title: High resolution in vivo 31P-MRS of the liver: potential advantages in the assessment of non-alcoholic fatty liver disease.
abstract: BACKGROUND
  Biopsy remains the current gold-standard for assessing non-alcoholic fatty liver disease (NAFLD). To develop a non-invasive means of assessing the disease, 31P magnetic resonance spectroscopy (31P-MRS) has been explored, but the severe spectral overlaps and low signal-to-noise-ratio in 31P-MRS spectra at clinical field strength are clearly limiting factors.
  
  
  OBJECTIVE
  To investigate potential advantages of high resolution in vivo 31P-MRS in assessing NAFLD.
  
  
  METHODS
  The study was conducted at 9.4T in control and carbon tetrachloride (CCl4)-treated rats. Rats were divided according to histopathologic findings into a control group (n = 15), a non-alcoholic steatohepatitis group (n = 17), and a cirrhosis group (n = 12). Data were presented with different reference peaks that are commonly used for peak normalization such as total phosphorous signal, phosphomonoester + phosphodiester (PME + PDE), and nucleotide triphosphate (NTP). Then, multivariate analyses were performed.
  
  
  RESULTS
  In all spectra PME and PDE were well resolved into phosphoethanolamine (PE) and phosphocholine (PC), and into glycerophosphorylethanolamine (GPE) and glycerophosphorylcholine (GPC), respectively. Those MRS measures quantifiable only in highly resolved spectra had higher correlations with histology than those conventional MRS measures such as PME, PDE, and NTP. The optimized partial least-squares discriminant analysis (PLS-DA) model correctly classified 79% (22/28) of the rats in the training set and correctly predicted 69% (11/16) of the rats in the test set.
  
  
  CONCLUSIONS
  PE, PC, GPE, GPC, and nicotinamide adenine dinucleotide phosphate (NADP) that can be separately quantifiable in highly resolved spectra may further improve the potential efficacy of 31P-MRS in the diagnosis of NAFLD.
authors.affiliation: Department of Biomedical Sciences, Graduate School, Seoul National University, Seoul, Republic of Korea Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Jeon
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Yunjung
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Chung-Ang University, Seoul, Republic of Korea.
authors.forename: Sangdoo
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Division of Magnetic Resonance Research, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea.
authors.forename: Chulhyun
authors.initials: C
authors.lastname: Lee
authors.affiliation: Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea.
authors.forename: Ok-Hee
authors.initials: OH
authors.lastname: Kim
authors.affiliation: Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea.
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Oh
authors.affiliation: Bioneer, Daejeon, Republic of Korea.
authors.forename: Ungsik
authors.initials: U
authors.lastname: Yu
authors.affiliation: Department of Biomedical Sciences, Graduate School, Seoul National University, Seoul, Republic of Korea Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea hyeonjinkim@snu.ac.kr ungsik@gmail.com.
authors.forename: Hyeonjin
authors.initials: H
authors.lastname: Kim
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004983:Ethanolamines / Q000378:metabolism; D005997:Glycerylphosphorylcholine / Q000378:metabolism; D008103:Liver Cirrhosis / Q000175:diagnosis / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D009249:NADP / Q000378:metabolism; D065626:Non-alcoholic Fatty Liver Disease / Q000175:diagnosis* / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010758:Phosphorus; D010767:Phosphorylcholine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004983:Ethanolamines; D010714:Phosphatidylethanolamines; D010767:Phosphorylcholine; C002449:glycerophosphoethanolamine; D010758:Phosphorus; D009249:NADP; D005997:Glycerylphosphorylcholine; C005448:phosphorylethanolamine
keywords: 31P magnetic resonance spectroscopy (31P-MRS); carbon tetrachloride (ccl4) animal model; diagnosis; non-alcoholic fatty liver disease (NAFLD); phosphorous metabolism