Accurate Localization Methods In Complex Congenital Heart Disease Malformation Using Electromagnetic Navigation And Augmented Reality

Complex congenital heart disease is one of the most common congenital defects that are harmful to the health of young children.Early orthodontic surgery is the only effective therapy for complex congenital heart disease.Even so,whether domestic or abroad,the mortality and disability rates of complex congenital heart disease after surgical therapy are still high.The main reason is that the surgical field is too small to identify malformations within and around the heart intraoperatively.Although there is currently an angiographic imaging technique,the anatomy of the heart and its surrounding blood vessels in the surgery is different from the preoperative image after the chest is exposed.It is difficult for doctors to compare the preoperative images with the actual intraoperative results.Therefore,the current congenital heart disease surgery mainly depends on surgeons' clinical experience and the guidance of medical imaging,which leads to complicated surgical operations,low accuracy of the positioning of the lesions,and low efficiency of surgery.To solve the problem in the operation of congenital heart disease,we designed a surgical navigation system for malformations of congenital heart disease,combining with electromagnetic navigation and augmented reality technology,to assist surgeons in identifying and locating malformations precisely.Based on the system,we separately study the related technologies in the system workflow.The surgical navigation technique in this paper are exhibited as follows:(1)We designed an electromagnetic surgery navigation system for congenital heart disease.To achieve the goal about malformations location,we constructed an integrated surgical navigation system,including medical image processing,3D visualization,chest incision planning,marker extraction,surgical registration,instruments tracking,and augmented reality based on endoscopic.(2)We proposed a surgical thoracic incision planning technique based on preoperative images.To render a more realistic anatomical structure,we completed 3D visualization from preoperative images,and proposed a technique for chest incision planning based on the location of malformations.According to this technique,the contour of malformations will be extracted from current projection angle,and finally the thoracic incision will be generated automatically on the virtual thoracic model to reduce the surgical trauma.(3)We studied registration technology for electromagnetic navigation system.The mainstream registration technology in optical navigation systems is mainly based on reflective paste-type markers,and the registration between surgical and image space is achieved by markers in two spaces.However,due to the large deformation of the chest,markers will be displaced,resulting in the decrease of registration accuracy.We constructed a surgical platform,which is embedded with electromagnetic sensor at the bottom and fixed with multiple markers around.Thus,the surgical space will be determined and the registration accuracy can be prevented from declining due to the displacement of markers.(4)We studied the augmented reality technology based on flexible endoscope.During the surgery,the cardiac deformation is significant,the latest location of malformation cannot be obtained by navigation system.Therefore,we used augmented reality to uniformly display virtual and actual malformation structures.We fixed a flexible endoscope and an electromagnetic sensor and calibrate them for tracking endoscope in real time.According to the results of registration,it is transformed into the image space,and finally the virtual model will be superimposed on the real surgical scene taken by the endoscope to achieve the effect of augmented reality.According to the model experiment,the localization technology of congenital heart disease malformations based on electromagnetic navigation and augmented reality can precisely present the location and structure of the current malformation.It can solve some problems in traditional congenital heart disease surgery and improve the efficiency of surgery.