Use Of Micro-computed Tomography Research Articles

The use of micro-computed tomography to investigate splenic control of resting oxygen consumption in Tenrec ecaudatus

The canonical functions of the spleen e.g. immune function, blood filtering, and iron recycling overshadow its known role as a blood storage organ in mammals. Boreoeutherians or modern mammals, such as race horses and dogs, experience splenic contractions during exercise where a 30-40% increase in red blood cell availability is associated with an increase in oxygen consumption. Early data (pre-1960) suggest that splenic sequestration may be used in hibernators. Tenrec ecaudatus are basoendothermic mammals that possess numerous ancestral features such as a cloaca. We posit that tenrecs may provide evolutionary insight into the ancestral function of the spleen. Tenrecs may experience as much as a 25-fold variation in resting oxygen consumption as well as a 14-fold variation in spleen size. We contend that sequestration of red blood cells to the spleen in tenrecs controls oxygen consumption. Here, we present data that directly tests the association of spleen size and oxygen consumption using micro-computed tomography. We contend the boreoeutherian functions of the spleen may be a derived condition afforded by a heightened level of endothermy/homeothermy and its associated higher level of homeostasis. National Science Foundation, Department of Education. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Use of micro-computed tomography and scanning electron microscopy with energy-dispersive spectroscopy to distinguish natural white spot enamel lesions from sound enamel in human premolars.

The aim of the present study was to develop a novel method for distinguishing white spot lesions (WSLs) from sound enamel in human premolars using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and to examine differences in surface morphology, chemical composition, and mineral density (MD) between these two areas. Fourteen premolars with natural WSLs on the enamel surface of the crowns were examined. After sectioning the teeth, each specimen containing WSLs adjacent to intact enamel was examined for MD, surface morphology, and atomic percentages (At%) of chemical components using micro-CT and SEM/EDS, respectively. Differences between these areas of the same specimen were analyzed statistically using paired t-test. SEM images highlighted increased roughness and irregularity in the lesion area. EDS analysis revealed significant reductions in calcium (Ca), phosphorus (P), fluorine (F), chlorine (Cl), and sodium (Na) levels at the lesion surface in comparison to intact enamel (P < 0.05). The decreases in the MD of the lesions were statistically significant in comparison to sound enamel (P < 0.05). These findings provide standard measurements for evaluating the essential characteristics of WSLs and intact enamel, being vital for assessment of treatment outcomes and development of innovative biomaterials for management of hypo-mineralized enamel lesions.

Study of the effect of defects on fatigue life prediction of additive manufactured Ti-6Al-4V by combined use of micro-computed tomography and fracture-mechanics-based simulation

The significant variability in the high-cycle fatigue of additive manufactured (AM) Ti-6Al-4V has impeded its confident application in fatigue-critical components. One of the major factors responsible for the fatigue-life variability is the presence of intrinsic defects left by the additive manufacturing process. The goal of this work is to investigate the fatigue-life variability as the function of (i) the locations of the defects, viz., internally or on the surface, (ii) the distance to the free surface if it is an internal defect, (iii) the sizes of defects and (iv) the accurate stress at the defect locations. In this study, AM Ti-6Al-4V specimens were firstly scanned by micro-computed tomography, then tested in air under high-cycle fatigue with stereo-digital image correlation, and finally examined post-mortem using scanning electron microscopy. Defects detected by micro-computed tomography have been mapped with the local stress reproduced from the stereo-digital image correlation measurement and correlated with the defects found in post-mortem fractography by scanning electron microscope. Wide variation in the fatigue life was indeed found from the tests and more than half of the tested specimens initiated cracks from the internal defects. A fracture mechanics-based approach was developed to account not only for the defect sizes but also for different crack growth rates between surface cracks in air and internal cracks in vacuum. In comparison with the nominal stress-based approach, the scatter of the fatigue life prediction can be significantly reduced from ± 60 times to ± 6 times by applying this fracture mechanics-based methodology.

New information on the Eocene frog Thaumastosaurus (Anura, Pyxicephalidae) from the Phosphorites du Quercy, France

Abstract We present new disarticulated cranial elements of the Eocene frog Thaumastosaurus from several localities in the Phosphorites du Quercy, France, providing novel information about the variation of its anatomical characteristics. With the use of micro-computed tomography (μCT) scanning technology, we examine and discuss various types of dermal cranial ornamentation in extant Pyxicephalus, the closest extant relative of Thaumastosaurus, in which these features are useful in species diagnoses, paying particular attention to the individual and ontogenetic variation, and sexual dimorphism, as well as interspecific variation among extant species. We suggest that various types of dermal cranial ornamentation in Thaumastosaurus could be potentially used in diagnoses at species level, although ontogenetic variation should be taken into consideration. Apart from ornamentation, the size and general morphology of the maxillae and squamosa in Thaumastosaurus reveal an unexpected disparity of morphotypes, which suggests the potential presence of cryptic taxa. Some squamosa reveal that their processus zygomaticus extended up to the postnasal wall, so their associated maxillae were excluded from the orbital margin, whereas others were short and their respective maxillae participated in the formation of the orbital margin. Thaumastosaurus is envisaged as the product of an Early Palaeogene direct, potentially overseas, dispersal from isolated Afro-Arabia to Europe.

Protetik Diş Hekimliğinde Mikro Bilgisayarlı Tomografi Kullanımı

Today, the use of micro-computed tomography is becoming widespread in almost every field of dental research. When the national review articles on micro-computed tomography are examined, it is seen that the focus is on endodontic and surgical dental applications. As prosthodontists, our article, which was compiled in order to deepen the specific usage areas of micro-computed tomography applications and to review the studies done in this area, provides information about the use of micro-computed tomography method in prosthetic dentistry. Micro-computed tomography is a powerful in vitro research method. Micro-computed tomography was used; marginal and internal compatibility of restorations, cement spacing of restorations, adaptation of denture bases, accuracy of prosthetic measurements, effects of occlusal irregularities, volumetric changes in teeth due to dental post application, biomechanical evaluation of implant-abutment connection, and compatibility of maxillofacial prostheses.

Micro-CT and deep learning: Modern techniques and applications in insect morphology and neuroscience.

Advances in modern imaging and computer technologies have led to a steady rise in the use of micro-computed tomography (µCT) in many biological areas. In zoological research, this fast and non-destructive method for producing high-resolution, two- and three-dimensional images is increasingly being used for the functional analysis of the external and internal anatomy of animals. µCT is hereby no longer limited to the analysis of specific biological tissues in a medical or preclinical context but can be combined with a variety of contrast agents to study form and function of all kinds of tissues and species, from mammals and reptiles to fish and microscopic invertebrates. Concurrently, advances in the field of artificial intelligence, especially in deep learning, have revolutionised computer vision and facilitated the automatic, fast and ever more accurate analysis of two- and three-dimensional image datasets. Here, I want to give a brief overview of both micro-computed tomography and deep learning and present their recent applications, especially within the field of insect science. Furthermore, the combination of both approaches to investigate neural tissues and the resulting potential for the analysis of insect sensory systems, from receptor structures via neuronal pathways to the brain, are discussed.

Correlative tomography and authentication features of a shrunken head (tsantsa).

Museum personnel and the general public have become quite familiar with the presence of shrunken heads in museum collections, but the procedures to authenticate the history and origin of these unique cultural items are not yet reliable. These shrunken heads, called tsantsas, are meant to be the cultural material remains of ceremonies conducted by the Shuar and Achuar Peoples of South America. This project seeks to integrate the use of micro-computed tomography (micro-CT) scanning with methods used in previous studies (clinical computed tomography (CT) and visual inspections) to examine authentication procedures of shrunken heads (tsantsas) held in contemporary museum collections. We use a correlative tomographic approach using several scans at successively higher resolutions to determine whether a tsantsa was created from human remains, and if so, what key features can best contribute to its authentication. Conclusively, our correlative tomographic approaches provide new insights into the determination process of whether a tsantsa was created from real human remains or not. Also, this study questions whether the previously conceptualized dichotomy of ceremonial or commercial might be better thought of as a continuum of practice. Investigating and redefining the examination and authentication procedures of tsantsas is crucial for future ethical curation, management, and repatriation efforts of this unique cultural material of the Shuar and Achuar Peoples.

Hybrid material additive manufacturing: interlocking interfaces for fused filament fabrication on laser powder bed fusion substrates

ABSTRACT The fabrication of polymer–metal hybrids in an additive process makes it possible to further improve the geometrical and material adaption in a multi-material design. In this work, PLA is fabricated through a fused filament fabrication process on AlSi10Mg structures manufactured by laser powder bed fusion. The mechanical connection is realised by form fit, for which different geometries are examined through tensile tests. Deep penetration of the PLA into the metallic structures is achieved by optimisation of the process parameters. The penetration depth is assessed through the use of micro-computed tomography. Finally, the interplay of mechanisms leading to a firm connection is discussed.

Micro-computed tomography for assessing the internal and external voids of bulk-fill composite restorations: A technical report.

PurposeThis technical report aims to describe and detail the use of micro-computed tomography for a reliable evaluation of the bulk-fill composite/tooth interface.Materials and MethodsBulk-fill composite restorations in tooth cavities were scanned using micro-computed tomography to obtain qualitatively and quantitatively valuable information. Two-dimensional information was processed using specific algorithms, and ultimately a 3-dimensional (3D) specimen reconstruction was generated. The 3D rendering allowed the visualization of voids inside bulk-fill composite materials and provided quantitative measurements. The 3D analysis software VG Studio MAX was used to perform image analysis and assess gap formation within the tooth-restoration interface. In particular, to evaluate internal adaptation, the Defect Analysis add-on module of VG Studio Max was used.ResultsThe data, obtained with the processing software, highlighted the presence and the shape of gaps in different colours, representing the volume of porosity within a chromatic scale in which each colour quantitatively represents a well-defined volume.ConclusionMicro-computed tomography makes it possible to obtain several quantitative parameters, providing fundamental information on defect shape and complexity. However, this technique has the limit of not discriminating materials without radiopacity and with low or no filler content, such as dental adhesives, and hence, they are difficult to visualise through software reconstruction.

On the Use of Micro-Computed Tomography for Pre-Clinical Testing of Cardiovascular Devices that Treat Intravascular Calcium

Micro-computed tomography (µCT) is a powerful, non-destructive tool that generates three-dimensional images of objects using penetrative X-rays. µCT is useful when imaging hardened, biological tissues and is particularly useful when studying the efficacy of cardiovascular devices for the treatment of intravascular calcium (IVC). IVC is an advanced state of atherosclerosis that commonly afflicts the elderly and is associated with vessel hardening (i.e., calcification) and narrowing. If left untreated, adverse events due to IVC include myocardial infarction, stroke, and amputation. However, because of its high strength and the fragility of the surrounding artery, IVC is difficult to treat. Further, device innovations are stymied because of the lack of readily available, pre-clinical models. Currently, the best model of IVC is diseased cadaveric and endarterectomy tissue, but the morphological inconsistencies of these tissues require a standardized approach when used for evaluating IVC treatments. We report a generalized approach that employs µCT to enable qualitative and quantitative analyses of the treatment effect of new devices on IVC tissue. This approach consists of 1) specimen screening, storage, and preparation, 2) pre-, peri-, and post-treatment µCT imaging, and 3) image analysis of IVC morphology and treatment effect. Various examples are provided to guide future bioengineering and medical device testing applications in this space.

Micro-computed tomography assessment of dentinal microcracks after the preparation of curved root canals with rotary and reciprocal systems.

Root canal preparation with nickel-titanium (NiTi) instruments may lead to the formation of microcracks in the root canal wall. Vertical root fractures may initiate from dentinal cracks, and eventually necessitate tooth extraction. This study aimed to assess the effect of the instrumentation of curved root canals of mandibular molars with the 2Shape (2S) sequential rotary, EdgeFile® X1 (EFX1) reciprocating and NeoNiTi (NN) rotational single-file systems on the formation of dentinal microcracks with the use of micro-computed tomography (micro-CT). Thirty curved mandibular molar root canals were instrumented with the 2S, EFX1 and NN systems (10 in each group). The teeth underwent micro-CT before and after instrumentation. Next, the pre-instrumentation and post-instrumentation cross-sectional images were evaluated and compared for the detection of dentinal microcracks. The number of microcracks in each group was calculated and reported as percentage. The data was analyzed using the McNemar's test with the IBM SPSS Statistics for Windows software, v. 25.0 (α = 0.05). Out of the 29,280 cross-sectional images evaluated in this study, 11.5% showed dentinal microcracks (n = 3,362). On the post-instrumentation images, the frequency percentage of microcracks was 12.0% (n = 585) in the 2S group, 8.8% (n = 402) in the EFX1 group and 13.3% (n = 694) in the NN group. All of the microcracks detected on the post-instrumentation images were also present on the preinstrumentation images and no new microcracks were formed after root canal instrumentation with the aforementioned systems. Root canal instrumentation with the 2S, EFX1 and NN systems did not result in the formation of new dentinal microcracks.

Use of Micro-Computed Tomography to Visualize and Quantify COVID-19 Vaccine Efficiency in Free-Breathing Hamsters.

The SARS-CoV-2 pandemic has impacted the health of humanity after the outbreak in Hubei, China in late December 2019. Ever since, it has taken unprecedented proportions and rapidity causing over a million fatal cases. Recently, a robust Syrian golden hamster model recapitulating COVID-19 was developed in search for effective therapeutics and vaccine candidates. However, overt clinical disease symptoms were largely absent despite high levels of virus replication and associated pathology in the respiratory tract. Therefore, we used micro-computed tomography (μCT) to longitudinally visualize lung pathology and to preclinically assess candidate vaccines. μCT proved to be crucial to quantify and noninvasively monitor disease progression, to evaluate candidate vaccine efficacy, and to improve screening efforts by allowing longitudinal data without harming live animals. Here, we give a comprehensive guide on how to use low-dose high-resolution μCT to follow-up SARS-CoV-2-induced disease and test the efficacy of COVID-19 vaccine candidates in hamsters. Our approach can likewise be applied for the preclinical assessment of antiviral and anti-inflammatory drug treatments in vivo.

Craniofacial Phenomics: Three-Dimensional Assessment of the Size and Shape of Cranial and Dentofacial Structures.

Craniofacial phenomics has opened up numerous opportunities to correlate genetic and epigenetic factors to craniofacial phenotypes in order to improve our understanding of growth and development in health and disease. Three-dimensional (3D) imaging has played a key role in advancing craniofacial phenomics by facilitating highly sensitive and specific characterizations of craniofacial and dental morphology. Here we describe the use of micro-computed tomography (micro-CT) to image the murine craniofacial complex, followed by surface reconstruction for traditional morphometric analyses. We also describe the application of geometric morphometrics, based on Generalized Procrustes Analysis, for use in human premolars. These principles are interchangeable between various vertebrate species, and between various surface imaging techniques (including micro-CT and 3D surface scanners), offering a high level of versatility and precision for extensive phenotyping of the entire craniofacial complex.

Technical ceramics for salt production in Western Sahara

ABSTRACT This paper presents evidence of ceramic technology in western Tiris (Western Sahara), dated by thermoluminescence to the third millennium cal. BP. Western Tiris is an arid region mostly covered by desert where recent archaeological fieldwork has nevertheless revealed a significant network of settlements from the Neolithic period inhabited by nomadic people. Domestic pottery and lithic materials are common in the archaeological register of these sites, but three sherds found in the Lejuad XVII rockshelter present features typical of technical ceramics. Laboratory analyses reveal that abundant mineral and organic temper was added to the natural clay which, in addition to the presence of thicker walls than those usually found in domestic pottery, is interpreted as an attempt to increase resistance to thermal shocks. However, the fragments present only mild signals of exposure to high temperatures, up to a maximum of 900 °C. Discussion of these contradictory data leads to the conclusion that the sherds may have been part of a briquetage mould to extract salt by evaporation, a pyrotechnical industry previously unknown in Western Sahara. Its appearance in an arid environment far from production centres is explained as result of sporadic economic activity rather than cross-cultural mobility and trading, which seems to have been intense in the area from Neolithic times. In addition, this paper introduces the use of micro-computed tomography (µ-CT) as a technique for measuring large porosity derived from burned organic materials.

The use of micro-computed tomography to determine the accuracy of electronic working length with two apex locators.

This study evaluated the precision of electronic working length by microcomputed tomography using two electronic apex locators (EALs). Twenty single-rooted permanent teeth without caries or restorations were selected as the subject teeth. The positions of the minor apical constriction (AC) and major apical foramen (AF) were measured by electronic root canal length, and microcomputed tomography was performed with the file inserted and fixed in the root canal. All teeth were measured individually and independently by two operators. The Mann-Whitney U-test was used to statistically test the AC and AF values using two EALs; P < 0.05 was defined as statistically significant. This was 65.0% within 1.5 mm in the case of two EALs on AC. This was more than 90.0% within 1.0 mm in the case of two EALs on AF. Comparison of the differences between the respective AC and AF of the measurements obtained using the two EALs revealed no significant difference. The two EALs are devices that can greatly improve the accuracy of WL control.

Micro-computed tomography in preventive and restorative dental research: A review.

PurposeThe use of micro-computed tomography (micro-CT) scans in biomedical and dental research is growing rapidly. This study aimed to explore the scientific literature on approaches and applications of micro-CT in restorative dentistry.Materials and MethodsAn electronic search of publications from January 2009 to March 2021 was conducted using ScienceDirect, PubMed, and Google Scholar. The search included only English-language articles. Therefore, only studies that addressed recent advances and the potential uses of micro-CT in restorative and preventive dentistry were selected.ResultsMicro-CT is a tool that enables 3-dimensional imaging on a small scale with very high resolution. In this method, there is no need for sample preparation or slicing. Therefore, it is possible to examine the internal structure of tissue and the internal adaptation of materials to surfaces without destroying them. Due to these advantages, micro-CT has been recommended as a standard imaging tool in dental research for many applications such as tissue engineering, endodontics, restorative dentistry, and research on the mineral density of hard tissues and bone growth. However, the high costs of micro-CT, the time necessary for scanning and reconstruction, computer expertise requirements, and the enormous volume of information are drawbacks.ConclusionThe potential of micro-CT as an emerging, accurate, non-destructive approach is clear, and the valuable research findings reported in the literature provide an impetus for researchers to perform future studies focusing on employing this method in dental research.

Braincase and endocranium of the Placodont Parahenodus atancensis de Miguel Chaves, Ortega &amp; Pérez-García, 2018, a representative of the highly specialized clade Henodontidae

Parahenodus atancensis de Miguel Chaves, Ortega &amp; Pérez-García, 2018 is a recently described bizarre cyamodontoid placodont, based on a partial but well-preserved Spanish Upper Triassic skull. It was identified as the sister taxon of the German highly specialized Henodus chelyops Huene, 1936. The use of micro-computed tomography has been able to significantly increase knowledge of the cranial anatomy of Parahenodus atancensis by the characterization of several bones and structures previously unknown for this taxon, as well as to obtain a partial reconstruction of its brain endocast and associated endocranial structures, poorly known in most Triassic sauropterygians. In addition, we identify several synapomorphies of the braincase of Cyamodontoidea so far unknown in Henodontidae, improving knowledge about this clade. The study of the endocranium and neurosensory structures of Parahenodus atancensis suggests a relatively lower reliance on vision, the pineal system and the pituitary than in other Triassic sauropterygians.

Evaluating Microelectrode Arrays in Peripheral Nerve Using Micro Computed Tomography.

Many advances have been made with imaging of implanted neural devices; however, the ability to image whole nerve samples remains limited. Further, few imaging modalities are well suited for visualizing both whole devices in vivo and individual microelectrodes within a nerve. In this study, we used micro-computed tomography (micro-CT) to evaluate Wireless Floating Microelectrode Arrays (WMFAs) implanted in rat sciatic nerve at the level of whole devices and individual electrodes. WFMAs were also used to track selective recruitment of plantar flexion and dorsiflexion of the rear paw, which was achieved by each implanted device (n=6) during chronic implantation. Evoked limb motion was correlated to end-of-study assessments using micro-CT to visualize electrode locations within the fascicular structure of the sciatic nerve. Results of this study show that micro-CT imaging can provide valuable assessments of microelectrode arrays implanted in peripheral nerves for both whole devices visualized in vivo and individual electrodes visualized in whole nerve tissue samples.Clinical relevance- This work informs the use of micro-computed tomography as a tool for correlating neural device performance with physical attributes of the implant location.

The combined effects of teriparatide and anti-RANKL monoclonal antibody on bone defect regeneration in ovariectomized mice.

The purpose of this study was to investigate the combined effects of teriparatide (TPTD) and anti-murine receptor activator of nuclear factor-κB ligand monoclonal antibody (anti-RANKL Ab) on both cancellous and cortical bone healing in ovariectomized mice. Thirteen-week-old mice were divided into the sham-operated group (n=11) or the ovariectomized group (n=44). At 1 month post-operation, all mice underwent bone defect surgery on the left femoral metaphysis (cancellous bone healing model) and right femoral mid-diaphysis (cortical bone healing model). After creating the bone defects, all ovariectomized mice were assigned to one of four groups to receive 1) saline (5 times a week; CNT group), 2) TPTD (40μg/kg 5 times a week; TPTD group), 3) anti-RANKL Ab (5mg/kg once; Ab group), or 4) a combination of TPTD and anti-RANKL Ab (COMB group). The following analyses were performed: Time-course microstructural analysis of healing in both cancellous and cortical bone in the bone defect, measuring the volumetric bone mineral density and the cortical bone thickness of the tibia as a representative of whole body bone with the use of micro-computed tomography, and histological analysis. Regeneration of cancellous bone volume in the COMB group was the highest among the four groups, and combined treatment accelerated the formation of medullary callus during the early phase of bone regeneration. On the other hand, there were no significant differences in the regeneration of cortical bone volume during the early phase of bone regeneration among the four groups. Furthermore, lamellar bone was not well identified in the all four groups. Volumetric bone mineral density in the tibia in the COMB group was significantly higher compared with that in the CNT and TPTD groups and tended to be higher compared with that in the Ab group. The mean values of cortical bone thickness in the TPTD and COMB groups were significantly higher than that in the CNT group. In a mouse model of postmenopausal osteoporosis, combination therapy of TPTD and anti-RANKL Ab accelerates regeneration of cancellous bone more effectively than either agent alone during the early phase of bone regeneration.

The use of micro-computed tomography in dental applications

Together with developments in digital imaging systems, there has been increasing use of micro-computed tomography (μCT) in many areas, primarily in dentistry. As this method allows 3-dimensional images to be taken providing safe and high quality results, without damaging the samples being examined, it is often preferred. Consequently, it has become possible to record rapid progression in endodontic studies in particular and to research and easily compare several techniques. Furthermore, this method can be used in tissue engineering, forming data for FEM analysis, the growth and development of craniofacial bones, imaging bone structure, and in the evaluation of implants and surrounding bone in root tip surgery, to determine mineral concentration in the teeth and to measure the thickness of enamel.&#x0D; The aim of this review was to focus on the areas of use of μCT in dentistry and state the advantages.&#x0D; Key Words: Micro-computed tomography, X-ray micro-CT, dental application, three-dimensional imaging&#x0D; &#x0D; How to cite this article: Erpaçal B, Adıgüzel Ö, Cangül S. The use of micro-computed tomography in dental applications. Int Dent Res 2019;9(2):78-91.&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.