Research On Personalized Prediction Of HIFU Treatment Dose Based On MRI Images Of Patients With Uterine Fibroids

Background:High-intensity focused ultrasound(HIFU),as a non-invasive treatment technique,can completely preserve the patient’s uterus,has good safety and effectiveness,and has been widely used in the clinical treatment of uterine fibroids.The principle of HIFU treatment is:outside the body,a low-energy ultrasound beam is focused by a certain focusing method,and it spreads to the diseased area through skin,fat,muscle and other tissues,and the focal point rapidly rises to 65℃ or more,causing irreversible coagulation of the target tissue Sexual necrosis,while the normal tissues that the sound waves pass through are not affected.However,due to the specificity of the tissues of different patients,such as the location,depth,type,blood perfusion,and thickness of the fat layer,the efficacy of HIFU varies for each patient.In order to ensure the safety and effectiveness of HIFU treatment,it is necessary to consider the structure and tissue specificity of different patients to achieve personalized prediction of HIFU treatment.Traditional HIFU therapeutic dose prediction usually does not consider the influence of tissue structure distribution.In the simulation,the tissue is regarded as a uniform tissue with parallel layers.However,in the actual HIFU treatment process,the ultrasound beam will pass through the skin,fat,muscle and other tissues,and the spatial distribution of each layer of tissues is not uniform,and the boundary is irregular.Therefore,the prediction of HIFU treatment dose using the parallel uniform multi-layer structure will produce certain errors.To this end,this paper establishes a personalized prediction of HIFU therapeutic dose based on MRI image data of patients with uterine fibroids,and compares the dose prediction with the the hyperecho area and the dose prediction established based on the parallel uniform multilayer structure,aiming to provide clinical HIFU The establishment of the therapeutic dose prediction system provides a reference basis.Objective:1.The dose prediction of HIFU ablation is realized based on the preoperative MRI images of patients with uterine fibroids and the parallel uniform multi-layer structure.The hyperecho area can be obtained from the B-mode ultrasound images collected during the operation.It will be based on the patient’s image and the parallel uniform multi-layer The simulation damage area of the layered structure is compared with the the hyperecho area area to verify the accuracy of the simulation model.2.Explore the relationship between the thickness of the patient’s abdominal wall,the thickness of the uterine fibroids and the irradiation dose on the area of HIFU treatment of uterine fibroids the hyperecho area and the area of simulated injury,and the influencing factors of HIFU therapeutic dose.Method:1.64 patients with MRI T2WI and other signal uterine fibroids who received HIFU treatment in the First Affiliated Hospital of Chongqing Medical University from 2013 to 2018 were taken as the research objects.Based on the clinical image data of the patient before treatment,the dose prediction based on the MRI image of the patient with uterine fibroids and the parallel uniform multi-layered structure is realized respectively.2.The numerical calculation grid drawing steps based on MRI images of patients with uterine fibroids are as follows:interactive extraction of the region of interest,image filtering to sharpen the edges and retain the texture information inside the image,and image morphology processing to extract the shape of the expression and description area Useful image boundary,enhance the boundary of the original image to increase the contrast between the boundary and the internal area,and finally extract the tissue area with different acoustic channels to draw a numerical calculation grid.Grid rendering of parallel uniform multi-layered structure is based on clinical MRI image data,and the tissue thickness on the acoustic axis is extracted as the thickness of each layer of tissue.The theoretical calculation grid is drawn.3.Obtain the hyperecho area at the focal area of the first treatment point for clinical treatment of uterine fibroids through the B-ultrasound images collected during the operation.Theoretically,combining the Westervelt nonlinear acoustic propagation equation and the Pennes biological heat conduction equation,the equivalent thermal dose model is used the equivalent thermal dose model to take 240EM as the damage threshold.Based on the MRI images of patients with uterine fibroids and the parallel uniform multi-layered structure,the dose prediction was performed,and the simulated injury area of the first treatment point was obtained.Further Sperman correlation analysis and comparative study with the hyperecho area。4.Further explore the correlation of abdominal wall thickness,uterine fibroids layer thickness and radiation dose with B-ultrasonic echo area and simulated damage area,analyze from the single factor and multi-factor perspectives,and further clarify the influencing factors of HIFU efficacy.The verification is based on MRI images of patients realize the accuracy of HIFU treatment dose prediction.Results:1.The hyperecho area at the first treatment point of 64 patients was41.705±13.506mm~2,and the simulated injury area based on the patient’s MRI image and the parallel uniform multilayer structure were 41.725±18.472mm~2and 39.854±17.094mm~2,respectively.The Sperman correlation coefficients of the hyperecho area at the first treatment point,the simulated damage area based on patient images,and the simulated damage area based on the parallel uniform multilayer structure are 0.827(P=0.01)and 0.692(P=0.01),respectively.2.Compared with the focus sound pressure distribution based on the parallel uniform multilayer structure,the focus sound pressure simulated based on the patient’s real MRI image data deviates from the preset focus position and moves toward the transducer direction,and the waveform is distorted,which is parallel to the ideal the results obtained by the uniform multi-layered structure are quite different.The corresponding temperature and tissue damage results show that the focus temperature obtained based on the patient’s real MRI image data is lower than the focus temperature obtained by an ideal uniform parallel layered tissue structure.Due to the non-uniformity of the tissue,the damage point deviates from the preset focus area,and the damage area is evenly distributed around the target focus based on the parallel and uniform multi-layered structure.3.The correlation between the thickness of the abdominal wall,the thickness of the uterine fibroids and the radiation dose,the hyperecho area and the area of simulated injury can be seen,within the range of the thickness of the abdominal wall of human tissues(13～41.1mm),the thickness of the abdominal wall has an effect on the area of the hyperecho area there was no statistical difference in the area of simulated injury and the area of simulated injury(P=0.636/P=0.984);the thickness of uterine fibroids was statistically different from the area of the hyperecho area(P=0.025),and there was no statistical difference between the area of simulated injury(P=0.222);There is a statistical difference between the radiation dose and the area of the hyperecho area and the area of simulated damage(P=0.000),which is positively correlated.Conclusions:1.The simulated damage area based on patient images and the the hyperecho area have significant consistency,which verifies the effectiveness of the non-uniform tissue model constructed using clinical MRI patient image data,which is helpful for the personalized prediction and dosage of HIFU radiation dose planning.2.Within the range of human tissue abdominal wall thickness(13～41.1mm),the abdominal wall thickness has no significant effect on the hyperecho area and the simulated damage area;the thickness of uterine fibroids is negatively correlated with the hyperecho area,while uterine fibroids There is no statistical difference between the thickness and the simulated damage area;the radiation dose is positively correlated with the hyperecho area and the simulated damage area.