Abstract
Radiofrequency ablation (RFA) and microwave ablation (MWA) are currently the dominant modalities to treat unresectable liver tumors. Monitoring the ablation process with b-mode-sonography is often hampered by artefacts. Furthermore, vessels may cause cooling in the adjacent tumor target (heat-sink-effect) with risk of local recurrence. The present study evaluated infrared-thermography to monitor surgical RFA/MWA and detect heat-sink-effects in real-time. RFA and MWA of perfused porcine livers was conducted at peripheral and central-vessel-adjacent locations, and monitored by real-time thermography. Ablation was measured and evaluated by gross pathology. The mean time for ablation was significantly longer in RFA compared with MWA (8 vs. 2 min). Although mean macroscopic ablation diameter was similar (RFA, 3.17 cm; MWA, 3.38 cm), RFA showed a significant heat-sink-effect compared with MWA. The surface temperature during central RFA near vessels was 1/3 lower compared with peripheral RFA (47.11±8.35°C vs. 68.72±12.70°C; P<0.001). There was no significant difference in MWA (50.52±8.35°C vs. 50.18±10.35°C; P=0.74). In conclusion, thermography is suitable to monitor the correct ablation with MWA and RFA. The results of the current study demonstrated a significant heat-sink-effect for RFA, but not MWA near vessels. MWA reaches consistent surface temperatures much faster than RFA. With further in vivo validation, thermography may be useful to ensure appropriate ablation particularly near vulnerable or vascular structures.
Highlights
Surgical resection remains the gold standard therapy for primary and secondary liver malignancies, but resectability largely depends on factors such as extent of the disease, concurrent liver steatosis or cirrhosis, amount of remaining healthy liver tissue after resection as well as patient comorbidities
Representative examples of real‐time thermography of an microwave ablation (MWA) and radiofrequency ablation (RFA) ablative run are given in Figs. 4A, B and 5A
To the best of our knowledge, the present study is the first to investigate the feasibility of thermography as a monitoring tool for open surgical hepatic MWA/RFA
Summary
Surgical resection remains the gold standard therapy for primary and secondary liver malignancies, but resectability largely depends on factors such as extent of the disease, concurrent liver steatosis or cirrhosis, amount of remaining healthy liver tissue after resection (the future liver remnant‐FLR) as well as patient comorbidities. Thermal ablation is widely used as an alternative or additional technique in cases were resection deems hazardous, or in unresectable disease with multiple lesions when only the combined ablation‐and‐resection [1] or two‐stage hepatectomy approach seems feasible to achieve tumor‐free margins with sufficient FLR. The two currently most common thermal ablation modalities are radiofrequency ablation (RFA) and microwave ablation (MWA) [2,3], both applied either percutaneously or during open or laparoscopic surgery (‘surgical ablation’) [4]. In RFA an electrical current within the radiofrequency range is transported through either a monopolar electrode or between two bipolar electrodes to produce heat‐induced cytotoxicity in the liver tissue [5,6]. MWA technique is different, as microwave radiation leads to high frequency oscillation in water molecules, subsequent frictional heating and cell death through coagulation necrosis [4,7]. MWA is mostly applied through a single coaxial electrode device [3,4,8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
