FC 054FUNCTIONAL SODIUM MAGNETIC RESONANCE IMAGING OF THE HUMAN KIDNEY
Notice bibliographique
Résumé
Abstract Background and Aims Maintenance of a cortico-medullary concentration gradient (CMG) required for urine concentration, is one of most important tubular function. However, we are lacking of functional tubular parameters to explore this function. The only tool available to assess it currently, is urinary osmolarity that is an indirect and nonspecific maker of CMG. In this study, we explore the ability of 23NaMRI in measuring 1) the dynamics of CMG for the first time compared to urinary osmolarity after a water load 2) the CMG in kidney disease. Method We conducted an exploratory pilot study for 10 healthy controls with water load then 5 cardiorenal patients with kidney disease. 1) Healthy controls were asked to be fasting since midnight. Urines sample were collected to measure fasting osmolarity and a first MRIscan were performed to acquire baseline anatomical and sodium images. Once the baseline was completed, healthy participants were asked to ingest water (15 mL/kg) within 15 minutes. Four subsequent sodium pictures were acquired an hour after water ingestion. Urine samples were obtained after each sodium acquisition every 15 min during one hours. 2) Cardiorenal patients underwent an MRI scan, provided a spot urine sample and have blood work collected. All MR experiments were carried out on a GE MR750 3T (GE Healthcare, WI). A custom-built two-loop (18cm in diameter) butterfly radiofrequency surface coil tuned for 23Na frequency (33.786 MHz) was used to acquire renal 23Na images. Results Mean age of the 10 healthy controls was 41.8 ± 15.3 years, mean body mass index (BMI) was 24.3 ± 3.8 kg/m2. Mean water intake was 1092 ± 233 mL, total water excreted was 1250 ± 301 mL . Mean age of the 5 cardiorenal patients was 76.6 ± 12.2 years, mean BMI was 28.1 ± 6.9 kg/m2. eGFR was 54 ± 37 mL/min/1.73m2. Urinary osmolarity was 498 ± 145 mosm/L and medulla/cortex ratio was 1.35 ± 0.11. Sodium imaging was successfully acquired in all volunteers. In the morning fasting, medulla/cortex ratio was 1.55 ± 0.11 regarding to a urinary osmolarity to 814 ± 121 mosm/L. Mean ± SD fasting urinary osmolarity dropped significantly to 73 ± 14 mosm/L for maximal dilution, p=0.001. Mean medulla/cortex ratio dropped significantly to 1.31 ± 0.09 mosm/L for maximal dilution, p=0.002. Figure 1 displays changes of 23NaMRI pictures before (A) then 1h (B), 1H15 (C), 1h30 (D) and 1h45 (E) after a water load. Urinary osmolarity and medulla/cortex ratio are significantly correlated, r=0.54, p=0.0001. We measured corticomedullary gradient in cardiorenal patient with different level of eGFR to show the ability and feasibility to measure this gradient in pathological settings. We were able to measure medulla/cortex ratio in patients with CKD with a mean SNR of 20.45 ± 9.45. Conclusion We explored CMG dynamically every 15 min and we were able to discriminate significant changes after a water load. We were also able to provide efficient 23NaMRI pictures in cardiorenal patients with kidney disease. CMG exploration would provide a relevant assessment of tubular dysfunction independently of glomerular alteration and thus could be of prognostic value.
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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 | 0,001 | 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 | 0,000 | 0,000 |
| 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) | 0,006 | 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 ».