Acoustic Radiation Force Impulse Imaging (ARFI) : a New Technique to Assess Liver Elasticity (NARFI)

Acoustic Radiation Force Impulse Imaging (ARFI) : a New Technique to Assess Liver Elasticity - Norms in ARFI: Distribution and Reproducibility of ARFI Values in Disease-free Livers or Pathological Livers.

Liver stiffness measurement (LSM) by non invasive methods is increasingly used to estimate liver fibrosis in patients with chronic liver diseases. However, there is growing evidence that fibrosis is not the only determinant of liver stiffness. Indeed inflammation, cholestasis, congestion could also interfere with stiffness measurements. Acoustic radiation force impulse imaging (ARFI) is a new technology to perform real time LSM. Using a standard ultrasonographic probe, it offers elastography with a flexible metering box at variable depth, allowing the examination of specific area.

There are many causes of chronic liver diseases such as hepatitis C infection, hepatitis B infection, alcohol, NAFLD (non-alcoholic fatty liver disease), drugs and auto-immune liver disease. Although the causes differ the pathological response to injury tends to be similar leading to fibrosis and cirrhosis. Liver biopsy is the current gold standard for the assessment of liver fibrosis but is poorly suited for active monitoring because of its expense and morbidity. Thus, development of alternatives that are safe, inexpensive, and reliable is a priority. Liver stiffness measurement (LSM) by non invasive method is increasingly used to estimate liver fibrosis in patient with chronic liver disease. Acoustic radiation force impulse imaging (ARFI) is a new technology to perform real time LSM. Using a standard ultrasonographic probe, it offers elastography with a flexible metering box at variable depth, allowing the examination of specific area. The purpose of this work was to evaluate by ARFI, the efficiency of this new technique, the reproducibility inter and intra observer, and the liver elasticity obtained by this method in different patient groups. The primary endpoint of this work is to evaluate by ARFI, the efficiency of the technique, the reproducibility inter and intra observer, and the elasticity of liver in 6 different patient groups and healthy volunteers. The different population groups are: healthy volunteers Group A patients with supposed disease free liver (normal hepatic and pancreatic biochemistry). Group B patients with non cirrhotic hepatopathy. Group C patients with cirrhosis. Group D patients with liver tumour and surgery indication. Group E patients with reversible liver diseases: patients with acute left cardiac insufficiency. Group F patients with biliary cholestasis. Group G ARFI measurements will be performed in a single liver ultrasound exam visit except for patients with reversible liver diseases who will have a second visit with ARFI measurement after clinical healing. The ARFI values are expressed as a speed in m/s.

Liver Fibrosis, Liver Cirrhosis, Viral Hepatitis, Liver Tumour, Cardiac Failure, Biliary Cholestasis.

ARFI values are measured during a standard liver ultrasound examination, with patient lying on his back and performing a "light" apnea. For group A the measurement is made by a second and a third investigator during the same examination.

ARFI values are measured during a standard liver ultrasound examination, with patient lying on his back and performing a "light" apnea. For all other groups (B, C, D, E) ARFI is measured only once.

ARFI values are measured during a standard liver ultrasound examination, with patient lying on his back and performing a "light" apnea. For groups F and G : ARFI is measured again after clinical healing.

The elasticity parameter will be for each patient the median of ten ARFI values (m/s) in the right liver.

Median (m/s) of ARFI values between before and after effective treatment for liver reversible disease

Inclusion Criteria: Man or Woman Age> 18 years old Able to understand the study and to give informed consent Informed consent signed by patient and investigator before any study required examination With a valid health insurance Groups specific inclusion criteria are: Group A : healthy volunteers without known liver disease Group B : voluntary patients without known liver disease Group C and D Patient with a diagnosed chronic liver disease Group E : patients with liver tumors (benign or malignant) with surgical indication Group F : patients with acute right heart insufficiency diagnosed by a cardiologist Group G :patients with biliary cholestasis and imaging evidence of biliary dilatation Exclusion Criteria: Patient under 18 years old Not able to understand the study or to give their consent. Pregnant woman Severe respiratory insufficiency Unable to perform a "light" apnea . hemodynamic instability (cardiogenic shock, septic or anaphylactic) possibility of disruption of the elasticity and inability to carry patient. Chronic heart insufficiency. deprived of their liberty by court

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