Search results for "Tomography"
showing 10 items of 2332 documents
Vascular structure of the earliest shark teeth
2018
Here we use synchrotron tomography to characterise dental vasculature in the oldest known tooth-bearing sharks, Leonodus carlsi Mader, 1986 and Celtiberina maderi Wang, 1993. Three dimensional reconstruction of the vascular system and microstructure of both taxa revealed a complex and dense network of canals, including horizontal, ascending and secondary bifurcated canals, as well as histological features consistent with an osteodont histotype. However, L. carlsi and C. maderi also exhibit significant morphological differences, showing Leonodus a typical diplodont tooth morphology with a linguo-labially elongated base, that contrast with Celtiberina’s teeth that show a single conical cusp c…
Use of cbct in the endodontic management of a second mandibular premolar with three roots : clinical case
2022
Background Reports and studies on dental anatomy describe variations in the morphology, number and shape of the roots and root canals, with the mandibular premolars being one of the dental groups with special complexity. In the bibliographic review published on the morphology of mandibular second premolars, the presence of three roots being extremely rare, finding differences according to the ethnic group studied. The aim of this case is to describe an unusual case of the anatomy of a mandibular second premolar. Material and Methods A 59-year-old male patient presented with pain in the right mandibular second premolar. After taking the clinical history and the examination, he was diagnosed …
Relationship between volume of submandibular salivary stones in vivo determined with cone-beam computer tomography and in vitro with micro-computer t…
2021
Background Successful removal of salivary stones depends on exact pretreatment information of the location, the size and shape of the stones. This study aimed to compare the volume of submandibular sialoliths determined by preoperative Cone-Beam Computer Tomography (CBCT) scans with the volume of the removed stones on micro-Computer Tomography (micro-CT) scans. Material and Methods In this study, using twenty-one submandibular sialoliths, the pretreatment volumes in-vivo measured on CBCT were compared to the volumes of removed stones determined by micro-CT scans. The volume measured on micro-CT scans served as the gold standard. Pre-operative CBCT’s and in-vitro micro-CT’s were converted in…
Interface Detection Using a Quenched-Noise Version of the Edwards-Wilkinson Equation
2015
We report here a multipurpose dynamic-interface-based segmentation tool, suitable for segmenting planar, cylindrical, and spherical surfaces in 3D. The method is fast enough to be used conveniently even for large images. Its implementation is straightforward and can be easily realized in many environments. Its memory consumption is low, and the set of parameters is small and easy to understand. The method is based on the Edwards-Wilkinson equation, which is traditionally used to model the equilibrium fluctuations of a propagating interface under the influence of temporally and spatially varying noise. We report here an adaptation of this equation into multidimensional image segmentation, an…
Justification of point electrode models in electrical impedance tomography
2011
The most accurate model for real-life electrical impedance tomography is the complete electrode model, which takes into account electrode shapes and (usually unknown) contact impedances at electrode-object interfaces. When the electrodes are small, however, it is tempting to formally replace them by point sources. This simplifies the model considerably and completely eliminates the effect of contact impedance. In this work we rigorously justify such a point electrode model for the important case of having difference measurements ("relative data") as data for the reconstruction problem. We do this by deriving the asymptotic limit of the complete model for vanishing electrode size. This is s…
Curvelet-based method for orientation estimation of particles
2013
A method based on the curvelet transform is introduced for estimating from two-dimensional images the orientation distribution of small anisotropic particles. Orientation of fibers in paper is considered as a particular application of the method. Theoretical aspects of the suitability of this method are discussed and its efficiency is demonstrated with simulated and real images of fibrous systems. Comparison is made with two traditionally used methods of orientation analysis, and the new curvelet-based method is shown to perform clearly better than these traditional methods.
Evaluation of alveolar cortical bone thickness and density for orthodontic mini-implant placement.
2013
Objective: Mini-implant stability is primarily related to bone quality and quantity. This study evaluated alveolar cortical bone thickness and density differences between interradicular sites at different levels from the alveolar crest, and assessed the differences between adolescents (12-18 years of age) and adults (19-50 years of age), males and females, upper and lower arch, anterior and posterior region of jaws and buccal and oral side. Study Design: In this retrospective study, 48 Computed Tomography scans, performed for oral surgery purposes were selected from dental records of 3,223 Caucasian orthodontic patients. The SimPlant software (Materialise, Leuven, Belgium) was used to measu…
The Beginning and Development of the Theranostic Approach in Nuclear Medicine, as Exemplified by the Radionuclide Pair
2017
In the context of radiopharmacy and molecular imaging, the concept of theranostics entails a therapy-accompanying diagnosis with the aim of a patient-specific treatment. Using the adequate diagnostic radiopharmaceutical, the disease and the state of the disease are verified for an individual patient. The other way around, it verifies that the radiopharmaceutical in hand represents a target-specific and selective molecule: the “best one” for that individual patient. Transforming diagnostic imaging into quantitative dosimetric information, the optimum radioactivity (expressed in maximum radiation dose to the target tissue and tolerable dose to healthy organs) of the adequate radiotherapeutica…
Images - Computed tomography urographic appearance of traumatic rupture of renal cyst into the pyelocaliceal system.
2019
Spontaneous or traumatic rupture of renal cysts, documented by radiological imaging, occurs infrequently. The pathogenesis of a cyst rupture is still unclear, except when it has occurred following trauma or when the cyst has become infected. Imaging plays a crucial role in the diagnosis, management, surveillance, and choice of lesions that need treatment.
Role of post mortem computed tomography in diagnosis of upper cervical fractures in child due to road accident: A case report and literature review
2019
The upper cervical spine has unique anatomical features that distinguish it from the remainder of the cervical spine. Its motion segments make up a large amount of total cervical spine motion and, as a result,predispose it to a unique set of injuries. Cervical spine trauma is a common problem with a wide range of severity from minor ligamentous injury to section of the spinal cord. The use of post mortem CT (PMCT), and the subsequent multi-planar and volume rendering reconstruction techniques can provide non-invasive, objective operator-independent imaging data set that may be further reviewed by other specialists. and can substantially add to forensic examinations of the skeleton, especial…