Medical Device Daily

PARIS — Companies are panning for gold in the tiny specks that fly across the screen of an ultrasound scanner.

Where it was astonishing to see a lump in the snowy black-and-white pattern and be told this is your unborn child, today a mother-to-be can order a portrait of the baby's face rendered in vivid 3-D imagery.

Advancements in ultrasound include colorful Doppler displays to measure blood flow and pressure and astonishing 4-D reconstructions showing real-time images of a beating heart.

The next hard target for ultrasound is extracting more data from the "noise" of the ultrasound signal to more precisely assess the organs of the abdomen with three companies focusing on fibrosis of the liver where there is a vast opportunity in the unmet clinical need for non-invasive evaluations of the progression of this disease.

At the annual French radiology congress, Journées Françaises de Radiologie, held here last week, Toshiba Medical Systems Europe (Zoetermeer, the Netherlands), Hitachi Medical Systems (Zug, Switzerland,) and Supersonic Imagine (Aix-en-Provence, France) were presenting their advances toward this next frontier for ultrasound.

The lower cost and ready availability of ultrasound makes it an attractive imaging modality and it is currently used in gastroentreology for assessment, and more recently on endoscopes for needle guidance during biopsies.

Yet diagnosis of the liver by ultrasound using the recent innovation of elastography, that assesses the elasticity of tissue, remains more art than science with interpretation of the results subject to experience.

While the new technology for sonographic elastography provides a qualificative assessment by ultrasound of the liver, there is not a quantifiable, reproducible result required for clinical evidence and confidence in diagnosis.

Toshiba is the first to introduce to the market a signal processor and software, called Acoustic Structure Quantification (ASQ), for its high-end Aplio XG platform that can quantify the stage of fibrosis in a liver.

Toshiba officially launched ASQ at Ultraschall 2009 in Salzburg, Austria on Oct. 14, 2009 and demonstrated the new tool for Medical Device Daily at JFR 2009 in Paris.

Toshiba said it received the CE mark for marketing ASQ in Europe and is currently awaiting a 510(k) approval from the FDA.

Hitachi said it will release its quantification analysis processor on board the new compact version of the HI-Vision Preirus at the European Congress of Radiology in March, 2010 in Vienna while Supersonic said it is working with clinics in Bordeaux and Paris to evaluate a new transducer for this application on the Aixplorer.

First clinical results published by Toshiba

In the October issue of the American Journal of Radiology, a paper authored by Hidenori Toyoda at the Department of Gastroenterology of Ogaki Hospital in Japan and the oft-cited pioneer in ultrasound signal processing, Takashi Kumada, a clinical investigator with Toshiba, reports findings on fibrosis staging for 148 patients that shows a strong correlation between histological results and the classifications assigned by the ASQ analysis.

ASQ developer Naohise Kamiyama, the Manager for Toshiba Ultrasound Systems Application & Research (Otawara, Japan), told MDD, "Most ultrasound units can not accept the pure acoustical radio frequency (RF) data, taking only selected segments for display in the conventional B-Mode image on the screen."

ASQ begins with a signal processor that receives the raw RF signal and extracts data that may indicate extremely small structures, or fiber strands.

"The liver is a smooth, rather silky organ, which does not have any structures in a healthy state," he explained.

After analyzing the data, ASQ then displays the extracted information for the radiologist offering two modes for presentation either a statistical graph mapping the parameter Toshiba selected to show the probability of fiber structures, and a second Doppler-like image with colors associated to the different values superimposed over the B-mode view.

Toyoda and Kumada reported a correlation between the analysis of data by ASQ and the histological results of the liver tissue where the median values displayed by ASQ agreed with the histological results for a given patient with proven chronic hepatitis without cirrhosis.

The ASQ range values accurately indicated the increasing severity of chronic hepatitis for patients within the international classification standards of F1 to F4.

Toshiba is currently developing ASQ algorithms for metabolic quantification of fatty liver diseases.

Hitachi poised to enter 'enormous market'

It is estimated that between 170 million to 200 million individuals worldwide live with chronic hepatitis, a condition that progressively hardens the liver over several decades leading to cirrhosis or end-stage liver disease.

An evidence-based ultrasound capability for non-invasive diagnosis presents a potential for multiple clinical applications for screening hepatic disease during routine medical examinations, for explaining the risk of cancer to patients to receive an informed consent for therapy, and for the staging of patients with fibrosis who refuse or can not undergo the invasive biopsy procedures.

"There is an enormous market in gastroenterology for a quantitative algorithm for liver fibrosis evaluation and for the pancreas," said Heinz Schreiber, head of ultrasound for Hitachi Europe.

Arguably, Hitachi is more familiar for clinicians in ultrasound assessments of the liver.

For two years the company has steadily presented clinical evaluations of its real-time elastography (HT-RTE) for noninvasive diagnosis of liver fibrosis and many independent clinicians utilize Hitachi probes and processors for their investigations of the abdomen.

Hitachi pioneered elastography when it presented its first clinical evaluations of the technology at ECR 2004 in Vienna.

Yet elastography is not precisely tissue characterization, said Schreiber, who said fibrosis of the liver requires a separate, dedicated quantitative capability to be used in conjunction with an elastographic assessment.

Quantitative evaluation of tissue from the ultrasound RF signal can include measurement of raw signal intensity, the extent of scattering or the speed of transmission of an audible vibration generated by the probe.

Where Toshiba was quick to launch ASQ with a single parameter for assessment of fibrosis, Hitachi is preparing the release of an assessment capability for the HI-Vision Preirus that analyzes nine parameters to present what Schreiber described as a "spectral histogram."

"This is a very complex diagnosis," he said. "The liver is the most exposed organ of the body because it is a chemical factory through which all metabolism passes."

"We expect to have up to two years advantage because our competitors will need to conduct quite a bit of university level research to set the parameters for a clinically relevant quantifiable evaluation."