Use of intra-procedural fusion imaging combining contrast-enhanced ultrasound using a perflubutane-based contrast agent and auto sweep three-dimensional ultrasound for guiding radiofrequency ablation and evaluating its efficacy in patients with hepatocellular carcinoma

Figures & data

Figure 1. Comparison of three-dimensional ultrasound (3DUS) volume data images obtained by manual sweep scanning and AutoSweep scanning for an HCC lesion (maximum diameter, 28 mm) in segment VIII of the liver. (a) 3DUS volume data image obtained by manual sweep scanning. Blue lines indicate the locus of the manual sweep scanning. Arrow indicates the first frame of the manual sweep scanning. The distances between the blue lines are not equal, which indicates a non-constant scanning speed. (b) 3DUS volume data image obtained by manual sweep scanning. (c) 3DUS obtained by manual sweep allows viewing of the volume of interest in three orthogonal planes (this image shows plane B), which can be translated from right to left. The shape of the arc is not symmetrical due to the non-constant scanning speed (arrow). (d) US volume data image obtained by AutoSweep scanning. Comparison with the image in Figure 1(b) obtained by manual sweep shows that the images look almost the same. (e) 3DUS image obtained by AutoSweep allows viewing of the volume of interest in three orthogonal planes (this image shows plane B), which can be translated from right to left. Comparison with the image shown in Figure 1(c) obtained by manual sweep shows that the shape of the arc is symmetrical and the scanning range is slightly wider than that in the image shown in Figure 1(c) (arrow). Arrowhead indicates the margin of the HCC.

Table 1. Baseline characteristics of the patients with HCC.^a,b

Characteristics	HCC (n = 50)
Number of patients	43
Single lesion/two lesions/three lesions	37/5/1
Age (mean, range; years)	68, 44–88
Sex (male/female)	28/15
Etiology of HCC
Hepatitis B/hepatitis C/others	11/26/6
Child-Pugh classification
Class A/B	40/3
Mean diameter of the lesions (range) in mm	15.3 (8–29)
Number of lesions measuring 1–10/11–20/21–30 mm in diameter	9/36/5
Mean follow-up period (range) in months	21.4 (15–27)
Number of lesions locating less than 5mm from vessels/bile duct/liver surface	14/4/5

^a Others: alcohol, primary biliary cholangitis, idiopathic.

^b Vessels: the relatively large vessels such as the portal vein or hepatic vein.

Table 2. Mean number of insertions for the initial RFA and additional RFA.

	Initial RFA^a	Additional RFA^b	Total
Number of nodules	50	17	50
Mean number of punctures (range)^c	2.6 (1–6)	1.6 (1–4)	3.2 (1–6)

RFA: radiofrequency ablation.

^a First treatment session.

^b Additional ablation performed immediately after the ablative margin was evaluated as being inadequate by intra-procedural CEUS-US fusion imaging performed at the first treatment session.

^c Mean number of insertions of the RFA needle.

Figure 3. Flow chart of evaluation of therapeutic efficacy of RFA by CEUS/US fusion imaging performed during the RFA procedure.

Table 3. Comparison of evaluation by CEUS-US fusion imaging and CECT/EOB-MRI for assessment of the tumor response after radiofrequency ablation in cases of hepatocellular carcinoma.

	CT/MRI
US/US fusion	Grade A^a	Grade B^b	Grade C^c	Grade D^d	Tumor (n = 50)
Grade A	21	3	0	0	24
Grade B	3	22	0	0	25
Grade C	0	0	0	0	0
Grade D	0	0	0	1	1
Total	24	25	0	1	50

^aGrade A (curative): a 5 mm or greater ablative margin around the entire tumor.

^bGrade B (relatively curative): an ablative margin around the tumor, but less than 5 mm in diameter in some places.

^cGrade C (relatively non-curative): only an incomplete ablative margin around the tumor, although no residual tumor was apparent.

^dGrade D (non-curative): the tumor was not completely ablated.