Appearances and significance of gray-scale ultrasound in percutaneous microwave ablation of uterine myometrium benign lesions

Objective To investigate the image appearances and clinical significance of two-dimensional gray-scale ultrasound in percutaneous microwave ablation(PMA) for the treatment of uterine myometrium benign lesions.Methods Nineteen patients with 21 benign uterine lesions(13 uterine fibroids and 8 adenomyosis) who received PMA were selected.Before ablation,the location,echo and blood supply characteristics of uterine lesions were observed with conventional ultrasound.During ablation,the hyperechoic range of the ablation area was monitored with gray-scale ultrasound.Immediately after ablation,the hyperechoic volume was calculated and compared to the volume of non-enhancement area by CEUS.Results Two-dimensional gray-scale ultrasound revealed that uterine myoma and adenomyosis were both leaning low-echo before ablation.About 3 s after the beginning of microwave emit,gray-scale ultrasound showed hyperecho starting from the seam of microwave electrode,and enhanced as the time of microwave emission prolonged.When the hyperecho region reached the envelope of uterine myoma or 0.3 cm apart from the margin of the anticipated ablation area of adenomyosis,the microwave radialization was stopped,then the hyperecho region stopped increasing.Two-dimensional gray-scale hyperecho region immediately after the ablation([97.94±72.88]cm3) was a little larger than that of non-enhancement area by CEUS([88.82±70.06]cm3),but the difference was not statistical significant,and positive correlation was found between them(r=0.859,P0.01).Conclusion Changes of two-dimensional gray-scale ultrasound in microwave ablation for myometrium benign lesions are distinct during ablation.The hyperechoic range can approximately represent the extent of the coagulation necrosis area.