Radiofrequency electrode vibration-induced shear wave imaging for tissue modulus estimation: A simulation study

Abstract

Quasi-static electrode displacement elastography, used for in-vivo imaging of radiofrequency ablation-induced lesions in abdominal organs such as the liver and kidney, is extended in this paper to dynamic vibrational perturbations of the ablation electrode. Propagation of the resulting shear waves into adjoining regions of tissue can be tracked and the shear wave velocity used to quantify the shear (and thereby Young's) modulus of tissue. The algorithm used utilizes the time-to-peak displacement data (obtained from finite element analyses) to calculate the speed of shear wave propagation in the material. The simulation results presented illustrate the feasibility of estimating the Young's modulus of tissue and is promising for characterizing the stiffness of radiofrequency-ablated thermal lesions and surrounding normal tissue.

Kidney Ultrasound Elastography: Review

“…Some of them were about animals [36][37][38][39][40][41][42] , some of them were about MRI or MR elastography [43][44][45][46][47][48][49][50][51][52] , some of them were about other organ systems [53][54][55][56][57][58][59][60][61][62][63][64][65] , some of them were about elastography technic 28,[66][67][68][69] and some of them were about non elastography related kidney studies 70 . We excluded these articles.…”

Three-Dimensional Sheaf of Ultrasound Planes Reconstruction (SOUPR) of Ablated Volumes

“…It has potential to augment traditional B-scans and assist the clinician in delineating ablation boundaries more accurately. Unlike X-ray computed tomography (CT) or magnetic resonance imaging (MRI), traditional ultrasound elastography has been limited to single imaging planes, over which strain is estimated, and the Young's modulus (stiffness) is reconstructed by solving the inverse problem [6], [7], [8], [9]. Shear wave velocity (SWV) and shear modulus can also be estimated for these imaging planes [10].…”

“…The 3D reconstruction algorithm is termed “ S heaf O f U ltrasound P lanes R econstruction” or SOUPR . This cylindrically symmetric method of acquisition is naturally suited to electrode vibration elastography (EVE) where shear wavefronts travel outward from a vibrating needle which acts as a line source of shear waves [7]. Moreover, the overall shape of the ablation is approximately cylindrically symmetric with the ablation needle as the axis of symmetry.…”

A comparison of model based and direct optimization based filtering algorithms for shearwave velocity reconstruction for electrode vibration elastography

“…Other forms of mechanical excitation include the use of external pushing rods [6] and manual palpation. In electrode vibration elastography, the ablation needle is itself used as a means for generating shear waves [7]. …”