High-intensity focused ultrasound liver destruction through the gastric wall under endoscopic ultrasound control: first experience in living pigs High-intensity focused ultrasound (HIFU) was first developed to ablate prostatic tissue [1]. The ultrasound beam is focused at the focal point of the transducer and the energy concentration produces tissue necrosis [2]. HIFU has also been used to ablate metastases on the surface of the liver either surgically or via the transcutaneous approach [3,4]. However, beam reflection on gastric gas has produced necrosis of the interposed abdominal wall [5]. An endoscopic device is potentially valuable in treating tumors localized near to the gastric lumen without the difficulties of gas interposition. We developed an endoscopic ultrasound (EUS) HIFU device. We report the first experience of the use of HIFU to treat lesions completely endoscopically under EUS control. We designed a miniaturized HIFU transducer with a 40-mm focal point, a working frequency of 3.8 MHz, and an acoustic power of 35 W. We adapted it to fit onto an Olympus linear echoendoscope (• " Fig. 1). To test this new device, a living pig model was chosen because of its similarity to the human digestive anatomy. The procedure was performed in two pigs that had been given general anesthetics. In each pig, the stomach was initially filled with degassed water. The prototype was then placed on a guide wire in the gastric lumen and focused onto the left lobe of the liver under EUS control (• " Fig. 2). We applied 10 consecutive shots each of 10 seconds and with an effective acoustic power of 35 W. This was repeated five times moving the scope 2 cm between each group of shots. No bleeding or other complications occurred during the procedures. The pigs were sacrificed immediately after the procedures. Examination showed that we had achieved complete necrosis of the liver at the five sites with lesions in the liver 10 mm in length and 8 mm in depth (• " Fig. 3). Only one of the five sites showed evidence of gastric mucosal erythema with whitening of the external gastric wall but with no evidence of perforation or muscle wall damage. The target zone appeared hypoechoic on the EUS endoscopy. We report for the first time the ability to make HIFU lesions on the liver with a completely endoscopic procedure under EUS control with no immediate adverse effects. Other possible targets that could be treated in this way include pancreatic tumors or nodes. This work was supported by a grant from the Agence Nationale de la Recherche (ANR) through the Programme Blanc 2008. Endoscopy_UCTN_Code_TTT_1AS_2AGCompeting interests: None UCTN -Unusual cases and technical notes E376Pioche M et al. HIFU liver destruction through the gastric wall under EUS control … Endoscopy 2012; 44: E376-E377
Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedure are described, such as stroke, tamponade, and atrioesophageal fistula, and a second intervention is often needed to avoid atrial fibrillation recurrence. For these reasons, a minimally-invasive device allowing performance of more complex treatments is still needed. High-intensity focused ultrasound (HIFU) can cause deep tissue lesions without damaging intervening tissues. Left atrial ultrasound-guided transesophageal HIFU ablation could have the potential to become a new ablation technique. The goal of this study was to design and test a minimally-invasive ultrasound-guided transesophageal HIFU probe under realistic treatment conditions. First, numerical simulations were conducted to determine the probe geometry, and to validate the feasibility of performing an AF treatment using a HIFU mini-maze (HIFUMM) procedure. Then, a prototype was manufactured and characterized. The 18-mm-diameter probe head housing contained a 3-MHz spherical truncated HIFU transducer divided into 8 rings, with a 5-MHz commercial transesophageal echocardiography (TEE) transducer integrated in the center. Finally, ex vivo experiments were performed to test the impact of the esophagus layer between the probe and the tissue to treat, and also the influence of the lungs and the vascularization on lesion formation. First results show that this prototype successfully created ex vivo transmural myocardial lesions under ultrasound guidance, while preserving intervening tissues (such as the esophagus). Ultrasound-guided transesophageal HIFU can be a good candidate for treatment of AF in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.