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J Magn Reson Imaging. 2018 Jul;48(1):274-282. doi: 10.1002/jmri.25929. Epub 2018 Jan 10.

Comparison of modified two-point dixon and chemical shift encoded MRI water-fat separation methods for fetal fat quantification.

Author information

1
Department of Medical Biophysics, Western University, London, Ontario, Canada.
2
Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London, Ontario, Canada.
3
Department of Paediatrics, Western University, London, Ontario, Canada.
4
Department of Obstetrics and Gynaecology, Western University, London, Ontario, Canada.

Abstract

BACKGROUND:

Fetal fat is indicative of the energy balance within the fetus, which may be disrupted in pregnancy complications such as fetal growth restriction, macrosomia, and gestational diabetes. Water-fat separated MRI is a technique sensitive to tissue lipid content, measured as fat fraction (FF), and can be used to accurately measure fat volumes. Modified two-point Dixon and chemical shift encoded MRI (CSE-MRI) are water-fat separated MRI techniques that could be applied to imaging of fetal fat. Modified two-point Dixon has biases present that are corrected in CSE-MRI which may contribute to differences in the fat measurements.

PURPOSE:

To compare the measurement of fetal fat volume and FF by modified two-point Dixon and CSE-MRI.

STUDY TYPE:

Cross-sectional study for comparison of two MRI pulse sequences.

POPULATION:

Twenty-one pregnant women with singleton pregnancies.

FIELD STRENGTH/SEQUENCE:

1.5T, modified two-point Dixon and CSE-MRI.

ASSESSMENT:

Manual segmentation of total fetal fat volume and mean FF from modified 2-point Dixon and CSE-MRI FF images.

STATISTICAL TESTS:

Reliability was assessed by calculating the intraclass correlation coefficient (ICC). Agreement was assessed using a one-sample t-test on the fat measurements difference values (modified two-point Dixon - CSE-MRI). The difference scores were tested against a value of 0, which would indicate that the measurements were identical.

RESULTS:

The fat volume and FF measured by modified two-point Dixon and CSE-MRI had excellent reliability, demonstrated by ICCs of 0.93 (P < 0.001) and 0.90 (P < 0.001), respectively. They were not in agreement, with CSE-MRI giving mean fat volumes 180 mL greater and mean FF 3.0% smaller than modified two-point Dixon.

DATA CONCLUSION:

The reliability between modified two-point Dixon and CSE-MRI indicates that either technique can be used to compare fetal fat measurements in different participants, but they are not in agreement possibly due to uncorrected biases in modified two-point Dixon.

LEVEL OF EVIDENCE:

4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.

KEYWORDS:

CSE-MRI; Dixon; adipose tissue; fat quantification; fetal; water-fat MRI

PMID:
29319918
DOI:
10.1002/jmri.25929
[Indexed for MEDLINE]

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