Experimental study on ablation of leiomyoma by combination high-intensity focused ultrasound and iodized oil in vitro.

AIM: The aim of the current study was to investigate whether iodized oil (IO) enhances high-intensity focused ultrasound (HIFU) ablation of uterine leiomyoma and to determine the features of hyperechoic changes in the target region. METHODS: Forty samples of uterine leiomyoma were randomly divided into an experimental group and a control group. In the experimental group, the leiomyoma was ablated by HIFU 30 min after 1 mL of iodized oil had been injected into the center of the myoma. The hyperechoic values and areas in the target region were observed by B-modal ultrasound after HIFU ablation. The samples were cut successively into slices and stained by triphenyltetrazolium chloride (TTC) solution within 1 h after HIFU ablation. The diameters of TTC-non-stained areas were measured and tissues in the borderline of the TTC-stained and -non-stained areas were observed pathologically. All procedures in the control group were the same as those in the experimental group except IO was replaced by physiological saline. RESULTS: The hyperechoic value in the target region in the experimental group was higher than that in the control group 4 min after HIFU ablation (P < 0.05). Hyperechoic areas in the target region as well as TTC-non-stained volumes in the experimental group were greater than those in the control group (P < 0.05). Routine pathologic observation showed that coagulation necrosis of leiomyoma occurred in the target region in both groups. CONCLUSION: IO causes coagulation necrosis, enlarges tissue damage, and postpones the attenuation of hyperechoic changes in the target region when HIFU ablation is carried out for leiomyoma in vitro.

Ablation of leiomyomas using a combination of HIFU and iodized oil in vitro.

This study investigates the enhancement effects of iodized oil and the features of hyperechoic focus changes in a target region of high-intensity focused ultrasound (HIFU) ablated uterine fibroids. Leiomyomas in the experimental group of 20 randomly assigned patients were ablated by HIFU under certain parameters 30 min after 1 mL of iodized oil was injected into the center of the myomas. The value of the gray scale and its area were observed by B-mode ultrasound in the target region and were carefully recorded at 0, 2, 4, and 5 min, respectively, after HIFU ablation. The samples were sectioned successively in a thickness of 1∼2 mm and stained by 2,3,5-triphenyltetrazolium chloride solution within 1 h after HIFU ablation. The TTC non-staining volumes were measured afterwards. All procedures in the control group of the other 20 randomly assigned patients were the same except that iodized oil was replaced by physiologic saline. The hyperechoic areas in the target region were observed in all fibroids of both groups. Compared with the control group, the gray scale values in the target region of the experimental group were higher 4 min after HIFU ablation. The enhanced gray scale area in the target region and the 2,3,5-triphenyltetrazolium chloride non-staining volumes in the experimental group were bigger. Based on our experience, HIFU sonication of leiomyomas injected with iodized oil produces hyperechoic foci that are greater than areas injected with saline. More studies are required to understand the clinical implications of these observations.