Research On Prostate Puncture Assisted By MR And TRUS Image

With the increase in the incidence of prostate cancer and getting younger,the early examination of the prostate has become more and more important.In the transrectal ultrasound-guided perineal prostate biopsy,the doctor determines the target of the puncture by observing the prostate area in transrectal ultrasound(TRUS)images.Due to the poor imaging quality of TRUS,blurring of the prostate margin,and low contrast between tumor and non-tumor areas,the efficacy of prostate cancer detection is limited.During this process,doctors need to determine the needle route based on experience and are vulnerable to interference.Taking into account the high resolution and contrast of soft tissue for magnetic resonance imaging(MRI),the internal and external tissues of the prostate can be well displayed.Therefore,this paper assists the puncture needle feeding mechanism to achieve prostate puncture by registering the MR image information to the intraoperative TRUS image,to improve the accuracy of the puncture and detection rate,reduce the number of needles and postoperative complications.In this paper,according to the medical needs of transperineal ultrasound-guided perineal prostate biopsy,the structure of the puncture needle feeding mechanism and the control unit are designed and find the inverse kinematic solution.Combining the preoperative image processing and registration with the ultrasound probe operating mechanism and ultrasound equipment required for guiding the puncture during surgery,a prostate puncture system assisted by MR and TRUS image was constructed.Because the registration of MR image information to the intraoperative TRUS image needs to be performed on the basis of contour extraction and three-dimensional reconstruction.In this paper,we use the prostate MR image training set to extract the prior shape information,combined with the region information and local gradient information of the image,and propose a prior-shape-based level set model combined with gradient and regional information for prostate MRI segmentation.Using this method to extract the contour series of MR images of prostate phantoms,three-dimensional reconstruction was performed based on the contour sequence to obtain a three-dimensional MRI model.For contour extraction and three-dimensional reconstruction of TRUS images,this paper extracts the Dense SIFT feature of the training set image and inputs SVM classifier training.Through this classifier,the initial contour of the prostate TRUS image is obtained.Combining the gray level and gradient information,a level set segmentation method combining local gray information and RBF gradient information is proposed.The internal and external parameters of the ultrasound probe were calibrated to obtain the transformation matrix of the image coordinates and the mechanism base coordinate,using this mechanism and the transformation matrix to obtain evenly spaced ultrasound image sequences for three-dimensional reconstruction,a three-dimensional TRUS model is obtained.In order to verify the feasibility of the prostate puncture technology assisted by MR and TRUS images,the prostate puncture system and related technologies were studied experimentally.Combined with practical requirements,an automatic prostate biopsy platform under the guidance of MR-TRUS images was constructed.Prostate contour extraction experiments of MR and TRUS images were performed to verify segmentation performance of the segmentation algorithm in corresponding modal images.The experiment of calibration of internal and external parameters of the ultrasound probe was carried out,and registration of the ultrasound image to the probe operating mechanism and registration of the MR to TRUS image were completed.The MR and TRUS image-assisted prostate biopsy experimentsp was performed to verify the effectiveness of MR and TRUS image-assisted prostate biopsy techniques.