Factors affecting effects of ultrasound guided high intensity focused ultrasound for single uterine fibroids: a retrospective analysis

Figures & data

Table 1. Patients baseline characteristics and treatment data.

Characteristics	Value*
No. of patients	207
Age (y)	37.7 ± 6.3 (24 − 53)
Size of UFs (mm)	55.3 ± 15.3 (26.0 − 104.0)
Volume of UFs (mm^3)^a	65189.1 (36748.2, 108343.4)^a
Uterine location:
Anteverted/midposition/retroverted	98/65/44 (47.3%/31.4%/21.3%)
Location of UFs:
Anterior/fundus/lateral/posterior	67/24/58/58 (32.4%/11.6%/28%/28%)
Sonication time (s)	1247.9 ± 865.0 (64 − 3686)
Sonication power (W)	380.1 ± 32.7 (216 − 400)
NPV (mm^3)^a	45365.6 (25055.6, 77.566.6)^a
NPVR (%)	74.7 ± 15.1% (16.7 − 97.9%)
EEF (j/mm^3)	7.4 ± 5.2 (0.1 − 27.8)

Unless otherwise noted, values are mean ± standard deviation.

^a Skewed distribution data were expressed as median and interquartile range.

* Values in parentheses represent ranges or percentage.

UFs: uterine fibroids; T1WI:T1 Weighted Image; SI: signal intensity; T2WI: T2 Weighted Image; NPV: non- perfusion volume; NPVR: non- perfusion volume ratio; EEF: energy efficiency factor.

Figure 1. Contrast enhanced magnetic resonance imaging (CE-MRI) before and after treatment: (A1) anterior wall and mildly enhanced uterine fibroids; (B1) lateral wall and moderately enhanced uterine fibroids; (C1) posterior wall and significantly enhanced uterine fibroids; CE-MRI after treatment shows that the ablation area is not enhanced (A2, B2 and C2).

Table 2. The multivariable regression model and analysis of varianceⁱ.

Model	R	R^2	Adjusted R^2	F	p
1	0.421	0.177	0.173	44.179	.000^a
2	0.490	0.240	0.232	32.166	.000^b
3	0.554	0.307	0.297	29.965	.000^c
4	0.592	0.350	0.337	27.222	.000^d
5	0.611	0.373	0.358	23.955	.000^e
6	0.629	0.396	0.378	21.847	.000^f
7	0.639	0.408	0.387	19.577	.000^g
8	0.648	0.420	0.397	17.920	.000^h

^a Predictors: (Constant), transmural.

^b Predictors: (Constant), transmural, anterior.

^c Predictors: (Constant), transmural, anterior, hyperintense.

^d Predictors: (Constant), transmural, anterior, hyperintense, enhancement type on T1WI.

^e Predictors: (Constant), transmural, anterior, hyperintense, enhancement type on T1WI, distance from UFs ventral side to skin.

^f Predictors: (Constant), transmural, anterior, hyperintense, enhancement type on T1WI, distance from UFs ventral side to skin, hypointense.

^g Predictors: (Constant), transmural, anterior, hyperintense, enhancement type on T1WI, distance from UFs ventral side to skin, hypointense, posterior.

^h Predictors: (Constant), transmural, anterior, hyperintense, enhancement type on T1WI, distance from UFs ventral side to skin, hypointense, posterior, anteverted uterus.

ⁱ Dependent variable: NPVR.

T1WI: T1-Weighted Image; UFs: uterine fibroids; NPVR: non-perfusion volume ratio.

Table 3. Coefficient of multivariable regression model^a of NPVR.

Model		Non-standardised Coefficient	Standardized Coefficient	p	Collinearity statistics
					Tolerance	VIF
8	(Constant)	0.904		.000
	Transmural	−0.136	−0.323	.000	0.945	1.058
	Anterior	0.071	0.221	.000	0.779	1.283
	Hyperintense	−0.071	−0.197	.001	0.862	1.160
	enhancement type on T1WI	−0.063	−0.173	.002	0.927	1.079
	Distance from UFs ventral side to skin	−0.001	−0.132	.021	0.919	1.088
	Hypointense	0.050	0.144	.015	0.856	1.169
	Posterior	−0.043	−0.128	.040	0.771	1.297
	Anteverted uterine	0.034	0.112	.043	0.966	1.035

Only the results of best-fit model (model 8) were shown in the table.

^a Dependent variable: NPVR: non- perfusion volume ratio; VIF: variance inflation factor; T1WI: T1- Weighted Image; UFs: uterine fibroids.

Table 4. The multivariable regression model and analysis of variance^g.

Model	R	R^2	Adjust R^2	F	p
1	0.386	0.149	0.145	35.924	.000^a
2	0.479	0.229	0.222	30.376	.000^b
3	0.527	0.278	0.267	26.036	.000^c
4	0.578	0.334	0.321	25.314	.000^d
5	0.595	0.354	0.338	22.003	.000^e
6	0.610	0.373	0.354	19.796	.000^f

^a Predictors: (constant), distance from UFs ventral side to skin.

^b Predictors: (constant), distance from UFs ventral side to skin, enhancement type on T1WI.

^c Predictors: (constant), distance from UFs ventral side to skin, enhancement type on T1WI, size of UFs.

^d Predictors: (constant), distance from UFs ventral side to skin, enhancement type on T1WI, size of UFs, transmural.

^e Predictors: (constant), distance from UFs ventral side to skin, enhancement type on T1WI, size of UFs, transmural, anteverted uterus.

^f Predictors: (constant), distance from UFs ventral side to skin, enhancement type on T1WI, size of UFs, transmural, anteverted uterus, hypointensity.

^g Dependent variable: EEF.

EEF: energy efficiency factor; UFs: uterine fibroids; T1WI: T1- Weighted Image.

Table 5. Coefficient of multivariable regression model^a of EEF.

Model		Non-standardizd Coefficient	Standardizd Coefficient		Collinearity statistics
				p	Tolerance	VIF
6	(Constant)	5.354		.013
	Distance from UFs ventral side to skin	0.049	0.211	.001	0.765	1.307
	Enhancement type on T1WI	3.192	0.254	.000	0.955	1.047
	Size of UFs	−0.101	−0.298	.000	0.778	1.285
	Transmural	3.160	0.217	.000	0.947	1.056
	Anteverted uterus	−1.483	−0.143	.013	0.962	1.039
	Hypointense	−1.689	−0.141	.015	0.945	1.058

Only the results of best-fit model (model 6) were shown in the table.

^a Dependent variable

EEF: energy efficiency factor; VIF: variance inflation factor; UFs: uterine fibroids; T1WI: T1- Weighted Image.