Cinematic Rendering in Anatomy: A Crossover Study Comparing a Novel 3D Reconstruction Technique to Conventional Computed Tomography

Using design thinking to create and implement a 3D digital library of anatomical specimens

Design thinking (DT) is a five-stage process (empathize, define, ideate, prototype, and test) that guides the creation of user-centered solutions to complex problems. DT is in common use outside of science but has rarely been applied to anatomical education. The use of DT in this study identified the need for flexible access to anatomical specimens outside of the anatomy laboratory and guided the creation of a digital library of three-dimensional (3D) anatomical specimens (3D Anatomy Viewer). To test whether the resource was fit for purpose, a mixed-methods student evaluation was undertaken. Student surveys (n = 46) were employed using the system usability scale (SUS) and an unvalidated acceptability questionnaire. These verified that 3D Anatomy Viewer was usable (SUS of 72%) and acceptable (agreement range of 77%-93% on all Likert-type survey statements, Cronbach's alpha = 0.929). Supplementary interviews (n = 5) were analyzed through content analysis and revealed three main themes: (1) a credible online supplementary learning resource; (2) learning anatomy with 3D realism and interactivity; (3) user recommendations for expanding the number of anatomical models, test questions, and gamification elements. These data demonstrate that a DT framework can be successfully applied to anatomical education for creation of a practical learning resource. Anatomy educators should consider employing a DT framework where student-centered solutions to learner needs are required.

Clinical implementation of cinematic rendering

Cinematic rendering is a recently developed photorealistic display technique for standard volumetric data sets. It has broad-reaching applications in cardiovascular, musculoskeletal, abdominopelvic, and thoracic imaging. It has been used for surgical planning and has emerging use in educational settings. We review the logistics of performing this post-processing step and its integration into existing workflow.

Realistic three-dimensional imaging of injuries in forensic medicine - Survey-based method comparison of CRT and VRT

OBJECTIVE

A comparison between Cinematic Rendering Technique (CRT) and Volume Rendering Technique (VRT) in cases with postmortem CT-angiography (PMCTA) was carried out.

METHODS

For different injuries seen in PMCTA, a VRT and a CRT image of exactly the same pathological section was generated. Two questionnaires were created, one with CRT and one with VRT reconstructions, with the same questions per 3D-image. The questionnaires were sent to forensic pathologists, lawyers and police officers. In total eleven different injuries had to be analyzed.

RESULTS

In total 109 questionnaires were answered fully. Of these returnees, 36 stated that they were forensic pathologists. Seventy-three people were assigned to the group of medical laypersons, in the study this group consists mainly of police officers, judges and lawyers. Between the two software programs CRT and VRT that were compared, no significant difference could be identified in any of the participating groups with regard to the assessment of the life-threatening nature of the injury images shown. When asked about the comprehensibility of pathology, there was a significant difference in favour of CRT. This advantage was apparent to named medical laypersons and to forensic pathologists.

CONCLUSIONS

The study showed a positive trend that CRT may be more understandable than VRT. Not only the medical laypersons, but also the forensic physicians found CRT to be beneficial.

Cinematic rendering improves the AO/OTA classification of distal femur fractures compared to volume rendering: a retrospective single-center study

Purpose: Correctly classifying distal femur fractures is essential for surgical treatment planning and patient prognosis. This study assesses the potential of Cinematic Rendering (CR) in classifying these fractures, emphasizing its reported ability to produce more realistic images than Volume Rendering (VR). Methods: Data from 88 consecutive patients with distal femoral fractures collected between July 2013 and July 2020 were included. Two orthopedic surgeons independently evaluated the fractures using CR and VR. The inter-rater and intra-rater agreement was evaluated by using the Cicchetti-Allison weighted Kappa method. Accuracy, precision, recall, and F1 score were also calculated. Diagnostic confidence scores (DCSs) for both imaging methods were compared using chi-square or Fisher's exact tests. Results: CR reconstruction yielded excellent inter-observer (Kappa = 0.989) and intra-observer (Kappa = 0.992) agreement, outperforming VR (Kappa = 0.941 and 0.905, respectively). While metrics like accuracy, precision, recall, and F1 scores were higher for CR, the difference was not statistically significant (p > 0.05). However, DCAs significantly favored CR (p < 0.05). Conclusion: CR offers a superior visualization of distal femur fractures than VR. It enhances fracture classification accuracy and bolsters diagnostic confidence. The high inter- and intra-observer agreement underscores its reliability, suggesting its potential clinical importance.

Musculoskeletal CT Imaging: State-of-the-Art Advancements and Future Directions

CT is one of the most widely used modalities for musculoskeletal imaging. Recent advancements in the field include the introduction of four-dimensional CT, which captures a CT image during motion; cone-beam CT, which uses flat-panel detectors to capture the lower extremities in weight-bearing mode; and dual-energy CT, which operates at two different x-ray potentials to improve the contrast resolution to facilitate the assessment of tissue material compositions such as tophaceous gout deposits and bone marrow edema. Most recently, photon-counting CT (PCCT) has been introduced. PCCT is a technique that uses photon-counting detectors to produce an image with higher spatial and contrast resolution than conventional multidetector CT systems. In addition, postprocessing techniques such as three-dimensional printing and cinematic rendering have used CT data to improve the generation of both physical and digital anatomic models. Last, advancements in the application of artificial intelligence to CT imaging have enabled the automatic evaluation of musculoskeletal pathologies. In this review, the authors discuss the current state of the above CT technologies, their respective advantages and disadvantages, and their projected future directions for various musculoskeletal applications.

Role of Living Anatomy in Medical Education: A Narrative Review

Introduction

There has been a significant change noticed in the way in how anatomy is taught and learned in last two decades. The use of teaching approaches such as body painting, peer physical examination, medical imaging, and virtual anatomy software in the teaching and learning of living anatomy was made possible by advancements in medical technology. This study focuses on a review of the historical context and contemporary developments in teaching and learning of live and surface anatomy with a special emphasis on its pedagogical elements, some opinions of medical educationists, and undergraduates.

Conclusions

It is suggested that living anatomy be included as a core subject in the curriculum. Learning about living anatomy will be improved in an integrated and pertinent framework with the inclusion and execution of teaching and learning modalities such as body painting, peer physical examination, medical imaging, and virtual anatomy software.

On the added benefit of virtual anatomy for dissection-based skills

Technological approaches deploying three-dimensional visualization to integrate virtual anatomy are increasingly used to provide medical students with state-of-the-art teaching. It is unclear to date to which extent virtual anatomy may help replace the dissection course. Medical students of Johannes Kepler University attend both a dissection and a virtual anatomy course. This virtual anatomy course is based on Cinematic Rendering and radiological imaging and teaches anatomy and pathology. This study aims to substantiate student benefits achieved from this merged teaching approach. Following their dissection course, 120 second-year students took part in objective structured practical examinations (OSPE) conducted on human specimens prior to and following a course on Cinematic Rendering virtual anatomy. Likert-based and open-ended surveys were conducted to evaluate student perceptions of both courses and their utility. Virtual anatomy teaching was found to be unrelated to improvements in student's ability to identify anatomical structures in anatomical prosections, yielding only a 1.5% increase in the OSPE score. While the students rated the dissection course as being more important and impactful, the virtual anatomy course helped them display the learning content in a more comprehensible and clinically applicable way. It is likely that Cinematic Rendering-based virtual anatomy affects knowledge gain in domains other than the recognition of anatomical structures in anatomical prosections. These findings underline students' preference for the pedagogic strategy of the dissection course and for blending this classical approach with novel developments like Cinematic Rendering, thus preparing future doctors for their clinical work.

Cinematic rendering to improve visualization of supplementary and ectopic teeth using CT datasets

OBJECTIVES

Ectopic, impacted, and supplementary teeth are the number one reason for cross-sectional imaging in pediatric dentistry. The accurate post-processing of acquired data sets is crucial to obtain precise, yet also intuitively understandable three-dimensional (3D) models, which facilitate clinical decision-making and improve treatment outcomes. Cinematic rendering (CR) is anovel visualization technique using physically based volume rendering to create photorealistic images from DICOM data. The aim of the present study was to tailor pre-existing CR reconstruction parameters for use in dental imaging with the example of the diagnostic 3D visualization of ectopic, impacted, and supplementary teeth.

METHODS

CR was employed for the volumetric image visualization of midface CT data sets. Predefined reconstruction parameters were specifically modified to visualize the presented dental pathologies, dentulous jaw, and isolated teeth. The 3D spatial relationship of the teeth, as well as their structural relationship with the antagonizing dentition, could immediately be investigated and highlighted by separate, interactive 3D visualization after segmentation through windowing.

RESULTS

To the best of our knowledge, CR has not been implemented for the visualization of supplementary and ectopic teeth segmented from the surrounding bone because the software has not yet provided appropriate customized reconstruction parameters for dental imaging. When employing our new, modified reconstruction parameters, its application presents a fast approach to obtain realistic visualizations of both dental and osseous structures.

CONCLUSIONS

CR enables dentists and oral surgeons to gain an improved 3D understanding of anatomical structures, allowing for more intuitive treatment planning and patient communication.

Path Tracing vs. Volume Rendering Technique in Post-Surgical Assessment of Bone Flap in Oncologic Head and Neck Reconstructive Surgery: A Preliminary Study

This study aims to compare a relatively novel three-dimensional rendering called Path Tracing (PT) to the Volume Rendering technique (VR) in the post-surgical assessment of head and neck oncologic surgery followed by bone flap reconstruction. This retrospective study included 39 oncologic patients who underwent head and neck surgery with free bone flap reconstructions. All exams were acquired using a 64 Multi-Detector CT (MDCT). PT and VR images were created on a dedicated workstation. Five readers, with different expertise in bone flap reconstructive surgery, independently reviewed the images (two radiologists, one head and neck surgeon and two otorhinolaryngologists, respectively). Every observer evaluated the images according to a 5-point Likert scale. The parameters assessed were image quality, anatomical accuracy, bone flap evaluation, and metal artefact. Mean and median values for all the parameters across the observer were calculated. The scores of both reconstruction methods were compared using a Wilcoxon matched-pairs signed rank test. Inter-reader agreement was calculated using Spearman's rank correlation coefficient. PT was considered significantly superior to VR 3D reconstructions by all readers (p < 0.05). Inter-reader agreement was moderate to strong across four out of five readers. The agreement was stronger with PT images compared to VR images. In conclusion, PT reconstructions are significantly better than VR ones. Although they did not modify patient outcomes, they may improve the post-surgical evaluation of bone-free flap reconstructions following major head and neck surgery.

Augmented Reality With Cinematic Rendered 3-Dimensional Images From Volumetric Computed Tomography Data

ABSTRACT

Recent advances in 3-dimensional visualization of volumetric computed tomography data have led to the novel technique of cinematic rendering (CR), which provides photorealistic images with enhanced surface detail and realistic shadowing effects that are generally not possible with older methods such as volume rendering. The emergence of CR coincides with the increasingly widespread availability of virtual reality (VR)/augmented reality (AR) interfaces including wearable headsets. The intersection of these technologies suggests many potential advances, including the ability of interpreting radiologists to look at photorealistic images of patient pathology in real time with surgeons and other referring providers, so long as VR/AR headsets are deployed and readily available. In this article, we will present our initial experience with viewing and manipulating CR images in the context of a VR/AR headset. We include a description of key aspects of the software and user interface, and provide relevant pictorial examples that may help potential adopters understand the initial steps of using this exciting convergence of technologies. Ultimately, trials evaluating the added value of the combination of CR with VR/AR will be necessary to understand the potential impact of these methods on medical practice.

Evaluation of the use of cadaveric computed tomography in anatomy education: An overview

OBJECTIVE

We aimed to explore to what extent the literature supports that the use of cadaveric computed tomography can play an important role in anatomy education.

MATERIALS AND METHODS

PubMed, SCOPUS, Education Resources Information Center and Cochrane Databases were searched for papers with purpose to explore the outcomes of the use of cadaveric computed tomography scans in anatomy education. The following data were obtained from each paper: authors, number of participants, type of study (comparative or not), level of outcome according to Kirkpatrick hierarchy, possible evaluation of statistical significance, acquisition of anatomical knowledge after the educational intervention and perceptions about the effectiveness of this intervention in anatomy learning.

RESULTS

Seven articles were included. Four of them evaluated students' knowledge after the use of cadaveric computed tomography scans in anatomy education and three papers evaluated only students' perceptions. Generally, the outcomes, which mainly concerned students' perceptions, were positive, while it was showed that students' academic performance may also be improved.

CONCLUSIONS

The outcomes of the use of cadaveric computed tomography scans in anatomy education encourage the implementation of this teaching modality in anatomy curricula. Further research, including comparative studies with evaluation of acquisition of students' knowledge, is needed to show if cadaveric computed tomography will be proved a remarkable supportive tool in anatomy educators' hands.

3D and cinematic rendering of abdominopelvic pathology in the peripartum period

3D with volume rendering and the more recently described technique of cinematic rendering are post-processing techniques that create reconstructions of cross sectional imaging data which enhance image interpretation. This review illustrates the potential applications of volume rendering, 3D, and cinematic rendering in the evaluation of abdominopelvic pathology in the peripartum period. These techniques show promise in improving visualization of pelvic structures, vascular mapping, highlighting textural differences between tissues, and improving understanding of spatial relationships.

Photorealistic three-dimensional visualization of fusion datasets: cinematic rendering of PET/CT

PURPOSE

Cinematic rendering (CR) is a method of photorealistic 3D visualization of volumetric imaging data. We applied this technique to fusion PET/CT data.

METHODS

Two recent PET/CT cases were selected, one each of prostate-specific membrane antigen (PSMA)-targeted ¹⁸F-DCFPyL, and somatostatin-receptor-targeted ⁶⁸ Ga-DOTATATE. Targeted radiotracers were selected in order to provide high-contrast images for this proof-of-principle study. Cinematic rendering was performed with an enhanced algorithm that incorporated internal lighting within the PET-avid organs and lesions to allow for a distinct visual signature.

RESULTS

The use of internal lighting for PET data provided CR of fused PET/CT scans. The interpreting radiologist must make judicious use of presets and cut planes in order to ensure important findings are not missed.

CONCLUSIONS

CR of PET/CT data provides a photorealistic means of visualizing complex fusion imaging datasets. Such visualizations may aid anatomic understanding for surgical or procedural applications, may improve teaching of trainees, and may allow improved communication with patients.

Photorealistic Depiction of Intracranial Tumors Using Cinematic Rendering of Volumetric 3T MRI Data

RATIONALE AND OBJECTIVES

Cinematic Rendering (CR) incorporates a complex lightning model that creates photorealistic models from isotropic 3D imaging data. The utility of CR in depicting volumetric MRI data for pre-therapeutic planning is discussed, with intracranial tumors as a demonstrative example.

MATERIALS AND METHODS

We present a series of Cinematically Rendered intracranial tumors and discuss their utility in multidisciplinary pre-therapeutic evaluation. Isotropic, high-resolution, volumetric MRI data was collected, and CR was performed utilizing a proprietary application, "Anatomy Education" Siemens, Munich, Germany.

RESULTS

Discrimination of cortex to white matter, brain surface to vessels, subarachnoid space to cortex and skull to intracranial structures was achieved and optimized by using various display settings on the Anatomy education application. Progressive removal of tissue layers allowed for a comprehensive assessment of the entire region of interest. Complex, small structures were demonstrated in very high detail. The depth and architecture of the sulci was appreciated in a format that more closely mimicked gross pathology than traditional imaging modalities. With appropriate display settings, the relationship of the cortical surface to the adjacent vasculature was also delineated.

CONCLUSION

CR depicts the anatomic location of brain tumors in a format that depicts the relative proximity of adjacent structures in all dimensions and degrees of freedom. This allows for better conceptualization of the pathology and greater ease of communication between radiologists and other clinical teams, especially in the context of pretherapeutic planning.

Clinical application of cinematic rendering in maxillofacial fractures

The purpose of this study was to evaluate the clinical application of cinematically rendered reconstructions of maxillofacial fractures. Ten surgeons and eight radiologists were shown three-dimensional images of 25 different patient cases, generated using both the volume rendering (VR) technique and the cinematic rendering (CR) technique. They were asked to mark the site of the fracture on the three-dimensional images and record the time this activity took. The effectiveness of the reconstructions to communicate with patients was assessed through the opinions of the surgeons and radiologists, as well as 25 patients. Subjective evaluations of the clinical value of the images were performed by the 18 surgeons and radiologists using a 10-item questionnaire. The percentages of correctly identified fractures of the nasal bone (P = 0.034), fracture dislocation (P < 0.001), and free bone fragments (P < 0.001) were significantly higher for CR images when compared to VR images, and identification took an average of 20.81 seconds for CR and 27.48 seconds for VR (P < 0.001). CR images were found to be more beneficial for communication with patients and scored higher for the display of fracture dislocation and free bone fragments than VR images (P < 0.05). CR images were found to have high clinical value in the visualization of maxillofacial fractures.

Cinematic rendering of paediatric musculoskeletal pathologies: initial experiences with CT

Cinematic rendering (CR) is a novel post-processing technique similar to volume rendering (VR), which allows for a more photorealistic imaging reconstruction by using a complex light modelling algorithm, incorporating information from multiple light paths and predicted photon scattering patterns. Several recent publications relating to adult imaging have argued that CR gives a better "realism" and "expressiveness" experience over VR techniques. CR has also been shown to improve visualisation of musculoskeletal and vascular anatomy compared with conventional CT viewing, and may help non-radiologists to understand complex patient anatomy. In this review, we provide an overview of how CR could be used in paediatric musculoskeletal imaging, particularly in complex diagnoses, surgical planning, and patient consent processes. We present a direct comparison of VR and CR reconstructions across a range of congenital and acquired musculoskeletal pathologies, highlighting potential advantages and areas for further research.

Three-dimensional perception of cinematic rendering versus conventional volume rendering using CT and CBCT data of the facial skeleton

The aim of this exploratory study is to analyse whether three-dimensional cinematic rendering image reconstructions offer advantages over conventional volume rendering in the visualisation of cone beam computed tomography (CBCT) and computed tomography (CT) images of the facial skeleton. This is of interest, as some information gets lost during the rendering process. This especially applies to structures in the background of the image and some surface information which can be lost. The commonly applied two-dimensional representation of CBCT or CT images in three different axes requires experience for interpretation. Cinematic rendering is a new three-dimensional post processing reconstruction technique, creating photo realistic visualisations, thus possibly enabling an easier interpretation of the images. In this study, ten investigators assessed ten separate patient cases of the orofacial skeleton. For each case, a conventional volume rendering image reconstruction and a cinematic rendering reconstruction of the same area was created. A specially designed questionnaire assessed both objective and subjective criteria of image perception. Objective criteria were assessed by predefined questions on the visual perception of anatomical image characteristics, showing the two reconstruction types of each case randomly to the investigators in two sessions. Subjective criteria were assessed via a visual analogue scale, showing both reconstructions simultaneously in a third session. The results show that cinematic rendering offers advantages especially in the evaluation of depth perception and three-dimensionality. Volume rendering shows advantages in surface sharpness. Cinematic Rendering was subjectively rated higher for almost all reconstructions. The cinematic rendering process however may cause loss of information and blurring of surfaces compared to volume rendering. With respect to the subjective impression, cinematic rendering scored better than volume rendering. The visualisation is perceived as being very close to reality.

Strengths and Weaknesses of Non-enhanced and Contrast-enhanced Cadaver Computed Tomography Scans in the Teaching of Gross Anatomy in an Integrated Curriculum

Cadaver-specific postmortem computed tomography (PMCT) has become an integral part in anatomy teaching at several universities. Recently, the feasibility of contrast-enhanced (CE)-PMCT has been demonstrated. The purpose of this study was to identify particular strengths and weaknesses of both non-enhanced and contrast-enhanced PMCT compared to conventional cadaver dissection. First, the students' perception of the learning effectiveness of the three different modalities have been assessed using a 34-item survey (five-point Likert scale) covering all anatomy course modules. Results were compared using the nonparametric Friedman Test. Second, the most frequent artifacts in cadaver CT scans, were systematically analyzed in 122 PMCT and 31 CE-PMCT data sets to quantify method-related limitations and characteristics. Perfusion quality was assessed in 57 vascular segments (38 arterial and 19 venous). The survey was answered by n = 257/320 (80.3%) students. Increased learning benefits of PMCT/ CE-PMCT compared to cadaver dissection were found in osteology (2/3 categories, P < 0.001), head and neck (2/5 categories, P < 0.01), and brain anatomy (3/3 categories, P < 0.01). Contrast-enhanced-PMCT was perceived particularly useful in learning vascular anatomy (10/10 categories, P < 0.01). Cadaver dissection received significantly higher scores compared to PMCT and CE-PMCT in all categories of the abdomen and thorax (7/7 categories, P < 0.001), as well as the majority of muscular anatomy (5/6 categories, P < 0.001). Frequent postmortem artifacts (total n = 28, native-phase n = 21, contrast injection-related n = 7) were identified and assessed. The results of this work contribute to the understanding of the value of integrating cadaver-specific PMCT in anatomy teaching.

3D Reconstruction Methods Purporting 3D Visualization and Volume Estimation of Brain Tumors

This work proposes the Crust algorithm for 3D reconstruction of brain tumor, an effective mechanism in the visualization of tumors for presurgical planning, radiation dose calculation. Despite the promising performance of Crust algorithm in reconstruction of Stanford models, it has not yet been considered in 3D reconstruction of brain tumor. Validation of the results is done using the comparison of the 3D models from two cutting edge techniques namely the Marching Cube and the Alpha shape algorithm. The obtained result shows that Crust algorithm provides the brain tumor model with an average quality of triangle meshes ranging from 0.85 to 0.95. Concerning the visual realism, the quality of Crust algorithm models is higher on comparison to the other models. Precision of tumor volume measurement by convex hull method is analysed by repeatability and reproducibility. The standard deviations of repeatability were between 2.03 % and 3.97 %. The experimental results show that Linear Crust algorithm produces high quality meshes with average quality of equilateral triangles close to 1.

Proposal of a Standardized Questionnaire to Structure Clinical Peer Reviews of Mortality and Failure of Rescue in Pancreatic Surgery

Background: Quality management tools such as clinical peer reviews facilitate root cause analysis and may, ultimately, help to reduce surgery-related morbidity and mortality. This study aimed to evaluate the reliability of a standardized questionnaire for clinical peer reviews in pancreatic surgery. Methods: All cases of in-hospital-mortality following pancreatic surgery at two high-volume centers (n = 86) were reviewed by two pancreatic surgeons. A standardized mortality review questionnaire was developed and applied to all cases. In a second step, 20 cases were randomly assigned to an online re-review that was completed by seven pancreatic surgeons. The overall consistency of the results between the peer review and online re-review was determined by Cohen’s kappa (κ). The inter-rater reliability of the online re-review was assessed by Fleiss’ kappa (κ). Results: The clinical peer review showed that 80% of the patient mortality was related to surgery. Post-operative pancreatic fistula (POPF) (36%) followed by post-pancreatectomy hemorrhage (PPH) (22%) were the most common surgical underlying (index) complications leading to in-hospital mortality. Most of the index complications yielded in abdominal sepsis (62%); 60% of the cases exhibited potential of improvement, especially through timely diagnosis and therapy (42%). There was a moderate to substantial strength of agreement between the peer review and the online re-review in regard to the category of death (surgical vs. non-surgical; κ = 0.886), type of surgical index complication (κ = 0.714) as well as surgical and non-surgical index complications (κ = 0.492 and κ = 0.793). Fleiss’ kappa showed a moderate to substantial inter-rater agreement of the online re-review in terms of category of death (κ = 0.724), category of common surgical index complications (κ = 0.455) and surgical index complication (κ = 0.424). Conclusion: The proposed questionnaire to structure clinical peer reviews is a reliable tool for root cause analyses of in-hospital mortality and may help to identify specific options to improve outcomes in pancreatic surgery. However, the reliability of the peer feedback decreases with an increasing specificity of the review questions.