Relationship between MRI First pass Perfusion Parameters and Biventricular Performance in Pulmonary Hypertension
Bibliographic record
Abstract
The amount of blood flow through the lungs is determined by pulmonary by pressure gradient as well as cardiac function in PH. Dynamic contrast-enhanced MRI (DCE-MRI) enables high temporal resolution imaging to track the first transit of contrast material bolus through the pulmonary circulation. First-pass parameters such as pulmonary transit time (PTT), left ventricular (LV) full width at half maximum (FWHM), and LV time to peak (TTP) have been shown to be impaired in PAH compared to controls. Little has been reported regarding the relationship between first pass perfusion parameters in other groups of PH. Our aim was to explore the relationship between first-pass parameters and RV and LV performance in patients with group I (PAH) and group IV (chronic thromboembolic pulmonary hypertension) PH We prospectively recruited 9 patients with PH (pulmonary arterial hypertension, n=5; chronic thromboembolic pulmonary hypertension, n=4) who underwent CMR at 3T. CMR studies included functional (bSSFP) cine imaging for assessment of ventricular function, as well as phase contrast velocity encoded cine imaging obtained perpendicular to the main pulmonary artery (MPA) for assessment of MPA distensibility (%). To assess PTT, FWHM, and TTP, a 1:10 diluted bolus (0.0025 mmol/kg) of Gadobutrol was injected intravenously at 5 mL/s and followed using a single-shot saturation-recovery gradient-echo sequence in the short axis orientation (at the basal third of both ventricles). First-pass bolus kinetic parameters were determined by sampling the signal intensities in the RV and LV cavities and generating time-intensity curves for each ventricle. PTT was defined as the transit time of blood between the RV and LV, while FWHM and TTP were derived from the shape of the bolus in the LV cavity (Figure). Differences in first-pass parameters between the two groups were assessed using Mann-Whitney U tests and the relationship between each first-pass and functional parameters were investigated using Spearman's rank correlation (rho). There were no significant differences in first-pass parameters between groups (P>0.05 for each comparison). Significant negative correlations were found between FWHM and LV ejection fraction (rho=-0.72, p = 0.03) and LV cardiac output (rho=-0.68, p = 0.04) and FWHM was positively correlated with MPA distensibility (rho=0.73, p = 0.02). Trends towards negative correlations between PTT and RV (rho=-0.65, p = 0.06) and LV stroke volume indexed (rho=-0.60, p = 0.09) were also revealed. First pass perfusion parameters are similar in Group I and IV patients with PH. An increase in MPA distensibility is associated with an increase in FWHM. This may be attributed to advanced disease when RV cardiac output is decreased resulting in a paradoxical decrease in pulmonary pressures. Increased first-pass bolus dispersion (FWHM) may be a noninvasive marker of impaired pulmonary hemodynamics and biventricular dysfunction in groups I and IV patients with PH. Time intensity curves show transit of the contrast material bolus through the regions of interest in the right (blue) and left (red) ventricular cavities and indicate the first pass bolus parameters peak to peak PTT, FWHM and TTP .
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".