Fatty liver quantification with line scan echo planar spectroscopic imaging (LSEPSI)

INTRODUCTION: Although fatty infiltration of liver is a benign process that generally results from chronic alcohol uptake or obesity, such lifestyle factors may lead to chronic disease. Measuring the fat concentration in liver may therefore prove useful in assessing disease status. In this study, we report the usefulness of line scan echo planar spectroscopic imaging (LSEPSI) for this problem. METHODS: Rapid successive column sampling was accomplished using orthogonal slice-selective 90 degrees and 180 degrees pulses and echo planar spectral/spatial encodings. Phantom and clinical studies of 13 patients suspected of having fatty liver were carried out with LSEPSI. Estimated fat fractions obtained with LSEPSI were compared with ultrasound findings. RESULTS: The results showed a good correlation between the actual fat content of phantoms and the estimated fat fraction obtained with LSEPSI (r = 0.95). In the clinical study, the estimated fat fraction tended to rise as the US grade of fatty liver increased. DISCUSSION: LSEPSI is largely free from T1 and T2 relaxation owing to its infinite TR and minimal T2 weighting. Thus, there is no need for relaxation analysis. In addition, the lack of phase encoding reduces motion-related ghosting artifacts. Rapid fat/water spectral quantification of liver with this technique is useful for fatty liver assessment in a clinical setting.