title: Intra-operative ultrasound hand-held strain imaging for the visualization of ablations produced in the liver with a toroidal HIFU transducer: first in vivo results.
abstract: The use of hand-held ultrasound strain imaging for the intra-operative real-time visualization of HIFU (high-intensity focused ultrasound) ablations produced in the liver by a toroidal transducer was investigated. A linear 12 MHz ultrasound imaging probe was used to obtain radiofrequency signals. Using a fast cross-correlation algorithm, strain images were calculated and displayed at 60 frames s(-1), allowing the use of hand-held strain imaging intra-operatively. Fourteen HIFU lesions were produced in four pigs. Intra-operative strain imaging of HIFU ablations in the liver was feasible owing to the high frame rate. The correlation between dimensions measured on gross pathology and dimensions measured on B-mode images and on strain images were R = 0.72 and R = 0.94 respectively. The contrast between ablated and non-ablated tissue was significantly higher (p < 0.05) in the strain images (22 dB) than in the B-mode images (9 dB). Strain images allowed equivalent or improved definition of ablated regions when compared with B-mode images. Real-time intra-operative hand-held strain imaging seems to be a promising complement to conventional B-mode imaging for the guidance of HIFU ablations produced in the liver during an open procedure. These results support that hand-held strain imaging outperforms conventional B-mode ultrasound and could potentially be used for the assessment of thermal therapies.
authors.affiliation: Inserm, U556, Lyon, F-69003, France. jeremy.chenot@inserm.fr
authors.forename: J
authors.initials: J
authors.lastname: Chenot
authors.forename: D
authors.initials: D
authors.lastname: Melodelima
authors.forename: W A
authors.initials: WA
authors.lastname: N'djin
authors.forename: Rémi
authors.initials: R
authors.lastname: Souchon
authors.forename: M
authors.initials: M
authors.lastname: Rivoire
authors.forename: J Y
authors.initials: JY
authors.lastname: Chapelon
mesh_terms: D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D003201:Computers; D054459:Elasticity Imaging Techniques / Q000379:methods; D004867:Equipment Design; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D008099:Liver / Q000473:pathology*; D013552:Swine; D013997:Time Factors; D014159:Transducers; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*