Delineation of Post-Procedure Ablation Regions with Electrode Displacement Elastography with a Comparison to Acoustic Radiation Force Impulse Imaging

Abstract

We compared a quasi-static ultrasound elastography technique, referred to as electrode displacement elastography (EDE), with acoustic radiation force impulse imaging (ARFI) for monitoring microwave ablation (MWA) procedures on patients diagnosed with liver neoplasms. Forty-nine patients recruited to this study underwent EDE and ARFI using a Siemens Acuson S2000 system after an MWA procedure. Based on visualization results from two observers, the ablated region in ARFI images was recognizable on 20 patients on an average in conjunction with B-mode imaging, while delineable ablation boundaries could be generated on 4 patients on average. With EDE, the ablated region was delineable on 40 patients on average, with less imaging depth dependence. Study of tissue mimicking phantoms demonstrated that the ablation region dimensions measured on EDE and ARFI images were within 8%, while the image contrast and contrast to noise ratio with EDE was 2 – 3 times higher than that obtained with ARFI. This study showed that EDE provided improved monitoring results for minimally invasive MWA in clinical procedures for liver cancer and metastases.

Comparison of Displacement Tracking Algorithms for in Vivo Electrode Displacement Elastography

“…This is continued until all pixels in the RF frame are processed. QGDT had been previously applied to EDE with a kernel size of 3.5 wavelengths x 7 A-lines using normalized correlation coefficient values greater than 0.75 as the quality metric (Yang et al 2016; Yang et al 2017).…”

“…HMI has shown good results for tumor detection and ablation monitoring (E Konofagou et al 2012; Chen et al 2015). However when staging liver fibrosis, all approaches using radiation force may fail for individuals with high liver fibrosis/cirrhosis or those with high body mass index (BMI) (Deng et al 2015), and for depths greater than 8 cm (Yang et al 2017).…”

“…To further validate EDE efficacy, in vivo animal models were utilized showing a high correlation between EDE strain and pathologic areas of ablated regions (Fernandez et al 2008; Rubert et al 2010). EDE was then performed on human patients scheduled for percutaneous minimally invasive ablation procedures to further verify its ability to delineate ablated regions (Yang et al 2016; Yang et al 2017). Yang et al has shown that image contrast, CNR, and delineation are significantly higher for strain images obtained using EDE than B-mode (Yang et al 2016) or ARFI (Yang et al 2017) imaging.…”

Two‐dimensional ultrasound‐computed tomography image registration for monitoring percutaneous hepatic intervention

“…EDE uses localized perturbations to detect differences in the tissue stiffness between normal liver and the ablated region to determine ablation zone dimensions. EDE has demonstrated high visualization and delineation in strain tensor images on phantoms, animal models, and human patients . In addition, to ablated region visualization using EDE, an important metric to be evaluated is the area of the ablation region.…”

“…EDE has demonstrated high visualization and delineation in strain tensor images on phantoms, [16][17][18] animal models, 19,20 and human patients. [21][22][23][24] In addition, to ablated region visualization using EDE, an important metric to be evaluated is the area of the ablation region. The hyperechoic area on the Bmode image has been previously segmented and utilized for comparison to EDE.…”