Real-Time Elastography, developed by Hitachi, similar to acoustic radiation
force impulse (ARFI) technology, is an add-on module that can be incorporated in standard
ultrasound devices, that uses conventional ultrasound transducers for the examination,
allowing the direct visualization of liver parenchyma while performing liver stiffness (LS)
evaluation. The method is reliable and reproducible also in patients with ascites and was
performed for the first time with Hitachi systems (EUB-8500 and EUB-900). The Hitachi
SonoElastography (HI-RTE) module uses an extended combined autocorrelation method to
produce a real-time elasticity image, by using a freehand approach to compress the tissues
with the ultrasound transducer. The relative tissue elasticity is calculated and displayed as a
color overlay on the conventional B-mode image.
The technique was further developed on the new HI VISION Preirus (Hitachi Medical
Systems Europe Holding AG) system with embedded elastography module. In this
system the device automatically captures the internal compression transmitted to the
liver parenchyma by the heartbeat. A ROI can be placed approximately 1 cm below the
liver capsule and on each image the histogram and the parameter values are displayed.
Until now several elasticity scores were evaluated and even if there still are limitations
of this method, the last results obtained with the new RT-E system seem to open new
perspectives for this type of hepatic elastography, over passing the subjective analysis
of color mode elastography.
Keywords: Real time elastography, liver stiffness, elasticity index.
