High intensity focused ultrasound ablation for submucosal fibroids: A comparison between type I and type II

Figures & data

Figure 1. Contrast-enhanced ultrasound images and MR images obtained from a patient with type I submucosal fibroid. (A) Pre-procedure contrast-enhanced ultrasound image shows a submucosal fibroid (arrow). (B) Contrast-enhanced ultrasound image obtained immediately after HIFU shows the non-perfused area (arrow). (C) Pre-procedure MRI shows a 4.5 × 4.3 × 4.0 cm submucosal fibroid located at the anterior wall of the uterus (arrow). (D) Contrast-enhanced MRI obtained 1 day after HIFU shows the fractional ablation was 90% (arrow).

Table 1. Comparison of demographic characteristics between patients with type I and type II submucosal fibroids.

Variable	Type I	Type II	p Value
No. of patients	27	28
Age (years)	40.9 ± 5.4	41.9 ± 6.1	0.46
BMI (kg/m^2)	22.4 ± 3.8	23.3 ± 3.1	0.12
Diameter of uterine fibroids (cm)	4.2 ± 1.9	4.6 ± 1.8	0.63
Volume of fibroids (cm^3)	47.8 ± 60.4	55.2 ± 53.7	0.43
MRI T2 signal intensity of fibroids
Hyper/iso/hypointensity	0/9/18	0/11/17	0.71
Symptoms
Menorrhagia (%)	74.1	67.9	0.61
Dysmenorrhoea (%)	33.3	42.9	0.47
Anaemia (%)	22.2	32.1	0.83

Data are numbers or mean value ± SD. No significant difference was observed between the two groups (p > 0.05).

Table 2. Comparison of HIFU treatment results between patients with type I and type II submucosal fibroids.

Variable	Type I (N = 27)	Type II (N = 28)	p
Sonication power (W)	388.7 ± 22.7	392.7 ± 17.7	0.63
Sonication time (s)	858.4 ± 595.1	769.2 ± 572.5	0.55
Sonication time/hour (s/h)	584.74 ± 139.9	581.8 ± 169.3	0.84
Total energy used (KJ)	339.1 ± 237.9	296.8 ± 233.4	0.45
NPV ratio* (%)	83.0 ± 17.3	92.0 ± 9.5	0.03

*Significant difference was observed between the two groups, p < 0.05. NPV, non-perfused volume.

Figure 2. MR images (T2WI) obtained from a 37-year-old patient with submucosal fibroids. (A) Pre-procedure T2WI shows a 5.5 × 3.8 × 4.3 cm submucosal fibroid located at the fundus of the uterus (arrow). (B) T2WI obtained 1 month after HIFU shows the size of the fibroid was 3.0 × 2.0 × 2.3 cm (arrow). (C) T2WI obtained 6 months after HIFU shows the size of the fibroid was 0.5 × 0.4 × 0.4 cm (arrow). (D) T2WI obtained 12 months after HIFU shows the treated fibroid tumour has disappeared (arrow).

Table 3. Comparison of fibroid volume changes between patients with type I and type II submucosal fibroids after HIFU treatment.

Variable	Type I N = 27	Type II N = 28	p
Baseline (cm^3)	47.8 ± 60.4	55.2 ± 53.7	0.43
1 month after HIFU (cm^3)	23.7 ± 43.7	31.1 ± 33.8	0.23
6 months after HIFU (cm^3)	12.6 ± 18.2	16.9 ± 17.7	0.18
12 months after HIFU (cm^3)	5.9 ± 7.8	8.7 ± 10.5	0.41

No significant difference was observed at any follow-up interval between the two groups, p > 0.05.

Table 4. Incidence rates of adverse effects during the HIFU procedure.

Variable	Type I N = 27	Type I N = 28	p
Transient leg pain (%)	7.4	7.1	1.00
Sciatic/buttock pain (%)	70.4	50.0	0.12
Lower abdominal pain (%)	66.7	75.0	0.50
‘Hot’ skin sensation (%)	44.4	50.0	0.68

No significant difference was observed between the two groups (p > 0.05).

Table 5. Comparison of adverse effect incidence rates and complications between patients with type I and type II submucosal fibroids after HIFU treatment.

Variable	Type I N = 27	Type II N = 28	p
Fever (%)	0.0	0.0	1.000
Lower abdominal pain (%)	29.6	28.6	0.93
Sciatic/buttock pain (%)	11.1	7.1	0.97
Leg pain (%)	3.7	0.0	0.23
Vaginal discharge or bleeding (%)	29.6	29.7	0.84

No significant difference was observed between the two groups, p > 0.05.