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Magnetic resonance spin–spin relaxation time estimation in a rat model of fatty liver disease
Author(s) -
Alghamdi Sami,
Sinclair Benjamin,
Cowin Gary,
Brereton Ian,
Tesiram Yasvir A.
Publication year - 2018
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25786
Subject(s) - akaike information criterion , exponential function , magnetic resonance imaging , fatty liver , relaxation (psychology) , nuclear magnetic resonance , spin echo , choline , physics , mathematics , statistics , medicine , pathology , disease , mathematical analysis , radiology
Purpose To compare mono‐ and bi‐exponential relaxation model equations to discriminate between normal and fatty liver disease. Materials and Methods Six rats on a choline deficient amino acid modified (CDAA) diet and six on normal chow were studied. Multiple spin echo images with increasing echo times (TEs) were collected at 9.4T. Pixel‐wise T 2 maps were generated using mono‐exponential decay function to calculate T 2M , and a bi‐exponential to calculate, short T 2 component (T 2S ), long T 2 component (T 2L ), and fractions of these components ( ρ S , ρ L ), respectively. Statistical F‐tests and Akaike's information criterion (AIC) were used to assess the relative performance of the two models. Results F‐test and AIC showed that in the CDAA group, T 2 bi‐exponential model described the signal of T 2 weighted imaging of the liver better than the mono‐exponential model. Controls were best described by the mono‐exponential model. Mean values for T 2M , T 2L , T 2S , ρ S , ρ L were 31.2 ± 0.7 ms, 72.8 ± 3.3 ms, 8.2 ± 0.6 ms,71.2 ± 2.1%, 30.4 ± 1.3%, respectively, in CDAA rats, compared with 18.8 ± 0.5 ms, 32.3 ± 0.7 ms, 9.2 ± 1.8 ms, 79 ± 2%, 21.0 ± 1.1% in controls. Conclusion In the fatty liver of CDAA rats we have shown that T 2 weighted images fit the bi‐exponential model better than mono‐exponential decays thus providing a better description of the data. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:468–476.