Liver fat quantification: Comparison of dual-echo and triple-echo chemical shift MRI to MR spectroscopy.
PURPOSE
To assess the diagnostic value of MRI using dual-echo (2PD) and triple-echo (3PD) chemical shift imaging for liver fat quantification against multi-echo T2 corrected MR spectroscopy (MRS) used as the reference standard, and examine the effect of T2(*) imaging on accuracy of MRI for fat quantification.


MATERIALS AND METHODS
Patients who underwent 1.5T liver MRI that incorporated 2PD, 3PD, multi-echo T2(*) and MRS were included in this IRB approved prospective study. Regions of interest were placed in the liver to measure fat fraction (FF) with 2PD and 3PD and compared with MRS-FF. A random subset of 25 patients with a wide range of MRS-FF was analyzed with an advanced FF calculation method, to prove concordance with the 3PD. The statistical analysis included correlation stratified according to T2(*), Bland-Altman analysis, and calculation of diagnostic accuracy for detection of MRS-FF>6.25%.


RESULTS
220 MRI studies were identified in 217 patients (mean BMI 28.0±5.6). 57/217 (26.2%) patients demonstrated liver steatosis (MRS-FF>6.25%). Bland-Altman analysis revealed strong agreement between 3PD and MRS (mean±1.96 SD: -0.5%±4.6%) and weaker agreement between 2PD and MRS (4.7%±16.0%). Sensitivity of 3PD for diagnosing FF> 6.25% was higher than that of 2PD. 3PD-FF showed minor discrepancies (coefficient of variation <10%) from FF measured with the advanced method.


CONCLUSION
Our large series study validates the use of 3PD chemical shift sequence for detection of liver fat in the clinical environment, even in the presence of T2(*) shortening.
['Satkunasingham|Janakan|J|', 'Besa|Cecilia|C|', 'Bane|Octavia|O|', 'Shah|Ami|A|', 'de Oliveira|André|A|', 'Gilson|Wesley D|WD|', 'Kannengiesser|Stephan|S|', 'Taouli|Bachir|B|']
D000273:Adipose Tissue D000328:Adult D000368:Aged D005234:Fatty Liver D005260:Female D006801:Humans D008099:Liver D008279:Magnetic Resonance Imaging D009682:Magnetic Resonance Spectroscopy D008297:Male D008875:Middle Aged D011446:Prospective Studies D015203:Reproducibility of Results
Liver Fat MR spectroscopy Dixon method