Virtual and augmented reality: potential applications in radiology

Abstract

The modern-day radiologist must be adept at image interpretation, and the one who most successfully leverages new technologies may provide the highest value to patients, clinicians, and trainees. Applications of virtual reality (VR) and augmented reality (AR) have the potential to revolutionize how imaging information is applied in clinical practice and how radiologists practice. This review provides an overview of VR and AR, highlights current applications, future developments, and limitations hindering adoption.

Keywords

Computer applications virtual imaging image manipulation/reconstruction interventional education

Introduction

Applications of virtual reality (VR) and augmented reality (AR) have the potential to revolutionize how imaging information is applied in clinical practice and how radiologists practice (1,2). In this review, we performed a targeted literature search (PubMed, Google Scholar) related to use of AR and VR in medicine, medical education, and radiology. References within manuscripts including other manuscripts and news media are included. Articles containing specific interventions were prioritized by study quality and publication date. This review provides an overview of VR and AR, highlights current applications, future developments, and limitations hindering adoption.

Definition of VR and AR

Both VR and AR, although distinct from each other, refer to simulations in which virtual elements are used to replace or supplement native sensory input. VR is an immersive simulation which creates the perception of being present within a non-physical virtual world. This is typically accomplished with a head-mounted display (HMD) in which a user receives sensory input from the display rather than their native surroundings (3). AR differs from VR in that the real world is not eliminated from the user’s view. Instead, virtual objects are superimposed onto the real world through a HMD or other display system, so that the user is able to interact simultaneously with the real world as well as with virtual objects (3 –5). Users may interact with graphics and virtual objects through the use of voice commands, hand gestures, or with a controller (3,6).

Technology development

VR and AR concepts have existed for several decades. Perhaps the earliest application of virtual reality was pioneered by cinematographer Morton Heilig, who in 1962 designed and patented a “sensorama,” a wide-angled video booth in which viewers were able to watch a film while having their sensory systems engaged through the use of fans, odor-emitters, stereoscopic sound, and motional chairs (7). An early version of the HMD, attached to large sensors and a mechanical arm suspended from the ceiling, was later developed by Ivan Sutherland in 1968 (8).

VR and AR applications were initially costly and had limited capabilities (9). However, advances in technology, such as decreased costs of smartphone display technology, graphics processing, and motion tracking (3), have led to a boom of VR and AR gaming applications and a renewed interest in medical imaging applications. The “miniaturization” of technology has resulted in the development of high-performance wireless HMDs (10). Immersive reality has been further popularized by increased web connectivity and open source software, which has facilitated exploration, collaboration, and development of VR and AR applications. Such advances have enabled innumerable applications within medicine, including in medical education, procedural planning, and therapeutic intervention. Total spending in VR and AR is expected to rise dramatically, from $11.4 billion in 2017 to nearly $215 billion in 2021, with spending in healthcare applications projected to reach $5.1 billion in 2025 (11,12).

Current and future applications

Alternative to 3D printing

In the last decade, physicians have increasingly utilized 3D-printing technology, in which reconstructions are printed into models that can be interactively explored (13,14). Use of 3D-printed models has improved procedural planning (15 –32), medical research, and medical education (26,33–37). Despite the benefits of 3D printing, there are several limitations which hinder its widespread adoption, including cost, turnaround time, and size constraints of printed models (14). VR and AR technologies provide several advantages over 3D printing (Table 1). Reconstructions can be generated at comparatively low costs and turnaround times. Specialized software allows models to be viewed at different sizes and manipulated in dynamic ways that may improve an understanding of complex anatomy (Fig. 1). The ease of use, lower cost, shorter turnaround time, and customizability are appealing features of VR and AR that can supplement or substitute 3D printing in specific applications (38). While controlled data comparing the two modalities are limited, some studies report advantages over 3D printing. For example, when evaluating cerebrovascular anatomy for neurosurgical training, users reported greater resolution and educational potential with VR over 3D printing (39).

Table 1.

Comparison between 3D printing to VR and AR.^*

	3D printing	VR and AR
Interactivity	Haptic experience	Visual simulation
Render customizability (e.g. resizing, coloring, morphing)	Before printing	Before and in real time
Associated costs	Software	Software
Associated costs	Access to 3D printer	HMD
	Printing material	HMD
Turnaround time	Hours to weeks (depending on how models are printed)	Minutes to hours
Ease of use for end-user	Easy	Easy to difficult, depending on complexity of the platform
Potential side effects for end-user	None	Cyber sickness

*Table based on the authors’ experience.

AR, augmented reality; HMD, head-mounted display; VR, virtual reality.

Fig. 1.

3D-printed model and virtual reconstruction of conjoined twins for surgical planning.

Diagnosis and surgical planning

VR and AR can aid in the understanding of complex anatomical relationships. For example, AR models of kidneys have been generated for surgical planning and decision-making before robotic-assisted partial nephrectomy (40). In the setting of camera-assisted surgery in which the operator is limited by the endoscope’s internal field of view, AR applications can transpose the endoscopic view onto the patient, aiding the surgeon’s ability to navigate (41). Successful use of this technology has been described for nephrectomy, nephrolithotomy, adrenalectomy, brain tumor resection, cerebral aneurysm clipping, splenectomy, and abdominal tumor resection (42 –53). In mammography, viewing images of the breast in AR allows for stereoscopic depth perception, 3D cursor use, and joystick navigation (54,55). Joystick navigation involves the use of a handheld controller, which can be used to “fly” throughout an image to better visualize target areas. These tools may ultimately improve detection and localization of abnormal microcalcifications and tumors (54,55). VR reconstructions of the breast have also been introduced for the assessment of tumor response after neoadjuvant chemotherapy and for aiding in surgical planning (55,56).

Interventional radiology

VR and AR have the potential to revolutionize image-guided interventions and improve patient outcomes. Real-time AR reconstructions superimposed onto patients for percutaneous and endovascular interventions may provide benefits over conventional localization techniques. A pilot study showed that viewing VR reconstructions of splenic artery aneurysms before endovascular embolization improved operator confidence (57). In one model, AR reconstructions of the aorta and its major branches were transposed onto a phantom and, with the use of electromagnetic markers, an endovascular catheter was tracked within the virtually generated vascular tree (58). This type of application could theoretically reduce procedure time and radiation exposure (58). AR also has growing promise in percutaneous interventions, such as biopsies and ablations (59). Although there are challenges associated with patient movement and image mismatch when using AR, advances in image reconstruction have significantly improved accurate lesion localization with AR, achieving a difference of <5 mm between virtual and real distances (60). Currently, however, studies evaluating objective benefits of AR over conventional localization techniques in interventional radiology (such as “road-mapping with fluoroscopy”) are limited and will require more robust research than “proof-of-concept” demonstrations to validate clinical utility.

The reading room

Attempts are underway to redesign the conventional reading room with virtual reality. Typical reading rooms require highly specialized equipment and specific lighting conditions to ensure accurate image interpretation. A novel virtual reality reading room has been introduced, where images can be interpreted using a commercially available HMD (61). Optimal image conditions can be reconstructed in a virtual environment, precluding the need for controlled external lighting conditions and specialized monitors (61). In this specific application, image navigation is performed with the use of hand gestures, which allows for dynamic visualization, such as real-time object rotation and tilting. Users found the platform to have sufficient ease of use and interpretability without reporting any discomfort (61). Use of VR reading rooms could cut equipment and maintenance costs, and by eliminating effects of ambient lighting conditions could potentially improve diagnostic accuracy.

Relaxation/Distraction therapy

Distraction or relaxation therapies aim to reduce patient pain and anxiety by using sensory stimuli in lieu of pharmacological substances. Common distraction methods include listening to music or viewing scenes on a standard digital screen (62 –64). A distinct benefit of using VR for distraction/relaxation therapy is due to its completely immersive nature. Multiple studies have shown that VR can help reduce the use of sedation during MR imaging (65 –67). VR has also benefited pediatric patients aged 4–6 years by decreasing pain and anxiety during dental procedures (68), intravenous line placement (69), and other procedural interventions (70). In adult burn victims, the use of VR distraction therapy during dressing changes reduced pain, anxiety, and length of hospitalization (71). Reductions in pain were more notable with higher quality headsets that covered a wider field of view, suggesting that more immersive VR experiences are more effective (72). In a separate pilot study, VR relaxation therapy was safely used during orthopedic surgery under regional anesthesia (73). Distraction therapy also decreased intravenous sedation and procedure related pain during preoperative adductor canal catheter placement before total knee arthroplasty (74). The efficacy of VR relaxation therapy has been validated by functional magnetic resonance imaging (fMRI) (75). Users exposed to painful thermal stimuli during fMRI scans reported less subjective pain and had statistically significant reductions in pain-related brain activity while using VR relaxation therapy (75). The reported successes of using VR for distraction therapy, during invasive surgical procedures warrants adoption in interventional radiology as well. Patients prone to anxiety, claustrophobia, or high analgesic requirements during interventional radiology procedures may find this therapy especially beneficial.

Informed consent process

Informed consent, generally speaking, is a process of communicating the purposes, risks, and benefits of procedures between a patient and provider (76). There has been a shift toward a more patient-centered model in which visual aids are used in an effort to overcome lower levels of patient health literacy and ultimately achieve a greater sense of autonomy in patients (77). Improving the informed consent process can result in decreased anxiety, higher patient satisfaction, and an improved understanding of procedures (78 –80). Part of the consent process is an explanation of the procedure, which could be accomplished by using VR. For example, patients who were primed with what to experience during the recovery process also experienced lower postoperative pain, a shorter length of stay, and less negative affect (81,82). Based on such positive effects, the use of VR to enhance patient education and consent for radiology procedures should be further explored.

Education and training

Advances in diagnostic and interventional radiology have increased the scope of procedures performed by radiologists. Despite the growing breadth of radiology procedures, time constraints in busy clinical services have made it challenging to provide standardized teaching for trainees. Trainees and faculty would favor implementation of standardized procedural training during radiology residency (83), and VR lends itself to creating such curricula. Current simulations based on phantoms do not provide an experience that accurately portrays a live situation, while VR simulations, such as for cardiopulmonary resuscitation, can provide an extremely high fidelity and customizable experience (84). VR and AR simulations may also be used to more accurately assess trainee performance, such as knowledge and skill levels in neurosurgery (1).

Patients may also prefer that trainees undergo procedural training in a simulated environment before performing procedures on patients. By using VR, trainees can be transported into a procedure room where they may observe and even participate in virtual procedures before performing them on patients. This allows educators to provide standardized and curated educational training material to all trainees. In a pilot program implemented by McCarthy et al. (10), radiology faculty and trainees were able to watch interventional radiology tutorials in VR. This program allowed trainees to experience the process of learning with an instructor in a procedure room. The majority of pilot participants reported that the module they watched was excellent or good and had the potential to contribute to the future of interventional radiology training (10). VR can also fill gaps in procedural experience by providing simulations of procedures that a trainee rarely encounters during their graduate medical training (85,86).

Teaching challenging anatomical concepts can be made simpler with VR and AR. 3D reconstructions of images and post-processing software can be used to generate high quality interactive VR and AR simulations. Such simulations will enable the user to manipulate and edit objects in ways that are not possible using other modalities, such as 3D printing (3). For example, virtual reality has been used to teach anatomy to medical students with “virtual dissections” (87).

Advances in HMDs and decreasing costs have enabled the “VR classroom.” For example, teaching modules recorded with specialized 360° cameras can be viewed in VR, which may provide more engagement than conventional teaching methods. Certain applications also enable users to convene in a virtual location (88). This technology can be used to enhance radiology collaboration and education, including in underserved locations. As commercial medical virtual reality applications continue to emerge, new interactive methods to teach radiology will be developed (3).

Overall, the advent of VR simulations in medical education can increase opportunities for providing high-quality standardized educational simulations and assessments at scale, while minimizing the need for dedicated physical space, costly simulation manikins, or need for human cadavers.

Limitations and ethical considerations in VR and AR

One of the most notable side effects of immersive reality is “cyber sickness.” In essence, this describes sensations of discomfort including nausea, headache, and dizziness when using VR and AR applications (89 –91). It is posited that cyber sickness is due to vestibular mismatch, in which there is the visual perception of motion in a simulation without matching input from the vestibular system (3). Multiple strategies aimed at reducing cyber sickness have been explored, such as developing VR simulations which only shows movement when there is actual movement of the user’s head (3). Advanced VR HMDs can track nuanced head movements to reduce vestibular mismatch (3). Eye strain may also contribute to discomfort with VR, which can be caused by low frame-rates and HMDs which do not properly accommodate the user’s eyes (3,91). Developers must anticipate potential discomfort with VR and find ways to mitigate unwanted side effects when creating applications.

AR must overcome several limitations to become useful during image-guided procedures. For example, when virtually reconstructed anatomy is transposed over a patient in real time with AR HMDs, the image location must be accurate. Inaccurate localization may result in a less efficient procedure or unnecessary patient harm. Techniques are being developed to optimize AR image reconstruction, including overcoming respiratory motion and organ deformation (60,92–94). In addition to accurate image localization, the device must feel like a “natural extension” of the operator’s senses (95). The image must move smoothly and accurately while the operator’s head position changes. The HMD must also be light, comfortable, and mobile enough for the operator to use during potentially long image-guided interventions (95).

VR and AR technology are still limited with regards to accurately portraying reality. Creating a realistic virtual experience, while feasible using current technology, can require significant time, financial resources, and expertise. Therefore, developing simulations that do not require high levels of accuracy, such as those simulating the performance of simple tasks may provide the highest initial value (86). In addition, more high-quality research is necessary to understand whether VR and AR educational and training applications in radiology provide a significant advantage over conventional methods to justify costs.

Caution should be taken when implementing this technology in medicine. Numerous VR and AR applications have already been cleared by the FDA using the 510(k) pathway, where safety and effectiveness are demonstrated by showing “substantial equivalence” to pre-existing 3D modeling software (96,97). However, more research is required to ensure that the introduction of this technology in specific use-cases confers a benefit to the radiologist workflow and patient care.

Ethical concerns have been raised regarding any unintended consequences when VR and AR supplement or replace existing methods (98). For example, inaccuracies in simulations may contribute to improper training. An analogy to this is flight training of military pilots, where a virtual simulation may not accurately replicate certain scenarios, leading to a distorted perception of real-time flight (98). In addition, trainees may not receive the same level of scrutiny as they would during live interventions, potentially fostering the development of flawed techniques.

As VR and AR technology evolves, thorough consideration should be given on how it is introduced into medicine. Special attention should be placed on major participants and their motivations in this arena. Oversight from a combination of professions including radiologist and non-radiologist physicians, informatics specialists, developers, artists, and other industry professionals are required to adequately test, facilitate, and record changes in this field. Cautious introduction of VR and AR will ensure that it is incorporated in a safe and effective manner.

Conclusion

Advances in VR and AR have enabled novel applications in education, training, and patient care in radiology. We are currently exploring the utility of VR for visualization of complex anatomy and procedural training in interventional radiology. We believe that further exploration and thorough research is warranted to better understand how to best utilize this technology to optimize radiology training and improve patient care.

Footnotes

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Mohammad Elsayed

Omran Al Dandan

References

Pelargos

Nagasawa

Lagman

, et al. Utilizing virtual and augmented reality for educational and clinical enhancements in neurosurgery. J Clin Neurosci 2017; 35:1–4.

Committee on Diagnostic Error in Health C, Board on Health Care S, Medicine Ioet al. Technology and Tools in the Diagnostic Process. In: Balogh

Miller

Ball

(eds) Improving Diagnosis in Health Care. Washington, DC: National Academies Press, 2015, pp.217–262.

Sutherland

Belec

Sheikh

, et al. Applying modern virtual and augmented reality technologies to medical images and models. J Digit Imaging 2019; 32:38–53.

Moro

Stromberga

Raikos

The effectiveness of virtual and augmented reality in health sciences and medical anatomy.

2017; 10:549–559.

Plasencia

DM.

One step beyond virtual reality: connecting past and future developments.

XRDS 2015; 22:18–23.

Pratt

Ives

Lawton

, et al. Through the HoloLens looking glass: augmented reality for extremity reconstruction surgery using 3D vascular models with perforating vessels. Eur Radiol Exp 2018; 2:2.

Drummond

Hamburger E Houston T , et al. The Rise and Fall and Rise of Virtual Reality. Available at: http://theverge.com/a/virtual-reality

Sutherland

IE.

A head-mounted three dimensional display. In: Proceedings of the December 9–11, 1968, fall joint computer conference, part I. New York, NY: ACM, 1968:757–764.

Schnipper

Seeing is believing: The state of virtual reality, https://www.theverge.com/a/virtual-reality (2017, accessed November 2019).

10.

McCarthy

AYC

, et al. Interventional Radiology Training Using a Dynamic Medical Immersive Training Environment (DynaMITE). J Am Coll Radiol 2018; 15: 789–793.

11.

Worldwide Spending on Augmented and Virtual Reality. Available At: https://www.idc.com/getdoc.jsp?containerId=prUS42959717 (last accessed Oct 2018).

12.

Healthcare Augmented & Virtual Reality Market Worth $5.1 Billion By 2025. 2017. Available at: https://www.grandviewresearch.com/press-release/global-augmented-reality-ar-virtual-reality-vr-in-healthcare-market (last accessed Oct 2018).

13.

Rengier

Mehndiratta

von Tengg-Kobligk

, et al. 3D printing based on imaging data: review of medical applications. Int J Comput Assist Radiol Surg 2010; 5:335–341.

14.

McGurk

Amis

Potamianos

, et al. Rapid prototyping techniques for anatomical modelling in medicine. Ann R Coll Surg Engl 1997; 79:169–174.

15.

Nekooei

Sardabi

Razavi

, et al. Implantation of Customized, Preshaped Implant for Orbital Fractures with the Aid of Three-dimensional Printing. Middle East Afr J Ophthalmol 2018; 25:56–58.

16.

D’Urso

Earwaker

Barker

, et al. Custom cranioplasty using stereolithography and acrylic. Br J Plast Surg 2000; 53:200–204.

17.

Faber

Berto

Quaresma

Rapid prototyping as a tool for diagnosis and treatment planning for maxillary canine impaction.

Am J Orthod Dentofacial Orthop 2006; 129:583–589.

18.

Mavili

Canter

Saglam-Aydinatay

, et al. Use of three-dimensional medical modeling methods for precise planning of orthognathic surgery. J Craniofac Surg 2007; 18:740–747.

19.

Muller

Krishnan

Uhl

, et al. The application of rapid prototyping techniques in cranial reconstruction and preoperative planning in neurosurgery. J Craniofac Surg 2003; 14:899–914.

20.

Poukens

Haex

Riediger

The use of rapid prototyping in the preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton.

Comput Aided Surg 2003; 8:146–154.

21.

Guarino

Tennyson

McCain

, et al. Rapid prototyping technology for surgeries of the pediatric spine and pelvis: benefits analysis. J Pediatr Orthop 2007; 27:955–960.

22.

Hurson

Tansey

O'Donnchadha

, et al. Rapid prototyping in the assessment, classification and preoperative planning of acetabular fractures. Injury 2007; 38:1158–1162.

23.

Wurm

Tomancok

Pogady

, et al. Cerebrovascular stereolithographic biomodeling for aneurysm surgery. Technical note. J Neurosurg 2004; 100:139–145.

24.

Giesel

Hart

Hahn

, et al. 3D reconstructions of the cerebral ventricles and volume quantification in children with brain malformations. Acad Radiol 2009; 16:610–617.

25.

Armillotta

Bonhoeffer

Dubini

, et al. Use of rapid prototyping models in the planning of percutaneous pulmonary valved stent implantation. Proc Inst Mech Eng H 2007; 221:407–416.

26.

Kim

Hansgen

Wink

, et al. Rapid prototyping: a new tool in understanding and treating structural heart disease. Circulation 2008; 117:2388–2394.

27.

Hiramatsu

Yamaguchi

Nimi

, et al. [ Rapid prototyping of the larynx for laryngeal frame work surgery]. Nihon Jibiinkoka Gakkai Kaiho 2004; 107:949–955.

28.

D’Urso

Barker

Earwaker

, et al. Stereolithographic biomodelling in cranio-maxillofacial surgery: a prospective trial. J Craniomaxillofac Surg 1999; 27:30–37.

29.

Kalet

Lease

, et al. Anatomical information in radiation treatment planning. Proc AMIA Symp 1999:291–295.

30.

Sun

CJ.

Using the full scale 3D solid anthropometric model in radiation oncology positioning and verification.

Conf Proc IEEE Eng Med Biol Soc 2004; 5:3432–3435.

31.

Zemnick

Woodhouse

Gewanter

, et al. Rapid prototyping technique for creating a radiation shield. J Prosthet Dent 2007; 97:236–241.

32.

Sulaiman

Boussel

Taconnet

, et al. In vitro non-rigid life-size model of aortic arch aneurysm for endovascular prosthesis assessment. Eur J Cardiothorac Surg 2008; 33:53–57.

33.

Suzuki

Ogawa

Kawano

, et al. Rapid prototyping of temporal bone for surgical training and medical education. Acta Otolaryngol 2004; 124:400–402.

34.

Knox

Kerber

Singel

, et al. Rapid prototyping to create vascular replicas from CT scan data: making tools to teach, rehearse, and choose treatment strategies. Catheter Cardiovasc Interv 2005; 65:47–53.

35.

Bruyere

Leroux

Brunereau

, et al. Rapid prototyping model for percutaneous nephrolithotomy training. J Endourol 2008; 22:91–96.

36.

Canstein

Cachot

Faust

, et al. 3D MR flow analysis in realistic rapid-prototyping model systems of the thoracic aorta: comparison with in vivo data and computational fluid dynamics in identical vessel geometries. Magn Reson Med 2008; 59:535–546.

37.

Sodian

Schmauss

Schmitz

, et al. 3-dimensional printing of models to create custom-made devices for coil embolization of an anastomotic leak after aortic arch replacement. Ann Thorac Surg 2009; 88:974–978.

38.

Radhika Dhuru AS. 3 Ways Virtual Reality Can Supplement Your Medical 3D Printing Activities (And 3 Ways It Won’t). Available at: https://www.materialise.com/en/blog/3-ways-virtual-reality-supplements-medical-3d-printing (last accessed Nov 2019).

39.

Bairamian

Liu

Eftekhar

Virtual reality angiogram vs 3-dimensional printed angiogram as an educational tool-A comparative study.

Neurosurgery 2019; 85:E343–e349.

40.

Wake

Bjurlin

Rostami

, et al. Three-dimensional printing and augmented reality: enhanced precision for robotic assisted partial nephrectomy. Urology 2018; 116:227–228.

41.

Nicolau

Soler

Mutter

, et al. Augmented reality in laparoscopic surgical oncology. Surg Oncol 2011; 20:189–201.

42.

Simpfendorfer

Gasch

Hatiboglu

, et al. Intraoperative computed tomography imaging for navigated laparoscopic renal surgery: first clinical experience. J Endourol 2016; 30:1105–1111.

43.

Teber

Guven

Simpfendorfer

, et al. Augmented reality: a new tool to improve surgical accuracy during laparoscopic partial nephrectomy? Preliminary in vitro and in vivo results. Eur Urol 2009; 56:332–338.

44.

L-M

Vagvolgyi

Agarwal

, et al. Augmented reality during robot-assisted laparoscopic partial nephrectomy: toward real-time 3D-CT to stereoscopic video registration. Urology 2009; 73:896–900.

45.

Ukimura

Gill

IS.

Imaging-Assisted Endoscopic Surgery: Cleveland Clinic Experience.

J Endourol 2008; 22:803–810.

46.

Marescaux

Rubino

Arenas

, et al. Augmented-reality-assisted laparoscopic adrenalectomy. JAMA 2004; 292:2214–2215.

47.

Baumhauer

Feuerstein

Meinzer

H-P

, et al. Navigation in endoscopic soft tissue surgery: perspectives and limitations. J Endourol 2008; 22:751–766.

48.

Besharati Tabrizi

Mahvash

Augmented reality-guided neurosurgery: accuracy and intraoperative application of an image projection technique.

J Neurosurg 2015; 123:206–211.

49.

Mahvash

Besharati Tabrizi

A novel augmented reality system of image projection for image-guided neurosurgery.

Acta Neurochir (Wien) 2013; 155:943–947.

50.

Stadie

Kockro

RA.

Mono-stereo-autostereo: the evolution of 3-dimensional neurosurgical planning.

Neurosurgery 2013; 72 Suppl 1:63–77.

51.

Konishi

Hashizume

Nakamoto

, et al. Augmented reality navigation system for endoscopic surgery based on three-dimensional ultrasound and computed tomography: Application to 20 clinical cases. International Congress Series 2005; 1281:537–542.

52.

Ieiri

Uemura

Konishi

, et al. Augmented reality navigation system for laparoscopic splenectomy in children based on preoperative CT image using optical tracking device. Pediatr Surg Int 2012; 28:341–346.

53.

Souzaki

Ieiri

Uemura

, et al. An augmented reality navigation system for pediatric oncologic surgery based on preoperative CT and MRI images. J Pediatr Surg 2013; 48:2479–2483.

54.

Rancati

Angrigiani

Nava

, et al. Augmented reality for breast imaging. Minerva Chir 2018; 73:341–344.

55.

Douglas

Boone

Petricoin

, et al. Augmented Reality Imaging System: 3D Viewing of a Breast Cancer. J Nat Sci 2016; 2:e215.

56.

Douglas

Petricoin

Liotta

, et al. D3D augmented reality imaging system: proof of concept in mammography. Med Devices (Auckl) 2016; 9:277–283.

57.

Devcic

Idakoji

Kesselman

, et al. 4:03 PM Abstract No. 30 Augmented virtual reality assisted treatment planning for splenic artery aneurysms: a pilot study. J Vasc Intervent Radiol 2018; 29:S17.

58.

Kuhlemann

Kleemann

Jauer

, et al. Towards X-ray free endovascular interventions - using HoloLens for on-line holographic visualisation. Healthc Technol Lett 2017; 4:184–187.

59.

Nicolau

Pennec

Soler

, et al. An augmented reality system for liver thermal ablation: Design and evaluation on clinical cases. Med Image Anal 2009; 13:494–506.

60.

Solbiati

Passera

Rotilio

, et al. Augmented reality for interventional oncology: proof-of-concept study of a novel high-end guidance system platform. Eur Radiol Exp 2018; 2:18.

61.

Sousa

Mendes

Paulo

, et al. VRRRRoom: Virtual Reality for Radiologists in the Reading Room. In: Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems, Denver, Colorado, May 6–11, 2017. New York, NY: ACM, 2017:4057–4062.

62.

Lechtzin

Busse

Smith

, et al. A randomized trial of nature scenery and sounds versus urban scenery and sounds to reduce pain in adults undergoing bone marrow aspirate and biopsy. J Altern Complement Med 2010; 16:965–972.

63.

Evans

The effectiveness of music as an intervention for hospital patients: a systematic review.

J Adv Nurs 2002; 37:8–18.

64.

Tan

SY.

Cognitive and cognitive-behavioral methods for pain control: a selective review.

Pain 1982; 12:201–228.

65.

Das

Grimmer

Sparnon

, et al. The efficacy of playing a virtual reality game in modulating pain for children with acute burn injuries: a randomized controlled trial [ISRCTN87413556]. BMC Pediatr 2005; 5:1.

66.

Hoffman

Chambers

Meyer

, 3rdet al. Virtual reality as an adjunctive non-pharmacologic analgesic for acute burn pain during medical procedures. Ann Behav Med 2011; 41:183–191.

67.

Khan

Donnelly

Koch

, et al. A program to decrease the need for pediatric sedation for CT and MRI. Applied Radiology 2007; 36:30.

68.

Asl Aminabadi

Erfanparast

Sohrabi

, et al. The impact of virtual reality distraction on pain and anxiety during dental treatment in 4-6 year-old children: a randomized controlled clinical trial. J Dent Res Dent Clin Dent Prospects 2012; 6:117–124.

69.

Gold

Kim

Kant

, et al. Effectiveness of virtual reality for pediatric pain distraction during i.v. placement. Cyberpsychol Behav 2006; 9:207–212.

70.

Won

Bailey

Bailenson

, et al. Immersive virtual reality for pediatric pain. Children (Basel) 2017; 4:E52.

71.

Scapin

Echevarria-Guanilo

Boeira Fuculo Junior

, et al. Virtual Reality in the treatment of burn patients: A systematic review. Burns 2018; 44:1403–1416.

72.

Hoffman

Seibel

Richards

, et al. Virtual reality helmet display quality influences the magnitude of virtual reality analgesia. J Pain 2006; 7:843–850.

73.

Chan

Scharf

Virtual reality as an adjunctive nonpharmacological sedative during orthopedic surgery under regional anesthesia: a pilot and feasibility study.

Anesth Analg 2017; 125:1200–1202.

74.

Pandya

Kim

TE.

Virtual reality distraction decreases routine intravenous sedation and procedure-related pain during preoperative adductor canal catheter insertion: a retrospective study. Korean J Anesthesiol

2017; 70:439–445.

75.

Hoffman

Richards

Coda

, et al. Modulation of thermal pain-related brain activity with virtual reality: evidence from fMRI. Neuroreport 2004; 15:1245–1248.

76.

Baheti

Thakur

Jankharia

Informed consent in diagnostic radiology practice: Where do we stand?

Ind J Radiol Imaging 2017; 27:517–520.

77.

Satyanarayana Rao

KH.

Informed consent: an ethical obligation or legal compulsion?

J Cutan Aesthet Surg 2008; 1:33–35.

78.

Coyne

Raich

, et al. Randomized, controlled trial of an easy-to-read informed consent statement for clinical trial participation: a study of the Eastern Cooperative Oncology Group. J Clin Oncol 2003; 21:836–842.

79.

Pereira

Hussaini

Wilkinson

ML.

Informed consent for upper gastrointestinal endoscopy.

Gut 1995; 37:151–153.

80.

Davis

Holcombe

Berkel

, et al. Informed consent for clinical trials: a comparative study of standard versus simplified forms. J Natl Cancer Inst 1998; 90:668–674.

81.

Powell

Scott

Manyande

, et al. Psychological preparation and postoperative outcomes for adults undergoing surgery under general anaesthesia. Cochrane Database Syst Rev 2016;(5):CD008646.

82.

Kruzik

Benefits of preoperative education for adult elective surgery patients.

AORN J 2009; 90:381–387.

83.

Prater

Rostad

Ebert

, et al. Towards consensus: training in procedural skills for diagnostic radiology residents-current opinions of residents and faculty at a large academic center. Curr Probl Diagn Radiol 2018; 47:387–392.

84.

Murphy

Virtual reality taking the dummies out of medical simulation. Available at: https://www.ama-assn.org/education/accelerating-change-medical-education/virtual-reality-taking-dummies-out-medical (last accessed 9 Jan 2018).

85.

Harrison

Raison

Abe

, et al. The validation of a novel robot-assisted radical prostatectomy virtual reality module. J Surg Educ 2018; 75:758–766.

86.

Olasky

Sankaranarayanan

Seymour

, et al. Identifying opportunities for virtual reality simulation in surgical education: a review of the Proceedings from the Innovation, Design, and Emerging Alliances in Surgery (IDEAS) Conference: VR Surgery. Surg Innov 2015; 22:514–521.

87.

Mitzi

How VR is Revolutionizing the Way Future Doctors are Learning About Our Bodies. Available at: https://www.ucsf.edu/news/2018/07/411366/musical-improvisation-brain (last accessed Oct 2018).

88.

Nijholt

Zwiers

Peciva

Mixed reality participants in smart meeting rooms and smart home environments.

Personal and Ubiquitous Computing 2009; 13:85–94.

89.

Rebenitsch

Owen

Review on cybersickness in applications and visual displays.

Virtual Reality 2016; 20:101–125.

90.

Rebenitsch

Managing cybersickness in virtual reality.

XRDS 2015; 22:46–51.

91.

Garzorz

MacNeilage

PR.

Visual-vestibular conflict detection depends on fixation.

Curr Biol 2017; 27:2856–2861.e2854.

92.

Zygomalas

Kehagias

Up-to-date intraoperative computer assisted solutions for liver surgery.

World J Gastrointest Surg 2019; 11:1–10.

93.

Cheung

She

, et al. Pure laparoscopic hepatectomy with augmented reality-assisted indocyanine green fluorescence versus open hepatectomy for hepatocellular carcinoma with liver cirrhosis: A propensity analysis at a single center. Asian J Endosc Surg 2018; 11:104–111.

94.

Kleemann

Deichmann

Esnaashari

, et al. Laparoscopic navigated liver resection: technical aspects and clinical practice in benign liver tumors. Case Rep Surg 2012; 2012:265918.

95.

Khor

Baker

Amin

, et al. Augmented and virtual reality in surgery-the digital surgical environment: applications, limitations and legal pitfalls. Ann Transl Med 2016; 4:454–454.

96.

Corporation PbN. 510(k) Pemarket Notification for OpenSight. Silver Spring, MD: U.S Food and Drug Administration, 2018.

97.

LLC PbST. 510 (k) Premarket Notification for SuRgical Planner (SRP). Silver Spring, MD: U.S Food and Drug Administration, 2018.

98.

Whalley

LJ.

Ethical issues in the application of virtual reality to medicine.

Comput Biol Med 1995; 25:107–114.