| Background:High intensity focused ultrasound (HIFU) is widely used in the treatment of uterine fibroids for its advantage of high safety, good curative effect and less complications, the principle of which is to use the characteristices of ultrasonic focusing, penetrating and sound absorption for tissues, tumor transforms the sound energy into heat energy to get at 60-100℃ instantly then go to coagulation necrosis. For the ultrasonic energy passing through the tissues to focus on the target organ, the tissue on the acoustic channel has high risk of getting hurt. Skin, adipose tissue and rectus abdominis muscle are on the acoustic channel, which will absorb the sound energy and get damaged, we can find signal change on MRI for the tissues on the acoustic channel.Objective:To explore the influencing factors of postoperative abdominal MRI signal change after high intensity focused ultrasound treatment of uterine fibroids and evaluate the risk of skin damage, providing help for the treatment of uterine fibroids safely in clinical practice.Methods:70 patients with single uterine fibroids treated with HIFU were choosed and divided to two group of A(with abdominal wall signal change, 35 cases) and B(without abdominal wall signal change,35 cases) according to the results of postoperative pelvic MRI examination. By comparing the two groups of patients’age, thickness of abdominal adipose tissue and rectus abdominis muscle, target distance, acoustic window adapter, operation scar, pubic symphysis cover, irradiation time, irradiation intensity and the total energy, the related factors influencing the abdominal MRI signal change and its correlation degree were analyzed.Results:1.In the two groups of patients’general conditions, height, weight, number of pregnancy, ablation rate, the volume of uterus and fibroid, there were no statistical difference (P> 0.05).2.In the single factor analysis of t test, for the signal change group, the age was 41.23±4.15y, the thickness of abdominal adipose tissue was 22.74±6.60mm, the thickness of rectus abdominis muscle was 7.51±2.13mm, target distance was 59.34±24.35mm, irradiation time was 763.80±306.88s, irradiation intensity was 663.51±90.10s/h, and the total energy was 300322.29±120756.95J; for the no signal change group, the age was 40.46±4.69y, the thickness of abdominal adipose tissue was 16.91±5.76mm, the thickness of rectus abdominis muscle was 8.00±2.67mm, target distance was 54.17±19.03mm, irradiation time was 485.91±298.17s, irradiation intensity was 509.46±105.34s/h, and the total energy was 195700.06±118260.31J. The result showed statistical difference in the thickness of abdominal adipose tissue, irradiation time, irradiation intensity and total energy (P< 0.05)3.In the single factor analysis of χ2 test, for the signal change group, small acoustic window adapter was 4 cases, middle acoustic window adapter was 21 cases, large acoustic window adapter was 10 cases, with operation scar was 13 cases, with pubic symphysis covered was 12 cases; For the no signal change group, small acoustic window adapter was 14 cases, middle acoustic window adapter was 16 cases, large acoustic window adapter was 5 cases, with operation scar was 5 cases, with pubic symphysis covered was 3 cases. The result showed statistical difference in acoustic window adapter, operation scar and pubic symphysis covered (P< 0.05)4.In the multiple-factor analysis of Logistic regression, the thickness of abdominal adipose tissue and irradiation intensity showed significant statistical difference (P< 0.05). The OR of abdominal adipose tissue thickness was 13.228,95% CI was 1.432-122.173; the OR of the irradiation intensity was 1.021,95% CI was 1.009-1.034.Conclusions:1.The thickness of abdominal adipose tissue and irradiation intensity are the independent influencing factors of postoperative abdominal MRI signal change.2.Abdominal adipose tissue thickness influences the abdominal MRI signal change to a greater extent than the irradiation intensity. |
PDF Full Text Request