Predicting the coagulation volume induced by microwave ablation of hepatocellular carcinoma: the role of deposited energy, bovine liver charts and central hyperdense area on post-treatment CT.

Purpose: To study the correlation between the overall coagulation zone (A) attained in percutaneous microwave ablation (MWA) of hepatocellular carcinomas (HCC) and: (1) the hyperdense zone (C) visible in the central part of zone A on post-treatment unenhanced CT scans; (2) the deposited energy; (3) the coagulation zones observed on bovine liver.

Materials And Methods: The post-procedural computed tomography (CT) scans of HCCs treated with a single energy deployment through the same 2450 MHz MWA system were retrospectively analyzed, retrieving the dimensions of A and C zones and the deposited energy (E). bovine liver MWA with the same system were performed and analyzed to determine the same quantities by gross-pathologic examination and CT imaging.

Results: A total of 101 HCC treatments were analyzed. The average coagulation volumes increased linearly with deposited energy (1.11 cc/kJ, = 0.90, 4.2 kJ ≤  ≤ 48 kJ), similarly to findings (1.38 cc/kJ, =0.97, 7.2 kJ ≤  ≤ 144 kJ). The long axis (L) and short axis (D) of zones A and C held a fairly constant ratio both (L/L=0.43 ± 0.13; D/D=0.42 ± 0.10) and (L/L= 0.49 ± 0.07; D/D= 0.28 ± 0.06).

Conclusions: The average dimensions of the ablation zone induced by the considered system on HCC increase linearly with the deposited energy and are fairly well predicted by the corresponding dimensions. The ratio between each linear dimension of A and C zones was found to be roughly constant over a large deposited energy span, both and .