Quantification of Tissue Shrinkage and Dehydration Caused by Microwave Ablation: Experimental Study in Kidneys for the Estimation of Effective Coagulation Volume

CT-Guided Percutaneous Cryoablation in Renal Cell Carcinoma: Factors Affecting Local Tumor Control

“…A heat-pump effect seemed to prevent ice-ball creation in such cases (16). In addition to RF ablation, the use of microwave ablation, which is less susceptible to the "heat-sink" effect than RF ablation, is another option to treat such tumors resistant to cryoablation (24).…”

Characterisation of tissue shrinkage during microwave thermal ablation

“…Recently, shrinkage of the ablated tissue volume has been reported in clinical practice and in experimental investigation of MW, and to a lesser extent in RF heating [13][14][15][16]. Looking at the spatial and temporal tissue contraction via CT scans performed during a MW ablation procedure, significant shrinkage was observed during the first minutes of heating [13,16].…”

Microwave ablation of hepatocellular carcinoma

“…Tissue carbonisation is not, therefore, an insurmountable barrier to the MW heating process, and temperatures far higher than 100 ℃ may be reached within the target tumor, allowing enhanced active and passive tissue heating, larger coagulation zones and more effective rejection of heat sinking effects [32,33] . When high power MWA treatments are performed, several qualitative and quantitative differences are observed in terms of RFA: (1) the hyper-echogenic spot around the probe-active tip detectable on ultrasound-scanning during a thermal ablation procedure forms and expands at a much higher rate, providing a visual feedback of the ongoing vaporization process; (2) post-MWA follow-up scans [either computed tomography (CT) or magnetic resonance imaging (MRI)] usually show, in the region surrounding what was the probe active tip position during the ablation, an inner hyper-dense core contrasting with an outer thicker and hypo-dense annulus, the former being charred tissue (not present on RFA) and the latter being the coagulated but not carbonized zone typical of any thermal ablation modality ( Figures 1 and 2); and (3) due to massive water evaporation, MWA treatments induce substantial contraction in target tissues (30%-70% in volume, according to several ex-vivo and in vivo experimental observations [34][35][36] ), far more than their RFA counterparts [37] . If the appropriate shrinkage correction factor is used for accurately calculating the actual ablation volume, the coagulative performance gap between MWA and RFA widens further.…”