Research On Visual Telepresence Technology Of Endovascular Minimally Invasive Surgery

Endovascular minimally invasive surgery (MIS) is a new kind of method tointervene medical catheter through blood vessel to perform the diagnosis andtreatment. This kind of surgery has the merits of small wound, rapid recovery, safetyand reliablility when compared with traditional open surgery. At present, MIS isimplemented under the real-time X-ray image which is a2dimension projectionmap.Therefore, multiple vascular images overlapped and surgeons have to imaginethe motion of catheter in the vessel. To solve this problem, our research team hasdeveloped an image navigation system. The three dimension vessel model in it wasreconstructed from MRI, which can display the vessel structure clearly. Thereal-time catheter position and orientation information transmitted from theelectromagnetic positioning tracking equipment. In real MIS environment, not onlythe position of catheter is changed real-timely, but also the vessel and blood is indynamic state. So in this paper, based on the cardiovascular biodynamics, real-timedynamic vessel model has been constructed, then the visualization of the blood flowfield has been researched and dynamic vector blood model and particle blood modelhave been built based on the field, which add visual telepresence function to theimage navigation system.The composition and mechanics characteristic of the vessel, the pulse wave, therelationship between pulse wave and electrocardio signals and three kind ofmathematics model of blood and vessel have been introduced, which have been thetheoretical foundation of building the vessel and blood model.Dynamic vessel model has been built based on the pulse signals. Solution ofsampling and transmitting pulse signals by cardiac cycle has been designed based onthe synchronous relationship of the pulse wave and electrocardio wave. Simulationexperiment has been done to validate the solution. Based on the sampling pulsesignals, real-time vessel model has been built on the3dimension vessel surfacemodels. The synchronism and accuracy of the dynamic model has been validated bycomputing the bias of input and output signals which got from the result ofexperiment.Dynamic blood model has been built based on the pulse signals. An algorithmis presented for establishing transient blood flow field in the vessel combining thewomersley theory and pulse signals. This algorithm was validated by the result ofthe blood fluid finite element analysis. Based on the transient blood flow field,dynamic blood vector model and blood particle model have been built.Finally, the vessel model, vector blood model, particle blood model and pulse wave graph have been integrated to the former image navigation system.Consequently, the image navigation system of MIS owned the function of visiontelepresence, which can not only present the real-time dynamic vessel model, bloodmodel and catheter model, but also display the abstract blood pressure and bloodvelocity in graph and icons. This function helps the surgeons perceive the operationenvironment and provides important reference for the surgeons in operationdetermination.