The objective was to investigate T(2) relaxation values and to optimize hepatic fat quantification using proton MR spectroscopy ((1)H MRS) at 3T in overweight and obese children and adolescents.
The study included 123 consecutive children and adolescents with a body mass index above the 97th percentile according to age and sex. (1)H MR spectroscopy was performed at 3.0T using point resolved spectroscopy sequence with series TE. T(2) relaxation values and hepatic fat content corrected for the T(2) relaxation effects were calculated.
T(2) values for water ranged from 22ms to 42ms (mean value 28ms) and T(2) values for fat ranged from 36ms to 99ms (mean value 64ms). Poor correlation was observed: (1) between T(2) relaxation times of fat and T(2) relaxation times of water (correlation coefficient r=0.038, P=0.79); (2) between T(2) relaxation times of fat and fat content (r=0.057, P=0.69); (3) between T(2) relaxation times of water and fat content (r=0.160, P=0.26). Correlation between fat peak content and the T(2) corrected fat content decreased with increasing echo time TE: r=0.97 for TE=45, r=0.93 for TE=75, r=0.89 for TE=105, P<0.0001.
(1)H MRS at 3T is an effective technique for measuring hepatic fat content in overweight and obese children and adolescents. It is necessary to measure T(2) relaxation values and to correct the spectra for the T(2) relaxation effects in order to obtain an accurate estimate of the hepatic fat content.
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