Virtual Reconstruction Research Articles

LOW-COST WORKFLOW FOR 3D URBAN FOREST VIRTUAL RECONSTRUCTION

Abstract. This contribution addresses, on one hand, the increasing need and demand of 3D data (e.g., point clouds) in urban forestry – for monitoring, analysis, and visualisation purposes –, on the other, the lack of standardised procedures to manage them, also towards engaging and empowering the broader audience. Practitioners in landscape architecture – as a potential bridging field between forestry, geomatics and computer science – could ‘smartly’ manage dynamic ecosystems as forests, parks, and gardens in urban contexts if efficiently provided with digital tools, technologies and techniques for design-oriented information. To this end, a low-cost workflow for 3D virtual reconstruction of under-storey urban vegetation is here proposed to allow exploiting the aesthetic, analytical, and generative potential of 3D point clouds in landscape and urban design. As a proof-of-concept, a combination of a wide range of methods (e.g., spherical photogrammetry, point cloud modelling, virtual reality), tools (e.g., 360° camera, tablet with lidar sensor), and software (e.g., Agisoft Metashape, 3DF Zephyr, CloudCompare, Unity) is tested in the development of a virtual plot of the Mesiano University park in Trento (Italy). Covering all the different steps of the information management activities (namely acquisition, processing, and visualisation), the presented workflow enables a GIS-based, texturized, real-world 3D point cloud rendering of urban forests to be intuitively and interactively experienced in Virtual Reality.

Computational techniques for virtual reconstruction of fragmented archaeological textiles

Archaeological artifacts play important role in understanding the past developments of the humanity. However, the artifacts are often highly fragmented and degraded, with many details and parts missing due to centuries’ long degradation. Archaeologists and conservators attempt to reconstruct the original state of the objects either physically or virtually. This process includes characterizing and matching fragments’ features to identify which ones belong together. However, this process currently requires an extensive and tedious manual labor. Recent development in computational techniques gave rise to computer-assisted ways of virtual reconstruction, where the computer suggests solutions to the puzzle of scattered fragments and supplements or fully replaces manual labor. However, the capabilities of computational techniques remain limited in many aspects. This review summarizes the state-of-the-art computational techniques for puzzle and virtual reconstruction problems in cultural heritage applications, in general – with a particular interest in archaeological textiles. We overview existing computational methods, their applications and limitations. Afterward, based on the current knowledge gaps, we discuss where the field should go next.

Digital Approach in Conservation of Heritage: 3D Virtual Reconstruction Applications in Ancient Cities

Digital Approach in Conservation of Heritage: 3D Virtual Reconstruction Applications in Ancient Cities

Effect of Virtual Aortic Arch Reconstruction After Norwood Procedure on Cardiac Function, Energy Efficiency, and Wall Shear Stress from Multiscale Simulations

Effect of Virtual Aortic Arch Reconstruction After Norwood Procedure on Cardiac Function, Energy Efficiency, and Wall Shear Stress from Multiscale Simulations

Reduction of contrast medium for transcatheter aortic valve replacement planning using a spectral detector CT: a prospective clinical trial

IntroductionThis study investigated the use of dual-energy spectral detector computed tomography (CT) and virtual monoenergetic imaging (VMI) reconstructions in pre-interventional transcatheter aortic valve replacement (TAVR) planning. We aimed to determine the minimum required contrast medium (CM) amount to maintain diagnostic CT imaging quality for TAVR planning.MethodsIn this prospective clinical trial, TAVR candidates received a standardized dual-layer spectral detector CT protocol. The CM amount (Iohexol 350 mg iodine/mL, standardized flow rate 3 mL/s) was reduced systematically after 15 patients by 10 mL, starting at 60 mL (institutional standard). We evaluated standard, and 40- and 60-keV VMI reconstructions. For image quality, we measured signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and diameters in multiple vessel sections (i.e., aortic annulus: diameter, perimeter, area; aorta/arteries: minimal diameter). Mixed regression models (MRM), including interaction terms and clinical characteristics, were used for comparison.ResultsSixty consecutive patients (mean age, 79.4 ± 7.5 years; 28 females, 46.7%) were included. In pre-TAVR CT, the CM reduction to 40 mL is possible without affecting the image quality (MRM: SNR: –1.1, p = 0.726; CNR: 0.0, p = 0.999). VMI 40-keV reconstructions showed better results than standard reconstructions with significantly higher SNR (+ 6.04, p < 0.001). Reduction to 30 mL CM resulted in a significant loss of quality (MRM: SNR: –12.9, p < 0.001; CNR: –13.9, p < 0.001), regardless of the reconstruction. Across the reconstructions, we observed no differences in the metric evaluation (p > 0.914).ConclusionAmong TAVR candidates undergoing pre-interventional CT at a dual-layer spectral detector system, applying 40 mL CM is sufficient to maintain diagnostic image quality. VMI 40-keV reconstructions improve the vessel attenuation and are recommended for evaluation.Clinical relevance statementContrast medium reduction to 40 mL in pre-interventional transcatheter aortic valve replacement CT using dual-energy CT maintains image quality, while 40-keV virtual monoenergetic imaging reconstructions enhance vessel attenuation. These results offer valuable recommendations for interventional transcatheter aortic valve replacement evaluation and potentially improve nephroprotection in patients with compromised renal function.Key Points• Patients undergoing transcatheter aortic valve replacement (TAVR), requiring pre-interventional CT, are often multimorbid with impaired renal function.• Using a spectral detector dual-layer CT, contrast medium reduction to 40 mL is feasible, maintaining diagnostic image quality.• The additional application of virtual monoenergetic image reconstructions with 40 keV improves vessel attenuation significantly in clinical practice.

Coronary calcium scoring on virtual non-contrast and virtual non-iodine reconstructions compared to true non-contrast images using photon-counting computed tomography

ObjectivesTo compare coronary artery calcification (CAC) scores measured on virtual non-contrast (VNC) and virtual non-iodine (VNI) reconstructions computed from coronary computed tomography angiography (CCTA) using photon-counting computed tomography (PCCT) to true non-contrast (TNC) images.MethodsWe included 88 patients (mean age = 59 years ± 13.5, 69% male) who underwent a TNC coronary calcium scan followed by CCTA on PCCT. VNC images were reconstructed in 87 patients and VNI in 88 patients by virtually removing iodine from the CCTA images. For all reconstructions, CAC scores were determined, and patients were classified into risk categories. The overall agreement of the reconstructions was analyzed by Bland–Altman plots and the level of matching classifications.ResultsThe median CAC score on TNC was 27.8 [0–360.4] compared to 8.5 [0.2–101.6] (p < 0.001) on VNC and 72.2 [1.3–398.8] (p < 0.001) on VNI. Bland–Altman plots depicted a bias of 148.8 (ICC = 0.82, p < 0.001) and − 57.7 (ICC = 0.95, p < 0.001) for VNC and VNI, respectively. Of all patients with CACTNC = 0, VNC reconstructions scored 63% of the patients correctly, while VNI scored 54% correctly. Of the patients with CACTNC > 0, VNC and VNI reconstructions detected the presence of coronary calcium in 90% and 92% of the patients. CACVNC tended to underestimate CAC score, whereas CACVNI overestimated, especially in the lower risk categories. According to the risk categories, VNC misclassified 55% of the patients, while VNI misclassified only 32%.ConclusionCompared to TNC images, VNC underestimated and VNI overestimated the actual CAC scores. VNI reconstructions quantify and classify coronary calcification scores more accurately than VNC reconstructions.Clinical relevance statementPhoton-counting CT enables spectral imaging, which might obviate the need for non-contrast enhanced coronary calcium scoring, but optimization is necessary for the clinical implementation of the algorithms.Key Points• Photon-counting computed tomography uses spectral information to virtually remove the signal of contrast agents from contrast-enhanced scans.• Virtual non-contrast reconstructions tend to underestimate coronary artery calcium scores compared to true non-contrast images, while virtual non-iodine reconstructions tend to overestimate the calcium scores.• Virtual non-iodine reconstructions might obviate the need for non-contrast enhanced calcium scoring, but optimization is necessary for the clinical implementation of the algorithms.

One, Two, Three! Can Everybody Hear Me? Acoustics of Roman Contiones. Case Studies of the Capitoline Hill and the Temple of Bellona in Rome

Abstract Rhetoric was one of the cornerstones of Roman education and public speaking, the essence of being a Roman politician. The speakers attempted to captivate the audience with their style and convince them of their arguments. Studying the audience is therefore just as important as investigating the speakers and their speeches. The aim of this article is to estimate the number of people who could intelligibly hear a speaker delivering a speech from two speaking platforms located in the city of Rome: the podium of the Temple of Bellona in the Campus Martius (in the Late Republican and Late Augustan periods) and the Capitoline Temple. To do this, we built virtual reconstructions of both venues according to the current state of knowledge about them, taking into account the geometry of the space as well as the materials from which they were built. On the models thus prepared, we carried out acoustic simulations for three different levels of background noise (36, 49, and 55 dBA), resulting in Speech Transmission Index maps. The results became the basis upon which we estimated the size of the maximum potential crowds that could hear speech intelligibly, using two methods based on the behaviour of contemporary crowds. We further compared our results with those of previous studies that concern other speaking platforms in Rome.

Abstract 15620: Diagnostic Accuracy of Virtual Non-Contrast CT for Aortic Valve Stenosis Severity Evaluation

Introduction: Computed tomography (CT) aortic valve calcium (AVC) score has important prognostic and diagnostic value in patients with aortic stenosis, especially in those evaluated for TAVR, but at the expense of an additional non-contrast scan. Dual-energy CT (DECT) allows virtual non-contrast reconstructions (VNC) from conventional contrast acquisitions. Aims: Compare the diagnostic performance of VNC-AVC score as compared to TNC-AVC score for identifying severe AS. Methods: We prospectively included patients undergoing pre-TAVR CT with a DECT system (IQon, Philips). TNC-AVC score was acquired using a prospective acquisition and VNC-AVC score derived from a contrast-enhanced retrospective scan. Both scores were calculated using the Agatston method. A correction proportionality constant was applied. Concordant severe AS was defined as AVA&lt;1cm2 and either Vmax &gt;4cm/s or mean gradient ≥40mmHg. Spearman, Cohen’s Kappa, and Bland-Altman were used to assess concordance. Results: In total, 109 patients were included: mean age of 79 ± 10 yrs, 55% female, 43% with concordant severe, 43% LF-LG, and 14% moderate AS. TNC scan median radiation was 116 mGy*cm (IQR 53-366). The median TNC-AVC was 2753 AU (1652-4135), while the median VNC-AVC was 1900 AU (946-2752) after applying the constant (1.43). A strong correlation was demonstrated between methods (r=0.89; p&lt;0.001; Figure). Using accepted thresholds (&gt;1300 AU for women and &gt;2000 AU for men), 68% (n=74) of patients had severe AS by TNC. After estimating thresholds for VNC (&gt;660 for women and &gt;1519 for men), 60% (n=65) had severe AS, demonstrating substantial agreement with TNC-AVC (K;=0.71). Among individuals diagnosed with LF-LG, 38% and 34% exhibited severe AS by TNC/VNC, respectively, and only 12% and 11% in those with moderate AS. Conclusions: DECT-derived VNC-AVC demonstrates substantial agreement with TNC AVC, without requiring an additional scan and reducing both radiation exposure and acquisition time.

Special issue from the Symposium on the acoustics of ancient theatres

Ancient theatres are some of the most significant cultural and architectural masterpieces of the ancient world. The Greeks and Romans developed these spaces for entertainment, political and social commentary, religious rituals and artistic expression. They were built with great attention to acoustics and sightlines. The use of materials such as marble, stone, and brick helped to reflect and amplify sound, while seating arrangements and other architectural features were used to optimize the audience's listening experience. Today, many ancient theatres have been restored or preserved and are often still used for public performances including opera, drama, speech and music. Furthermore, researchers continue to study the acoustic properties of these ancient spaces, seeking to better understand the technical and artistic innovations that enabled the creation of such remarkable buildings. These aspects, as well as more interdisciplinary studies, were presented and discussed during the Symposium on The Acoustics of Ancient Theatres, held in Verona from 6 to 8 July 2022. The Symposium, organized by the Acoustical Society of Italy (AIA) and the European Acoustics Association (EAA), with the collaboration of the Hellenic Institute of Acoustics (HELINA), was the second on this topic after the one held in Patras (Greece) in 2011. The program of the Symposium included keynote speeches, presentations in structured sessions, posters, technical visits to the Verona Arena and Roman Theatre, workshops and demos. The visit to the Verona Arena was particularly inspiring, as it was possible to enter the technical areas and backstage usually closed to visitors, thanks to the Stage Director who guided the visit. The evolution and development of new technologies for the multichannel measurement systems, together with acoustic simulations, auralisation methods and virtual reconstructions, have generated renewed interest in these ancient spaces and it is commendable that the Rivista Italiana di Acustica (RIA) is devoting an entire issue to publish some of the works presented during the Symposium. The special issue includes 10 papers, divided into 5 invited contributions, 3 scientific papers and 2 technical notes. Papers dealing with issues related to Italy and its theatres were prioritised.&amp;amp;nbsp;

A k-hop Constrained Reachability Based Proactive Connectivity Maintaining Mechanism of UAV Swarm Networks

&lt;p&gt;Harsh or hostile environments may lead to node failure and connectivity degradation of a UAV swarm system. In order to maintain or restore the connectivity of a network in case of node failure, this paper proposes a mechanism to adjust the network topology to resist the impact caused by node failure. Firstly, a network model of a UAV swarm network based on k-hop constrained reachability is proposed. Secondly, a k-hop constrained reachability based proactive connectivity maintaining mechanism of UAV swarm network is presented. In this mechanism, each node identifies the network abnormality distributed according to k-hop reachability, and reports the observed abnormality to the master node; then, a virtual edge-based topology reconstruction algorithm is put forward for the master node to derive a topology reconstruction solution in a centralized way; afterwards, the solution is delivered to the slave nodes to reconfigure the network topology in parallel. Thirdly, a quantitative method is introduced to optimize the total travel distance of nodes, and a spanning tree-based method is designed to maintain the connectivity during the topology transformation process. Both theoretical analysis and simulation results have shown that: on the one hand, the proposed mechanism are effective in maintaining a UAV swarm&amp;rsquo;s connectivity in case of node failure; on the other hand, the proposed mechanism outperforms existing mechanisms in terms of fault tolerance, connectivity, and total travel distance, and it&amp;rsquo;s less affected by the failure rate.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Prognostic implications of intracranial haemorrhage on dual-energy CT immediately following endovascular treatment for acute ischemic stroke

ObjectiveTo describe the incidence, risk factors, and prognostic relevance of intracranial haemorrhage (ICH) immediately after endovascular treatment (EVT) for ischaemic stroke in the anterior circulation. MethodsEVT records from 2010 to 2019 were screened. Included patients underwent DECT within 3h post-EVT. Virtual native reconstructions were evaluated for ICH according to the Heidelberg criteria and grouped into Heidelberg classes (HCs): [HC1] haemorrhagic infarction (HI)1, HI2 and parenchymal haematoma (PH)1; [HC2] PH2; [HC3] i.a. intraventricular and subarachnoid haemorrhage. If ICH corresponding to multiple HCs was observed, we assumed that the (largest) parenchymal ICH would have the greatest prognostic impact. Hence, a single HC was attributed by the following order of severity: HC2, HC1, HC3. The primary outcome was the modified Rankin Scale (mRS) at 90 days. The effect of asymptomatic ICH (aICH) and symptomatic ICH (sICH) of (1) HC1 or HC2 and (2) HC3 on patient outcomes was evaluated with multivariable regression after multiple imputation. ResultsOut of 651 records, 498 patients were included. Eighty-one (16%) patients showed ICH on post-EVT DECT, of which 19 were classified as HC1 (21% symptomatic), 6 as HC2 (100% symptomatic), and 56 as HC3 (14% symptomatic). ICH development was mainly associated with unfavourable procedural characteristics. Both aICH and sICH of HC1 or HC2 were associated with the mRS (aICH: adjusted [a]cOR 4.92, 95%CI [1.48–16.35]; sICH: acOR 12.97, 95%CI [2.39–70.26]) and mortality (aICH: aOR 10.08, 95%CI [2.48–40.88]; sICH: aOR 9.92, 95%CI [1.48–66.31]). Likewise, sICH of HC3 was associated with the mRS and mortality (acOR 19.91, 95%CI [4.03–98.35], and aOR 13.23, 95%CI [2.27–77.18], respectively). aICH of HC3 was not significantly associated with the mRS or mortality (acOR 0.87, 95%CI [0.48–1.57], and cOR 0.84, 95%CI [0.32–2.20], respectively). ConclusionsImmediate post-EVT ICH is a frequent finding. Except for aICH of HC3, any ICH is associated with poor long-term clinical outcomes.

Virtual non-enhanced dual-energy computed tomography reconstruction: a candidate to replace true non-enhanced computed tomography scans in the setting of suspected liver alveolar echinococcosis.

When a suspected hepatic alveolar echinococcosis (AE) lesion is detected on a contrast enhanced computed tomography (CT) scan, an additional triphasic or non-enhanced CT scan is required to determine the presence of calcification and enhancement. As a result, imaging costs and exposure to ionizing radiation will increase. We can create a non-enhanced series from routine contrast-enhanced images using dual-energy CT (DECT) and virtual non-enhanced (VNE) images. This study's objective is to assess virtual non-enhanced DECT reconstruction as a potential diagnostic tool for hepatic AE. Triphasic CT scans and a routine dual energy venous phase were acquired using a third-generation DECT system. A commercially available software package was used to generate VNE images. Individual evaluations were conducted by two radiologists. The study population consisted of 100 patients (30 AE, 70 other solid liver masses). All AE cases were diagnosed [no false positives/negatives, 95% confidence interval (CI) sensitivity: 91.3%-100%; 95% CI specificity: 95.3%-100%]. Interrater agreement was k: 0.79. In total, 33 (33.00%) of the patients had AE, which was detected using both true non-enhanced (TNE) and VNE images. The mean dose-length product of a standard triphasic CT was significantly higher than biphasic dual-energy VNE images. In terms of diagnostic confidence, VNE images are comparable with actual non-enhanced imaging when evaluating hepatic AE. Further, VNE images could replace TNE images with a substantial radiation dose reduction. Advances in knowledge: hepatic cystic echinococcosis and AE are serious and severe diseases with high fatality rates and a poor prognosis if managed incorrectly, especially AE. Moreover, VNE images produce equal diagnostic confidence to TNE images for assessing liver AE, with a significant reduction in radiation dose.

Digitalization of Historical Monuments in the Context of Architecture and Urban Planning: Creating Virtual Museums and Platforms

The process of digitalization has emerged as a transformative force in preserving and presenting Ukraine's historical heritage. The article titled "Digitization of Historical Landmarks in Ukraine: Creating Virtual Museums and Platforms" delves into the integration of modern information technologies in the realm of architecture and urban planning. Focused on the specialization of Architecture and Urban Planning, this research examines the impact of digitization on Ukraine's historical sites and the creation of virtual museums and platforms. The study explores the multifaceted effects of digitization, elucidating its role in safeguarding cultural heritage from various threats. Leveraging advancements in technology, the research assesses the application of virtual reconstructions as a means of preserving architectural treasures that have been damaged or destroyed over time. Additionally, it investigates the potential of virtual museums and platforms to offer immersive experiences that enable individuals to interact with historical landmarks in unprecedented ways. The article emphasizes the interdisciplinary nature of this endeavor, highlighting the collaboration between architects, historians, and technologists. It scrutinizes the challenges and opportunities presented by this digital transformation, including issues related to accuracy, accessibility, and the meaningful communication of historical and cultural significance to users. Furthermore, the paper addresses the importance of aligning cultural and information policies, streamlining methodologies, and technological approaches to ensure a cohesive and comprehensive approach to the digitization process. In the field of Architecture and Urban Planning, this research offers insights into the evolving landscape of historical preservation and presentation. By investigating the fusion of digital technologies and cultural heritage, the article contributes to the discourse on how Ukraine's historical landmarks can be effectively preserved, shared, and experienced in a rapidly advancing technological era. The findings of this study provide valuable insights for architects, urban planners, historians, and policymakers, enabling them to make informed decisions that harmonize modern technology with the rich legacy of Ukraine's architectural and cultural heritage.

Photon-counting detector CT-based virtual monoenergetic reconstructions: repeatability and reproducibility of radiomics features of an organic phantom and human myocardium

BackgroundPhoton-counting detector computed tomography (PCD-CT) may influence imaging characteristics for various clinical conditions due to higher signal and contrast-to-noise ratio in virtual monoenergetic images (VMI). Radiomics analysis relies on quantification of image characteristics. We evaluated the impact of different VMI reconstructions on radiomic features in in vitro and in vivo PCD-CT datasets.MethodsAn organic phantom consisting of twelve samples (four oranges, four onions, and four apples) was scanned five times. Twenty-three patients who had undergone coronary computed tomography angiography on a first generation PCD-CT system with the same image acquisitions were analyzed. VMIs were reconstructed at 6 keV levels (40, 55, 70, 90, 120, and 190 keV). The phantoms and the patients’ left ventricular myocardium (LVM) were segmented for all reconstructions. Ninety-three original radiomic features were extracted. Repeatability and reproducibility were evaluated through intraclass correlations coefficient (ICC) and post hoc paired samples ANOVA t test.ResultsThere was excellent repeatability for radiomic features in phantom scans (all ICC = 1.00). Among all VMIs, 36/93 radiomic features (38.7%) in apples, 28/93 (30.1%) in oranges, and 33/93 (35.5%) in onions were not significantly different. For LVM, the percentage of stable features was high between VMIs ≥ 90 keV (90 versus 120 keV, 77.4%; 90 versus 190 keV, 83.9%; 120 versus 190 keV, 89.3%), while comparison to lower VMI levels led to fewer reproducible features (40 versus 55 keV, 8.6%).ConclusionsVMI levels influence the stability of radiomic features in an organic phantom and patients’ LVM; stability decreases considerably below 90 keV.Relevance statementSpectral reconstructions significantly influence radiomic features in vitro and in vivo, necessitating standardization and careful attention to these reconstruction parameters before clinical implementation.Key points• Radiomic features have an excellent repeatability within the same PCD-CT acquisition and reconstruction.• Differences in VMI lead to decreased reproducibility for radiomic features.• VMI ≥ 90 keV increased the reproducibility of the radiomic features.Graphical

Utilizing Digital Art Virtual Reconstruction Technology in the Construction Industry for Modern Urban Landscape Sculpture Planning and Design

Utilizing Digital Art Virtual Reconstruction Technology in the Construction Industry for Modern Urban Landscape Sculpture Planning and Design

Low-iodine 40-keV virtual monoenergetic CT angiography of the lower extremities.

To evaluate a reduced iodine volume protocol for lower extremity CT angiography (CTA) using dual-energy CT (DECT). This retrospective study included consecutive patients who underwent lower extremity CTA from June to December 2022. A 10 ml 1:1 mixed test bolus was performed, followed by a 40 ml full bolus at a 2.5/s injection rate, using 400 mg/ml iodine contrast media. Conventional and 40 keV virtual monoenergetic images (VMI) were reconstructed. For both reconstructions, five main artery segments were assessed with a 3-point image quality score as well as quantitative attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements with diagnostic quality thresholds (respectively >150 HU and >3). Forty patients were included in the study (mean age 68 ± 12 yo). 200 artery segments were assessed. Median qualitative image scores were 3 [IQR, 3, 3] for both reconstructions. 40 keV VMI upgraded qualitative scores for 51 (26%) of patients, including 9 (5%) from nondiagnostic to diagnostic quality. 40 keV VMI obtained attenuation and CNR diagnostic quality for respectively 100% and 100% of segments, compared with 96% and 98% for conventional images (p < 0.001). Distal artery segments showed the most differences between 40 keV VMI and conventional images. A low-iodine lower extremity CTA protocol is feasible, with 40 keV virtual monoenergetic spectral reconstruction enabling maintained diagnostic image quality at the distal artery segments.

3D multiplexed tissue imaging reconstruction and optimized region of interest (ROI) selection through deep learning model of channels embedding.

Introduction: Tissue-based sampling and diagnosis are defined as the extraction of information from certain limited spaces and its diagnostic significance of a certain object. Pathologists deal with issues related to tumor heterogeneity since analyzing a single sample does not necessarily capture a representative depiction of cancer, and a tissue biopsy usually only presents a small fraction of the tumor. Many multiplex tissue imaging platforms (MTIs) make the assumption that tissue microarrays (TMAs) containing small core samples of 2-dimensional (2D) tissue sections are a good approximation of bulk tumors although tumors are not 2D. However, emerging whole slide imaging (WSI) or 3D tumor atlases that use MTIs like cyclic immunofluorescence (CyCIF) strongly challenge this assumption. In spite of the additional insight gathered by measuring the tumor microenvironment in WSI or 3D, it can be prohibitively expensive and time-consuming to process tens or hundreds of tissue sections with CyCIF. Even when resources are not limited, the criteria for region of interest (ROI) selection in tissues for downstream analysis remain largely qualitative and subjective as stratified sampling requires the knowledge of objects and evaluates their features. Despite the fact TMAs fail to adequately approximate whole tissue features, a theoretical subsampling of tissue exists that can best represent the tumor in the whole slide image. Methods: To address these challenges, we propose deep learning approaches to learn multi-modal image translation tasks from two aspects: 1) generative modeling approach to reconstruct 3D CyCIF representation and 2) co-embedding CyCIF image and Hematoxylin and Eosin (H&E) section to learn multi-modal mappings by a cross-domain translation for minimum representative ROI selection. Results and discussion: We demonstrate that generative modeling enables a 3D virtual CyCIF reconstruction of a colorectal cancer specimen given a small subset of the imaging data at training time. By co-embedding histology and MTI features, we propose a simple convex optimization for objective ROI selection. We demonstrate the potential application of ROI selection and the efficiency of its performance with respect to cellular heterogeneity.

The reconstructed cranium of Pierolapithecus and the evolution of the great ape face

Pierolapithecus catalaunicus (~12 million years ago, northeastern Spain) is key to understanding the mosaic nature of hominid (great ape and human) evolution. Notably, its skeleton indicates that an orthograde (upright) body plan preceded suspensory adaptations in hominid evolution. However, there is ongoing debate about this species, partly because the sole known cranium, preserving a nearly complete face, suffers from taphonomic damage. We 1) carried out a micro computerized tomography (CT) based virtual reconstruction of the Pierolapithecus cranium, 2) assessed its morphological affinities using a series of two-dimensional (2D) and three-dimensional (3D) morphometric analyses, and 3) modeled the evolution of key aspects of ape face form. The reconstruction clarifies many aspects of the facial morphology of Pierolapithecus. Our results indicate that it is most similar to great apes (fossil and extant) in overall face shape and size and is morphologically distinct from other Middle Miocene apes. Crown great apes can be distinguished from other taxa in several facial metrics (e.g., low midfacial prognathism, relatively tall faces) and only some of these features are found in Pierolapithecus, which is most consistent with a stem (basal) hominid position. The inferred morphology at all ancestral nodes within the hominoid (ape and human) tree is closer to great apes than to hylobatids (gibbons and siamangs), which are convergent with other smaller anthropoids. Our analyses support a hominid ancestor that was distinct from all extant and fossil hominids in overall facial shape and shared many features with Pierolapithecus. This reconstructed ancestral morphotype represents a testable hypothesis that can be reevaluated as new fossils are discovered.

Comparative analysis of methods for creating virtual three-dimensional models of the lungs from computed tomography images in the practice of a tuberculosis organization using Materialise software

Background. One of the important conditions for the final victory over tuberculosis is not only the prevention of its development and early detection, but also the provision of high-quality personalized medical care to the patient. Additive technologies and virtualization technologies are ways to fully reveal this principle in phthisiatric practice.&#x0D; Aim. Demonstrate the possibilities and evaluate the labor costs (time spent on virtualization and the size of the final digital files of models) while working with the Mimics inPrint 2.0.0.159 and Mimics Medical 21.0.0.406 software systems in the aspect of virtual reconstruction of the lungs of a patient with a destructive form of tuberculosis.&#x0D; Materials and methods. A comparative analysis of methods for creating virtual three-dimensional models of the lungs from CT images was carried out at the Nizhny Novgorod Regional Clinical Tuberculosis Dispensary. The study involved one patient with a destructive form of tuberculosis of the upper lobe of the left lung. Virtual three-dimensional models were made according to a specially developed algorithm. The time spent for the formation of virtual lung models was analyzed using the built-in function in the "Log" software. The analysis of the size of the obtained virtual lung models in the STL format was carried out using the operating system function from the Windows family "Properties", section "General", subsection "Size".&#x0D; Results. The most practical software package for virtual lung reconstructions turned out to be Mimics inPrint 2.0.0.159 with the result of the time spent on creating a model of 2 minutes (Mimics Medical 21.0.0.406 7 minutes 17 seconds) and a model size of 125 megabytes (Mimics Medical 21.0.0.406 26.1 megabyte). The technical nuances and algorithms of lung reconstruction covered in the article using the Mimics inPrint 2.0.0.159 and Mimics Medical 21.0.0.406 software packages will allow the interested person not to make a mistake in realizing their scientific and practical interests in the process of providing personalized care to the patient. The article focuses on the main advantages of the Mimics inPrint 2.0.0.159 software package in comparison with Mimics Medical 21.0.0.406. A brief description of similar programs is given.&#x0D; Conclusion. The studied software systems successfully coped with the goal assigned to them, which concerned the demonstration of their capabilities and the assessment of labor costs for virtualization. Mimics inPrint 2.0.0.159 turned out to be the most understandable and promising software and application complex for use in everyday clinical practice.

Optimal conspicuity of pancreatic ductal adenocarcinoma in virtual monochromatic imaging reconstructions on a photon-counting detector CT: comparison to conventional MDCT

PurposeTo analyze the conspicuity of pancreatic ductal adenocarcinoma (PDAC) in virtual monoenergetic images (VMI) on a novel photon-counting detector CT (PCD-CT) in comparison to energy-integrating CT (EID-CT).MethodsInclusion criteria comprised initial diagnosis of PDAC (reference standard: histopathological analysis) and standardized contrast-enhanced CT imaging either on an EID-CT or a PCD-CT. Patients were excluded due to different histopathological diagnosis or missing tumor delineation on CT. On the PCD-CT, 40–190 keV VMI reconstructions were generated. Image noise, tumor-to-pancreas ratio (TPR) and contrast-to-noise ratio (CNR) were analyzed by ROI-based measurements in arterial and portal venous contrast phase. Two board-certified radiologist evaluated image quality and tumor delineation at both, EID-CT and PCD-CT (40 and 70 keV).ResultsThirty-eight patients (mean age 70.4 years ± 10.3 [range 45–91], 27 males; PCD-CT: n=19, EID-CT: n=19) were retrospectively included. On the PCD-CT, tumor conspicuity (reflected by low TPR and high CNR) was significantly improved at low-energy VMI series (≤ 70 keV compared to > 70 keV), both in arterial and in portal venous contrast phase (P < 0.001), reaching the maximum at 40 keV. Comparison between PCD-CT and EID-CT showed significantly higher CNR on the PCD-CT in portal venous contrast phase at < 70 keV (P < 0.016). On the PCD-CT, tumor conspicuity was improved in portal venous contrast phase compared to arterial contrast phase especially at the lower end of the VMI spectrum (≤ 70 keV). Qualitative analysis revealed that tumor delineation is improved in 40 keV reconstructions compared to 70 keV reconstructions on a PCD-CT.ConclusionPCD-CT VMI reconstructions (≤ 70 keV) showed significantly improved conspicuity of PDAC in quantitative and qualitative analysis in both, arterial and portal venous contrast phase, compared to EID-CT, which may be important for early detection of tumor tissue in clinical routine. Tumor delineation was superior in portal venous contrast phase compared to arterial contrast phase.