© NIH National Center for Image-Guided Therapy Image-Registered Ultrasound Jeffrey Stoll, NCIGT, CIMIT Kirby Vosburgh, CIMIT

© NIH National Center for Image-Guided Therapy IGT Data Flow 3D ModelsResampled CTUltrasound Image Computer Tracking transmitter on OR table calibration registration segmentation

© NIH National Center for Image-Guided Therapy Real-time Display 3D models Vascular anatomy forms a road map in the abdomen; good for correlation with ultrasound (doppler, movement, etc.)‏ Aorta and kidneys are retroperitoneal; limited motion CT reformatting Accuracy is relaxed without need for overlays Fast display no display lag; good for physicians threaded data recording IRUS data capture class

© NIH National Center for Image-Guided Therapy Tracking Embedding trackers in instruments – laparoscopic ultrasound, flexible endoscopes (multiple trackers) Currently organizing human trials

© NIH National Center for Image-Guided Therapy Segmentation/Registration Segmentation method - manual thresholding and level sets; >1 hr Registration method – fiducial-based initial, image-based update optimal fiducials via CT online registration via US/CT phase correlation registration to anatomical atlas unsupervised segmentation in CT for model construction (ribs, kidneys, vessels)‏ (collaborating with Kilian Pohl)‏ online kidney segmentation in US (collaborating with Marcos Fernandez, Madrid, Spain)‏ Goals: Goals: fast results, sufficient accuracy for application

© NIH National Center for Image-Guided Therapy Clinical Example: IRFAST Image-Registered Focused Assesment with Sonography for Trauma Detects internal hemorrhage Gates surgical exploration/intervention Minimal preparation Goals improve accuracy enable use in field by first responders Benefits Shows user where to scan Shows physician where images were taken

© NIH National Center for Image-Guided Therapy Kinematics Analysis Analyze motion of instruments to determine operator skill High novice/expert specificity with few subjects Factors: time, path length, depth perception, jerk, rotation Compare results to known experts: z-score Useful tool for evaluating IGI applications Notes Experts tend to have low jerk and rotation, not always shortest path or time Depth perception is particularly useful for evaluating IGI Example result - IRGUS

© NIH National Center for Image-Guided Therapy Topics for Slicer Real-time processing online and/or unsupervised segmentation online/fast tracking registration Unconstrained data collection robust anatomy-based registration varying patient positions leads to organ deformation patient atlases, generic models