title: In vivo 1H MRS of human gallbladder bile at 3 T in one and two dimensions: detection and quantification of major biliary lipids.
abstract: In vitro (1)H MRS of human bile has shown potential in the diagnosis of various hepatopancreatobiliary (HPB) diseases. Previously, in vivo (1)H MRS of human bile in gallbladder using a 1.5 T scanner demonstrated the possibility of quantification of choline-containing phospholipids (chol-PLs). However, other lipid components such as bile acids play an important role in the pathophysiology of the HPB system. We have employed a higher magnetic field strength (3 T), and a custom-built receive array coil, to improve the quality of in vivo (1)H MRS of human bile in the gallbladder. We obtained significant improvement in the quality of 1D spectra (17 healthy volunteers) using a respiratory-gated PRESS sequence with well distinguished signals for total bile acids (TBAs) plus cholesterol resonating at 0.66 ppm, taurine-conjugated bile acids (TCBAs) at 3.08 ppm, chol-PLs at 3.22 ppm, glycine-conjugated bile acids (GCBAs) at 3.74 ppm, and the amide proton (-NH) arising from GCBAs and TCBAs in the region 7.76-8.05 ppm. The peak areas of these signals were measured by deconvolution, and subsequently the molar concentrations of metabolites were estimated with good accuracy, except for that of TBAs plus cholesterol. The concentration of TBAs plus cholesterol was overestimated in some cases, which could be due to lipid contamination. In addition, we report the first 2D L-COSY spectra of human gallbladder bile in vivo (obtained in 15 healthy volunteers). 2D L-COSY spectra will be helpful in differentiating various biliary chol-PLs in pathological conditions of the HPB system.
authors.affiliation: University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Sanaz
authors.initials: S
authors.lastname: Mohajeri
authors.forename: Omkar B
authors.initials: OB
authors.lastname: Ijare
authors.forename: Tedros
authors.initials: T
authors.lastname: Bezabeh
authors.forename: Scott B
authors.initials: SB
authors.lastname: King
authors.forename: M Albert
authors.initials: MA
authors.lastname: Thomas
authors.forename: Gerald
authors.initials: G
authors.lastname: Minuk
authors.forename: Jeremy
authors.initials: J
authors.lastname: Lipschitz
authors.forename: Iain
authors.initials: I
authors.lastname: Kirkpatrick
authors.forename: Mike
authors.initials: M
authors.lastname: Smith
authors.forename: Ian C P
authors.initials: IC
authors.lastname: Smith
mesh_terms: D000328:Adult; D001646:Bile / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000032:analysis; D002784:Cholesterol / Q000032:analysis; D002794:Choline / Q000032:analysis; D005260:Female; D005704:Gallbladder; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D019047:Phantoms, Imaging; D010743:Phospholipids / Q000032:analysis; D066244:Proton Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D013654:Taurine / Q000032:analysis
chemical_list: D001647:Bile Acids and Salts; D008055:Lipids; D010743:Phospholipids; D013654:Taurine; D002784:Cholesterol; D002794:Choline
keywords: L-COSY; PRESS; choline-containing phospholipids; glycine-conjugated bile acids; human bile; in vivo 1H MRS; taurine-conjugated bile acids