Application of Excitation Sculpting in the Quantification of Conjugated Bile Acids in Bile

Omkar B. Ijare¹, Tedros Bezabeh¹, Nils Albiin², Annika Bergquist², Urban Arnelo², Matthias Lohr², Ian C. P. Smith¹

Bile acids are major components of bile and are present mostly in conjugated forms with glycine and/or taurine. Amide bonds formed as a result of this conjugation provide well resolved NH signals in the down-field region of ¹H MR spectrum of bile. However, at physiologic pH, these amide protons are in dynamic exchange with biliary water and show decreased signal intensity. Lowering the pH of bile below physiologic value (~ 6.0) has been helpful in recovering such signal loss. In this study, we propose the use of excitation sculpting sequence for the quantification of conjugated bile acids using their NH signals without the need for pH adjustment.