Three-dimensional Virtual Reconstruction Research Articles

Based on 3D Virtual Reconstruction of Modern City Landscape Sculpture Planning Design

INTRODUCTION: With the continuous advancement of urbanization, urban landscape sculpture plays an increasingly important role in modern urban planning. Traditional planning and design methods make it challenging to demonstrate the three-dimensional sense and artistry of sculpture fully; therefore, this study explores a new method of planning and designing modern urban landscape sculpture based on three-dimensional virtual reconstruction.OBJECTIVES: This study aims to enhance the three-dimensional sense and artistry of urban landscape sculpture planning and design through three-dimensional virtual reconstruction technology to meet the needs of modern urban development better. By using advanced technical means, the planning and design can be made more intuitive and specific and provide urban residents with a more artistic public space.METHODS: The study adopts advanced three-dimensional virtual reconstruction technology, combined with urban planning and design theory, to plan and design modern urban landscape sculpture. Firstly, relevant literature on urban planning and sculpture design is collected to understand the existing design concepts and technical means. Secondly, a detailed virtual reconstruction of the sculpture is carried out by using three-dimensional modeling software to show the three-dimensional effect of the sculpture. Finally, the design scheme is optimized and improved through fieldwork and expert review.RESULTS: Through three-dimensional virtual reconstruction technology, this study successfully shows the whole picture of modern urban landscape sculpture. The design scheme not only has a three-dimensional sense but it has also been improved in artistry. The results of fieldwork and expert evaluation show that the new design scheme is more in line with the needs of urban development and adds a unique artistic atmosphere to the urban space.CONCLUSION: This study has achieved positive results in the field of modern urban landscape sculpture planning and design through 3D virtual reconstruction technology. The new design method not only provides a more specific tool for urban planners but also creates a more creative and artistic public space for urban residents. In the future, the application of this method in different urban contexts can be further explored and expanded to inject more innovation and vitality into urban planning and sculpture design.

Three-Dimensional Virtual Reconstruction of External Nasal Defects Based on Facial Mesh Generation Network.

(1) Background: In digital-technology-assisted nasal defect reconstruction methods, a crucial step involves utilizing computer-aided design to virtually reconstruct the nasal defect's complete morphology. However, current digital methods for virtual nasal defect reconstruction have yet to achieve efficient, precise, and personalized outcomes. In this research paper, we propose a novel approach for reconstructing external nasal defects based on the Facial Mesh Generation Network (FMGen-Net), aiming to enhance the levels of automation and personalization in virtual reconstruction. (2) Methods: We collected data from 400 3D scans of faces with normal morphology and combined the structured 3D face template and the Meshmonk non-rigid registration algorithm to construct a structured 3D facial dataset for training FMGen-Net. Guided by defective facial data, the trained FMGen-Net automatically generated an intact 3D face that was similar to the defective face, and maintained a consistent spatial position. This intact 3D face served as the 3D target reference face (3D-TRF) for nasal defect reconstruction. The reconstructed nasal data were extracted from the 3D-TRF based on the defective area using reverse engineering software. The '3D surface deviation' between the reconstructed nose and the original nose was calculated to evaluate the effect of 3D morphological restoration of the nasal defects. (3) Results: In the simulation experiment of 20 cases involving full nasal defect reconstruction, the '3D surface deviation' between the reconstructed nasal data and the original nasal data was 1.45 ± 0.24 mm. The reconstructed nasal data, constructed from the personalized 3D-TRF, accurately reconstructed the anatomical morphology of nasal defects. (4) Conclusions: This paper proposes a novel method for the virtual reconstruction of external nasal defects based on the FMGen-Net model, achieving the automated and personalized construction of the 3D-TRF and preliminarily demonstrating promising clinical application potential.

Three-dimensional virtual reconstruction guides robot-assisted partial nephrectomy in a horseshoe kidney.

Three-dimensional virtual reconstruction guides robot-assisted partial nephrectomy in a horseshoe kidney.

Preservation and Reproduction of an Ancient Human Humerus through X-ray Microscopy and 3D Printing

The combination of X-ray Microscopy (XRM) and three-dimensional virtual reconstruction has enabled the digitization and restoration of broken artifacts. By scanning, acquiring, and virtually stitching together the 3D reconstructions of individual broken pieces, damaged relics can be visualized as if they were intact objects. These virtually reconstructed samples can then be reproduced as physical copies through 3D printing, allowing for the sharing of rare findings in museum exhibits worldwide so that printed copies can be displayed for public exposure, while the original pieces remain preserved. This paper aims to demonstrate the application of these reconstruction principles to an artificially modified human humerus belonging to the II–I millennium BC. The humerus was bent into the shape of a serpent for ritual purposes related to the ancient “Snake Cult”, which was widespread in the Persian Gulf area during the Iron Age. Following the scanning and software elaboration processes, the pieces were printed in Polylactic Acid (PLA) as a single object and made available to the public, thus giving new life to a unique piece of history.

"Mixed Reality" in patient education prior to abdominal aortic aneurysm repair.

Background: To investigate the usability of Mixed-Reality (MR) during patient education in patients scheduled for abdominal aortic aneurysm (AAA) repair. Patients and methods: Consecutive patients scheduled for elective AAA repair were block-randomized in either the Mixed-Reality group (MR group) or the conventional group (control group). Patients of both groups were educated about open and endovascular repair of their respective AAA. The MR group was educated using a head-mounted display (HMD) demonstrating a three-dimensional virtual reconstruction of the respective patient's vascular anatomy. The control group was educated using a conventional two-dimensional monitor to display the patient's vasculature. Outcomes were informational gain as well as patient satisfaction with the educational process. (DRKS-ID:DRKS00025174). Results: 50 patients were included with 25 patients in either group. Both groups demonstrated improvements in scores in the Informational Gain Questionnaire (IGQ) when comparing pre- and post-education scores. (MR group: 6.5 points (±1.8) versus 7.9 points (±1.5); Control group: 6.2 points (±1.8) versus 7.6 points (±1.6); p<0.01) There was no significant difference between the MR group and the control group either in informational gain (MR group: 1.4±1.8; Control group: 1.4±1.8; p=0.5) nor in patient satisfaction scores (MR group: mean 18.3 of maximum 21 points (±3.7); Control group: mean 17 of 21 points (±3.6); p=0.1) Multiple regression revealed no correlation between the use of MR and informational gain or patient satisfaction. Usability of the system was rated high, and patients' subjective assessment of MR was positive. Conclusions: The use of MR in patient education of AAA patients scheduled for elective repair is feasible. While patients reported positively on the use of MR in education, similar levels of informational gain and patient satisfaction can be achieved with MR and conventional methods.

Neuroanatomical Study and Three-Dimensional Cranial Reconstruction of the Brazilian Albian Pleurodiran Turtle Euraxemys essweini

Pleurodira represent one of the two clades that compose the crown Testudines, and their temporal range is Late Jurassic–present. However, knowledge about the neuroanatomy of extinct pleurodires is still very limited. In this context, scarce neuroanatomical information about the Cretaceous clade Euraxemydidae is currently available, limited to some characters of the Moroccan Cenomanian Dirqadim schaefferi. In the present work, we perform the detailed neuroanatomical study of its sister taxon, the Brazilian Albian Euraxemys essweini, based on the analysis of the skull of its holotype and only known individual of the species. The detailed virtual three-dimensional reconstruction of all its cranial bones is performed, also improving the information about its osseous anatomy. The different neuroanatomical cavities (i.e., cranial, nasal, and labyrinthic ones) and canals (i.e., nervous and circulatory ones) are compared with those identified thus far for other extinct and extant members of the Pleurodira in order to characterize the neuroanatomy of the extinct clade Euraxemydidae in detail.

Minimally invasive and invasive liver surgery based on augmented reality training: a review of the literature.

A liver surgeon's knowledge of anatomy is critical. Due to the patient's small field of vision, patient specific, complex nerve system, and other factors, even a minor loss can result in irreversible damage. Surgeons could benefit from the use of augmented reality (AR) technology, which would bring three-dimensional image data into the operating room. AR visualization can improve surgical procedures, facilitate intraoperative planning, and enhance surgical guidance for the anatomy of interest, all of which contribute to the application's minimal invasiveness. This literature review on image guidance in liver surgery provides the reader with information about AR techniques. To ascertain the current state of Augmented reality technology's application in liver surgery, a PubMed and Embase search were conducted using the following keywords: < (Augmented reality) AND (liver surgery) > and < 'Augmented reality' AND 'liver surgery' > (publication date from January 1991 until Jun 2022). The query yielded a total of 205 publications-excluded papers in other languages, virtual reality (VR), and reviews leaving 135 studies for review. After removing duplication, the titles and abstracts of those studies were manually reviewed. Finally, 31 pertinent studies were determined to be pertinent to the subject. Generally, augmented reality technology includes preoperative planning and three-dimensional reconstruction, intraoperative three-dimensional navigation, and registration. Visualization may be aided by virtual three-dimensional reconstruction models of the liver from Computed Tomography/Magnetic Resonance Imaging scans. The results demonstrate that by utilizing augmented reality technology, blood vessels and tumor structures in the liver can be visualized during surgery, allowing for precise navigation during complicated surgical procedures. Augmented reality has been demonstrated to be safe and effective in both minimally invasive and invasive liver surgery. With recent advancements and significant effort by liver surgeons, augmented reality technologies have the potential to increase hepatobiliary surgical procedures dramatically. However, further clinical trials will be necessary to evaluate augmented reality as a tool for reducing post-operative morbidity and mortality. The impact of these cutting-edge computerized image guidance techniques on clinically relevant outcome parameters should be assessed in the future.

Structure characterization of interior invisible single grain boundary by nanorobot pick-and-place grain in bulk ZnO under SEM

• Invisible grain boundary is first creatively characterized using nanorobot in SEM. • Irregular shape of invisible grain boundary can be exhibited in plane X-Y. • Three-dimensional virtual reconstruction is utilized to verify irregular structure. In order to independently characterize invisible structure, a new approach is first creatively proposed to express interior invisible single grain boundary using nanorobot pick-and-place single grain in SEM. Picking of a single grain handled by single probe and then rolling-over placing manipulated by dual-probes can be sequentially conducted by nanorobot. The upper and lower invisible surface interface layer profile of single grain can be extracted by SEM imaging in plane X-Y. Experimental results demonstrate that interior invisible single grain boundary characterized by nanorobot seems to be reasonably feasible. The upper and lower surface structures of single grain in plane X-Y can also be virtually modeled by 3D software. This method can further provide a unique characterization approach of interior invisible structure of single grain boundary.

Virtual Reconstruction in 3D Documentation of Built Cultural Heritage

The documentation process is considered one of the most important procedures in preserving the built cultural heritage. Studies have proven that there are many ancient architectural structures that are constantly deteriorating or disappearing, so it is important to document them correctly and accurately to preserve them for future generations. In recent decades, the field of architectural documentation has witnessed great developments. The use of innovative technologies has contributed to the development of the role of virtual architecture in preserving archaeological heritage. Virtual 3D reconstruction models have become the future of representing the archaeological heritage, whether existing or even vanished. Therefore, the research aims to study the concept of virtual three-dimensional reconstruction and the steps to create virtual three-dimensional scenes, and what are the possibilities of its application in the field of documentation of architectural heritage. The research showed that virtual reconstructions have many possibilities in the field of digital documentation and present it to the public in a way that can be roamed and interacted with. But on the other hand, it also has some challenges, the most important of which is the high cost, it needs computer and software experts and there are many people in the community who are not familiar enough with how to use the interactive tools of virtual reconstruction.

Accessing interactively the spatio-temporal data-model of an archaeological site through its 3D virtual reconstruction

Information and communication technologies are increasingly used in all archaeological processes. However, archaeologists sometimes consider them as intrusive, too far from the traditional work methodology and even a hindrance. In this article we propose a framework to allow natural and therefore intuitive access to the archaeological record. The information retrieval process is carried out through a three-dimensional virtual reconstruction of the archaeological site. In this system, navigation and interaction with the three-dimensional elements of the environment triggers database queries. To achieve such functionality, a client-server architecture is designed in which the server maintains a spatio-temporal database with heterogeneous information, including the 3D models of the finds. To do this, a virtual replica of the site is created considering spatial restrictions and topological relationships among the finds.

Algorithm of 3D Virtual Reconstruction of Ancient Buildings in Qing Dynasty Based on Image Sequence

Aiming at the problem of low accuracy and poor integrity of traditional Qing Dynasty ancient architecture 3D virtual reconstruction algorithm, a 3D virtual reconstruction algorithm of Qing Dynasty ancient architecture based on image sequence is proposed. Acquire the sequence images of ancient buildings in the Qing Dynasty through the pinhole camera model, analyze the projective space and reconstruction space of the sequence images, redefine the similarity measurement coefficient according to the improved 2DPCA-SIFT feature matching algorithm, match the feature points of the ancient architecture images in the Qing Dynasty, and use random sampling to be consistent. The algorithm solves the basic matrix, removes the interference error in the image reconstruction process, and realizes the design of the three-dimensional reconstruction algorithm through image sequence fusion. The experimental results show that, compared with the existing methods, the completeness of the three-dimensional virtual reconstruction 3D model of ancient Qing Dynasty buildings constructed by the designed algorithm is 87.26% on average, and the completeness and accuracy of the 3D model construction of the subparts of the ancient Qing Dynasty buildings of this method are better. The height of the building fully shows that the designed building has good performance in the construction of the three-dimensional model of ancient buildings in the Qing Dynasty.

A systematic review of the clinical value and applications of three-dimensional virtual reconstructions in renal tumors.

Three-dimensional (3D) virtual reconstruction (VR) in the medical sciences has emerged as a novel, exciting and effective tool, with promising results for patients, trainees, and even experienced surgeons. The purpose of this review is to summarize the information on the clinical value and applications of 3D VR in renal tumors published in the last ten years. A literary search of PubMed-MEDLINE databases was performed to identify studies reporting the clinical application and usefulness of 3D VR models in renal tumors. Thirty-seven studies were found to meet the selection criteria and were included in the analysis. Most studies have provided a quantitative assessment focused on the accuracy of 3D VR models in replication of anatomy and renal tumor, on measuring 3D tumor volume and on the clinical value and utility of 3D VR in pre-surgical planning and simulation of renal procedures, with significant reductions of intraoperative complications. Fourteen studies provided a qualitative assessment of the usefulness of 3D VR models, with results showing an improved patient understanding of renal anatomy and pathology, improved undergraduate and postgraduate urology education. Moreover, 3D printing technology is a novel technique, and we are currently in the dynamic era, expanding into new surgical nephron-sparing procedures and the development of printed kidneys for transplantation.

PEEK-Barium sulfate composite for three-dimensional virtual reconstruction of a printed human in vitro model using CT

PurposeThe purpose of this study is to test the concept of a relatively low cost but biocompatible customized surgical guide printing method using a new composite material for the FDM process to support accurate virtual model reconstruction in CT.Design/methodology/approachCurrent additive manufacturing printed surgical guides have problems of scanning artifacts or low computed tomography (CT) values for virtual model reconstruction in CT-assisted surgical operations. These tools always face difficulties in precise positioning due to the effect of human soft tissues and manually made unstable landmarks. To solve this problem, this paper proposes a modified material, polyetheretherketone powder mixed with barium sulfate powder, for printing customized surgical guides with relatively low cost to support a synchronized scanning strategy, for the accurate reconstruction of human tissues and in vitro models.FindingsA set of benchmarking experiments and clinical simulation cases were conducted. The results showed that the proposed solution can be used to print surgical guides to form stable and clear CT graphs for three-dimensional digital model reconstruction. Human tissues and in vitro models can be accurately reconstructed using clear CT graphs without any scanning artifacts or difficulties in image segmentation for virtual model reconstruction, thus facilitating accurate operation guidance and positioning.Originality/valueThis method has wide application potential for printing modular or customized surgical guides with low cost and reusability, especially for surgical operations using CT-assisted navigation systems in underdeveloped regions where medical device costs are a critical issue.

Simulation of surgery for supratentorial gliomas in virtual reality using a 3D volume rendering technique: a poor man's neuronavigation.

Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described. The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows. The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs). Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.

Modified Takazawa anatomical classification of renal pelvicalyceal system based on three-dimensional virtual reconstruction models.

BackgroundPrevious classification of renal pelvicalyceal anatomical structure may be difficult to intuitively understand and unpractical for endourological surgery. We aim to put forward a modified Takazawa anatomical classification of renal pelvicalyceal system based on three-dimensional (3D) virtual reconstruction models for endourological surgery.MethodsWe retrospectively collected data on 225 patients (320 kidneys) in total between Apr. 2017 and Dec. 2020, spatial anatomical structure of renal pelvis and calyces were modeled and corresponding morphological parameters were measured after 3D virtual reconstruction of computed tomography urography (CTU). The modified Takazawa renal pelvicalyceal anatomical classification was advanced based on the renal pelvicalyceal morphological parameters [bifurcated branches of renal pelvis, cross sectional area of renal pelvis and ureteropelvic junction (UPJ), infundibuloureteral angle (IUA), lower pole infundibular calyceal length (IL)] by 3D virtual reconstruction models, and comparison of renal pelvicalyceal system morphological parameters were performed to evaluate the differences in various classification types of renal pelvis and calyces.ResultsAnatomical structure of renal pelvis and calyces were divided into two main types (Type A and Type B) according to renal pelvic branch patterns. A single pelvis without bifurcated branch was regarded as Type A (62%) and subclassified into three subtypes: Type A1 (22%), Type A2 (27%) and Type A3 (13%), the slimline pelvis was classified as Type A1, the typical pelvis as Type A2 and the broad pelvis as Type A3. A divided pelvis with bifurcated branches was seen as Type B (38%) and subclassified into two subtypes: Type B1 (15%) with the wide and flat lower calyx branch, Type B2 (23%) with the narrow and steep lower calyx branch.ConclusionsPrevious studies have reported that the visualization and classification of renal pelvicalyceal anatomical structure by endocast, autopsy, ultrasonography and excretory urography, the modified Takazawa classification system based on 3D virtual reconstruction models enables to standardized different anatomical morphology of renal pelvicalyceal system and provide intuitive and concise information on anatomy, thus leading to the improvement in treatment modality.

Real-time navigation by three-dimensional virtual reconstruction models in robot-assisted laparoscopic pyeloplasty for ureteropelvic junction obstruction: our initial experience.

BackgroundThe aim of this study was to evaluate the effectiveness and safety of real-time surgical navigation by three-dimensional (3D) virtual reconstruction models in robot-assisted laparoscopic pyeloplasty (RALP).MethodsBetween November 2018 and January 2020, 38 patients with ureteropelvic junction obstruction (UPJO) who underwent RALP were retrospectively enrolled. The operations were assisted in real time by 3D models in 16 patients, while 22 patients underwent surgery without navigation. Based on whether patients had a prior intervention history, crossing vessels or congenital deformities, we further divided them into the “complicated UPJO” cohort and the “regular UPJO” cohort for subgroup analysis. The demographic characteristics, intraoperative parameters, perioperative data and follow-up data were recorded and compared between the groups.ResultsAll of the procedures were successfully performed without open or laparoscopic conversion. The mean dissection time to the UPJ was shorter in the navigation group than in the non-navigation group, both in the whole cohort (15.3 vs. 24.8 min, P=0.011) and in the complicated cohort (15.4 vs. 27.5 min, P=0.004), while there was no significant difference in the regular cohort. The overall operative time and estimated blood loss in the navigation group tended to be less, although the difference was not statistically significant. No difference in anastomosis time, postoperative hospital stay or complications was noted between the two groups in either cohort. At a mean follow-up of 11.2 months, the overall success rate was 94.7% (36/38), and there was no significant difference between the two groups.ConclusionsReal-time navigation by 3D virtual reconstruction models might be helpful to improve surgical efficiency and safety of RALP by facilitating the dissection around the UPJ, especially for cases of complicated UPJO. However, the prospective study with larger sample size is further needed to confirm the results.

Walking among Mammoths. Remote Sensing and Virtual Reality Supporting the Study and Dissemination of Pleistocene Archaeological Sites: The Case of Fuente Nueva 3 in Orce, Spain

Remote sensing is a useful tool for the documentation of archaeological sites. The products derived from a photogrammetric project applied to archaeology such as orthophotos and three-dimensional virtual reconstruction (3DVR), allow for detailed study of the Fuente Nueva 3 site in Orce. In our study of the Fuente Nueva 3 site in Orce, we used 3DVR intensively to map out the morphometric features of mammoth tusks exposed on the surface and a geological fault affecting the site’s deposits. To do so, we used imagery captured since 2017 in order to follow the evolution of ongoing excavations during each subsequent field season. We also integrated the 3DVR model in a videogame environment, to create a virtual reality (VR) that allows a VR navigation experience around the scenario using a head mounted display like Oculus Rift. The main features of this VR experience are: (1) It is ideal for the diffusion of archaeological contents since it permits an attractive presentation mode thanks to stereo visualization and realistic immersion sensations; (2) it provides a high level of detail all along the navigation experience, without incurring any damage to the archaeological remains; (3) it allows users to observe more details than they would in an in situ visit to the site; (4) it makes it possible to convert an archaeological site into portable heritage, opening up the possibility to extend visits to vulnerable groups: specifically those with reduced mobility. Our results show that using VR should permit enhancements to a visitor’s experience and contribute to the socio-economic development of the town of Orce, one of the Spanish municipalities with the lowest income.

Virtual Reconstruction of Petrovskoe-Alabino Manor near Moscow: Research Sources, Methods and Technologies

The article describes methods and technologies of virtual 3D architectural historical reconstruction by the example of the exterior restoration process of Petrovskoye-Alabino manor (18th century) located in Naro-Fominsk District of Moscow Oblast. Currently the object is ruined, the interiors have been completely lost, the facades have also been almost unpreserved and the park has completely disappeared. Petrovskoe-Alabino was a summer country estate built by Nikita Akinfievich Demidov for his wife Aleksandra Evtikhievna who had not seen the manor completion. Having not achieved its main purpose, the manor, despite its unique appearance and aesthetic splendor, did not become famous and left no noticeable traces in historical sources. The primary purpose of the estate determined its special architectural type that is "Monplaisir" which is not often found in Russia. The manor was ruined in the 20th century and is now unprotected. It has not been reconstructed before and all the studies at stake are rather art reviews than historical studies. This article emphasizes the need to preserve cultural heritage and record the current state of destroyed objects as well as describes the process of virtual three-dimensional reconstruction of the manor based on archival and published materials as well as those collected during the research. The work grounds on drawings, sketches and measurements made by professional commissions in the 20th century as well as photographs of various eras, text descriptions of the manor and a set of graphic files created during the process of aerial and land photography of the current state of Petrovskoe-Alabino. Not only have the buildings of the complex been reconstructed, but also the courtyard, the main park alley and the landscape of the main manor territory. The work was carried out in close cooperation with the Central State Archive of Moscow Oblast.

Computed tomography angiography findings of abdominal aortic disease: A review of emergencies

Introduction. The aorta is a major blood vessel that supplies all segments of the human body. Acute aortic syndrome is a term that implies a life-threatening aortic disease. Due to the speed of examination and widespread availability, computed tomography angiography is a front-line diagnostic modality for emergencies and diseases of the abdominal aorta. The aim of this study was to provide a wide range of potentially life-threatening abnormalities of the abdominal aorta in daily clinical and radiological practice through a series of computed tomography angiography images and three-dimensional virtual reconstruction. Abdominal aortic aneurysm is defined as a 50% increase in diameter more than the normal arterial diameter. One of the most important complications of an aneurysm is a rupture that can be acute or chronic, presenting with various clinical manifestations. Aortic dissections are caused by abnormality of the tunica media layer, forming an intimal-medial flap and two types of lumen. A penetrating aortic ulcer may erode through the internal elastic lamina of the aortic wall and allow formation of hematoma within the tunica media. Occlusive disease of the abdominal aorta may refer to the late stage of chronic aortoiliac occlusive disease, whereas the acute and/or subacute form occurs due to sudden thrombosis or occlusion. Conclusion. The recognition of specific radiological signs of abdominal aortic disease using computed tomography angiography contributes to optimal treatment of patients and reduces mortality.

Traditional face-bow transfer versus three-dimensional virtual reconstruction in orthognathic surgery

Face-bow transfer is an essential step in articulator-based orthognathic surgery planning. However, it can be a source of inaccuracy. Virtual computer-based planning avoids this error through the use of direct patient-related three-dimensional imaging data. The aim of this prospective observational study was to determine the error of face-bow transfer three-dimensionally and correlate it to the different types of malocclusion. Orthognathic surgery performed on 38 patients (10 male, 28 female; mean (standard deviation) age 24.7 (6.9) years) was planned twice: first articulator-based with plaster models and second computer-based with surgery planning software. Both models were digitized and compared regarding the angle between the Frankfort horizontal plane and the occlusal plane. In most cases, the angle in the sagittal dimension was higher in the articulator-based model than in the computer-based model. The angle in the transverse dimension was as often under- as over-represented. The type of malocclusion, i.e. skeletal class, vertical relationship, and degree of asymmetry, had no significant impact on the amount of error. In conclusion, this study indicates that computer-based planning should be considered as an advantageous alternative in orthognathic surgery planning.