| Background:Uterine fibroids or leiomyomas are the most common benign tumors found in gynecologic practice. Heavy bleeding, pelvic pain (including dyspareunia), urinary frequency or urgency, and constipation are the most common symptoms associated with fibroids or leiomyomas and present in half of the patients. Currently, many techniques are used in treating uterine fibroids. They are classified into two categories: hysterectomy and uterus-sparing treatment. High intensity focused ultrasound (HIFU) is a new non-invasive technique in treating solid tumors and is now widely used in treating uterine fibroids. After HIFU treatment, patients had symptoms relief with uterus-sparing. However, the treatment time seems to be long. So, scientists and doctors are focus on how to improve therapeutic efficacy. Studies have shown that oxytocin combines with its receptor in the target organ to cause contraction of uterine artery. Oxytocin is often used in hysteromyomectomy to reduce bleeding in the surgical procedure. Based on the above results, we ask if oxytocin could reduce the reqired ultrasound energy for uterine fibroids ablation?Objective:1 To explore the effect of oxytocin on the ultrasound ablation of uterine fibroids with single point sonication.2 To explore the effect of oxytocin on the ultrasound ablation of uterine fibroids by comparing EEF(energy- efficiency factor) and the required time to sonicate a single unit of volume of uterine fibroids.Methods:1 Eighty-two single points in 29 uterine fibroids of 26 patients were ablated with magnetic resonance imaging-guided high intensity focused ultrasound (MRgHIFU) before and after using oxytocin. The required total energy, sonication time required to reach 60℃and the acoustic energy for increasing 1℃of temperature at the single point before and after using oxytocin were compared.2 Twenty-two patients with uterine fibroids were treated with ultrasound imaging-guided high intensity focused ultrasound (USgHIFU). The patients were randomly divided into using oxytocin group and without using oxytocin group. EEF (energy- efficiency factor) and the required time to sonicate a single unit of volume of uterine fibroids between the two groups were compared.Results1 Control study of single point sonication with MRgHIFU between patients with using oxytocin and patients without using oxytocin:(1)In these two groups, the distance between targets and uterine fibroids was( 26.1±7.9 )mm and ( 25.3±6.8 ) mm, respectively; the distance between target and uterus was ( 27.9±7.0) mm and ( 27.7±7.2 ) mm, respectively; the distance between the target and skin was( 55.2±11.1 )mm and( 54.0±11.6 )mm, respectively. No significantly difference between the two groups was observed.(2)Before intravenous infusion of oxytocin, the average total sonication energy required to reach 60℃was (5319.5±909.7) joules and it took (21±20) seconds for a single point sonication, the energy required for increasing 1℃was (255±302) joules. In contrast, after intravenous infusion of oxytocin, the average total sonication energy required to reach 60℃was (2890.2±324.6) joules, and it took (12±7) seconds for a single point sonication, the energy required for increasing 1℃was (126±94) joules. The P values were 0.002, 0.001, 0.002, respectively.(3)Based on T2 weighted images, uterine fibroids were categorized as hyperintense, isointense, hypointense. Comparison between before and after intravenous infusion of oxytocin, the total sonication energy required to reach 60℃reduced by 42.4%, 32.6%, 60%, respectively in those three types of uterine fibroids.2. Comparison of unit volume sonication with USgHIFU between patients with using oxytocin and patients without using oxytocin: (1)In the group that without using oxytocin, the average power used was (3 68.3±12.8) W, treatment intensity was (568.1±35.5 ) s/h, non-perfused rate was( 80.2±5.1 )%. In the group that using oxytocin, the average power used for ablation was ( 379.1±10.0) W, treatment intensity was ( 536.4±35.5) s/h, non-perfused volume ratio was (85.2±4 .4 )%.(2)In the group that using oxytocin, the EEF (energy- efficiency factor) was (12.9±13.0)joules/cm3 and it took (55.1±18.7) seconds for ablating 1 cm3 of uterine fibroids. In contrast, the EEF (energy- efficiency factor) was (5.1±4.0) joules/cm3 and it took 1(9.0±42.4) seconds for ablating 1cm3 of uterine fibroids. The P values were 0.012,0.015, respectively.Conclusion:It seems that oxytocin could significantly decrease the energy required for ablating uterine fibroids, thus shortening the treatment time, improve the treatment efficiency. Therefore, it may play a key role in treating uterine fibroids in clinical practice. |
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