been previously described in newborns with CHD. This is of interest because delayed brain development is associated with greater susceptibility to white matter injury around neonatal cardiac surgery.
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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) | 0.003 | 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".