Measurement of Liver Stiffness With Two Imaging Techniques: Magnetic Resonance Elastography and Ultrasound Elastometry

Purpose: To cross-validate the magnetic resonance elastography (MRE) technique with a clinical device, based on an ultrasound elastometry system called Fibroscan. Materials and Methods: Ten healthy subjects underwent an MRE and a Fibroscan test. The MRE technique used a round pneumatic driver at 60 Hz to generate shear waves inside the liver. An elastogram representing a map of the liver stiffness was generated allowing for the measurement of the average liver stiffness inside a region of interest. The Fibroscan technique used an ultrasound probe (3.5 MHz) composed of a vibrator that sent low-frequency (50 Hz) shear waves inside the right liver lobe. The probe acts as an emitter-receptor that measures the velocity of the waves propagated inside the liver tissue. Results: The mean shear stiffness measured with the MRE and Fibroscan techniques were 1.95 +/- 0.06 kPa and 1.79 +/- 0.30 kPa, respectively. A higher standard deviation was found for the same subject with Fibroscan. Conclusion: This study shows why MIRE should be investigated beyond the Fibroscan. The MRE technique provided elasticity of the entire liver, meanwhile the Fibroscan provided values of elasticity locally.