posters 5th Asia-Pacific NMR Symposium 2013

Respiration has no effect on in vivo measurement of liver stiffness. (#189)

Alice Pong 1 2 , Kristy Tan 2 3 , Alice Hatt 2 , Lauriane Juge 2 , Shaokoon Cheng 2 4 , Lynne E Bilston 2 5
  1. School of Medical Sciences, University of New South Wales, Kensington, New South Wales, Australia
  2. Neuroscience Research Australia (NeuRA), Randwick, Sydney, NSW, Australia
  3. Graduate School of Biomedical Engineering, University of New South Wales, Kensington, New South Wales, Australia
  4. Engineering, Macquarie University, North Ryde, New South Wales, Australia
  5. Prince of Wales Clinical School, University of New South Wales, Kensington, New South Wales, Australia

Introduction: The mechanical properties of liver are known to change with disease1,2,3   and other factors. For example, liver stiffness measured by transient elastography was reported to be higher at expiration than during inspiration in patients with liver cirrhosis due to increased intrahepatic blood volume4 . Magnetic Resonance Elastography (MRE) has also been used to measure liver stiffness in clinical populations but whether liver compression due to respiration in MRE causes bias in measurements is not known. In this study, we aim to understand whether the effects of respiration should be considered when measuring liver stiffness using MRE.

Methods: The effect of respiration on the elastic (G’) and viscous (G”) components of the shear modulus of the liver was assessed using MRE in seven healthy female volunteers, (27±5.2) years with no history of liver or respiratory disease. MRE parameters were: 56 Hz vibration frequency; TR/TE 75.9/6.91ms; matrix = 64 x 64, FOV 220 mm, and slice thickness 10 mm. Matching T2-weighted anatomical imaging sequences were acquired at end-inspiration (maximal liver compression), and at end-expiration (minimal liver compression).

Results: No differences were seen in either the elastic or viscous components of the liver shear modulus between measurements taken at end-inspiration and end-expiration (p >0.05, Student’s t-Test).

1232-Liver%20results.pngConclusion: The results of this study show that the mechanical properties of liver as measured by MRE are not affected by liver compression during respiration. Our results are different to the aforementioned study in which liver stiffness was increased at end-expiration compared with inspiration among chronic liver patients4 . 

  1. 1.Wong, V.W.S., et al., Diagnosis of fibrosis and cirrhosis using liver stiffness measurement in nonalcoholic fatty liver disease. Hepatology, 2010. 51(2): p. 454-462.
  2. 2.Gao, L., et al., Imaging of the elastic properties of tissue—A review. Ultrasound in medicine & biology, 1996. 22(8): p. 959-977.
  3. 3.Arena, U., et al., Acute viral hepatitis increases liver stiffness values measured by transient elastography. Hepatology, 2008. 47(2): p. 380-384.
  4. 4.Yun, M., et al., The effect of the respiratory cycle on liver stiffness values as measured by transient elastography. Journal of viral hepatitis, 2011. 18(9): p. 631-636.