MRI evaluation of endopelvic fascial swelling and analysis of influencing factors in patients with uterine fibroids after high-intensity focused ultrasound ablation

Figures & data

Table 1. Inclusion and exclusion criteria.

Inclusion criteria Clinically diagnosed with no other pelvic diseases except uterine fibroids; Scanning range from the navel to the pelvis with initial ultrasound ablation; A well-filled bladder and rectum with clear fat around the rectum; Symptomatic uterine fibroids or asymptomatic uterine fibroids requiring urgent treatment; Complete MRI and clinical data before and after HIFU treatment.

Exclusion criteria Broad ligament fibroid or pelvic cervical fibroid; A history of other gynecological diseases, such as endometriosis or pelvic inflammatory disease; A uterus at more than 24 weeks gestation (navel height) or larger; A uterine fibroid diameter less than 3 cm or greater than 12 cm; Pregnancy or actively breast-feeding; Existing contraindications for magnetic resonance examination.

Figure 1. Patient number 13, 36 years old. (A–C) MR images before HIFU treatment; (D–F) MR images after HIFU treatment. A sagittal T2-weighted image (A) demonstrates anterior wall fibroids (triangle) that are almost hypointense on T2-weighted scans; (C) is a diffusion-weighted image. Fascial swelling has a stripe-like high-intensity signal (long arrow).

Figure 2. Patient number 125, 39 years old. (A–C) MR images before HIFU treatment; (D–F) MR images after HIFU treatment. A sagittal T2-weighted image (A) demonstrates anterior wall fibroids (triangle) that are almost hypointense on T2-weighted scans; (C) is a diffusion-weighted image. Fascial swelling has a stripe-like high-intensity signal (long arrow).

Table 2. Univariate analysis to evaluate the relationship between the endopelvic fascial swelling and the features of fibroids.

Characteristics	Swelling group	Non-swelling group	p Value
Samples	128 (68.09%)	60 (31.91%)
Age	41 ± 5.85	42 ± 4.93	0.058^a
Maximal diameter (cm)	5.21 ± 1.30	5.44 ± 1.24	0.838^a
Fibroid volume (cm^3)	117.65 ± 69.54	112.65 ± 62.85	0.762^a
Position of uterine
Anteverted	80 (42.6%)	46 (24.5%)
Mid-position	9 (4.8%)	3 (1.6%)
Retroverted	39 (20.7%)	11 (5.9%)	0.164^b
Type of fibroids
Intramural	105 (55.9%)	43 (22.9%)
Submucosal	10 (5.3%)	7 (3.7%)
Subserosal	13 (6.9%)	10 (5.3%)	0.267^c
Location of fibroids
Anterior wall	60 (31.9%)	38 (20.2%)
Posterior wall	49 (26.1%)	8 (4.3%)
Lateral wall	19 (10.1%)	14 (7.4%)	0.002^c
Subcutaneous fat thickness (mm)	21.45 ± 0.74	23.64 ± 0.79	0.632^a
Distance from the fibroid to the sacrum (mm)	42.04 ± 19.74	53.69 ± 17.86	0.001^a
T2WI
Hypointense	108 (57.4%)	47 (25.0%)
Isointense	7 (3.7%)	4 (2.1%)
Hyperintense	13 (6.9%)	9 (4.8%)	0.492^b
Degree of enhancement
Slight	24 (12.8%)	12 (6.38%)
Intermediate	55(29.3%)	32 (17.0%)
Progressive	49 (26.1%)	16 (8.5%)	0.276^c

T2WI: T2-weighted imaging.

^a From the independent t test.

^b From the Fisher’s exact test.

^c From the χ² test.

Table 3. Univariate analysis to evaluate the relationship between the endopelvic fascial swelling and ultrasound ablation parameters.

Variables	Swelling group	Non-swelling group	p Value
Samples	128	60
Sonication power (W)	400 (385, 400)	393 (365, 400)	0.087^a
Sonication time (s)	884 (606, 1250)	588 (367, 757)	0.000^a
Treatment time (min)	79 (56, 109)	60 (47, 82)	0.003^a
Treatment intensity (s/h)	681.45 ± 142.84	594.40 ± 135.28	0.001^b
TD (J)	354,796 (254,920, 446,780)	227,900 (167,420, 305,910)	0.000^a
EEF (J/cm^3)	6.83 ± 5.00	3.57 ± 3.34	0.001^b
NPV	93.45 ± 62.71	89.39 ± 50.00	0.827^b
NPV ratio	0.24 (0.19, 0.39)	0.23 (0.17, 0.41)	0.931^a

TD: therapeutic dose; EEF: energy efficiency factor; NPV: non-perfused volume; NPV ratio: the ratio (%) of NPV-to-fibroid volume.

^a From the independent t test.

^b From the χ² test.

Table 4. Multivariable binary logistic regression analysis to evaluate the correlation of fascial swelling with the significant factors of univariate analysis.

Variables	B	SE	Wald	p Value	Ors [Exp(B)]	95% CI Lower Upper		Colinearity Statistics
								Tolerance	VIF
Constant	−5.006	1.458	11.785	0.001	0.007			–	–
Location of fibroids			3.348	0.187
Anterior wall	1.856	1.135	2.675	0.102	6.400	0.692	59.177	0.940	1.064
Posterior wall	0.327	1.290	0.064	0.800	1.387	0.111	17.372
Lateral wall	0.468	1.505	1.742	0.113	1.576	0.586	13.016
Distance from the fibroid to the sacrum	0.806	0.017	25.618	0.000	1.090	1.054	1.127	0.940	1.064
TD	0.000	0.000	1.150	0.283	1.000	1.000	1.000	0.327	3.057
EEF	−0.002	0.005	0.103	0.748	0.998	0.988	1.008	0.328	3.049

Table 5. Correlation between the location of the fibroid and the degree of endopelvic fascial swelling.

Degree of enhancement	Anterior wall	Posterior wall	Lateral wall	p Value
Degree 1	29 (22.7%)	24 (18.8%)	4 (3.1%)
Degree 2	18 (14.1%)	19 (18.4%)	5 (3.9%)
Degree 3	12 (9.4%)	14 (10.0%)	3 (2.3%)	0.730

Table 6. Correlation among the quantitive factors (TD, sonication time, EEF and the distance from the fibroid to the sacrum) and the degree of endopelvic fascial swelling.

Degree of fascial swelling	Degree 1	Degree 2	Degree 3 and above	H	p Value
TD (J)	355,200 (229,580, 466,000)	360,400 (255,546, 574,250)	532,175 (486,600, 691,990)	24.85	0.000
Sonication time (s)	730 (600, 1215)	752 (548, 1067)	805 (596, 1055)	10.169	0.006
EEF (J/cm^3)	6.35 ± 5.11	7.15 ± 6.33	6.63 ± 5.89	3482	0.206
Distance from the fibroid to the sacrum (mm)	35.94 ± 18.80	30.90 ± 26.74	37.99 ± 12.40	5.153	0.157

According to the Kruskal–Wallis test, the differences of TD and sonication time among the groups were statistically significant. The values of Hwere 24.85 and 10.169, respectively, p < 0.05. The Mann–Whitney test was used to make further comparisons.

In the TD variable, Mann–Whitney test showed that degree 1 to degree 2, U = 1.034, p = 0.301; degree 1 to degree 3 and above, U = 4.601, p = 0.000; degree 2 to degree 3 and above, U = 4.012, p = 0.000. In the sonication time variable, degree 1 to degree 2, U = 3.684, p = 0.000; degree 2 to degree 3 and above, U = 4.062, p = 0.000; degree 1 to degree 3 and above, U = 4.810, p = 0.005.

Table 7. Summary of postoperative adverse events.

Items	The swelling group (n = 128)		The non-swelling group (n = 60)		p Value
	SIR class A	SIR class B	SIR class A	SIR class B
Lower abdominal pain	59 (46.1%)	41 (32.0%)	27 (45.0%)	18 (30.0%)	0.634^a
Sacrococcygeal pain	49 (38.3%)	23 (18.0%)	9 (16.0%)	7 (11.7%)	0.000^a*
Lower limb paresthesia	11 (8.59%)	7 (5.47%)	5 (8.33%)	4 (6.7%)	0.864^a
Vaginal discharge	12 (9.38%)	9 (7.03%)	7 (11.7%)	6 (10.0%)	0.382^a

^a From the χ2 test.

* Significant difference was observed between the two groups, p < 0.05.

Data availability statement

The data that support the findings of this study are available from the corresponding author Zhang upon reasonable request.