Specific CT 3D rendering of the treatment zone after Irreversible Electroporation (IRE) in a pig liver model: the “Chebyshev Center Concept” to define the maximum treatable tumor size

Table 3 Diameter and position of the largest inscribed sphere within the treatment zone as well as of the largest possible treatable tumor sphere

	Diameter of the largest inscribed sphere within the treatment zone (mm)		Diameter of the largest possible treatable tumor sphere (mm)		Barycenter offset¹(mm)
	Technique A²	Technique B³	Technique A²	Technique B³	Technique A²	Technique B³
Protocol 1⁴	19.6 ± 3.3^#,*	19.9 ± 4.6^#,**	9.6 ± 3.3^+,***	9.9 ± 4.6^+,****	9.1 ± 2.1^*****	n.a.
Protocol 1⁴	(16.6 - 24.6)	(15.4 - 26.4)	(6.6 - 14.6)	(5.4 - 16.4)	(5.4 - 10.6)	n.a.
Protocol 2⁵	24.8 ± 3.4^##,*	31.1 ± 10.5^##,**	14.8 ± 3.4^++,***	21.1 ± 10.5^++,****	5.4 ± 3.6^*****	n.a.
Protocol 2⁵	(22.2 - 30.2)	(17.5 - 42.1)	(12.2 - 20.2)	(7.5 - 32.1)	(1.2 - 10.1)	n.a.
Protocol 3⁶	39.0 ± 8.4^###,*	53.8 ±1.1^###,**	29.0 ± 8.4^+++,***	43.8 ±1.1^+++,****	5.9 ± 3.8^*****	n.a.
	(26.8 - 47.0)	(52.4 - 54.9)	(16.8 - 37.0)	(42.4 - 44.9)	(2.4 - 11.7)

¹distance between the barycenter of the treatment zone (intersection point of long, intermediate and short diameter) and the “Chebyshev Center”
²semi-automated software prototype for CT 3d rendering with the “Chebyshev Center Concept” implemented;
³standard CT 3d analysis;
⁴Protocol 1 with n = 5 IREs (three applicators, tip exposure of 20 mm, distance between pairs of applicators of 15 mm, pulse number of 90, pulse length of 90 μs, and electric field of 1500 V/cm);
⁵Protocol 2 with n = 5 IREs (three applicators, tip exposure of 25 mm, distance between pairs of applicators of 20 mm, pulse number of 90, pulse length of 90 μs, and electric field of 1500 V/cm);
⁶Protocol 3 with n = 5 IREs (six applicators, tip exposure of 30 mm, distance between pairs of applicators of 15 mm, pulse number of 70, pulse length of 90 μs, and electric field of 1400 V/cm);
statistical differences between Technique A and Technique B were analyzed with the Wilcoxon signed-rank test: ^#p > 0.05; ^##p > 0.05; ^###p < 0.01; ⁺ p > 0.05; ⁺⁺ p > 0.05; ⁺⁺⁺p < 0.01;
statistical differences between Protocol 1, Protocol 2 and Protocol 3 were analyzed with the Kruskal-Wallis test: ^*p < 0.005; ^**p < 0.005; ^***p < 0.005; ^****p < 0.005; ^*****p > 0.05;
n.a. not assessable.

ISSN: 1471-2342