| Focused ultrasound ablation(FUA),that is,high intensity focused ultrasound(HIFU),is a novel non-invasive technique for the treatment of benign gynecological diseases.It has opened a new field in the treatment of gynecological benign diseases.However,in clinical practice,we sometimes encounter some patients with sacrococcyx pain or leg pain.The follow-up MRI also revealed that some patients had MRI signal intensity changes in the sacrum and edema in the soft tissue adjacent the sacrum after FUA treatment.Therefore,we were trying to retrospectively evaluate the occurrence of MRI signal changes in the sacrum and the soft tissue adjacent to the sacrum and further analyze the related factors that cause MRI signal changes in the sacrum and the soft tissue adjacent to the sacrum.Furthermore,to reduce the incidence of sacroccygeal tissue damage through the optimized protocol.Objective1.To investigate the effect of FUA on the sacrum and the soft tissue adjacent to the sacrum in patients with uterine fibroids and further analyze the related factors that cause the MRI signal changes in the sacrum and the soft tissue adjacent to the sacrum.2.To explore the correlation between the pain of sacrococcygeal or leg pain after FUA treatment and the MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum.MethodsFrom 2016 to 2018,613 patients with uterine fibroids who received FUA treatment in Chongqing Haifu Hospital were enrolled in this study.All patients underwent MRI before and after FUA treatment.The signal intensity changes on MRI in the sacrum and the soft tissue adjacent to the sacrum were observed on T2-weighted imaging(T2WI)and contrast enhanced images.1.The signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum were considered as dependent variables,and the baseline characteristics of the patients and the uterine fibroids,and the treatment parameters were regarded as independent variables.Multivariate analysis was used to evaluate the correlation between the parameters and the signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum.2.The proportion of the sacral pain and leg pain in 293 patients with MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum was analyzed.3.The MRI signal intensity changed volume in the sacrum and the soft tissue adjacent to the sacrum was measured and the relationship between the MRI signal intensity changed volume in in the sacrum and the soft tissue adjacent to the sacrum and sacral pain and leg pain was further analyzed.Results1.Post-FUA MRI showed that the MRI signal intensity chages in the sacrum and the soft tissue adjacent to the sacrum was observed in 293patients(47.8%),while 320 patients(52.2%)didn’t have MRI signal intensity in the sacrum and the soft tissue adjacent to the sacrum(1)The mean BMI of the group of patients with signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum and the group of patients without signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum was 22±3,23±3;the mean abdominal wall thickness was 26±8mm,28±9mm;the mean distance from the ventral side of the lesion to the skin was 52±24mm,42±19mm;the median distance from the dorsal side of the lesion to the sacrococcygeal bone was 17(12-24)mm,32(21-47)mm,respectively.The BMI,abdominal wall thickness and the distance from the back of the lesion to the sacrum were smaller in the group with signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum than that of the group without signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum(P<0.05).Meanwhile,there were significant differences in uterine position,myoma position,myoma type,T2WI signal intensity of the fibroids and the enhancement of the fibroids between the two groups(P<0.05);(2)The mean value of treatment intensity for the group of patients with signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum and the group of patients without signal intensity changes in the sacrum or/and the soft tissue adjacent to the sacrum was 591±170s/h,535±157s/h,the median value of total acoustic energy was320000(200000-500000)J,230000(150213-360000)J and the median value of ablation efficiency was 79(37-164)mm~3/s,122(57-240)mm~3/s;EEF was3.5(1.7-7.6)J/mm~3 and 2.3(1.1-4.9)J/mm~3 respectively.There is a statistical difference between the two groups(P<0.05).Multivariate analysis showed that BMI,uterine position,the signal intensity of the fibroids on T2WI,distance from the dorsal side of the fibroid to sacrum,Ablation volume per unit irradiation time were significantly related to the MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum.1.Based on the location of the MRI signal intensity changed area,the patients with MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum were divided into three groups:MRI signal intensity changes only in the sacrum(33cases)(11.3%),signal intenstity changes only in the soft tissue adjacent to the sacrum(86cases)(29.3%),and MRI signal intensity changes in both the sacrum and the soft tissue adjacent to the sacrum(174cases)(59.4%).The mean BMI,the mean maximum diameter of the uterine fibroids and the mean distance from the ventral side of the lesion to the skin in the group of patients with MRI signal intensity changes only in the sacrum were 23±3,76±28mm and 42±21mm,respectively;the mean BMI,the mean maximum diameter of the uterine fibroids and the mean distance from the ventral side of the lesion to the skin in the group of patients with MRI signal intensity changes only in the soft tissue adjacent to the sacrum were 22±3,61±22mm and 57±26mm,respectively;the mean BMI,the mean maximum diameter of the uterine fibroids and the mean distance from the ventral side of the lesion to the skin in the group of patients with MRI signal intensity changes in both the sacrum and the soft tissue adjacent to the sacrum were 22±2,52±24mm and 62±19mm,respectively.The median uterine volume and the median uterine fibroid volume were 486(260-755)cm~3 and 131(75-350)cm~3 in the group with MRI signal intensity changes only observed in the sacrum;The median uterine volume and the median uterine fibroid volume were 239(160-382)cm~3 and 75(40-150)cm~3 in the group with MRI signal intensity changes only observed in the group of patients with MRI signal changes only in the soft tissue adjacent to the sacrum;while they were260(188-406)cm~3 and 90(41-149)cm~3 in the group of patients with MRI signal intensity changes in both the sacrum and the soft tissue adjacent to the sacrum.The results showed that BMI,uterine volume,the distance from the abdominal side of the fibroid to the skin,the signal intensity of the fibroids on T2WI,the degree of enhancement of the fibroids were significantly correlated with the type of MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum(P<0.05).2.In patients with sacrum and the soft tissue adjacent to the sacrum MRI signal changes.T2WI and the contrast enhanced sequence both showed that the signal intensity changed volume in patients with sacral pain was significant larger than that of patients without sacral pain(P<0.05).Leg pain after FUA was mainly seen in the group of patients with MRI signal intensity changes in both the sacrum and the soft tissue adjacent to the sacrum.T2WI show no significant difference in MRI signal intensity changed volume between the patients with leg pain and the patients without leg pain after FUA.The sacrococcygeal T2WI sequence showed that the volume of sacral MRI signal in patients with lower extremity pain was significantly larger than that in patients without lower extremity pain(P<0.05).But there was no significant difference between T2WI sequence soft tissue and enhancementthere was no significant difference in T2WI sequence.ConclusionsAlthough MRI signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum are common after FUA ablation,the incidence of sacral pain and lower leg pain is low.However,the sacral pain and especially leg pain,has a great impact on the quality of life of patients,it is necessary to optimize the indication and make individualized FUA treatment plan according to the patient’s BMI,the distance from the focus to the skin,the location,size,signal intensity of the fibroids to reduce the risk of sacral injury and the edema of soft tissue adjacent to the sacrum. |
PDF Full Text Request