Diffusion-weighted magnetic resonance imaging for staging liver fibrosis is less reliable in the presence of fat and iron

作者：Buelow Robin; Mensel Birger; Meffert Peter; Hernando Diego; Evert Matthias; Kuehn Jens Peter

来源：European Radiology, 2013, 23(5): 1281-1287.

DOI：10.1007/s00330-012-2700-2

• Diffusion magnetic resonance imaging
• Liver cirrhosis
• Iron overload
• Fatty liver
• Liver diseases

To investigate the reliability of diffusion-weighted magnetic resonance imaging (DW-MRI) for staging liver fibrosis in the presence of fat and iron.
Ninety-five patients, including 48 men and 47 women, aged 57.0 +/- 14.2 years, underwent liver biopsy. Ninety-six samples were histologically staged for liver fibrosis (0-Ishak score 0; 1-Ishak score 1-4; 2-Ishak score 5-6) and semiquantitatively graded for hepatic iron (0, no; 1, low; 2, moderate; 3, high iron) and for hepatic steatosis. Within 72 h after biopsy, navigator-triggered DW-MRI using b-values of 50/400/800 s/mm(2) was performed in a 1.5-T system, and apparent diffusion coefficients (ADC) were analysed. ADCs were correlated with fibrosis stage, steatosis grade, and iron grade using linear regression.
ADC did not correlate with fibrosis stages in either the overall group (n = 96; R (2) = 0.38; P = 0.17) or in the subgroup without liver iron and steatosis (n = 40; R (2) = 0.01; P = 0.75). ADC decreased significantly with steatosis grade in cases without iron and fibrosis (n = 42; R (2) = 0.28; = -5.3; P < 0.001). Liver iron was modestly correlated with ADC in patients without fibrosis and steatosis (n = 33; R (2) = 0.29; P = 0.04), whereas high iron concentrations were associated with low ADC values (group 3: beta = -489; P = 0.005; reference:group 0) but intermediate levels were not (group 1/group 2: P = 0.93/P = 0.54; reference group: 0).
ADC values are confounded by fat and iron. However, even in patients without fat or iron, DW-MRI does not adequately discriminate the stage of fibrosis.
aEuro cent Diffusion-weighted magnetic resonance imaging (DW-MRI) is increasingly used to evaluate liver disease.
aEuro cent DWI using b-values of 50/400/800 s/mm (2) does not adequately quantify fibrosis.
aEuro cent Assessment of the apparent diffusion coefficient (ADC) is confounded by fat and iron.
aEuro cent Fat may influence ADCs by altering water diffusion.
aEuro cent Iron may influence ADCs by signal decay and noise floor effects.

• 出版日期2013-5