IROS2019國(guó)際學(xué)術(shù)會(huì)議論文集 1894

Toward a Versatile Robotic Platform for Fluoroscopy and MRI Guided Endovascular Interventions A Pre Clinical Study Mohamed E M K Abdelaziz1 Dennis Kundrat1 Marco Pupillo1 Giulio Dagnino1 Trevor M Y Kwok2 Wenqiang Chi1 Vincent Groenhuis3 Franc oise J Siepel3 Celia Riga2 Stefano Stramigioli3 Guang Zhong Yang1 4 Abstract Cardiovascular diseases remain as the most com mon cause of death worldwide Remotely manipulated robotic systems are utilized to perform minimally invasive endovascular interventions The main benefi ts of this methodology include reduced recovery time improvement of clinical skills and procedural facilitation Currently robotic assistance precision and stability of instrument manipulation are compensated by the lack of haptic feedback and an excessive amount of radiation to the patient This paper proposes a novel master slave robotic platform that aims to bring the haptic feedback benefi t on the master side providing an intuitive user interface and clinical familiar workfl ow The slave robot is capable of manipulating conventional catheters and guidewires in multi modal imaging environments The system has been initially tested in a phantom cannulation study under fl uoroscopic guidance evaluating its reliability and procedural protocol As the slave robot has been entirely produced by additive manufacturing and using pneumatic actuation MR compatibility is enabled and was evaluated in a preliminary study Results of both studies strongly support the applicability of the robot in different imaging environments and prospective clinical translation I INTRODUCTION Cardiovascular diseases CVDs are a global health threat accounting for one third of all deaths 17 9 million each year worldwide 1 CVDs are disorders and diseases af fecting the heart or blood vessels which lead to heart attacks and strokes However with the combined efforts of surgeons radiologists cardiologists physicists and engin eers endovascular interventions have become a mainstay of treatment for vascular diseases These minimally invasive and image guided treatments are performed by manipulating thin and fl exible instruments catheters and guidewires to targeted blood vessels combined with different treatment options including stenting embolization and ablation These procedures not only reduce the recovery time of patients they also decrease operating time hospitalization and overall time to recovery Recently there has been a growing interest in robotic platforms that can perform the tasks mentioned above Compared to manual interventions these systems can improve precision stability and comfort eliminating physiological tremor and reducing radiation exposure both for patients and operators Research supported by the UK EPSRC EP N024877 1 1M E M K Abdelaziz D Kundrat M Pupillo G Dagnino W Chi G Z Yang are with The Hamlyn Centre for Robotic Surgery Imperial College London UK e mail m abdelaziz16 imperial ac uk 2T M Y Kwok and C Riga are with the Faculty of Medicine Department of Surgery and Cancer Imperial College London UK 3V Groenhuis F J Siepel and S Stramigioli are with Robotics and Mechatronics University of Twente Enschede Netherlands 4 G Z Yang is also affi liated with the Institute of Medical Robotics Shanghai Jiao Tong University China Fig 1 Novel robotic platform with versatile MR safe slave robot right and intuitive master device left for endovascular interventions A State of the Art A variety of robotic systems for endovascular or cardiac catheterization were reported in research or translated to commercialisation In general such systems show low levels of robotic autonomy 2 and consider a master slave set up for teleoperated manipulation of instrumentation Com mercial systems targeting different fi elds of application in endovascular and cardiac cases comprise the Magellan and Sensei R X2 platforms AurisHealth Redwood city CA USA the Amigo platform Catheter Precision Mt Olive NJ USA the R one TM robot Robocath Rouen France or the CorPath R GRX platform Corindus Waltham MA USA The corresponding master with human machine in terfaces HMI make use of conventional stationary joy sticks hand held joysticks or 3D input devices with force feedback capabilities Commercial platforms enable electro mechanical manipulation of customised steerable catheters and guidewires in up to 6 degrees of freedom DOF and were successfully used in clinical scenarios 3 6 Novel master devices were proposed to improve the transparency of teleoperation Exemplary motion due to manipulation of standard catheters was sensed without user feedback and replicated to a slave robot 7 More recently magnetorhe ological fl uid was used in combination with a catheter to mimic friction and generate user feedback 8 Slave robots generally show alternative concepts with different electro mechanical mechanisms for driving and clamping of instru mentation as reported in 9 11 Device compliance with MR environments is restricted to 12 13 and focuses on steerable catheters For the sake of completeness the reader is kindly referred to a comprehensive review of devices 14 B Limitations 4 where scat insand sgw insare the executable insertion strokes of the catheter and guidewire respectively b1is the width of platforms P1 and P4 b2is the width of platform P2 lrackis the total length of the rack as shown in Fig 3 For retraction scat ret xs 2 pb2 xs 4q 5 sgw ret xs 4 b1 6 where scat retand sgw retare the achievable retraction strokes 5414 of the catheter and guidewire respectively Boundary condi tions of positions xs 2and xs 4are pb1 b2q xs 2 lrack b1 7 b1 xs 4 pb1 b2q 8 5 Fabrication The parts of the slave robot were printed with Objet 500 Connex3 Stratasys Ltd Eden Prairie MN USA in materials VeroClear and VeroBlack standard quality glossy fi nish The seals were laser cut from 0 5mm silicone rubber Silex Ltd Bordon UK The moving parts were lubric ated and the motor clamp housings and covers were glued together Polyetheretherketone PEEK fasteners were used to assemble components and pairs of epoxy glass rods 10mm and PEEK rods 6mm were used to guide the platforms Misumi Europa GmbH Frankfurt Germany 6 MRI Compatibility Since the robot is composed of materials that are elec trically non conductive non metallic and non magnetic it complies with the MR Safe classifi cation of the American Society for Testing and Materials ASTM standard F2503 A preliminary MR study was conducted as presented in Sec V C IV CONTROL ARCHITECTURE The system control architecture is based on the integration of the robotic system in Sec III with subsequently de scribed navigation system which includes real time image guidance and haptic feedback This confi guration provides the following benefi ts 1 the surgeon is always in control of the procedure by teleoperating the slave robot through the master manipulator 2 real time navigation and haptic feedback guides the surgeon throughout the procedure in creasing the instrument manipulation accuracy and minim ising endothelial damages to the vessel wall thus potentially improving the overall safety of the procedure The control architecture employs a host target structure based on a PC host and two real time controllers with FPGA targets The PC Windows 7 Intel i7 6700 3 4GHz 16GB RAM runs the navigation system GUI 30Hz while the two real time controllers compactRIO 9022 National Instruments Austin TX USA run the control algorithms 1kHz for the haptic master device 1st target and the slave robot 2nd target The host PC and the targets communicate via Ethernet User inputs are captured by the master manip ulator and processed by the control algorithms to generate corresponding motion commands on the slave robot which replicates the input into the surgical fi eld The overall system architecture is summarised in Fig 5 a and further described below A Navigation System The navigation system introduced in 18 has two main functions 1 receive and display in real time the intra operative video of the surgical scene on a GUI and 2 gen erate dynamic active constraints with safety margins adapt ively enforced in real time to constrain the catheter motion for vision based haptic feedback A real time video stream of the surgical scene is acquired using an image grabber DVI2USB3 Epiphan Video Ottawa Canada from a vas cular imaging system in this study we used a fl uoroscopic system for interventional radiology procedure Innova 4100 IQ GE Healthcare Chicago Il USA The video stream is displayed on the navigation system GUI and processed to generate vision based haptic feedback The matching pattern algorithm NI Vision 2018 National Instruments Austin TX USA introduced in 18 was improved to track both catheter and guidewire in a fl uoroscopy video stream providing tip position in pixels and orientation in degrees The vessel wall is dynamically tracked using the vessel tracker algorithm described in 18 Data from instrument and vessel trackers are used to generate and render vision based haptic feedback to the master device The clinical user perceives a viscous friction which increases proportionally to the instrument vessel distance i e the closer the instrument is to the vessel the higher is the generated force feedback The viscous friction is modelled for both DOF as 9 xM 1 d IM t 9 9 M 1 d IM a 10 where IM tand IM aare surgeon inputs i e currents of the linear and rotary motor when a force is applied on the user handle 9 xMand 9 Mare control outputs i e nominal master motor velocity and d 0 is the damping of the virtual contacts i e dis generated by the proximity of the catheter tip to the vessel wall and by the direction and orientation of motion of the catheter with respect to the vessel wall A comprehensive description is provided in 18 and summarised as follows 1 The viscous friction is minimum if the instrument is located in the centre of the vessel and not pointing toward the vessel wall 2 The viscous friction increases if the instrument wall distance is closer and moving toward the vessel wall B Robot Control Master velocities related to user input and navigation in Eq 9 and Eq 10 are mapped to the slave robot with 9 q S j 9 xS 2j 1 9 xS 2j 9 R j 10 10 01 looomooon B S t 0 0Sr loooomoooon S 9 xM 9 M 11 where matrix S P R2 2applies input scaling for translation and rotation with user adaptive scalars StP R 0and SrP R 0 B P R3 2describes a selection matrix to sync both linear motors during feeding and retraction and j t1 2u According to the user selection velocities are computed for actuators driving the catheter pj 1q or guidewire manip ulator pj 2q Hence nominal frequencies of pulse width modulated PWM signal pairs for dual valve control see Sec III B of each linear motor i yield to fS i 9 xS i stwith i t1 4u and for each rotary motor to fS k 9 S k sa with k t1 2u Phase shift 0 25 within signal pairs and duty cycle 0 5 are constant parameters of the corresponding period 21 The maximum frequency for safe operating conditions of actuators is set to fmax 35Hz 5415 Fig 5 a Control architecture and b experimental set up for fl uoroscopy based trials where 1 Vascular phantom 2 Pulsatile and continuous fl ow pump 3 Slave robot 4 C arm 5 Force Torque sensor which allows linear actuator velocities of 9 xmax 10mms 1 and angular velocities of 9 max 300 s 1 The 12 channel PWM output is implemented on FPGA level for reliable timing V EXPERIMENTALVALIDATION A Clinical Workfl ow and Set Up for Robotics Procedure The main system architecture is shown in Fig 5 a The master device is placed in the control room of the CathLab together with the host PC running the navigation system The latter is connected to the vascular imaging system to grab the surgical video display it on the navigation GUI and perform image processing as described in Sec IV Pneumatic valves real time controllers and air compressor are placed in the control room as well Plastic tubes to connect valves and slave robot are passed through the wall between the control and patient rooms The robotic slave is located on the surgical table in the patient room as depicted in Fig 5 a close to the patient This confi guration presents two major benefi ts 1 it allows the surgeon to perform the procedure from the control room thus not being exposed to radiation when x ray guidance is used 2 it allows to perform an MRI guided procedure by locating the entire hardware in the control room except of the MR safe slave robot When the robotic set up is completed the surgeon enters the patient room and manually accesses the arterial system as in a conventional procedure e g through the femoral artery Once vascular access is gained the instruments catheter and guidewire are connected to the slave robot and the surgeon performs the surgical procedure using the master device from the control room If needed the procedure can be reverted to manual in a few seconds by quickly releasing the instruments from the slave as shown in the supplemental video B X Ray Fluoroscopy Pre Clinical Trials This section discusses the experimental set up and methods undertaken to validate the robot in a number of simulated clinical scenarios which involved a series of arterial cannu lation maneuvers performed by a qualifi ed vascular surgeon both with the robot i e using the clinical workfl ow above and manually i e using conventional techniques without the robot under fl uoroscopy guidance Experiments were conducted in a research angiography theatre Northwick Park Hospital London UK The experimental set up was as shown in Fig 5 b A vascular phantom a semi radiolucent soft silicone full scale model of a normal adult human aortic arch Elastrat Geneva Switzerland was rigidly coupled to 6 DOF force torque sensor Mini40 ATI Industrial Automa tion Apex NC USA to measure forces 25Hz applied to the vascular model during the procedure This apparatus was placed underneath an x ray imaging system Innova 4100 IQ GE Healthcare Barrington IL USA to simulate a patient lying on the angiography table to undergo an endovascu lar procedure The robot was then positioned and oriented relative to the phantom to simulate access into the arterial system via the femoral artery The phantom was connected to a pulsatile pump to simulate normal human blood fl ow To reduce the effect of a learning curve the operator was given a familiarization period of 6min to manipulate the guidewire and catheter within the setup both manually and with the robot A single guidewire Radifocus Guide Wire M 035 180cm angled Terumo Tokyo Japan and catheter Beacon Tip 5 Fr VanSchie2 Cook Medical Bloomington IN USA were used throughout the experiment The operator was then asked to perform in turn by manipulation of wire and catheter cannulation of 3 arteries with increasing diffi culty in the following order the left subclavian LSA left common carotid LCCA and right common carotid RCCA arteries Each task consisted of traversing the descending aorta navigating the aortic arch and fi nally cannulating the artery At the start of the experiment a coin toss was used to determine whether the fi rst maneuver would be robotic or manual The operator performed cannulation of the nominated artery 4 times with the determined modality i e robot or manual each time guidewire and catheter were returned to a standard starting position in the descending aorta The task is repeated with the second modality Attention was then turned to the next artery and the above sequence was repeated Modality was not changed upon moving to a new artery so that at least one artery would be cannulated with the robot fi rst and at least one would be cannulated manually fi rst During each maneuver fl uoroscopy was activated by the operator using a pedal The feed from the video display of the imaging system the time taken for the maneuver and fl uoroscopy time were recorded Within each sequence of 4 arterial cannulations the fi rst maneuver was excluded from the analysis to minimize the effect of a learning curve For each artery modality pair means and standard deviations 5416 LSALCCARCCA ManualRoboticManualRoboticManualRobotic Mean force pNq0 37 0 210 18 0 090 59 0 220 28 0 120 68 0 330 35 0 18 Maximum force pNq1 01 0 410 37 0 041 45 0 090 68 0 221 85 0 891 10 0 29 Cannulation time psq6 7 4 550 0 28 332 0 2 865 0 10 858 3 24 943 7 15 0 Fluoroscopy time psq9 7 7 3134 0 48 669 3 31 6302 0 56 086 7 31 4189 3 9 0 TABLE I Results of fl uoroscopy pre clinical trials mean SD Bold values indicate statistically signifi cant results p 0 05 according to Student s t test were compared for time taken for cannulation fl uoroscopy time mean overall force and mean maximum force Results are summarised in Tab I and discussed in Sec VI C MRI Preliminary Study To demonstrate the versatility and MRI compatibility of the slave robot a preliminary study was conducted in an MRI scanner The robot was placed in an Achieva 3T MR imaging system Philips Healthcare Best the Netherlands equipped with a SENSE Torso coil with 16 elements and placed adjacent to a plastic phantom of abdominal aorta fi lled with water Elastrat S arl Geneva Switzerland The phantom was placed inside the coil at the isocenter of the scanner as shown in Fig 6 a With this setup an MR conditional guidewire EPfl ex GmbH Dettingen Germany was initially manipulated manually and then robotically The guidewire consists of passive negative paramagnetic MR markers at discrete steps of 5 cm which provide MRI visibility The images were acquired using a 2D imaging sequence with a large slice thickness to project the guidewire and anatomy onto a plane emulating a fl uoroscopic projection The 2D imaging sequence used was a real time 2D Turbo Spin Echo TSE with the shortest possible echo spacing The MRI acquisition settings were Echo Time TE 35ms Repetition Time TR 536ms Field of View FOV p300 142qmm2 Slice thickness 100mm Slice Orientation coronal Dynamic scans 100 Total scan duration 55 2s VI DISCUSSION A Fluoroscopy Pre clinical Trials Results Results reported in Tab I