3.0 T proton magnetic resonance spectroscopy of the liver: quantification of choline.

Aim: To investigate the normal hepatic magnetic resonance spectroscopy findings choline/lipid2 (Cho/Lip2) associated with age and body mass index (BMI).

Methods: A total of 58 single-voxel proton spectra of the liver were acquired at 3.0 T using the eight-channel phased array abdominal coil as the receiver coil. Consecutive stacks of breath-hold spectra were acquired using the point resolved spectroscopy technique at a short echo time of 30 ms and a repetition time of 1500 ms. The spectra were processed with the SAGE software package. Areas and heights for metabolite resonance were obtained. Student's t test for unpaired data was used for comparisons of shimming, Cho/Lip2, and lipid content.

Results: There were significant negative correlations between the Cho/Lip2 peak height ratios and BMI (r = -0.615) and age (r = -0.398) (all P < 0.01). Compared with the high-BMI group, the low-BMI group was younger (39.1 ± 13.0 years vs 47.6 ± 8.5 years, t = -2.954, P = 0.005); had better water suppression (93.4% ± 1.4% vs 85.6% ± 11.6%, t = 2.741, P = 0.014); had higher Cho/Lip2 peak heights ratio (0.2 ± 0.14 vs 0.05 ± 0.04, t = 6.033, P < 0.000); and had lower lipid content (0.03 ± 0.08 vs 0.29 ± 0.31, t = -3.309, P = 0.004). Compared with the older group, the younger group had better shimming effects (17.1 ± 3.6 Hz vs 22.0 ± 6.8 Hz, t = -2.919, P = 0.008); higher Cho/Lip2 peak heights ratios (0.03 ± 0.05 vs 0.09 ± 0.12, t = 2.4, P = 0.020); and lower lipid content (0.05 ± 0.11 vs 0.23 ± 0.32, t = -2.337, P = 0.031). Compared with the low-choline peak group, the high-choline peak group had lower lipid content (0.005 ± 0.002 vs 0.13 ± 0.23, t = -3.796, P < 0.000); lower BMI (19.6 ± 2.4 vs 23.9 ± 3.0, t = -4.410, P < 0.000); and younger age (34.7 ± 10.0 years vs 43.2 ± 12.5 years, t = -2.088, P = 0.041).

Conclusion: Lipid accumulation could result from the increased fat in the body depending on age and BMI. Lipid can mask the resonance signal of choline.