MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors. | ||||||||
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Technical evaluation of in vivo abdominal fat and IMCL quantification using MRI and MRSI at 3 T.Li X, Youngren JF, Hyun B, Sakkas GK, Mulligan K, Majumdar S, Masharani UB, Schambelan M, Goldfine ID Musculoskeletal Quantitative Imaging Research, Department of Radiology, University of California, San Francisco, CA 94107, USA. OBJECTIVES: The objectives of this study were to develop protocols that measure abdominal fat and calf muscle lipids with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), respectively, at 3 T and to examine the correlation between these parameters and insulin sensitivity. MATERIALS AND METHODS: Ten nondiabetic subjects [five insulin-sensitive (IS) subjects and five insulin-resistant (IR) subjects] were scanned at 3 T. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were segmented semiautomatically from abdominal imaging. Intramyocellular lipids (IMCL) in calf muscles were quantified with single-voxel MRS in both soleus and tibialis anterior muscles and with magnetic resonance spectroscopic imaging (MRSI). RESULTS: The average coefficient of variation (CV) of VAT/(VAT+SAT) was 5.2%. The interoperator CV was 1.1% and 5.3% for SAT and VAT estimates, respectively. The CV of IMCL was 13.7% in soleus, 11.9% in tibialis anterior and 2.9% with MRSI. IMCL based on MRSI (3.8+/-1.2%) were significantly inversely correlated with glucose disposal rate, as measured by a hyperinsulinemic-euglycemic clamp. VAT volume correlated significantly with IMCL. IMCL based on MRSI for IR subjects was significantly greater than that for IS subjects (4.5+/-0.9% vs. 2.8+/-0.5%, P=.02). CONCLUSION: MRI and MRS techniques provide a robust noninvasive measurement of abdominal fat and muscle IMCL, which are correlated with insulin action in humans. Published 1 February 2008 in Magn Reson Imaging, 26(2): 188-97.
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