Factors Influencing The Ablative Efficiency Of High Intensity Focused Ultrasound(HIFU) Treatment For Adenomyosis

High intensity focused ultrasound(HIFU) ablation is a novel noninvasive therapeutic technique. Because of its advantages of less invasive,lower cost, short recovery time, this technique has been widely used inthe treatment of adenomyosis. The mechanism of HIFU treatment for adenomyosis is to induce typical coagulative necrosis in adenomyotic lesion through the thermal effect produced by a tightly and precisely focus of high-intensity ultrasound beams, the adenomyoticlesion would lose its function and thus relieve symptoms related toadenomyosiswithout harming tissues outside the lesion.However, in clinical practice, we found that a high NPV ratio is easy to achieve in some lesions, but difficult to achieve in other lesions. To the best of our knowledge, no study has investigated the related factors that affect NPV ratio. Therefore, it is necessary to explore the factors influencing the ablative efficiency of HIFU treatment for adenomyosis.The aim of study was to investigate factors affecting ablative efficiency of HIFU for adenomyosis by analyzingnon-perfused volume(NPV) ratio, energy efficiency factor(EEF) and significant gray scale changes, toprovide evidence for indication optimization.Objectives:To investigate factors affecting ablative efficiency of high intensity focused ultrasound(HIFU) for adenomyosis.Materials and Methods:Two hundred and forty-five patients with adenomyosis who underwent ultrasound guided HIFU(USgHIFU) were retrospectively reviewed.All patients underwent dynamic contrastenhanced magnetic resonance imaging(MRI) before and after HIFU treatment. The non-perfused volume(NPV) ratio, energy efficiency factor(EEF) and gray scale change were set as dependent variables, while the factors possibly affecting ablation efficiency were set as independent variables. These variables were used to build multiple regression models.Results:Two hundred and forty-five patients with adenomyosis successfully completed HIFU treatment. Enhancement type on T1 WI, abdominal wall thickness, volume of adenomyotic lesion, the number of hyperintense points, location of the uterus, and location of adnomyosis all had a linear relationship with the NPV ratio. Distance from skin to the adenomyotic lesion vental side, enhancement type on T1 WI, volume of adnomyotic lesion, abdominal wall thickness, and signal intensity on T2 WI all had a linear relationship with EEF. Location of the uterus and abdominal wall thickness also both had a linear relationship with gray scale change.Conclusion:The enhancement type on T1 WI, signal intensity on T2 WI, volume of adenomyosis, location of uterus, location of adenomyosis, the number of hyperintense points, abdominal wall thickness, and distance from the skin to the adenomyotic lesion vental side all can be used as predictors of HIFU for adenomyosis.