T1 mapping of the right ventricle in heart transplant recipients: how does it correlate with endomyocardial biopsy findings?
Bibliographic record
Abstract
Abstract Aim Noninvasive detection of cardiac allograft rejection is highly desirable. We sought to assess how right ventricular (RV) T1 mapping correlates with endomyocardial biopsy findings. Methods All patients underwent right heart catheterization with biopsy and cardiac magnetic resonance (CMR) irrespective of symptoms, as part of the institutional registry protocol dedicated to heart transplant (HTx) recipients. CMR studies were performed using a 1.5 T scanner and analyses by using a commercially available software (CMR42, Circle CVI, Calgary, Canada). Endocardial and epicardial borders were drawn on end-systolic and end-diastolic phases for ventricular function analysis. For T1 measurements, region of interests located at the RV free-wall were drawn manually on midventricular short-axis slices avoiding blood pool and epicardial fat. Extracellular volume (ECV) was calculated as ECV = (1 − hematocrit) × (ΔR1 myocardium/ΔR blood), where R1 = 1/T1. Late gadolinium enhancement (LGE) images were also obtained using a phase-sensitive inversion recovery segmented gradient echo sequence. Hyperenhancement was assessed semi-quantitatively as segmental (2–3 cm) or diffuse (>3 cm). Allograft rejection was determined based on the severity of inflammatory infiltrates and myocyte damage on pathological specimens according to the standardized International Society for Heart and Lung Transplantation (ISHLT) nomenclature. Results In all, 61 paired studies were evaluated. None of the patients had heart failure symptoms. We defined 3 subgroups: Group I; never rejected (n=23), group II; biopsy remarkable for rejection (n=19) and group III; history of past rejection(s) (n=19). RV volumes and ejection fraction (EF) did not differ between the groups. However, rejections were nicely mirrored by T1 time and particularly by ECV. Of note, T1 time and ECV improved but not completely normalized after resolution of rejection. Overall, T1 time (cut off 1060ms) and ECV (cut off 35%) were sensitive (84%, both) and had high negative predictive values (88% and 87%, respectively) but not specific (43% and 52% respectively) for discriminating rejection related subclinical RV damage. Their specificity slightly improved to 52 and 61% respectively, if patients with previous rejection were excluded (Figure 1). LGE did not discriminate rejection. Conclusion RV volumes and EF are insensitive to detect allograft rejection. Native T1 time and ECV of the RV, as a means of extracellular expansion, likely reflect interstitial fibrosis, oedema, and inflammation that are typical for, but not limited to allograft rejection. Hence, these parameters can help to exclude rejection but have limited standalone value for making the nonivasive diagnosis due to their low specificity. These results cannot be extrapolated to the left ventricle. Funding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): University of Baskent
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".