Gaspard D'Assignies MD, Abstract Co-Author: Nothing to Disclose

An Tang MD, Presenter: Nothing to Disclose

Claude Kauffmann PhD, Abstract Co-Author: Nothing to Disclose

Yvan Boulanger PhD, Abstract Co-Author: Nothing to Disclose

Gilles P. Soulez MD, Abstract Co-Author: Speaker, Bracco Group Speaker, Siemens AG Research grant, Siemens AG Research grant, Bracco Group Research grant, Cook Group Incorporated

Marc Bilodeau, Abstract Co-Author: Nothing to Disclose

To compare accuracy and distribution of liver fat content measured by MRI using single ROI and liver segmentation with magnetic resonance spectroscopy (MRS).

Institutional review board approval and written informed content were obtained. Quantification of hepatic fat fraction (HFF) in 20 patients was compared by single ROI, liver segmentation of MRI using in-phase/out-of-phase (IP/OP) with T2* correction and single voxel MRS. To assess measurement reproducibility and agreement, the intraclass correlation coefficient (ICC) and the Bland-Altman plot were used. Patients were stratified according to the level of heterogeneity of fat distribution based on consensus reading by radiologist review.

Eleven patients were categorized as homogeneous and 9 as heterogeneous steatosis. A close correlation was demonstrated between MRS assessment of steatosis and single ROI (r=0.941, p<0.001) and whole liver (r=0.937, p<0.001) measurements. Measurement of HFF and liver volume after segmentation was highly reproducible, with inter-observer ICC values of 0.999 (p<0.001) for HFF and 0.996 (p<0.001) for liver volume. Mean HFF difference between single ROI and whole-liver VOI measurements was -0.99% (95% limits of agreement: -2.97%, 0.99%).

These findings suggest that single ROI measurement of fat content by standard MRI protocols provide an accurate quantitative assessment of hepatic steatosis in most patients. This is important because liver segmentation for every patient is impractical in routine liver imaging. Fat content calculated by liver segmentation may be more useful in heterogeneous steatosis or patients awaiting hepatectomy in whom volumetry is already required.

Single ROI measurement of fat content by standard dual echo GRE protocols provides accurate quantitative assessment of hepatic steatosis in patients with homogeneous or midly heterogeneous steatosis.

D'Assignies, G, Tang, A, Kauffmann, C, Boulanger, Y, Soulez, G, Bilodeau, M, Assessment of Liver Fat Content: Comparison of Single ROI and Volumetric Measurement after Liver Segmentation.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8010001.html