Absolute Quantification of Phosphor-Containing Metabolites in the Liver Using 31 P MRSI and Hepatic Lipid Volume Correction at 7T Suggests No Dependence on Body Mass Index or Age.
J Magn Reson Imaging
; 49(2): 597-607, 2019 02.
Article
em En
| MEDLINE
| ID: mdl-30291654
ABSTRACT
BACKGROUND:
Hepatic disorders are often associated with changes in the concentration of phosphorus-31 (31 P) metabolites. Absolute quantification offers a way to assess those metabolites directly but introduces obstacles, especially at higher field strengths (B0 ≥ 7T).PURPOSE:
To introduce a feasible method for in vivo absolute quantification of hepatic 31 P metabolites and assess its clinical value by probing differences related to volunteers' age and body mass index (BMI). STUDY TYPE Prospective cohort. SUBJECTS/PHANTOMS Four healthy volunteers included in the reproducibility study and 19 healthy subjects arranged into three subgroups according to BMI and age. Phantoms containing 31 P solution for correction and validation. FIELD STRENGTH/SEQUENCE Phase-encoded 3D pulse-acquire chemical shift imaging for 31 P and single-volume 1 H spectroscopy to assess the hepatocellular lipid content at 7T. ASSESSMENT A phantom replacement method was used. Spectra located in the liver with sufficient signal-to-noise ratio and no contamination from muscle tissue, were used to calculate following metabolite concentrations adenosine triphosphates (γ- and α-ATP); glycerophosphocholine (GPC); glycerophosphoethanolamine (GPE); inorganic phosphate (Pi ); phosphocholine (PC); phosphoethanolamine (PE); uridine diphosphate-glucose (UDPG); nicotinamide adenine dinucleotide-phosphate (NADH); and phosphatidylcholine (PtdC). Correction for hepatic lipid volume fraction (HLVF) was performed. STATISTICAL TESTS Differences assessed by analysis of variance with Bonferroni correction for multiple comparison and with a Student's t-test when appropriate.RESULTS:
The concentrations for the young lean group corrected for HLVF were 2.56 ± 0.10 mM for γ-ATP (mean ± standard deviation), α-ATP 2.42 ± 0.15 mM, GPC 3.31 ± 0.27 mM, GPE 3.38 ± 0.87 mM, Pi 1.42 ± 0.20 mM, PC 1.47 ± 0.24 mM, PE 1.61 ± 0.20 mM, UDPG 0.74 ± 0.17 mM, NADH 1.21 ± 0.38 mM, and PtdC 0.43 ± 0.10 mM. Differences found in ATP levels between lean and overweight volunteers vanished after HLVF correction. DATACONCLUSION:
Exploiting the excellent spectral resolution at 7T and using the phantom replacement method, we were able to quantify up to 10 31 P-containing hepatic metabolites. The combination of 31 P magnetic resonance spectroscopy imaging data acquisition and HLVF correction was not able to show a possible dependence of 31 P metabolite concentrations on BMI or age, in the small healthy population used in this study. LEVEL OF EVIDENCE 2 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2019;49597-607.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fósforo
/
Imageamento por Ressonância Magnética
/
Índice de Massa Corporal
/
Fígado
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
J Magn Reson Imaging
Assunto da revista:
DIAGNOSTICO POR IMAGEM
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Áustria