Rôle of contrast media viscosity in altering vessel wall shear stress and relation to the risk of contrast extravasations

Iodinated contrast media (CM) are the most commonly used injectables in radiology today. A range of different media are commercially available, combining various physical and chemical characteristics (ionic state, osmolality, viscosity) and thus exhibiting distinct in vivo behaviour and safety profiles. In this paper, numerical simulations of blood flow with contrast media were conducted to investigate the effects of contrast viscosity on generated vessel wall shear stress and vessel wall pressure to elucidate any possible relation to extravasations. Five different types of contrast for Iodine fluxes ranging at 1.5–2.2 gI/s were modelled through 18 G and 20 G cannulae placed in an ideal vein at two different orientation angles. Results demonstrate that the least viscous contrast media generate the least maximum wall shear stress as well as the lowest total pressure for the same flow rate. This supports the empirical clinical observations and hypothesis that more viscous contrast media are responsible for a higher percentage of contrast extravasations. In addition, results support the clinical hypothesis that a catheter tip directed obliquely to the vein wall always produces the highest maximum wall shear stress and total pressure due to impingement of the contrast jet on the vessel wall

Exploring the Development Requirements for Virtual Reality Gait Analysis

The hip joint is highly prone to traumatic and degenerative pathologies resulting in irregular locomotion. Monitoring and treatment depend on high-end technology facilities requiring physician and patient co-location, thus limiting access to specialist monitoring and treatment for populations living in rural and remote locations. Telemedicine offers an alternative means of monitoring, negating the need for patient physical presence. In addition, emerging technologies, such as virtual reality (VR) and immersive technologies, offer potential future solutions through virtual presence, where the patient and health professional can meet in a virtual environment (a virtual clinic). To this end, a prototype asynchronous telemedicine VR gait analysis system was designed, aiming to transfer a full clinical facility within the patients’ local proximity. The proposed system employs cost-effective alternative motion capture combined with the system’s immersive 3D virtual gait analysis clinic. The user interface and the tools in the application offer health professionals asynchronous, objective, and subjective analyses. This paper investigates the requirements for the design of such a system and discusses preliminary comparative data of its performance evaluation against a high-fidelity gait analysis clinical application

Exploring the Development Requirements for Virtual Reality Gait Analysis

The hip joint is highly prone to traumatic and degenerative pathologies resulting in irregular locomotion. Monitoring and treatment depend on high-end technology facilities requiring physician and patient co-location, thus limiting access to specialist monitoring and treatment for populations living in rural and remote locations. Telemedicine offers an alternative means of monitoring, negating the need for patient physical presence. In addition, emerging technologies, such as virtual reality (VR) and immersive technologies, offer potential future solutions through virtual presence, where the patient and health professional can meet in a virtual environment (a virtual clinic). To this end, a prototype asynchronous telemedicine VR gait analysis system was designed, aiming to transfer a full clinical facility within the patients’ local proximity. The proposed system employs cost-effective alternative motion capture combined with the system’s immersive 3D virtual gait analysis clinic. The user interface and the tools in the application offer health professionals asynchronous, objective, and subjective analyses. This paper investigates the requirements for the design of such a system and discusses preliminary comparative data of its performance evaluation against a high-fidelity gait analysis clinical application

Design and implementation of augmented reality environment for complex anatomy training: inguinal canal case study

Adhering to contemporary requirements for reduction of cadaveric training of medical trainees we have developed a prototype augmented reality environment which investigates complex anatomical sections. A human 3D model has been implemented in order to facilitate educational tactics presented in a Virtual Reality (VR) environment. Opting for a sophisticated approach of interaction, the interface elements are based on simplified visual representation of real anatomical elements, and can be operated through haptic devices and surround auditory cues. This paper discusses the challenges involved in the development process of the augmented reality environment, and the HCI design, introduces the visual components of the interface and presents the outcome of a preliminary evaluation of the proposed VR training method on a group of twelve medical doctors. The paper concludes with a tentative plan of future work which aims to expand the context and interactivity of the system so as to enable the trainees to rehearse surgical methods in a simulated VR environment