Automatic patient positioning based on robot rotational workspace for extended reality.

PURPOSE: Understanding the properties and aspects of the robotic system is essential to a successful medical intervention, as different capabilities and limits characterize each. Robot positioning is a crucial step in the surgical setup that ensures proper reachability to the desired port locations and facilitates docking procedures. This very demanding task requires much experience to master, especially with multiple trocars, increasing the barrier of entry for surgeons in training. METHODS: Previously, we demonstrated an Augmented Reality-based system to visualize the rotational workspace of the robotic system and proved it helps the surgical staff to optimize patient positioning for single-port interventions. In this work, we implemented a new algorithm to allow for an automatic, real-time robotic arm positioning for multiple ports. RESULTS: Our system, based on the rotational workspace data of the robotic arm and the set of trocar locations, can calculate the optimal position of the robotic arm in milliseconds for the positional and in seconds for the rotational workspace in virtual and augmented reality setups. CONCLUSIONS: Following the previous work, we extended our system to support multiple ports to cover a broader range of surgical procedures and introduced the automatic positioning component. Our solution can decrease the surgical setup time and eliminate the need to repositioning the robot mid-procedure and is suitable both for the preoperative planning step using VR and in the operating room-running on an AR headset.

Validation of collaborative cyberspace virtual reality oculometry enhanced with near real-time spatial audio.

Currently, most medical image data, such as optical coherence tomography (OCT) images, are displayed in two dimensions on a computer screen. Advances in computer information technology have contributed to the growing storage of these data in electronic form. However, the data are usually processed only locally on site. To overcome such hurdles, a cyberspace virtual reality (csVR) application was validated, in which interactive OCT data were presented simultaneously to geographically distant sites (Lucerne, London, and Barcelona) where three graders independently measured the ocular csVR OCT diameters. A total of 109 objects were measured, each three times, resulting in a total of 327 csVR measurements. A minor mean absolute difference of 5.3 µm was found among the 3 measurements of an object (standard deviation 4.2 µm, coefficient of variation 0.3% with respect to the mean object size). Despite the 5 h of online work, csVR was well tolerated and safe. Digital high-resolution OCT data can be remotely and collaboratively processed in csVR. With csVR, measurements and actions enhanced with spatial audio communication can be made consistently in near real time, even if the users are situated geographically far apart. The proposed visuo-auditory framework has the potential to further boost the convenience of digital medicine toward csVR precision and collaborative medicine.

Prognostic value of myocardial perfusion imaging after first-line coronary computed tomography angiography: A multi-center cohort study.

PURPOSE: Further diagnostic testing may be required after a coronary computed tomography angiography (CTA) showing suspected coronary stenosis. Whether myocardial perfusion imaging (MPI) provides further prognostic information post-CTA remains debated. We evaluated the prognosis for patients completing CTA stratified for post-CTA diagnostic work-up using real-world data. METHODS: We identified all patients in our uptake area with angina symptoms undergoing first-time CTA over a 10-year period. Follow-up time was a median of 3.7 years [1.9-5.8]. The primary endpoint was a composite of myocardial infarction or death. The secondary endpoint was late revascularization. RESULTS: During the study period 53,351 patients underwent CTA. Of these, 24% were referred for further down-stream testing, 3,547 (7%) to MPI and 9,135 (17%) to invasive coronary angiography (ICA). The primary and secondary endpoints occurred in 2,026 (3.8%) and 954 (1.8%) patients. Patient-characteristic-adjusted hazard ratios for the primary and secondary endpoint using patients with a normal CTA as reference were 1.37 (1.21-1.55) and 2.50 (1.93-3.23) for patient treated medically, 1.68 (1.39-2.03) and 6.13 (4.58-8.21) for patients referred to MPI and 1.94 (1.69-2.23) and 9.18 (7.16-11.78) for patients referred for ICA, respectively. Adjusted analysis with stratification for disease severity at CTA showed similar hazard ratios for patients treated medically after CTA and patients referred for MPI and treated medically after the MPI. CONCLUSION: In patients completing coronary CTA, second-line MPI testing seems to identify patients at low risk of future events. MPI seems to have the potential to act as gatekeeper for ICA after coronary CTA.

The challenge in diagnosing cardiac tumors to avoid unnecessary cardiac surgery.

Cardiac magnetic resonance in cardiac mass: Cardiac magnetic resonance (CMR) should be considered in the evaluation of patients with cardiac mass. Especially, when the diagnosis is not certain, CMR could provide paramount information that could be helpful for the decision on cardiac surgery.

Implementation of coronary computed tomography angiography as nationally recommended first-line test in patients with suspected chronic coronary syndrome: impact on the use of invasive coronary angiography and revascularization.

AIMS: To investigate the impact of applying coronary computed tomography angiography (CCTA), as the recommended first-line diagnostic test in patients with suspected chronic coronary syndrome (CCS) on the use of invasive coronary angiography (ICA) and revascularization practice. METHODS AND RESULTS: We included all patients undergoing a first-time CCTA (n = 53555) and first-time ICA (n = 41451) from 2008 to 2017 due to suspected CCS in Western Denmark (3.3 million inhabitants). The number of CCTA procedures increased from 352 (2008) to 7739 (2017) (2098%), ICA examinations declined from 4538 to 3766 (17%). The average proportion of no- or non-obstructive coronary artery disease by CCTA was 77.5%. Referral to ICA after CCTA occurred in 16.9% of patients in 2008-10 vs. 13.9% in 2014-17 (P < 0.0001). Revascularization in patients referred to ICA after CCTA increased from 33.8% in 2008-10 vs. 44.4% in 2014-17 (P < 0.0001). The revascularization proportion in patients undergoing ICA with no preceding CCTA was 32.3% in 2008-10 vs. 33.3% in (2014-17) (P = 0.1063). Stratified by age, the overall revascularization proportion increased in the younger age groups and was unchanged or decreased in older age groups: <50 years: 60% increase, 50-59 years: 33% increase, 60-69 years: 0%, and >70 years: 9.5% decrease. CONCLUSION: The introduction of CCTA as a first-line diagnostic test in patients with suspected CCS does not associate with increased use of invasive angiography and seems to have facilitated a more appropriate revascularization practice.

Validation of virtual reality orbitometry bridges digital and physical worlds.

Clinical science and medical imaging technology are traditionally displayed in two dimensions (2D) on a computer monitor. In contrast, three-dimensional (3D) virtual reality (VR) expands the realm of 2D image visualization, enabling an immersive VR experience with unhindered spatial interaction by the user. Thus far, analysis of data extracted from VR applications was mainly qualitative. In this study, we enhance VR and provide evidence for quantitative VR research by validating digital VR display of computed tomography (CT) data of the orbit. Volumetric CT data were transferred and rendered into a VR environment. Subsequently, seven graders performed repeated and blinded diameter measurements. The intergrader variability of the measurements in VR was much lower compared to measurements in the physical world and measurements were reasonably consistent with their corresponding elements in the real context. The overall VR measurements were 5.49% higher. As such, this study attests the ability of VR to provide similar quantitative data alongside the added benefit of VR interfaces. VR entails a lot of potential for the future research in ophthalmology and beyond in any scientific field that uses three-dimensional data.

A computational model to design neural interfaces for lower-limb sensory neuroprostheses.

BACKGROUND: Leg amputees suffer the lack of sensory feedback from a prosthesis, which is connected to their low confidence during walking, falls and low mobility. Electrical peripheral nerve stimulation (ePNS) of upper-limb amputee's residual nerves has shown the ability to restore the sensations from the missing limb via intraneural (TIME) and epineural (FINE) neural interfaces. Physiologically plausible stimulation protocols targeting lower limb sciatic nerve hold promise to induce sensory feedback restoration that should facilitate close-to-natural sensorimotor integration and therefore walking corrections. The sciatic nerve, innervating the foot and lower leg, has very different dimensions in respect to upper-limb nerves. Therefore, there is a need to develop a computational model of its behavior in response to the ePNS. METHODS: We employed a hybrid FEM-NEURON model framework for the development of anatomically correct sciatic nerve model. Based on histological images of two distinct sciatic nerve cross-sections, we reconstructed accurate FEM models for testing neural interfaces. Two different electrode types (based on TIME and FINE) with multiple active sites configurations were tested and evaluated for efficiency (selective recruitment of fascicles). We also investigated different policies of stimulation (monopolar and bipolar), as well as the optimal number of implants. Additionally, we optimized the existing simulation framework significantly reducing the computational load. RESULTS: The main findings achieved through our modelling study include electrode manufacturing and surgical placement indications, together with beneficial stimulation policy of use. It results that TIME electrodes with 20 active sites are optimal for lower limb and the same number has been obtained for FINE electrodes. To interface the huge sciatic nerve, model indicates that 3 TIMEs is the optimal number of surgically implanted electrodes. Through the bipolar policy of stimulation, all studied configurations were gaining in the efficiency. Also, an indication for the optimized computation is given, which decreased the computation time by 80%. CONCLUSIONS: This computational model suggests the optimal interfaces to use in human subjects with lower limb amputation, their surgical placement and beneficial bipolar policy of stimulation. It will potentially enable the clinical translation of the sensory neuroprosthetics towards the lower limb applications.