99mTc-Pyrophosphate Scintigraphy for the Diagnosis of ATTR Cardiac Amyloidosis: Early Phase Planar and SPECT Images versus Late Phase SPECT Images
Notice bibliographique
Résumé
666 Objectives: 99mTc-PYP bone scintigraphy can accurately diagnose transthyretin cardiac amyloidosis (ATTR-CA) and distinguish it from light-chain cardiac amyloidosis (AL-CA), with diffuse myocardial uptake of 99mTc-PYP being very specific for ATTR-CA. Two methods have been validated to analyze 99mTc-PYP scintigraphy: a quantitative heart-to-contralateral (H/CL) ratio calculated on planar images obtained 1h post injection, and a visual grading system based on planar or SPECT images obtained at 3h. The purpose of this multicentric study was to compare the 1h H/CL ratio to the visual grading system at 3h and to compare the visual grading system at 1h and 3h. Methods: A total of 122 consecutive subjects, from 2 centers, who underwent both 1h and 3h planar and SPECT 99mTc-PYP imaging were retrospectively included. Circular regions of interest drawn over the heart and mirrored on the contralateral thorax were used to calculate the H/CL on 1h planar anterior images. Myocardial uptake intensity was compared to bone activity on both 1h and 3h SPECT images using the visual grading system. H/CL between 1.0 and 1.5 were considered equivocal for ATTR-CA, as was Grade 1 uptake on 3h imaging, as per current ASNC Practice Points. Agreement was evaluated using Cohen’s Kappa. Results: 77 (63%), 10 (8%), 12 (10%), and 23 (19%) subjects had grade 0, 1, 2, and 3 myocardial uptake respectively at 3h. 10 (8%), 81 (66%) and 31 (25%) subjects had 1h H/CL ratio 1.5 respectively. Amongst those with H/CL between 1.0 and 1.5, 9 (11%) had grade 1 uptake at 3h while 67 (83%) had grade 0 and 5 (6%) and grade 2 or 3. The proportion of equivocal studies was significantly less when using the 3h grade compared to the H/CL method (p<0.0001). For two subjects, 3h grading and H/CL yielded discordant results; one had biopsy proven ATTR-CA with a H/CL of 0.91 and a grade 2 uptake while the other had biopsy proven AL-CA with a H/CL of 1.96 and a grade 0 uptake. Uptake grade was the same at 1h and at 3h on SPECT imaging in most patients, with 5 subjects having different grading at 1h and 3h. One subject had grade 1 uptake at 1h and grade 0 at 3h, 3 had grade 3 uptake at 1h and grade 2 at 3h, and 1 had grade 2 uptake at 1h and grade 3 at 3h. The agreement between uptake grade at 1h and at 3h was 99% when combining grade 2 and 3 (both considered positive for ATTR-CA as per current ASNC Practice Points). Conclusions: A significant proportion of PYP scans yielded equivocal H/CL on 1h imaging, with significantly fewer equivocal results using the visual grading system on SPECT images at 3h, which in turn seems very comparable to the visual grading system on SPECT images at 1h. These results indicate that the use of 1h imaging H/CL alone, with current ASNC Practice Points interpretation thresholds, may lead to high proportion of equivocal studies, and 3h imaging remains necessary in a large proportion of patients.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,008 | 0,006 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».