Analysis Of Factors,safety And Effectiveness Of High-intensity Focused Ultrasound In The Treatment Of Single Uterine Fibroids

Objective:To investigate the factors affecting energy efficiency factor(EEF)and non-perfusion volume ratio(NPVR)of high intensity focused ultrasound(HIFU)in the ablation of single and symptomatic uterine fibroids,and to analyze its safety and effectiveness.Methods:The clinical data of single and symptomatic uterine fibroids treated with HIFU in the First Affiliated Hospital of Kunming Medical University from June 2011 to October 2018 were retrospectively analyzed.All patients underwent MR plain and enhanced examination before HIFU treatment.Two senior imaging diagnosticians evaluated fibroids,measured target skin distance,posterior field distance and the three-dimensional diameter,calculated fibroids' volume,and recorded fibroids'signal intensity on T2-weighted image(SI on T2WI)(hypointense,isointense,hyperintense and mixed),enhancement degree on T1WI+C(mild,moderate or significant),uterine location(anteverted,mid-position and retroverted),fibroids location(anterior,lateral(left or right),fundus and posterior),fibroids type(intramural,submucosal,subserosal and transmural),enhancement uniformity on T1WI and other MRI features.HIFU ablation was performed using a point-line-face-body combination,and ablation parameters and adverse events(AEs)were recorded in this process.According to the MRI characteristics before and after HIFU treatment and the treatment parameters during HIFU treatment,EEF,non-perfusion volume(NPV)and NPVR were calculated.All the factors that may affect HIFU ablation were set as independent variables(where dummy variables were introduced into polytomous variables respectively),and EEF and NPVR were set as dependent variables,using a stepwise regression method to establish multiple linear regression models(the inclusion and exclusion criteria were 0.05 and 0.1,respectively).Record the type and frequency of AEs associated with treatment during and after HIFU,and analyze the causes of the occurrence.The symptomatic relief of 49 patients with uterine fibroids before and 1,3,and 6 months after ablation was followed up by telephone,uterine fibroids severity and health-related quality of life(UFS-QOL)questionnaire was completed.For some patients who underwent imaging examination(B-mode ultrasound or MRI),the volume changes of each uterine fibroids were recorded and analyzed.Analysis of variance was used to compare UFS-QOL scores and fibroids volumes at different times to evaluate the clinical efficacy of HIFU in the treatment of single uterine fibroids.Results:A total of 945 patients underwent HIFU treatment within the prescribed time period.After excluding 557 cases of perioperative MRI or B-mode ultrasound incomplete or poor quality or HIFU treatment parameters were incomplete,234 of the remaining 388 patients with single uterine fibroids were included in the study.The age of the patients was 24?53 years old,with an average of 37.73�6.29 years old.The volume of uterine fibroids ranged from 7.63 to 544.18 cm3,with an average of 93.66�76.46 cm3.All patients successfully completed HIFU ablation,the treatment success rate was 100%,and no serious AEs were observed.After HIFU treatment,the NPV of fibroids was 5.50?443.35 cm3,with an average of 69.67�61.99 cm3;NPVR was 16.69?97.87%with an average of 74.74� 15.15%;EEF was 0.15?27.80 j/mm3,with an average of 7.13�5.13 j/mm3.The results of the statistical analysis indicated that a total of 6 predictors(target target distance,maximum diameter of fibroids,enhancement degree on T1WI+C,transmural fibroids,hypointense on T2WI,anteverted uterus)were introduced into the EEF multiple linear regression model;a total of 6 predictors(hyperintense on T2WI,target skin distance,enhancement degree on TIWI+C,transmural fibroids,anterior fibroids,hypointense on T2WI)were introduced into the NPVR multiple linear regression model.The multiple linear regression equation of EEF was:y=5.160+0.484X1+3.134X2-0.944X3+3.130X4-1,824X5-1.317X6,where X1=target skin distance,X2=enhancement degree on T1WI+C,X3=maximum diameter of fibroids,X4=fibroid type(transmural),X5=SI on T2WI(hypointense),X6=uterine location(anteverted);the multiple linear regression equation of NPVR was:y=0.917-0.149X1+0.083X2-0.059X3-0.066X4+0.065X5-0.011X6,where X1=fibroid type(transmural),X2=fibroid location(anterior),X3=SI on T2WI(hyperintense),X4=enhancement degree on T1WI+C,X5=SI on T2WI(hypointense),X6=target skin distance.Therefore,the EEF was negatively correlated with SI on T2WI(hypointense),maximum diameter of fibroids,anteverted uterus but positively correlated with transmural fibroids,enhancement degree on T1WI+C and target skin distance fibroid type;the NPVR was negatively correlated with transmural fibroids,hyperintense on T2WI,enhancement degree on T1WI+C and target skin distance,but positively correlated with anterior fibroids,hypointense on T2WI.The result of collinearity diagnosis also showed that all models matched well and no serious collinearity was observed.Among the 234 patients with single uterine fibroids,104(44.44%)had AEs,of which lower abdominal pain was the most common.The incidence was as follows:83 cases of lower abdominal pain(35.47%),37 cases of vaginal abnormal fluid(15.81%),24 cases of skin burns(10.26%),20 cases of sacral pain(8.55%),28 cases of lower limb numbness(12.0%),12 cases of lower extremity swelling(5.13%),and 1 case of positive fecal occult blood test(0.43%).Except for 2 patients with severe skin burns and long hospitalization,the other skin burns were not treated specially for several days after treatment.According to International Society of Interventional Radiology(SIR)classification,201 cases(85.90%)had AEs of type A,26 cases(11.11%)of type B,4 cases(1.71%)of type C,3 cases(1.28%)of type D,and no AEs of type E and F were recorded.Before HIFU ablation,the SSS score of 49 patients was 26.32�0.64;the SSS scores at 1 month,3 months,and 6 months after HIFU treatment were 20.93�0.56 points,17.46�0.48 points and 16.00�0.52 points,respectively.The SSS scores of patients with uterine fibroids at different locations showed a downward trend with the change of time,and the difference was statistically significant(P<0.001).The QOL scores of all patients before HIFU treatment,1 month,3 months and 6 months after treatment,were 80.23�1.84 points,69.36�1.78 points,59.55�1.20 points and 57.65�1.17 points,respectively.The QOL scores of fibroids in different locations gradually decreased with time,and the difference was statistically significant(P<0.001).Among those,34 patients had volume records of uterine fibroids,and the preoperative average fibroid volume was 70.40�50.66 cm3.The average fibroid volume at 1 month,3 months,and 6 months after HIFU was 35.11�40.18 cm3,20.60�33.17 cm3,and 15.75�32.79 cm3,respectively;the volume of fibroids showed a downward trend,and the difference was statistically significant(P<0.05).Conclusions:1.The EEF and NPVR of HIFU ablation for single and symptomatic uterine fibroids are affected by various factors such as acoustic channel status,anatomical location of fibroids and uterine,and composition of fibroids.Fibroids of anteverted uterus,hypointense on T2WI,large size,small target skin distance and mild enhancement on T1WI+C can be easily ablated with high ablation efficiency.And for single uterine fibroids of anterior wall,hypointense on T2WI,mild enhancement on T1WI and small target skin distance,high NPVR is easier to reach during HIFU ablation.2.The common AEs of HIFU in the ablation of uterine fibroids are lower abdominal pain,abnormal vaginal fluid,skin burns,appendical pain,numbness of the lower extremities,etc.,which occur mildly and temporarily,and serious AEs are extremely rare.Thus,HIFU is still highly safe for the treatment of uterine fibroids.3.HIFU is effective in the treatment of uterine fibroids.It can significantly reduce the severity of uterine fibroids symptoms,improve health-related quality of life,eliminate or reduce the size of uterine fibroids,and bring benefits to patients.