Guiding Vascular Access with the Sonic Flashlight - Preclinical Development and Validation

This dissertation concerns the development of a device called the Sonic Flashlight, which employs a novel method for viewing real-time ultrasound images inside the body exactly at the location where it is being scanned. While other augmented reality methods have previously been developed to view ultrasound and other medical imaging modalities within the body, they are generally much more complicated, slower and less robust than the Sonic Flashlight.In this dissertation, we aim to develop the Sonic Flashlight towards one particular clinical application, central vascular access, and lay the groundwork leading to the first clinical trials. The goal of central vascular access is to insert a catheter into a major vein to deliver medications in large quantities. These veins are usually not visible to the naked eye, so real-time ultrasound is employed to guide the needle into them. While real-time ultrasound guidance significantly enhances the safety of central venous access, learning this skill can be a challenge for the novice user, one major obstacle being the displaced sense of hand-eye coordination that occurs when the operator must look away from the operating field to view the conventional ultrasound monitor.We developed the 5th generation Sonic Flashlight, as well as a novel calibration method, called thin-gel calibration, as part of this dissertation. The thin-gel system allows us to accurately calibrate the Sonic Flashlight and measure the calibration accuracy. Finally, experiments were conducted with a variety of subject populations using vascular ultrasound phantoms and cadavers to validate Sonic Flashlight guidance, demonstrating that the device is ready for clinical trials

Development and evaluation of a novel method for in-situ medical image display

Three-dimensional (3D) medical imaging, including computed tomography (CT) and magnetic resonance (MR), and other modalities, has become a standard of care for diagnosis of disease and guidance of interventional procedures. As the technology to acquire larger, more magnificent, and more informative medical images advances, so too must the technology to display, interact with, and interpret these data.This dissertation concerns the development and evaluation of a novel method for interaction with 3D medical images called "grab-a-slice," which is a movable, tracked stereo display. It is the latest in a series of displays developed in our laboratory that we describe as in-situ, meaning that the displayed image is embedded in a physical 3D coordinate system. As the display is moved through space, a continuously updated tomographic slice of a 3D medical image is shown on the screen, corresponding to the position and orientation of the display. The act of manipulating the display through a "virtual patient" preserves the perception of 3D anatomic relationships in a way that is not possible with conventional, fixed displays. The further addition of stereo display capabilities permits augmentation of the tomographic image data with out-of-plane structures using 3D graphical methods.In this dissertation we describe the research and clinical motivations for such a device. We describe the technical development of grab-a-slice as well as psychophysical experiments to evaluate the hypothesized perceptual and cognitive benefits. We speculate on the advantages and limitations of the grab-a-slice display and propose future directions for its use in psychophysical research, clinical settings, and image analysis

Integrating images from a moveable tracked display of three-dimensional data

abstract: This paper describes a novel method for displaying data obtained by three-dimensional medical imaging, by which the position and orientation of a freely movable screen are optically tracked and used in real time to select the current slice from the data set for presentation. With this method, which we call a “freely moving in-situ medical image”, the screen and imaged data are registered to a common coordinate system in space external to the user, at adjustable scale, and are available for free exploration. The three-dimensional image data occupy empty space, as if an invisible patient is being sliced by the moving screen. A behavioral study using real computed tomography lung vessel data established the superiority of the in situ display over a control condition with the same free exploration, but displaying data on a fixed screen (ex situ), with respect to accuracy in the task of tracing along a vessel and reporting spatial relations between vessel structures. A “freely moving in-situ medical image” display appears from these measures to promote spatial navigation and understanding of medical data.The electronic version of this article is the complete one and can be found online at: http://cognitiveresearchjournal.springeropen.com/articles/10.1186/s41235-017-0069-

Augmented Reality Ultrasound Guidance in Anesthesiology

Real-time ultrasound has become a mainstay in many image-guided interventions and increasingly popular in several percutaneous procedures in anesthesiology. One of the main constraints of ultrasound-guided needle interventions is identifying and distinguishing the needle tip from needle shaft in the image. Augmented reality (AR) environments have been employed to address challenges surrounding surgical tool visualization, navigation, and positioning in many image-guided interventions. The motivation behind this work was to explore the feasibility and utility of such visualization techniques in anesthesiology to address some of the specific limitations of ultrasound-guided needle interventions. This thesis brings together the goals, guidelines, and best development practices of functional AR ultrasound image guidance (AR-UIG) systems, examines the general structure of such systems suitable for applications in anesthesiology, and provides a series of recommendations for their development. The main components of such systems, including ultrasound calibration and system interface design, as well as applications of AR-UIG systems for quantitative skill assessment, were also examined in this thesis. The effects of ultrasound image reconstruction techniques, as well as phantom material and geometry on ultrasound calibration, were investigated. Ultrasound calibration error was reduced by 10% with synthetic transmit aperture imaging compared with B-mode ultrasound. Phantom properties were shown to have a significant effect on calibration error, which is a variable based on ultrasound beamforming techniques. This finding has the potential to alter how calibration phantoms are designed cognizant of the ultrasound imaging technique. Performance of an AR-UIG guidance system tailored to central line insertions was evaluated in novice and expert user studies. While the system outperformed ultrasound-only guidance with novice users, it did not significantly affect the performance of experienced operators. Although the extensive experience of the users with ultrasound may have affected the results, certain aspects of the AR-UIG system contributed to the lackluster outcomes, which were analyzed via a thorough critique of the design decisions. The application of an AR-UIG system in quantitative skill assessment was investigated, and the first quantitative analysis of needle tip localization error in ultrasound in a simulated central line procedure, performed by experienced operators, is presented. Most participants did not closely follow the needle tip in ultrasound, resulting in 42% unsuccessful needle placements and a 33% complication rate. Compared to successful trials, unsuccessful procedures featured a significantly greater (p=0.04) needle-tip to image-plane distance. Professional experience with ultrasound does not necessarily lead to expert level performance. Along with deliberate practice, quantitative skill assessment may reinforce clinical best practices in ultrasound-guided needle insertions. Based on the development guidelines, an AR-UIG system was developed to address the challenges in ultrasound-guided epidural injections. For improved needle positioning, this system integrated A-mode ultrasound signal obtained from a transducer housed at the tip of the needle. Improved needle navigation was achieved via enhanced visualization of the needle in an AR environment, in which B-mode and A-mode ultrasound data were incorporated. The technical feasibility of the AR-UIG system was evaluated in a preliminary user study. The results suggested that the AR-UIG system has the potential to outperform ultrasound-only guidance

The Effect of Augmented Reality Treatment on Learning, Cognitive Load, and Spatial Visualization Abilities

This study investigated the effects of Augmented Reality (AR) on learning, cognitive load and spatial abilities. More specifically, it measured learning gains, perceived cognitive load, and the role spatial abilities play with students engaged in an astronomy lesson about lunar phases. Research participants were 182 students from a public university in southeastern United States, and were recruited from psychology research pool. Participants were randomly assigned to two groups: (a) Augmented Reality and Text Astronomy Treatment (ARTAT); and (b) Images and Text Astronomy Treatment (ITAT). Upon entering the experimental classroom, participants were given (a) Paper Folding Test to measure their spatial abilities; (b) the Lunar Phases Concept Inventory (LPCI) pre-test; (c) lesson on Lunar Phases; (d) NASA-TLX to measure participants’ cognitive load; and (e) LPCI post-test. Statistical analysis found (a) no statistical difference for learning gains between the ARTAT and ITAT groups; (b) statistically significant difference for cognitive load; and (c) no significant difference for spatial abilities scores

Ultrasound-Augmented Laparoscopy

Laparoscopic surgery is perhaps the most common minimally invasive procedure for many diseases in the abdomen. Since the laparoscopic camera provides only the surface view of the internal organs, in many procedures, surgeons use laparoscopic ultrasound (LUS) to visualize deep-seated surgical targets. Conventionally, the 2D LUS image is visualized in a display spatially separate from that displays the laparoscopic video. Therefore, reasoning about the geometry of hidden targets requires mentally solving the spatial alignment, and resolving the modality differences, which is cognitively very challenging. Moreover, the mental representation of hidden targets in space acquired through such cognitive medication may be error prone, and cause incorrect actions to be performed. To remedy this, advanced visualization strategies are required where the US information is visualized in the context of the laparoscopic video. To this end, efficient computational methods are required to accurately align the US image coordinate system with that centred in the camera, and to render the registered image information in the context of the camera such that surgeons perceive the geometry of hidden targets accurately. In this thesis, such a visualization pipeline is described. A novel method to register US images with a camera centric coordinate system is detailed with an experimental investigation into its accuracy bounds. An improved method to blend US information with the surface view is also presented with an experimental investigation into the accuracy of perception of the target locations in space

The future of portable ultrasound : business strategies for survival

Thesis (S.M. in System Design and Management)--Massachusetts Institute of Technology, Engineering Systems Division, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 63-68).The growth of healthcare costs in the USA, coupled with the desire for access to care in the developing world, is driving the need for low cost, high quality imaging services. The miniaturization of signal processing electronics continues to reduce the size and cost of ultrasound devices. This convergence of demand and technology has led to the rise of portable ultrasound products, disrupting the entire industry. Market share for conventional cart-based systems is being eroded by compact mobile devices. This threatens the large, multi-modality imaging companies as more focused competitors, such as SonoSite, rise to dominate the portable market. New companies continue to arrive with innovative portable products, while domestic companies in emerging markets arise with low cost devices targeting local demand. In the face of these changes, what should companies do to adapt their business strategies and compete? In short, the established companies need to disrupt themselves and develop a portfolio of portable products. GE seems to have already acknowledged this reality and embraced the disruptive trend. Products with modular architectures will help companies reduce product cost and increase cycle times, improving their competiveness in an increasingly crowded space. SonoSite will need to find a wealth of resources to maintain its advantage, ideally leveraging the strong brand name that it has established. Looking to the future of this disruptive cycle, companies need to embrace new business models for low cost products. Verathon's line of application specific products may be a glimpse into the future. In addition, in response to this need for, and trend towards, low cost devices, some companies, such as GE, have created a new segment of pocket portable ultrasound devices: a "visual stethoscope" that could be in the hand of every doctor. Will this type of device succeed? The reality is that they will find mixed success. Disintegrated health systems, the predominant type in the USA, present a challenging environment for value capture and will only embrace these products once they become significantly cheaper and demonstrate success as a process improvement tool. Integrated health systems, more common globally, will slowly embrace them as a screening tool. Companies in this product category need to be in it for the long haul and focus on the compelling applications in the EMT/paramedic market segment to achieve short-term success.by Matthew Richard Thompson.S.M.in System Design and Managemen

Recent advances in robot-assisted echography: Combining perception, control and cognition

Echography imaging is an important technique frequently used in medical diagnostics due to low-cost, non-ionising characteristics, and pragmatic convenience. Due to the shortage of skilful technicians and injuries of physicians sustained from diagnosing several patients, robot-assisted echography (RAE) system is gaining great attention in recent decades. A thorough study of the recent research advances in the field of perception, control and cognition techniques used in RAE systems is presented in this study. This survey introduces the representative system structure, applications and projects, and products. Challenges and key technological issues faced by the traditional RAE system and how the current artificial intelligence and cobots attempt to overcome these issues are summarised. Furthermore, significant future research directions in this field have been identified by this study as cognitive computing, operational skills transfer, and commercially feasible system design