Magnetic Resonance Imaging of Fresh Cadavers: Initial Experiences
Notice bibliographique
Résumé
Introduction We seek the capacity to relate structural data obtained from Magnetic Resonance Imaging of intact specimens to the information gained from subsequent dissection. The first step in this process is evaluation and optimization of MRI protocols for studying fresh cadavers, and our first experiences with this process are presented here. Methods This work was conducted per the Queen's University HSREB study DBMS‐051‐15. Four specimens were obtained over a period of approximately 7 months for use in this study, and three (identified as specimens 1–3) of these were selected for study in the MRI. Specimens were collected from the morgue as soon as possible in all cases. Each specimen was first perfused with 10L of a 1% ethylenediaminetetraacetic acid (EDTA) and 72mM NaCl pH7 perfusion buffer; exsanguination was simultaneously performed. The purpose of the EDTA was to attempt to ensure blood and any residual clotting was removed. A second perfusion was 5L of MnCl (0.5g/L), which was used to attempt to ensure low MRI signal in the vascular space and thereby enhance tissue contrast and identification. The venesections used for exsanguination were clamped with hemostats both proximally and distally to the section prior to the MnCl perfusion. Both solutions were injected via the brachial artery with an average pressure of 10–18psi. Each specimen was imaged using a Siemens Tim Trio (3 T) MRI system. No specific attempt was made to maintain consistency of the applied imaging protocol across the samples, as the purpose of the study was in part to evaluate and optimize a protocol suitable for cadaver imaging; however, in all three cases the following pulse sequences were used: Flash‐3D VIBE‐DIXON, T2w SPACE, DESS, and DTI. The typical total imaging session duration for each specimen was between 2 and 3 hours. Results shows example MR data from three different sequences acquired from Specimen 3 (which was considered to be the most successful). This indicates the different image data that can be acquired from a single specimen. shows representative images from one sequence (VIBE‐DIXON, “water” image) from each of the three specimens, thereby providing an indication of the variation between specimens. Discussion Each of the MR sequences used provides different information on the specimen; however, for structural assessment it appears that the VIBE‐DIXON sequence, which provides separate images of “water” and “fat”, is particularly useful in this application. Both T2w SPACE and DESS performed well. Further sequence optimization is underway for this application. Not surprisingly, it was apparent that the best quality results were obtained by attempting to keep the post‐mortem hours prior to analysis at a minimum. In the case Specimen 2 (40 hours post‐mortem) it was noticeably more difficult to optimize the exsanguination and subsequent perfusion. Specimen 3 was the most successful, in approximately equal parts due to the better condition of the specimen itself, shorter time post‐mortem, and improved procedures due to experience gained. Support or Funding Information Funding from Natural Sciences and Engineering Research Council of Canada and the Ontario Research Fund.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
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 tête enseignante, 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 ».