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Evaluation of the Feasibility, Safety, and Accuracy of an Intraoperative High-intensity Focused Ultrasound Device for Treating Liver Metastases

Today, the only potentially curative option in patients with colorectal liver metastases is surgery. However, liver resection is feasible in less than 20% ...

Université Lyon

Esophageal tumors generally bear a poor prognosis. Radical surgery is generally the only curative method available but is not feasible in the majority of patients; palliative therapy with stent placement is generally performed. It has been demonstrated that High Intensity Ultrasound can induce rapid, complete and well-defined coagulation necrosis. Thus, for the treatment of esophageal tumors, we have designed an ultrasound applicator that uses an intraluminal approach to fill up this therapeutic gap.

Treatment of esophageal tumors using high intensity intraluminal ultrasound: first clinical results.

Surgical resection is the only treatment of colorectal liver metastases that can ensure long-term survival and cure in some patients. However, only 20% of patients are suitable for surgery. As a result, many nonresectional modalities of treatment have been assessed to provide an alternative to liver resection. Several limitations have been observed when using these techniques and available evidence is limited. Here, we report that a new design of high intensity focused ultrasound transducer can significantly enlarge the coagulated volume over short periods of time and that treatment in the liver can be guided in real-time using an integrated ultrasound imaging probe. Our long-term objective is to develop a device that can be used during surgery for eventual clinical use in conjunction with resection. Eight ultrasound emitters, divided into 256 elements, were created by sectioning a single toroid piezocomposite transducer. The focal zone was conical in shape and located 70 mm from the transducer; enabling the treatment of deep-seated tumors. A single thermal lesion was created when the eight emitters performed alternative and consecutive 5-s ultrasound exposures. This article presents in vivo evidence that the coagulated volume obtained from a 40 s total exposure in the liver was 7.0 +/- 2.5 cm(3) (minimum 1.5 - maximum 20.0 cm(3)) with an average diameter of 17.5 +/- 3.8 mm (minimum 10.0 - maximum 29.0 mm). All lesions were visible with high contrast on sonograms. The correlation between the diameter of lesions observed on sonograms and during gross examination was 92%. This method also allowed the user to easily enlarge the coagulated volume by juxtaposing single lesions. This approach may have a role in treating unresectable colorectal liver metastases and may also be used in conjunction with resection to extend its limits.

Thermal ablation by high-intensity-focused ultrasound using a toroid transducer increases the coagulated volume. Results of animal experiments.

Surgical resection is the only curative option for colorectal hepatic metastases. Intra-operative localisation of these metastases during hepatic resection is performed by intra-operative B-mode imaging and palpation. Because liver metastases are stiffer than normal tissues, elastography may be a useful complement to B-mode imaging. This paper reports quantitative measures of the image quality attained during intra-operative real-time elastographic visualisation of liver metastasis.

Article	Year
Treatment of esophageal tumors using high intensity intraluminal ultrasound: first clinical results. Journal of translational medicine\| PubMed ID: 18533990	2008
Thermal ablation by high-intensity-focused ultrasound using a toroid transducer increases the coagulated volume. Results of animal experiments. Ultrasound in medicine & biology\| PubMed ID: 19081666	2009
Visualisation of liver tumours using hand-held real-time strain imaging: results of animal experiments. The British journal of radiology\| PubMed ID: 22253340	2012

David Melodelima

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