CT-based temperature monitoring during hepatic RF ablation: Feasibility in an animal model

Figures & data

Figure 1. Schematic drawing of the experimental setup used for the ex vivo study. The scattered lines represent the axial CT images that were reconstructed. Distances between RF applicator and temperature probes were 5, 10 and 15 mm, respectively.

Figure 2. Examples for ex vivo (A) and in vivo (B) measurements of local temperature around the tip of a temperature probe during Radiofrequency ablation. Note the beam hardening artefacts in (B) caused by the RF-applicator.

Figure 3. Experimental setup used for the in vivo experiments with the animal lying in supine position. RF applicator (black arrow) and three temperature probes (white arrow) are inserted parallel.

Figure 4. The scatter diagram for a single ex vivo experiment.

Table I.  Results of the ex vivo study. Temperature data and measured CT-numbers derived from the 10 experiments were pooled for each temperature probe position.

Distance to RF probe	Number of measurements (n)	Intercept	Regression coefficient
5 mm	379	77.02	−0.44
10 mm	371	74.42	−0.35
15 mm	373	79.57	−0.37

Figure 5. The scatter diagram for a single in vivo experiment.

Table II.  Results of the in vivo study (pig 1).

Distance to RF probe	Number of measurements (n)	Intercept	Regression coefficient
5 mm	30	27.59	−0.03
10 mm	28	39.79	−0.18
15 mm	30	43.46	−0.32

Table III.  Results of the in vivo study (pig 2).

Distance to RF probe	Number of measurements (n)	Intercept	Regression coefficient
5 mm	42	22.12	−0.43
10 mm	43	49.12	−0.30
15 mm	43	37.09	−0.13

Table IV.  Results of the in vivo study (pig 3).

Distance to RF probe	Number of measurements (n)	Intercept	Regression coefficient
5 mm	43	28.99	−0.03
10 mm	43	50.72	−0.31
15 mm	43	38.97	−0.16

Table V.  Results of the in vivo study (pig 4).

Distance to RF probe	Number of measurements (n)	Intercept	Regression coefficient
5 mm	41	42.29	−0.16
10 mm	41	48.36	−0.23
15 mm	41	55.17	−0.30