Three-Dimensional Holographic Guidance, Navigation, and Control (3D-GNC) for Endograft Positioning in Porcine Aorta: Feasibility Comparison With 2-Dimensional X-Ray Fluoroscopy

Using a novel three-dimensional holographic technology to perform open vascular surgery procedures

Augmented reality technology has been introduced during recent years into everyday clinical practice. Several surgical specialties have begun using such technology for preoperative planning as well as intraoperatively. Regarding vascular surgery, a limited number of reports have described the benefits, mainly for endovascular procedures. We aim to present a novel three-dimensional holographic system we used to perform an open vascular procedure.

Topology observing 3D device reconstruction from continuous-sweep limited angle fluoroscopy

BACKGROUND

Minimally invasive procedures usually require navigating a microcatheter and guidewire through endoluminal structures such as blood vessels and airways to sites of the disease. For numerous clinical applications, two-dimensional (2D) fluoroscopy is the primary modality used for real-time image guidance during navigation. However, 2D imaging can pose challenges for navigation in complex structures. Real-time 3D visualization of devices within the anatomic context could provide considerable benefits for these procedures. Continuous-sweep limited angle (CLA) fluoroscopy has recently been proposed to provide a compromise between conventional rotational 3D acquisitions and real-time fluoroscopy.

PURPOSE

The purpose of this work was to develop and evaluate a noniterative 3D device reconstruction approach for CLA fluoroscopy acquisitions, which takes into account endoluminal topology to avoid impossible paths between disconnected branches.

METHODS

The algorithm relies on a static 3D roadmap (RM) of vessels or airways, which may be generated from conventional cone beam CT (CBCT) acquisitions prior to navigation. The RM is converted to a graph representation describing its topology. During catheter navigation, the device is segmented from the live 2D projection images using a deep learning approach from which the centerlines are extracted. Rays from the focal spot to detector pixels representing 2D device points are identified and intersections with the RM are computed. Based on the RM graph, a subset of line segments is selected as candidates to exclude device paths through disconnected branches of the RM. Depth localization for each point along the device is then performed by finding the point closest to the previous 3D reconstruction along the candidate segments. This process is repeated as the projection angle changes for each CLA image frame. The approach was evaluated in a phantom study in which a catheter and guidewire were navigated along five pathways within a complex vessel phantom. The result was compared to static cCBCT acquisitions of the device in the final position.

RESULTS

The average root mean squared 3D distance between CLA reconstruction and reference centerline was1.87 ± 0.30 $1.87 \pm 0.30$ mm. The Euclidean distance at the device tip was2.92 ± 2.35 $2.92 \pm 2.35$ mm. The correct pathway was identified during reconstruction in100 % $100\%$ of frames (n = 1475 $n=1475$ ). The percentage of 3D device points reconstructed inside the 3D roadmap was91.83 ± 2.52 % $91.83 \pm 2.52\%$ with an average distance of0.62 ± 0.30 $0.62 \pm 0.30$ mm between the device points outside the roadmap and the nearest point within the roadmap.

CONCLUSIONS

This study demonstrates the feasibility of reconstructing curvilinear devices such as catheters and guidewires during endoluminal procedures including intravascular and transbronchial interventions using a noniterative reconstruction approach for CLA fluoroscopy. This approach could improve device navigation in cases where the structure of vessels or airways is complex and includes overlapping branches.

Endovascular navigation in patients: vessel-based registration of electromagnetic tracking to preoperative images

Electromagnetic tracking of instruments combined with preoperative images can supplement fluoroscopy for guiding endovascular aortic repair (EVAR). The aim of this study was to evaluate the in-vivo accuracy of a vessel-based registration algorithm for matching electromagnetically tracked positions of an endovascular instrument to preoperative computed tomography angiography. Five patients undergoing elective EVAR were included, and a clinically available semi-automatic 3D-3D registration algorithm, based on similarity measures computed over the entire image, was used for reference. Accuracy was reported as target registration error (TRE) evaluated in manually selected anatomic landmarks on bony structures, placed close to the volume-of-interest. The median TRE was 8.2 mm (range: 7.1 mm to 16.1 mm) for the vessel-based registration algorithm, compared to 2.2 mm (range: 1.8 mm to 3.7 mm) for the reference algorithm. This illustrates that registration based on intraoperative electromagnetic tracking is feasible, but the accuracy must be improved before clinical use.

A New Method for Common Femoral Arterial Access Using a Mixed Reality-Assisted Technique on a Phantom Model

PURPOSE

The purpose of this study was to investigate the technical feasibility and usability of a mixed reality (MiR)-assisted common femoral arterial (CFA) access technique using a sonography-assisted registration method.

MATERIALS AND METHODS

A total of 60 CFA punctures were performed on a phantom model by 2 observers. Thirty punctures were performed using MiR (MiR group) and 30 punctures were performed using a conventional sonography-guided access procedure (control group). In the MiR group, a virtual object was created based on a computed tomography (CT) angiography scan of the model and registered to the physical patient in an MiR environment utilizing a software prototype that allowed registration based on a sonography scan. Positional error assessment encompassed 4 measurements using cone beam CT scans: (1) distance of the needle tip to the centerline, (2) distance of the needle entry site from the mid-level of the ostium of the profound femoral artery, (3) angle of entry of the needle in coronal, and (4) sagittal planes. Technical success rates as well as positional errors were compared between both groups. In addition, the usability of the system was assessed according to the system usability scale (SUS).

RESULTS

Technical success was 96.7% and 100% in the MiR and control groups, respectively. The median distance between the needle tip and the centerline was 3.0 (interquartile range [IQR]: 2.0-4.6) in the MiR group and 3.2 mm (IQR: 2.3-3.9) (p=0.63) in the control group. Similarly, the median distance from the needle entry site to the mid-level of the ostium of the profound femoral artery was 3.0 mm (IQR: 2.0-5.0) in the MiR group and 4.5 mm (IQR: 2.0-7.8) (p=0.18) in the control group. The median coronal angles of needle entry were 7.5° (IQR: 6-11) and 6° (IQR: 2-12) (p=0.13), and the median sagittal angles were 50° (IQR: 47-51) and 51° (IQR: 50-55) (p<0.01) in the MiR and control groups, respectively. The mean SUS score provided by both observers was 51.3.

CONCLUSION

The feasibility of an MiR-assisted CFA access technique could be demonstrated on a phantom model. Further studies are needed to investigate the technique beyond phantom model experiments and in different anatomical settings.

CLINICAL IMPACT

This study demonstrates the technical feasibility of a Mixed-Reality-assisted common femoral arterial access procedure on a phantom model. The positional accuracy was comparable to a conventional sonography-guided technique. However, there are several limitations that need to be resolved prior to potential implementation into clinical practice. Further studies are needed to investigate its performance beyond phantom model experiments and the prototypical application requires further technical refinement to increase its usability.

3D Visualisation of Navigation Catheters for Endovascular Procedures Using a 3D Hub and Fiber Optic RealShape Technology: Phantom Study Results

Objective

Fiber Optic RealShape (FORS) is a new technology that visualises the full three dimensional (3D) shape of guidewires using an optical fibre embedded in the device. Co-registering FORS guidewires with anatomical images, such as a digital subtraction angiography (DSA), provides anatomical context for navigating these devices during endovascular procedures. The objective of this study was to demonstrate the feasibility and usability of visualising compatible conventional navigation catheters, together with the FORS guidewire, in phantom with a new 3D Hub technology and to understand potential clinical benefits.

Methods

The accuracy of localising the 3D Hub and catheter in relation to the FORS guidewire, was evaluated using a translation stage test setup and a retrospective analysis of prior clinical data. Catheter visualisation accuracy and navigation success was assessed in a phantom study where 15 interventionists navigated devices to three pre-defined targets in an abdominal aortic phantom using an Xray or computed tomography angiography (CTA) roadmap. Additionally, the interventionists were surveyed about the usability and potential benefits of the 3D Hub.

Results

The location of the 3D Hub and catheter along the FORS guidewire was detected correctly 96.59% of the time. During the phantom study, all 15 interventionists successfully reached the target locations 100% of the time and the error in catheter visualisation was 0.69 mm. The interventionists agreed or strongly agreed that the 3D Hub was easy to use and the greatest potential clinical benefit over FORS is in offering interventionists choice over which catheter they used.

Conclusion

This set of studies has shown that FORS guided catheter visualisation, enabled by a 3D Hub, is accurate and easy to use in a phantom setting. Further evaluation is needed to understand the benefits and limitations of the 3D Hub technology during endovascular procedures.

Incidence, Prognostic Significance, and Risk Factors of Acute Kidney Injury Following Elective Infrarenal and Complex Endovascular Aneurysm Repair

OBJECTIVE

Acute kidney injury (AKI) is a well known complication following cardiovascular procedures. The objective was to assess the incidence, risk factors, and prognostic significance of AKI after infrarenal endovascular aneurysm repair (EVAR) and complex EVAR (cEVAR; fenestrated or branched EVAR).

METHODS

Consecutive patients undergoing elective infrarenal EVAR or cEVAR between 2000 and 2018 in two large teaching hospitals in the Netherlands were included. AKI was determined by serum creatinine levels increasing > 1.5 times or by an absolute increase of 26.5 mmol/L from baseline value (KDIGO criteria). The primary outcome was incidence of peri-operative AKI development. Secondary outcomes included mid-term renal function (RIFLE criteria), overall survival, and risk factors for AKI development. To determine survival and risk factors for AKI, multivariable Cox regression and logistic regression analyses were performed, accounting for pre-operative renal function and other confounders.

RESULTS

In total, 540 patients who underwent infrarenal EVAR with 147 patients who underwent cEVAR also included. The incidence of AKI was 8.7% (n = 47) in infrarenal EVAR patients and 23% (n = 34) in cEVAR patients (fenestrated EVAR 18%; branched EVAR 38%). In contrast to patients without AKI, the renal function of surviving patients with AKI remained significantly reduced at six weeks and did not return to pre-operative values following infrarenal EVAR (three year estimated glomerular filtration rate [eGFR] 59.3 ± 23.1 mL/min/1.73m2vs. pre-operative eGFR 74.0 ± 21.7 mL/min/1.73m2; p = .006) or following cEVAR (three year eGFR 52.0 ± 23.7 mL/min/1.73m2vs. pre-operative eGFR 65.4 ± 18.6 mL/min/1.73m2; p = .082). After risk adjusted analysis, compared with non-AKI, post-operative AKI development was associated with a higher three year mortality rate following both infrarenal and cEVAR (infrarenal EVAR mortality hazard ratio [HR 1.6, 95% confidence interval [CI] 1.01 - 2.7 [p = .046]; cEVAR mortality HR 2.4, 95% CI 1.1 - 5.2 [p = .033]). Following multivariable logistic regression, pre-operative chronic kidney disease (eGFR < 60 mL/min/1.73m2; odds ratio [OR] 2.2, 95% CI 1.03 - 4.8) and neck diameter (OR 1.1, 95% CI 1.01 - 1.2) were significantly associated with AKI following infrarenal EVAR, whereas for cEVAR only contrast volume (OR 1.1, 95% CI 1.0 - 1.2]) was found to be statistically significantly associated with AKI.

CONCLUSION

AKI is a well described complication following infrarenal EVAR and is common after cEVAR. As AKI seems to be associated with permanent renal deterioration and lower survival, efforts to prevent AKI are essential. Future studies are required to assess what factors are associated with a higher risk of developing AKI following cEVAR.

Mixed Reality in der Gefäßchirurgie – ein Scoping Review

Hintergrund „Mixed Reality“ (MR) erlaubt die Projektion von virtuellen Objekten in das Sichtfeld des Anwenders durch ein Head-mounted Display (HMD). Im gefäßchirurgischen Behandlungsspektrum könnten MR-Anwendungen in Zukunft einen Nutzen darstellen. Im folgenden Scoping Review soll eine Orientierung über die aktuelle Anwendung der genannten Technologien im Bereich der Gefäßchirurgie gegeben und Forschungsziele für die Zukunft definiert werden. Material und Methoden Es erfolgte eine systematische Literaturrecherche in PubMed (MEDLINE) mit den Suchbegriffen „aorta“, „intervention“, „endovsacular intervention“, „vascular surgery“, „aneurysm“, „endovascular“, „vascular access“ jeweils in Kombination mit „mixed reality“ oder „augmented reality“. Die Suche erfolgte nach PRISMA-Leitlinie (Preferred Reporting Items for Systematic reviews and Meta-Analyses) für Scoping Reviews. Ergebnisse Aus 547 Literaturstellen konnten 8 relevante Studien identifiziert werden. Die Suchergebnisse konnten in 2 Anwendungskategorien eingeteilt werden: (1) MR mit dem Ziel des Informationsmanagements und zur Verbesserung der periprozeduralen Ergonomie gefäßchirurgischer Eingriffe (n = 3) sowie (2) MR mit dem Ziel der intraoperativen Navigation bei gefäßchirurgischen Eingriffen (n = 5). Die Registrierung des physischen Patienten mit dem virtuellen Objekt und das Tracking von Instrumenten in der MR-Umgebung zur intraoperativen Navigation ist dabei im Fokus des wissenschaftlichen Interesses und konnte technisch erfolgreich am Phantom- und Tiermodell gezeigt werden. Die bisher vorgestellten Methoden sind jedoch mit hohem infrastrukturellem Aufwand und relevanten Limitationen verbunden. Schlussfolgerung Der Einsatz von MR im Bereich der Gefäßchirurgie ist grundsätzlich vielversprechend. Für die Zukunft sollten alternative, pragmatische Registrierungsmethoden mit entsprechender Quantifizierung des Positionierungsfehlers angestrebt werden. Die entwickelten Soft- und Hardwarelösungen sollten auf das Anforderungsprofil der Gefäßchirurgie angepasst werden. Das elektromagnetische Instrumenten-Tracking erscheint als sinnvolle, komplementäre Technologie zur Umsetzung der MR-assistierten Navigation.

Bioengineering, augmented reality, and robotic surgery in vascular surgery: A literature review

Biomedical engineering integrates a variety of applied sciences with life sciences to improve human health and reduce the invasiveness of surgical procedures. Technological advances, achieved through biomedical engineering, have contributed to significant improvements in the field of vascular and endovascular surgery. This paper aims to review the most cutting-edge technologies of the last decade involving the use of augmented reality devices and robotic systems in vascular surgery, highlighting benefits and limitations. Accordingly, two distinct literature surveys were conducted through the PubMed database: the first review provides a comprehensive assessment of augmented reality technologies, including the different techniques available for the visualization of virtual content (11 papers revised); the second review collects studies with bioengineering content that highlight the research trend in robotic vascular surgery, excluding works focused only on the clinical use of commercially available robotic systems (15 papers revised). Technological flow is constant and further advances in imaging techniques and hardware components will inevitably bring new tools for a clinical translation of innovative therapeutic strategies in vascular surgery.

Updates in Endovascular Procedural Navigation In Canadian Journal of Cardiology

There have been significant advancements in endovascular technology over the past decade. Increasingly complex disease processes are being addressed in a less invasive fashion, while still relying on standard two-dimensional, gray-scale fluoroscopy imaging to guide the procedures. With the advent of flat panel detectors as standard on fluoroscopy units and the utilization of fluoroscopy cone-beam computed tomography, the development of improved imaging tools has occurred which will help improve the imaging modalities used to perform these endovascular procedures. . Fusion imaging, the overlay of pre-operative 3-dimensional computed tomography images helps interventionalists perform endovascular procedures. Building on this technology, improvements in its function and utilization have occurred with the additional application of artificial intelligence and machine learning - allowing the images to independently accommodate to changes in the visualized anatomy. Corresponding development of navigation systems, allowing for the tracking of endovascular tools within these images using either fiberoptics of electromagnetic field generators, are looking to improve the accuracy of the procedures while reducing the need for radiation and contrast agents. These tools are making a dramatic change in our ability to perform complex endovascular procedures, and are the future gold standard. Ultimately, these will allow procedures to occur more quickly and more safely.