Role of Cone Beam Computed Tomography in Evaluation of Radicular Cyst mimicking Dentigerous Cyst in a 7-year-old Child: A Case Report and Literature Review.

PubMed

Mahesh, B S; P Shastry, Shilpa; S Murthy, Padmashree; Jyotsna, T R

2017-01-01

To report a rare case of large radicular cyst-associated deciduous tooth and to discuss the importance of cone beam computed tomography (CBCT) in diagnosing the condition. Radicular cyst is the most common cyst affecting the permanent teeth, but its occurrence in deciduous teeth is rare. Most of the radicular cysts are asymptomatic and are discovered accidentally when radiographs are taken. Conventional radiographs show two-dimensional images of three-dimensional objects. Cone beam computed tomography provides undistorted three-dimensional information of hard tissues and gives adequate spatial resolution. A 7-year-old child, with a complaint of swelling in the maxillary anterior region, was diagnosed with radicular cyst in relation to primary maxillary right central incisor based on CBCT and histopathological features. Early diagnosis and prompt treatment of radicular cyst in primary dentition is important to prevent damage to permanent tooth. Mahesh BS, Shastry SP, Murthy PS, Jyotsna TR. Role of Cone Beam Computed Tomography in Evaluation of Radicular Cyst mimicking Dentigerous Cyst in a 7-year-old Child: A Case Report and Literature Review. Int J Clin Pediatr Dent 2017;10(2):213-216.

Computer-assisted surgical planning and automation of laser delivery systems

NASA Astrophysics Data System (ADS)

Zamorano, Lucia J.; Dujovny, Manuel; Dong, Ada; Kadi, A. Majeed

1991-05-01

This paper describes a 'real time' surgical treatment planning interactive workstation, utilizing multimodality imaging (computer tomography, magnetic resonance imaging, digital angiography) that has been developed to provide the neurosurgeon with two-dimensional multiplanar and three-dimensional 'display' of a patient's lesion.

Importance of preoperative imaging with 64-row three-dimensional multidetector computed tomography for safer video-assisted thoracic surgery in lung cancer.

PubMed

Akiba, Tadashi; Marushima, Hideki; Harada, Junta; Kobayashi, Susumu; Morikawa, Toshiaki

2009-01-01

Video-assisted thoracic surgery (VATS) has recently been adopted for complicated anatomical lung resections. During these thoracoscopic procedures, surgeons view the operative field on a two-dimensional (2-D) video monitor and cannot palpate the organ directly, thus frequently encountering anatomical difficulties. This study aimed to estimate the usefulness of preoperative three-dimensional (3-D) imaging of thoracic organs. We compared the preoperative 64-row three-dimensional multidetector computed tomography (3DMDCT) findings of lung cancer-affected thoracic organs to the operative findings. In comparison to the operative findings, the branches of pulmonary arteries, veins, and bronchi were well defined in the 3D-MDCT images of 27 patients. 3D-MDCT imaging is useful for preoperatively understanding the individual thoracic anatomy in lung cancer surgery. This modality can therefore contribute to safer anatomical pulmonary operations, especially in VATS.

A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept.

PubMed

Men, Kuo; Dai, Jianrong

2017-12-01

To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current-exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation [Formula: see text] within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,[Formula: see text]. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom. For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method. The proposed method could reduce the additional dose to the patient while not degrading the image quality for cone-beam computed tomography. The projection quality-driven tube current modulation method could be especially beneficial to patients who undergo cone-beam computed tomography frequently during a treatment course.

Computed tomography guided localization of clinically occult breast carcinoma-the ''N'' skin guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopans, D.B.; Meyer, J.E.

1982-10-01

Standard computed tomography (CT) can be used for the three-dimensional localization of clinically occult suspicious breast lesions whose exact position cannot be determined by standard mammographic views. A method is described that facilitates accurate preoperative needle localization using CT guidance, once the position of these lesions is defined.

Construction and validation of the midsagittal reference plane based on the skull base symmetry for three-dimensional cephalometric craniofacial analysis.

PubMed

Kim, Hak-Jin; Kim, Bong Chul; Kim, Jin-Geun; Zhengguo, Piao; Kang, Sang Hoon; Lee, Sang-Hwy

2014-03-01

The objective of this study was to determine the reliable midsagittal (MS) reference plane in practical ways for the three-dimensional craniofacial analysis on three-dimensional computed tomography images. Five normal human dry skulls and 20 normal subjects without any dysmorphoses or asymmetries were used. The accuracies and stability on repeated plane construction for almost every possible candidate MS plane based on the skull base structures were examined by comparing the discrepancies in distances and orientations from the reference points and planes of the skull base and facial bones on three-dimensional computed tomography images. The following reference points of these planes were stable, and their distribution was balanced: nasion and foramen cecum at the anterior part of the skull base, sella at the middle part, and basion and opisthion at the posterior part. The candidate reference planes constructed using the aforementioned reference points were thought to be reliable for use as an MS reference plane for the three-dimensional analysis of maxillofacial dysmorphosis.

Cone beam computed tomography in Endodontics - a review.

PubMed

Patel, S; Durack, C; Abella, F; Shemesh, H; Roig, M; Lemberg, K

2015-01-01

Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on the applications and limitations of CBCT; (ii) make recommendations for the use of CBCT in Endodontics; (iii) highlight areas of further research of CBCT in Endodontics. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Energy and Technology Review

NASA Astrophysics Data System (ADS)

Poggio, Andrew J.

1988-10-01

This issue of Energy and Technology Review contains: Neutron Penumbral Imaging of Laser-Fusion Targets--using our new penumbral-imaging diagnostic, we have obtained the first images that can be used to measure directly the deuterium-tritium burn region in laser-driven fusion targets; Computed Tomography for Nondestructive Evaluation--various computed tomography systems and computational techniques are used in nondestructive evaluation; Three-Dimensional Image Analysis for Studying Nuclear Chromatin Structure--we have developed an optic-electronic system for acquiring cross-sectional views of cell nuclei, and computer codes to analyze these images and reconstruct the three-dimensional structures they represent; Imaging in the Nuclear Test Program--advanced techniques produce images of unprecedented detail and resolution from Nevada Test Site data; and Computational X-Ray Holography--visible-light experiments and numerically simulated holograms test our ideas about an X-ray microscope for biological research.

Verification of the Robin and Graham classification system of hip disease in cerebral palsy using three-dimensional computed tomography.

PubMed

Gose, Shinichi; Sakai, Takashi; Shibata, Toru; Akiyama, Keisuke; Yoshikawa, Hideki; Sugamoto, Kazuomi

2011-12-01

We evaluated the validity of the Robin and Graham classification system of hip disease in cerebral palsy (CP) using three-dimensional computed tomography in young people with CP. A total of 91 hips in 91 consecutive children with bilateral spastic CP (57 males, 34 females; nine classified at Gross Motor Function Classification System level II, 42 at level III, 32 at level IV, and eight at level V; mean age 5 y 2 mo, SD 11 mo; range 2-6 y) were investigated retrospectively using anteroposterior plain radiographs and three-dimensional computed tomography (3D-CT) of the hip. The migration percentage was calculated on plain radiographs and all participants were classified into four groups according to migration percentage: grade II, migration percentage ≥ 10% but ≤ 15%, (four hips), grade III, migration percentage >15% but ≤ 30%, (20 hips); grade IV, migration percentage >30% but <100%, (63 hips); and grade V, migration percentage ≥ 100%, (four hips). The lateral opening angle and the sagittal inclination angle of the acetabulum, the neck-shaft angle, and the femoral anteversion of the femur were measured on 3D-CT. The three-dimensional quantitative evaluation indicated that there were significant differences in the lateral opening angle and the neck-shaft angle between the four groups (Kruskal-Wallis test, p ≤ 0.001). This three-dimensional evaluation supports the validation of the Robin and Graham classification system for hip disease in 2- to 7-year-olds with CP. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures.

PubMed

Castiglia, Marcello Teixeira; Nogueira-Barbosa, Marcello Henrique; Messias, Andre Marcio Vieira; Salim, Rodrigo; Fogagnolo, Fabricio; Schatzker, Joseph; Kfuri, Mauricio

2018-02-14

Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane-oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two-dimensional videos of computed tomography, and three-dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter- and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi-square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker ( p  < 0.01). The addition of computed tomography scans to plain radiographs improved the interobserver reliability of Schatzker classification. Computed tomography had a statistically significant impact in the selection of surgical approaches for the lateral tibial plateau. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Three-dimensional venous visualization with phase-lag computed tomography angiography for reconstructive microsurgery.

PubMed

Sakakibara, Shunsuke; Onishi, Hiroyuki; Hashikawa, Kazunobu; Akashi, Masaya; Sakakibara, Akiko; Nomura, Tadashi; Terashi, Hiroto

2015-05-01

Most free flap reconstruction complications involve vascular compromise. Evaluation of vascular anatomy provides considerable information that can potentially minimize these complications. Previous reports have shown that contrast-enhanced computed tomography is effective for understanding three-dimensional arterial anatomy. However, most vascular complications result from venous thromboses, making imaging of venous anatomy highly desirable. The phase-lag computed tomography angiography (pl-CTA) technique involves 64-channel (virtually, 128-channel) multidetector CT and is used to acquire arterial images using conventional CTA. Venous images are three-dimensionally reconstructed using a subtraction technique involving combined venous phase and arterial phase images, using a computer workstation. This technique was used to examine 48 patients (12 lower leg reconstructions, 34 head and neck reconstructions, and 2 upper extremity reconstructions) without complications. The pl-CTA technique can be used for three-dimensional visualization of peripheral veins measuring approximately 1 mm in diameter. The pl-CTA information was especially helpful for secondary free flap reconstructions in the head and neck region after malignant tumor recurrence. In such cases, radical dissection of the neck was performed as part of the first operation, and many vessels, including veins, were resected and used in the first free-tissue transfer. The pl-CTA images also allowed visualization of varicose changes in the lower leg region and helped us avoid selecting those vessels for anastomosis. Thus, the pl-CTA-derived venous anatomy information was useful for exact evaluations during the planning of free-tissue transfers. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Three-dimensional photoacoustic tomography based on graphics-processing-unit-accelerated finite element method.

PubMed

Peng, Kuan; He, Ling; Zhu, Ziqiang; Tang, Jingtian; Xiao, Jiaying

2013-12-01

Compared with commonly used analytical reconstruction methods, the frequency-domain finite element method (FEM) based approach has proven to be an accurate and flexible algorithm for photoacoustic tomography. However, the FEM-based algorithm is computationally demanding, especially for three-dimensional cases. To enhance the algorithm's efficiency, in this work a parallel computational strategy is implemented in the framework of the FEM-based reconstruction algorithm using a graphic-processing-unit parallel frame named the "compute unified device architecture." A series of simulation experiments is carried out to test the accuracy and accelerating effect of the improved method. The results obtained indicate that the parallel calculation does not change the accuracy of the reconstruction algorithm, while its computational cost is significantly reduced by a factor of 38.9 with a GTX 580 graphics card using the improved method.

Coronary imaging of anomalous origins and aneurysms of the left coronary artery by multislice computed tomography.

PubMed

Castorina, Sergio; Luca, Tonia; Privitera, Giovanna; Riccioli, Vincenzo

2010-01-01

In this paper, we describe two cases of anomalous origin of the left coronary artery and two cases of aneurysm on the left coronary artery. Detailed three-dimensional images were acquired by the multislice computed tomography (MSCT) SOMATOM Sensation Cardiac 64 during clinical studies of cardiac diseases. Copyright 2010. Published by Elsevier Inc.

Phase-contrast x-ray computed tomography for observing biological specimens and organic materials

NASA Astrophysics Data System (ADS)

Momose, Atsushi; Takeda, Tohoru; Itai, Yuji

1995-02-01

A novel three-dimensional x-ray imaging method has been developed by combining a phase-contrast x-ray imaging technique with x-ray computed tomography. This phase-contrast x-ray computed tomography (PCX-CT) provides sectional images of organic specimens that would produce absorption-contrast x-ray CT images with little contrast. Comparing PCX-CT images of rat cerebellum and cancerous rabbit liver specimens with corresponding absorption-contrast CT images shows that PCX-CT is much more sensitive to the internal structure of organic specimens.

Jini service to reconstruct tomographic data

NASA Astrophysics Data System (ADS)

Knoll, Peter; Mirzaei, S.; Koriska, K.; Koehn, H.

2002-06-01

A number of imaging systems rely on the reconstruction of a 3- dimensional model from its projections through the process of computed tomography (CT). In medical imaging, for example magnetic resonance imaging (MRI), positron emission tomography (PET), and Single Computer Tomography (SPECT) acquire two-dimensional projections of a three dimensional projections of a three dimensional object. In order to calculate the 3-dimensional representation of the object, i.e. its voxel distribution, several reconstruction algorithms have been developed. Currently, mainly two reconstruct use: the filtered back projection(FBP) and iterative methods. Although the quality of iterative reconstructed SPECT slices is better than that of FBP slices, such iterative algorithms are rarely used for clinical routine studies because of their low availability and increased reconstruction time. We used Jini and a self-developed iterative reconstructions algorithm to design and implement a Jini reconstruction service. With this service, the physician selects the patient study from a database and a Jini client automatically discovers the registered Jini reconstruction services in the department's Intranet. After downloading the proxy object the this Jini service, the SPECT acquisition data are reconstructed. The resulting transaxial slices are visualized using a Jini slice viewer, which can be used for various imaging modalities.

Terahertz Computed Tomography of NASA Thermal Protection System Materials

NASA Technical Reports Server (NTRS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Three-dimensional evaluation of human jaw bone microarchitecture: correlation between the microarchitectural parameters of cone beam computed tomography and micro-computer tomography.

PubMed

Kim, Jo-Eun; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul; Huh, Kyung-Hoe

2015-12-01

To evaluate the potential feasibility of cone beam computed tomography (CBCT) in the assessment of trabecular bone microarchitecture. Sixty-eight specimens from four pairs of human jaw were scanned using both micro-computed tomography (micro-CT) of 19.37-μm voxel size and CBCT of 100-μm voxel size. The correlation of 3-dimensional parameters between CBCT and micro-CT was evaluated. All parameters, except bone-specific surface and trabecular thickness, showed linear correlations between the 2 imaging modalities (P < .05). Among the parameters, bone volume, percent bone volume, trabecular separation, and degree of anisotropy (DA) of CBCT images showed strong correlations with those of micro-CT images. DA showed the strongest correlation (r = 0.693). Most microarchitectural parameters from CBCT were correlated with those from micro-CT. Some microarchitectural parameters, especially DA, could be used as strong predictors of bone quality in the human jaw. Copyright © 2015 Elsevier Inc. All rights reserved.

Three-Dimensional Computer Graphics Brain-Mapping Project

DTIC Science & Technology

1988-03-24

1975-76, one of these brains was hand digitized. It was then reconstructed three dimensionally, using an Evans and Sutherland Picture System 2. This...Yakovlev Collection, we use the Evans and Sutherland Picture System 2 which we have been employing for this purpose for a dozen years. Its virtue is...careful, experimentally designed new protocol (See Figure 20). Most of these heads were imaged with Computed Tomography, thanks to Clint Stiles of Picker

[Three-dimensional computer aided design for individualized post-and-core restoration].

PubMed

Gu, Xiao-yu; Wang, Ya-ping; Wang, Yong; Lü, Pei-jun

2009-10-01

To develop a method of three-dimensional computer aided design (CAD) of post-and-core restoration. Two plaster casts with extracted natural teeth were used in this study. The extracted teeth were prepared and scanned using tomography method to obtain three-dimensional digitalized models. According to the basic rules of post-and-core design, posts, cores and cavity surfaces of the teeth were designed using the tools for processing point clouds, curves and surfaces on the forward engineering software of Tanglong prosthodontic system. Then three-dimensional figures of the final restorations were corrected according to the configurations of anterior teeth, premolars and molars respectively. Computer aided design of 14 post-and-core restorations were finished, and good fitness between the restoration and the three-dimensional digital models were obtained. Appropriate retention forms and enough spaces for the full crown restorations can be obtained through this method. The CAD of three-dimensional figures of the post-and-core restorations can fulfill clinical requirements. Therefore they can be used in computer-aided manufacture (CAM) of post-and-core restorations.

Offset-electrode profile acquisition strategy for electrical resistivity tomography

NASA Astrophysics Data System (ADS)

Robbins, Austin R.; Plattner, Alain

2018-04-01

We present an electrode layout strategy that allows electrical resistivity profiles to image the third dimension close to the profile plane. This "offset-electrode profile" approach involves laterally displacing electrodes away from the profile line in an alternating fashion and then inverting the resulting data using three-dimensional electrical resistivity tomography software. In our synthetic and field surveys, the offset-electrode method succeeds in revealing three-dimensional structures in the vicinity of the profile plane, which we could not achieve using three-dimensional inversions of linear profiles. We confirm and explain the limits of linear electrode profiles through a discussion of the three-dimensional sensitivity patterns: For a homogeneous starting model together with a linear electrode layout, all sensitivities remain symmetric with respect to the profile plane through each inversion step. This limitation can be overcome with offset-electrode layouts by breaking the symmetry pattern among the sensitivities. Thanks to freely available powerful three-dimensional resistivity tomography software and cheap modern computing power, the requirement for full three-dimensional calculations does not create a significant burden and renders the offset-electrode approach a cost-effective method. By offsetting the electrodes in an alternating pattern, as opposed to laying the profile out in a U-shape, we minimize shortening the profile length.

Development of technique for three-dimensional visualization of grain boundaries by white X-ray microbeam

NASA Astrophysics Data System (ADS)

Kajiwara, K.; Shobu, T.; Toyokawa, H.; Sato, M.

2014-04-01

A technique for three-dimensional visualization of grain boundaries was developed at BL28B2 at SPring-8. The technique uses white X-ray microbeam diffraction and a rotating slit. Three-dimensional images of small silicon single crystals filled in a plastic tube were successfully obtained using this technique for demonstration purposes. The images were consistent with those obtained by X-ray computed tomography.

Preoperative (3-dimensional) computed tomography lung reconstruction before anatomic segmentectomy or lobectomy for stage I non-small cell lung cancer.

PubMed

Chan, Ernest G; Landreneau, James R; Schuchert, Matthew J; Odell, David D; Gu, Suicheng; Pu, Jiantao; Luketich, James D; Landreneau, Rodney J

2015-09-01

Accurate cancer localization and negative resection margins are necessary for successful segmentectomy. In this study, we evaluate a newly developed software package that permits automated segmentation of the pulmonary parenchyma, allowing 3-dimensional assessment of tumor size, location, and estimates of surgical margins. A pilot study using a newly developed 3-dimensional computed tomography analytic software package was performed to retrospectively evaluate preoperative computed tomography images of patients who underwent segmentectomy (n = 36) or lobectomy (n = 15) for stage 1 non-small cell lung cancer. The software accomplishes an automated reconstruction of anatomic pulmonary segments of the lung based on bronchial arborization. Estimates of anticipated surgical margins and pulmonary segmental volume were made on the basis of 3-dimensional reconstruction. Autosegmentation was achieved in 72.7% (32/44) of preoperative computed tomography images with slice thicknesses of 3 mm or less. Reasons for segmentation failure included local severe emphysema or pneumonitis, and lower computed tomography resolution. Tumor segmental localization was achieved in all autosegmented studies. The 3-dimensional computed tomography analysis provided a positive predictive value of 87% in predicting a marginal clearance greater than 1 cm and a 75% positive predictive value in predicting a margin to tumor diameter ratio greater than 1 in relation to the surgical pathology assessment. This preoperative 3-dimensional computed tomography analysis of segmental anatomy can confirm the tumor location within an anatomic segment and aid in predicting surgical margins. This 3-dimensional computed tomography information may assist in the preoperative assessment regarding the suitability of segmentectomy for peripheral lung cancers. Published by Elsevier Inc.

Processing And Display Of Medical Three Dimensional Arrays Of Numerical Data Using Octree Encoding

NASA Astrophysics Data System (ADS)

Amans, Jean-Louis; Darier, Pierre

1986-05-01

imaging modalities such as X-Ray computerized Tomography (CT), Nuclear Medecine and Nuclear Magnetic Resonance can produce three-dimensional (3-D) arrays of numerical data of medical object internal structures. The analysis of 3-D data by synthetic generation of realistic images is an important area of computer graphics and imaging.

Three dimensional characterization of laser ablation craters using high resolution X-ray computed tomography

NASA Astrophysics Data System (ADS)

Galmed, A. H.; du Plessis, A.; le Roux, S. G.; Hartnick, E.; Von Bergmann, H.; Maaza, M.

2018-01-01

Laboratory X-ray computed tomography is an emerging technology for the 3D characterization and dimensional analysis of many types of materials. In this work we demonstrate the usefulness of this characterization method for the full three dimensional analysis of laser ablation craters, in the context of a laser induced breakdown spectroscopy setup. Laser induced breakdown spectroscopy relies on laser ablation for sampling the material of interest. We demonstrate here qualitatively (in images) and quantitatively (in terms of crater cone angles, depths, diameters and volume) laser ablation crater analysis in 3D for metal (aluminum) and rock (false gold ore). We show the effect of a Gaussian beam profile on the resulting crater geometry, as well as the first visual evidence of undercutting in the rock sample, most likely due to ejection of relatively large grains. The method holds promise for optimization of laser ablation setups especially for laser induced breakdown spectroscopy.

Isotropic-resolution linear-array-based photoacoustic computed tomography through inverse Radon transform

NASA Astrophysics Data System (ADS)

Li, Guo; Xia, Jun; Li, Lei; Wang, Lidai; Wang, Lihong V.

2015-03-01

Linear transducer arrays are readily available for ultrasonic detection in photoacoustic computed tomography. They offer low cost, hand-held convenience, and conventional ultrasonic imaging. However, the elevational resolution of linear transducer arrays, which is usually determined by the weak focus of the cylindrical acoustic lens, is about one order of magnitude worse than the in-plane axial and lateral spatial resolutions. Therefore, conventional linear scanning along the elevational direction cannot provide high-quality three-dimensional photoacoustic images due to the anisotropic spatial resolutions. Here we propose an innovative method to achieve isotropic resolutions for three-dimensional photoacoustic images through combined linear and rotational scanning. In each scan step, we first elevationally scan the linear transducer array, and then rotate the linear transducer array along its center in small steps, and scan again until 180 degrees have been covered. To reconstruct isotropic three-dimensional images from the multiple-directional scanning dataset, we use the standard inverse Radon transform originating from X-ray CT. We acquired a three-dimensional microsphere phantom image through the inverse Radon transform method and compared it with a single-elevational-scan three-dimensional image. The comparison shows that our method improves the elevational resolution by up to one order of magnitude, approaching the in-plane lateral-direction resolution. In vivo rat images were also acquired.

Integrated Nondestructive Evaluation and Finite Element Analysis Predicts Crack Location and Shape

NASA Technical Reports Server (NTRS)

Abdul-Azia, Ali; Baaklini, George Y.; Trudell, Jeffrey J.

2002-01-01

This study describes the finite-element analyses and the NDE modality undertaken on two flywheel rotors that were spun to burst speed. Computed tomography and dimensional measurements were used to nondestructively evaluate the rotors before and/or after they were spun to the first crack detection. Computed tomography data findings of two- and three-dimensional crack formation were used to conduct finite-element (FEA) and fracture mechanics analyses. A procedure to extend these analyses to estimate the life of these components is also outlined. NDE-FEA results for one of the rotors are presented in the figures. The stress results, which represent the radial stresses in the rim, clearly indicate that the maximum stress region is within the section defined by the computed tomography scan. Furthermore, the NDE data correlate well with the FEA results. In addition, the measurements reported show that the NDE and FEA data are in parallel.

New horizons in forensic radiology: the 60-second digital autopsy-full-body examination of a gunshot victim by multislice computed tomography.

PubMed

Thali, Michael J; Schweitzer, Wolf; Yen, Kathrin; Vock, Peter; Ozdoba, Christoph; Spielvogel, Elke; Dirnhofer, Richard

2003-03-01

The goal of this study was the full-body documentation of a gunshot wound victim with multislice helical computed tomography for subsequent comparison with the findings of the standard forensic autopsy. Complete volume data of the head, neck, and trunk were acquired by use of two acquisitions of less than 1 minute of total scanning time. Subsequent two-dimensional multiplanar reformations and three-dimensional shaded surface display reconstructions helped document the gunshot-created skull fractures and brain injuries, including the wound track, and the intracerebral bone fragments. Computed tomography also demonstrated intracardiac air embolism and pulmonary aspiration of blood resulting from bullet wound-related trauma. The "digital autopsy," even when postprocessing time was added, was more rapid than the classic forensic autopsy and, based on the nondestructive approach, offered certain advantages in comparison with the forensic autopsy.

Three-dimensional shape analysis of miarolitic cavities and enclaves in the Kakkonda granite by X-ray computed tomography

NASA Astrophysics Data System (ADS)

Ohtani, Tomoyuki; Nakano, Tsukasa; Nakashima, Yoshito; Muraoka, Hirofumi

2001-11-01

Three-dimensional shape analysis of miarolitic cavities and enclaves from the Kakkonda granite, NE Japan, was performed by X-ray computed tomography (CT) and image analysis. The three-dimensional shape of the miarolitic cavities and enclaves was reconstructed by stacked two-dimensional CT slice images with an in-plane resolution of 0.3 mm and an inter-slice spacing of 1 mm. An ellipsoid was fitted to each reconstructed object by the image processing programs. The shortest, intermediate, and longest axes of the ellipsoids fitted to miarolitic cavities had E-W, N-S, and vertical directions, respectively. The shortest axes of the ellipsoids fitted to enclaves were sub-vertical to vertical. Three-dimensional strains calculated from miarolitic cavities and enclaves have E-W and vertical shortening, respectively. The shape characteristics of miarolitic cavities probably reflect regional stress during the late magmatic stage, and those of enclaves reflect shortening by later-intruded magma or body rotation during the early magmatic stage. The miarolitic cavities may not be strained homogeneously with the surrounding granite, because the competence of minerals is different from that of the fluid-filled cavities. Although the strain markers require sufficient contrast between their CT numbers and those of the surrounding minerals, this method has several advantages over conventional methods, including the fact that it is non-destructive, expedient, and allows direct three-dimensional observation of each object.

Insights into the dissolution and the three-dimensional structure of insensitive munitions formulations.

PubMed

Taylor, Susan; Ringelberg, David B; Dontsova, Katerina; Daghlian, Charles P; Walsh, Marianne E; Walsh, Michael R

2013-11-01

Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. For multi-component explosives the solubility of the individual constituents and the fraction of each constituent wetted by water controls the dissolution. We found that the order of magnitude differences in solubility amongst the constituents of these IM formulations quickly produced hole-riddled particles when these were exposed to water. Micro-computed tomography showed that particles resulting from field detonations were fractured, producing conduits by which water could access the interior of the particle. We think that micro-computed tomography can also be used to determine the initial composition of IM particles and to track how their compositions change as the particles dissolve. This information is critical to quantifying dissolution and developing physically based dissolution models. Published by Elsevier Ltd.

Broadband Terahertz Computed Tomography Using a 5k-pixel Real-time THz Camera

NASA Astrophysics Data System (ADS)

Trichopoulos, Georgios C.; Sertel, Kubilay

2015-07-01

We present a novel THz computed tomography system that enables fast 3-dimensional imaging and spectroscopy in the 0.6-1.2 THz band. The system is based on a new real-time broadband THz camera that enables rapid acquisition of multiple cross-sectional images required in computed tomography. Tomographic reconstruction is achieved using digital images from the densely-packed large-format (80×64) focal plane array sensor located behind a hyper-hemispherical silicon lens. Each pixel of the sensor array consists of an 85 μm × 92 μm lithographically fabricated wideband dual-slot antenna, monolithically integrated with an ultra-fast diode tuned to operate in the 0.6-1.2 THz regime. Concurrently, optimum impedance matching was implemented for maximum pixel sensitivity, enabling 5 frames-per-second image acquisition speed. As such, the THz computed tomography system generates diffraction-limited resolution cross-section images as well as the three-dimensional models of various opaque and partially transparent objects. As an example, an over-the-counter vitamin supplement pill is imaged and its material composition is reconstructed. The new THz camera enables, for the first time, a practical application of THz computed tomography for non-destructive evaluation and biomedical imaging.

Use of Cone Beam Computed Tomography in Endodontics

PubMed Central

Scarfe, William C.; Levin, Martin D.; Gane, David; Farman, Allan G.

2009-01-01

Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imaging adjunct for endodontics. PMID:20379362

Microscale Electromagnetic Heating in Heterogeneous Energetic Materials Based on X-ray Computed Tomography

NASA Astrophysics Data System (ADS)

Kort-Kamp, W. J. M.; Cordes, N. L.; Ionita, A.; Glover, B. B.; Duque, A. L. Higginbotham; Perry, W. L.; Patterson, B. M.; Dalvit, D. A. R.; Moore, D. S.

2016-04-01

Electromagnetic stimulation of energetic materials provides a noninvasive and nondestructive tool for detecting and identifying explosives. We combine structural information based on x-ray computed tomography, experimental dielectric data, and electromagnetic full-wave simulations to study microscale electromagnetic heating of realistic three-dimensional heterogeneous explosives. We analyze the formation of electromagnetic hot spots and thermal gradients in the explosive-binder mesostructures and compare the heating rate for various binder systems.

[Usefulness of computed tomography with three-dimensional reconstructions in visualization of cervical spine malformation of a child with Sprengel's deformity].

PubMed

Wawrzynek, Wojciech; Siemianowicz, Anna; Koczy, Bogdan; Kasprowska, Sabina; Besler, Krzysztof

2005-01-01

The Sprengel's deformity is a congenital anomaly of the shoulder girdle with an elevation of the scapula and limitation of movement of the shoulder. Sprengel's deformity is frequently associated with cervical spine malformations such as: spinal synostosis, spina bifida and an abnormal omovertebral fibrous, cartilaginous or osseus connection. The diagnosis of Sprengel's deformity is based on a clinical examination and radiological procedures. In every case of Sprengel's deformity plain radiography and computed tomography should be performed. Three-dimensional (3D) reconstructions allow to visualize precise topography and spatial proportions of examined bone structures. 3D reconstruction also enables an optional rotation of visualized bone structures in order to clarify the anatomical abnormalities and to plan surgical treatment.

Superimposition of 3-dimensional cone-beam computed tomography models of growing patients

PubMed Central

Cevidanes, Lucia H. C.; Heymann, Gavin; Cornelis, Marie A.; DeClerck, Hugo J.; Tulloch, J. F. Camilla

2009-01-01

Introduction The objective of this study was to evaluate a new method for superimposition of 3-dimensional (3D) models of growing subjects. Methods Cone-beam computed tomography scans were taken before and after Class III malocclusion orthopedic treatment with miniplates. Three observers independently constructed 18 3D virtual surface models from cone-beam computed tomography scans of 3 patients. Separate 3D models were constructed for soft-tissue, cranial base, maxillary, and mandibular surfaces. The anterior cranial fossa was used to register the 3D models of before and after treatment (about 1 year of follow-up). Results Three-dimensional overlays of superimposed models and 3D color-coded displacement maps allowed visual and quantitative assessment of growth and treatment changes. The range of interobserver errors for each anatomic region was 0.4 mm for the zygomatic process of maxilla, chin, condyles, posterior border of the rami, and lower border of the mandible, and 0.5 mm for the anterior maxilla soft-tissue upper lip. Conclusions Our results suggest that this method is a valid and reproducible assessment of treatment outcomes for growing subjects. This technique can be used to identify maxillary and mandibular positional changes and bone remodeling relative to the anterior cranial fossa. PMID:19577154

Use of cone beam computed tomography in periodontology

PubMed Central

Acar, Buket; Kamburoğlu, Kıvanç

2014-01-01

Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination. PMID:24876918

A COMPUTER MODEL OF LUNG MORPHOLOGY TO ANALYZE SPECT IMAGES

EPA Science Inventory

Measurement of the three-dimensional (3-D) spatial distribution of aerosol deposition can be performed using Single Photon Emission Computed Tomography (SPECT). The advantage of using 3-D techniques over planar gamma imaging is that deposition patterns can be related to real lun...

Comparative Evaluation of a Four-Implant-Supported Polyetherketoneketone Framework Prosthesis: A Three-Dimensional Finite Element Analysis Based on Cone Beam Computed Tomography and Computer-Aided Design.

PubMed

Lee, Ki-Sun; Shin, Sang-Wan; Lee, Sang-Pyo; Kim, Jong-Eun; Kim, Jee-Hwan; Lee, Jeong-Yol

The purpose of this pilot study was to evaluate and compare polyetherketoneketone (PEKK) with different framework materials for implant-supported prostheses by means of a three-dimensional finite element analysis (3D-FEA) based on cone beam computed tomography (CBCT) and computer-aided design (CAD) data. A geometric model that consisted of four maxillary implants supporting a prosthesis framework was constructed from CBCT and CAD data of a treated patient. Three different materials (zirconia, titanium, and PEKK) were selected, and their material properties were simulated using FEA software in the generated geometric model. In the PEKK framework (ie, low elastic modulus) group, the stress transferred to the implant and simulated adjacent tissue was reduced when compressive stress was dominant, but increased when tensile stress was dominant. This study suggests that the shock-absorbing effects of a resilient implant-supported framework are limited in some areas and that rigid framework material shows a favorable stress distribution and safety of overall components of the prosthesis.

Rapid prototyping raw models on the basis of high resolution computed tomography lung data for respiratory flow dynamics.

PubMed

Giesel, Frederik L; Mehndiratta, Amit; von Tengg-Kobligk, Hendrik; Schaeffer, A; Teh, Kevin; Hoffman, E A; Kauczor, Hans-Ulrich; van Beek, E J R; Wild, Jim M

2009-04-01

Three-dimensional image reconstruction by volume rendering and rapid prototyping has made it possible to visualize anatomic structures in three dimensions for interventional planning and academic research. Volumetric chest computed tomography was performed on a healthy volunteer. Computed tomographic images of the larger bronchial branches were segmented by an extended three-dimensional region-growing algorithm, converted into a stereolithography file, and used for computer-aided design on a laser sintering machine. The injection of gases for respiratory flow modeling and measurements using magnetic resonance imaging were done on a hollow cast. Manufacturing the rapid prototype took about 40 minutes and included the airway tree from trackea to segmental bronchi (fifth generation). The branching of the airways are clearly visible in the (3)He images, and the radial imaging has the potential to elucidate the airway dimensions. The results for flow patterns in the human bronchial tree using the rapid-prototype model with hyperpolarized helium-3 magnetic resonance imaging show the value of this model for flow phantom studies.

Computer system for definition of the quantitative geometry of musculature from CT images.

PubMed

Daniel, Matej; Iglic, Ales; Kralj-Iglic, Veronika; Konvicková, Svatava

2005-02-01

The computer system for quantitative determination of musculoskeletal geometry from computer tomography (CT) images has been developed. The computer system processes series of CT images to obtain three-dimensional (3D) model of bony structures where the effective muscle fibres can be interactively defined. Presented computer system has flexible modular structure and is suitable also for educational purposes.

Multicenter study of quantitative computed tomography analysis using a computer-aided three-dimensional system in patients with idiopathic pulmonary fibrosis.

PubMed

Iwasawa, Tae; Kanauchi, Tetsu; Hoshi, Toshiko; Ogura, Takashi; Baba, Tomohisa; Gotoh, Toshiyuki; Oba, Mari S

2016-01-01

To evaluate the feasibility of automated quantitative analysis with a three-dimensional (3D) computer-aided system (i.e., Gaussian histogram normalized correlation, GHNC) of computed tomography (CT) images from different scanners. Each institution's review board approved the research protocol. Informed patient consent was not required. The participants in this multicenter prospective study were 80 patients (65 men, 15 women) with idiopathic pulmonary fibrosis. Their mean age was 70.6 years. Computed tomography (CT) images were obtained by four different scanners set at different exposures. We measured the extent of fibrosis using GHNC, and used Pearson's correlation analysis, Bland-Altman plots, and kappa analysis to directly compare the GHNC results with manual scoring by radiologists. Multiple linear regression analysis was performed to determine the association between the CT data and forced vital capacity (FVC). For each scanner, the extent of fibrosis as determined by GHNC was significantly correlated with the radiologists' score. In multivariate analysis, the extent of fibrosis as determined by GHNC was significantly correlated with FVC (p < 0.001). There was no significant difference between the results obtained using different CT scanners. Gaussian histogram normalized correlation was feasible, irrespective of the type of CT scanner used.

The role of three-dimensional imaging in optimizing diagnosis, classification and surgical treatment of hepatocellular carcinoma with portal vein tumor thrombus.

PubMed

Wei, Xu-Biao; Xu, Jie; Li, Nan; Yu, Ying; Shi, Jie; Guo, Wei-Xing; Cheng, Hong-Yan; Wu, Meng-Chao; Lau, Wan-Yee; Cheng, Shu-Qun

2016-03-01

Accurate assessment of characteristics of tumor and portal vein tumor thrombus is crucial in the management of hepatocellular carcinoma. Comparison of the three-dimensional imaging with multiple-slice computed tomography in the diagnosis and treatment of hepatocellular carcinoma with portal vein tumor thrombus. Patients eligible for surgical resection were divided into the three-dimensional imaging group or the multiple-slice computed tomography group according to the type of preoperative assessment. The clinical data were collected and compared. 74 patients were enrolled into this study. The weighted κ values for comparison between the thrombus type based on preoperative evaluation and intraoperative findings were 0.87 for the three-dimensional reconstruction group (n = 31) and 0.78 for the control group (n = 43). Three-dimensional reconstruction was significantly associated with a higher rate of en-bloc resection of tumor and thrombus (P = 0.025). Using three-dimensional reconstruction, significant correlation existed between the predicted and actual volumes of the resected specimens (r = 0.82, P < 0.01), as well as the predicted and actual resection margins (r = 0.97, P < 0.01). Preoperative three-dimensional reconstruction significantly decreased tumor recurrence and tumor-related death, with hazard ratios of 0.49 (95% confidential interval, 0.27-0.90) and 0.41 (95% confidential interval, 0.21-0.78), respectively. For hepatocellular carcinoma with portal vein tumor thrombus, three-dimensional imaging was efficient in facilitating surgical treatment and benefiting postoperative survivals. Copyright © 2015 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.

Microscale electromagnetic heating in heterogeneous energetic materials based on x-ray computed tomography

DOE PAGES

Kort-Kamp, W. J. M.; Cordes, N. L.; Ionita, A.; ...

2016-04-01

Electromagnetic stimulation of energetic materials provides a noninvasive and nondestructive tool for detecting and identifying explosives. We combine structural information based on x-ray computed tomography, experimental dielectric data, and electromagnetic full-wave simulations to study microscale electromagnetic heating of realistic three-dimensional heterogeneous explosives. In conclusion, we analyze the formation of electromagnetic hot spots and thermal gradients in the explosive-binder mesostructures and compare the heating rate for various binder systems.

Microscale electromagnetic heating in heterogeneous energetic materials based on x-ray computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kort-Kamp, W. J. M.; Cordes, N. L.; Ionita, A.

Electromagnetic stimulation of energetic materials provides a noninvasive and nondestructive tool for detecting and identifying explosives. We combine structural information based on x-ray computed tomography, experimental dielectric data, and electromagnetic full-wave simulations to study microscale electromagnetic heating of realistic three-dimensional heterogeneous explosives. In conclusion, we analyze the formation of electromagnetic hot spots and thermal gradients in the explosive-binder mesostructures and compare the heating rate for various binder systems.

X-ray coherent scattering tomography of textured material (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zhu, Zheyuan; Pang, Shuo

2017-05-01

Small-angle X-ray scattering (SAXS) measures the signature of angular-dependent coherently scattered X-rays, which contains richer information in material composition and structure compared to conventional absorption-based computed tomography. SAXS image reconstruction method of a 2 or 3 dimensional object based on computed tomography, termed as coherent scattering computed tomography (CSCT), enables the detection of spatially-resolved, material-specific isotropic scattering signature inside an extended object, and provides improved contrast for medical diagnosis, security screening, and material characterization applications. However, traditional CSCT methods assumes materials are fine powders or amorphous, and possess isotropic scattering profiles, which is not generally true for all materials. Anisotropic scatters cannot be captured using conventional CSCT method and result in reconstruction errors. To obtain correct information from the sample, we designed new imaging strategy which incorporates extra degree of detector motion into X-ray scattering tomography for the detection of anisotropic scattered photons from a series of two-dimensional intensity measurements. Using a table-top, narrow-band X-ray source and a panel detector, we demonstrate the anisotropic scattering profile captured from an extended object and the reconstruction of a three-dimensional object. For materials possessing a well-organized crystalline structure with certain symmetry, the scatter texture is more predictable. We will also discuss the compressive schemes and implementation of data acquisition to improve the collection efficiency and accelerate the imaging process.

Tomographic techniques for the study of exceptionally preserved fossils

PubMed Central

Sutton, Mark D

2008-01-01

Three-dimensional fossils, especially those preserving soft-part anatomy, are a rich source of palaeontological information; they can, however, be difficult to work with. Imaging of serial planes through an object (tomography) allows study of both the inside and outside of three-dimensional fossils. Tomography may be performed using physical grinding or sawing coupled with photography, through optical techniques of serial focusing, or using a variety of scanning technologies such as neutron tomography, magnetic resonance imaging and most usefully X-ray computed tomography. This latter technique is applicable at a variety of scales, and when combined with a synchrotron X-ray source can produce very high-quality data that may be augmented by phase-contrast information to enhance contrast. Tomographic data can be visualized in several ways, the most effective of which is the production of isosurface-based ‘virtual fossils’ that can be manipulated and dissected interactively. PMID:18426749

Non-invasive three-dimensional imaging of Escherichia coli K1 infection using diffuse light imaging tomography combined with micro-computed tomography.

PubMed

Witcomb, Luci A; Czupryna, Julie; Francis, Kevin P; Frankel, Gad; Taylor, Peter W

2017-08-15

In contrast to two-dimensional bioluminescence imaging, three dimensional diffuse light imaging tomography with integrated micro-computed tomography (DLIT-μCT) has the potential to realise spatial variations in infection patterns when imaging experimental animals dosed with derivatives of virulent bacteria carrying bioluminescent reporter genes such as the lux operon from the bacterium Photorhabdus luminescens. The method provides an opportunity to precisely localise the bacterial infection sites within the animal and enables the generation of four-dimensional movies of the infection cycle. Here, we describe the use of the PerkinElmer IVIS SpectrumCT in vivo imaging system to investigate progression of lethal systemic infection in neonatal rats following colonisation of the gastrointestinal tract with the neonatal pathogen Escherichia coli K1. We confirm previous observations that these bacteria stably colonize the colon and small intestine following feeding of the infectious dose from a micropipette; invading bacteria migrate across the gut epithelium into the blood circulation and establish foci of infection in major organs, including the brain. DLIT-μCT revealed novel multiple sites of colonisation within the alimentary canal, including the tongue, oesophagus and stomach, with penetration of the non-keratinised oesophageal epithelial surface, providing strong evidence of a further major site for bacterial dissemination. We highlight technical issues associated with imaging of infections in new born rat pups and show that the whole-body and organ bioburden correlates with disease severity. Copyright © 2017 Elsevier Inc. All rights reserved.

Cadaveric and three-dimensional computed tomography study of the morphology of the scapula with reference to reversed shoulder prosthesis

PubMed Central

Torrens, Carlos; Corrales, Monica; Gonzalez, Gemma; Solano, Alberto; Cáceres, Enrique

2008-01-01

Purpose The purpose of this study is to analyze the morphology of the scapula with reference to the glenoid component implantation in reversed shoulder prosthesis, in order to improve primary fixation of the component. Methods Seventy-three 3-dimensional computed tomography of the scapula and 108 scapular dry specimens were analyzed to determine the anterior and posterior length of the glenoid neck, the angle between the glenoid surface and the upper posterior column of the scapula and the angle between the major craneo-caudal glenoid axis and the base of the coracoid process and the upper posterior column. Results The anterior and posterior length of glenoid neck was classified into two groups named "short-neck" and "long-neck" with significant differences between them. The angle between the glenoid surface and the upper posterior column of the scapula was also classified into two different types: type I (mean 50°–52°) and type II (mean 62,50°–64°), with significant differences between them (p < 0,001). The angle between the major craneo-caudal glenoid axis and the base of the coracoid process averaged 18,25° while the angle with the upper posterior column of the scapula averaged 8°. Conclusion Scapular morphological variability advices for individual adjustments of glenoid component implantation in reversed total shoulder prosthesis. Three-dimensional computed tomography of the scapula constitutes an important tool when planning reversed prostheses implantation. PMID:18847487

Cadaveric and three-dimensional computed tomography study of the morphology of the scapula with reference to reversed shoulder prosthesis.

PubMed

Torrens, Carlos; Corrales, Monica; Gonzalez, Gemma; Solano, Alberto; Cáceres, Enrique

2008-10-10

The purpose of this study is to analyze the morphology of the scapula with reference to the glenoid component implantation in reversed shoulder prosthesis, in order to improve primary fixation of the component. Seventy-three 3-dimensional computed tomography of the scapula and 108 scapular dry specimens were analyzed to determine the anterior and posterior length of the glenoid neck, the angle between the glenoid surface and the upper posterior column of the scapula and the angle between the major craneo-caudal glenoid axis and the base of the coracoid process and the upper posterior column. The anterior and posterior length of glenoid neck was classified into two groups named "short-neck" and "long-neck" with significant differences between them. The angle between the glenoid surface and the upper posterior column of the scapula was also classified into two different types: type I (mean 50 degrees-52 degrees ) and type II (mean 62.50 degrees-64 degrees ), with significant differences between them (p < 0.001). The angle between the major craneo-caudal glenoid axis and the base of the coracoid process averaged 18,25 degrees while the angle with the upper posterior column of the scapula averaged 8 degrees . Scapular morphological variability advices for individual adjustments of glenoid component implantation in reversed total shoulder prosthesis. Three-dimensional computed tomography of the scapula constitutes an important tool when planning reversed prostheses implantation.

Three-Dimensional Computed Tomography as a Method for Finding Die Attach Voids in Diodes

NASA Technical Reports Server (NTRS)

Brahm, E. N.; Rolin, T. D.

2010-01-01

NASA analyzes electrical, electronic, and electromechanical (EEE) parts used in space vehicles to understand failure modes of these components. The diode is an EEE part critical to NASA missions that can fail due to excessive voiding in the die attach. Metallography, one established method for studying the die attach, is a time-intensive, destructive, and equivocal process whereby mechanical grinding of the diodes is performed to reveal voiding in the die attach. Problems such as die attach pull-out tend to complicate results and can lead to erroneous conclusions. The objective of this study is to determine if three-dimensional computed tomography (3DCT), a nondestructive technique, is a viable alternative to metallography for detecting die attach voiding. The die attach voiding in two- dimensional planes created from 3DCT scans was compared to several physical cross sections of the same diode to determine if the 3DCT scan accurately recreates die attach volumetric variability

Use of cone beam computed tomography in implant dentistry: current concepts, indications and limitations for clinical practice and research.

PubMed

Bornstein, Michael M; Horner, Keith; Jacobs, Reinhilde

2017-02-01

Diagnostic radiology is an essential component of treatment planning in the field of implant dentistry. This narrative review will present current concepts for the use of cone beam computed tomography imaging, before and after implant placement, in daily clinical practice and research. Guidelines for the selection of three-dimensional imaging will be discussed, and limitations will be highlighted. Current concepts of radiation dose optimization, including novel imaging modalities using low-dose protocols, will be presented. For preoperative cross-sectional imaging, data are still not available which demonstrate that cone beam computed tomography results in fewer intraoperative complications such as nerve damage or bleeding incidents, or that implants inserted using preoperative cone beam computed tomography data sets for planning purposes will exhibit higher survival or success rates. The use of cone beam computed tomography following the insertion of dental implants should be restricted to specific postoperative complications, such as damage of neurovascular structures or postoperative infections in relation to the maxillary sinus. Regarding peri-implantitis, the diagnosis and severity of the disease should be evaluated primarily based on clinical parameters and on radiological findings based on periapical radiographs (two dimensional). The use of cone beam computed tomography scans in clinical research might not yield any evident beneficial effect for the patient included. As many of the cone beam computed tomography scans performed for research have no direct therapeutic consequence, dose optimization measures should be implemented by using appropriate exposure parameters and by reducing the field of view to the actual region of interest. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Three-dimensional electrical impedance tomography based on the complete electrode model.

PubMed

Vauhkonen, P J; Vauhkonen, M; Savolainen, T; Kaipio, J P

1999-09-01

In electrical impedance tomography an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the body. It is often assumed that the injected currents are confined to the two-dimensional (2-D) electrode plane and the reconstruction is based on 2-D assumptions. However, the currents spread out in three dimensions and, therefore, off-plane structures have significant effect on the reconstructed images. In this paper we propose a finite element-based method for the reconstruction of three-dimensional resistivity distributions. The proposed method is based on the so-called complete electrode model that takes into account the presence of the electrodes and the contact impedances. Both the forward and the inverse problems are discussed and results from static and dynamic (difference) reconstructions with real measurement data are given. It is shown that in phantom experiments with accurate finite element computations it is possible to obtain static images that are comparable with difference images that are reconstructed from the same object with the empty (saline filled) tank as a reference.

The Applications of Cone-Beam Computed Tomography in Endodontics: A Review of Literature

PubMed Central

Kiarudi, Amir Hosein; Eghbal, Mohammad Jafar; Safi, Yaser; Aghdasi, Mohammad Mehdi; Fazlyab, Mahta

2015-01-01

By producing undistorted three-dimensional images of the area under examination, cone-beam computed tomography (CBCT) systems have met many of the limitations of conventional radiography. These systems produce images with small field of view at low radiation doses with adequate spatial resolution that are suitable for many applications in endodontics from diagnosis to treatment and follow-up. This review article comprehensively assembles all the data from literature regarding the potential applications of CBCT in endodontics. PMID:25598804

Precision and accuracy of suggested maxillary and mandibular landmarks with cone-beam computed tomography for regional superimpositions: An in vitro study.

PubMed

Lemieux, Genevieve; Carey, Jason P; Flores-Mir, Carlos; Secanell, Marc; Hart, Adam; Lagravère, Manuel O

2016-01-01

Our objective was to identify and evaluate the accuracy and precision (intrarater and interrater reliabilities) of various anatomic landmarks for use in 3-dimensional maxillary and mandibular regional superimpositions. We used cone-beam computed tomography reconstructions of 10 human dried skulls to locate 10 landmarks in the maxilla and the mandible. Precision and accuracy were assessed with intrarater and interrater readings. Three examiners located these landmarks in the cone-beam computed tomography images 3 times with readings scheduled at 1-week intervals. Three-dimensional coordinates were determined (x, y, and z coordinates), and the intraclass correlation coefficient was computed to determine intrarater and interrater reliabilities, as well as the mean error difference and confidence intervals for each measurement. Bilateral mental foramina, bilateral infraorbital foramina, anterior nasal spine, incisive canal, and nasion showed the highest precision and accuracy in both intrarater and interrater reliabilities. Subspinale and bilateral lingulae had the lowest precision and accuracy in both intrarater and interrater reliabilities. When choosing the most accurate and precise landmarks for 3-dimensional cephalometric analysis or plane-derived maxillary and mandibular superimpositions, bilateral mental and infraorbital foramina, landmarks in the anterior region of the maxilla, and nasion appeared to be the best options of the analyzed landmarks. Caution is needed when using subspinale and bilateral lingulae because of their higher mean errors in location. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Automated computation of femoral angles in dogs from three-dimensional computed tomography reconstructions: Comparison with manual techniques.

PubMed

Longo, F; Nicetto, T; Banzato, T; Savio, G; Drigo, M; Meneghello, R; Concheri, G; Isola, M

2018-02-01

The aim of this ex vivo study was to test a novel three-dimensional (3D) automated computer-aided design (CAD) method (aCAD) for the computation of femoral angles in dogs from 3D reconstructions of computed tomography (CT) images. The repeatability and reproducibility of three manual radiography, manual CT reconstructions and the aCAD method for the measurement of three femoral angles were evaluated: (1) anatomical lateral distal femoral angle (aLDFA); (2) femoral neck angle (FNA); and (3) femoral torsion angle (FTA). Femoral angles of 22 femurs obtained from 16 cadavers were measured by three blinded observers. Measurements were repeated three times by each observer for each diagnostic technique. Femoral angle measurements were analysed using a mixed effects linear model for repeated measures to determine the levels of intra-observer agreement (repeatability) and inter-observer agreement (reproducibility). Repeatability and reproducibility of measurements using the aCAD method were excellent (intra-class coefficients, ICCs≥0.98) for all three angles assessed. Manual radiography and CT exhibited excellent agreement for the aLDFA measurement (ICCs≥0.90). However, FNA repeatability and reproducibility were poor (ICCs<0.8), whereas FTA measurement showed slightly higher ICCs values, except for the radiographic reproducibility, which was poor (ICCs<0.8). The computation of the 3D aCAD method provided the highest repeatability and reproducibility among the tested methodologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigating line- versus point-laser excitation for three-dimensional fluorescence imaging and tomography employing a trimodal imaging system

NASA Astrophysics Data System (ADS)

Cao, Liji; Peter, Jörg

2013-06-01

The adoption of axially oriented line illumination patterns for fluorescence excitation in small animals for fluorescence surface imaging (FSI) and fluorescence optical tomography (FOT) is being investigated. A trimodal single-photon-emission-computed-tomography/computed-tomography/optical-tomography (SPECT-CT-OT) small animal imaging system is being modified for employment of point- and line-laser excitation sources. These sources can be arbitrarily positioned around the imaged object. The line source is set to illuminate the object along its entire axial direction. Comparative evaluation of point and line illumination patterns for FSI and FOT is provided involving phantom as well as mouse data. Given the trimodal setup, CT data are used to guide the optical approaches by providing boundary information. Furthermore, FOT results are also being compared to SPECT. Results show that line-laser illumination yields a larger axial field of view (FOV) in FSI mode, hence faster data acquisition, and practically acceptable FOT reconstruction throughout the whole animal. Also, superimposed SPECT and FOT data provide additional information on similarities as well as differences in the distribution and uptake of both probe types. Fused CT data enhance further the anatomical localization of the tracer distribution in vivo. The feasibility of line-laser excitation for three-dimensional fluorescence imaging and tomography is demonstrated for initiating further research, however, not with the intention to replace one by the other.

The holographic display of three-dimensional medical objects through the usage of a shiftable cylindrical lens

NASA Astrophysics Data System (ADS)

Teng, Dongdong; Liu, Lilin; Zhang, Yueli; Pang, Zhiyong; Wang, Biao

2014-09-01

Through the creative usage of a shiftable cylindrical lens, a wide-view-angle holographic display system is developed for medical object display in real three-dimensional (3D) space based on a time-multiplexing method. The two-dimensional (2D) source images for all computer generated holograms (CGHs) needed by the display system are only one group of computerized tomography (CT) or magnetic resonance imaging (MRI) slices from the scanning device. Complicated 3D message reconstruction on the computer is not necessary. A pelvis is taken as the target medical object to demonstrate this method and the obtained horizontal viewing angle reaches 28°.

Compton imaging tomography technique for NDE of large nonuniform structures

NASA Astrophysics Data System (ADS)

Grubsky, Victor; Romanov, Volodymyr; Patton, Ned; Jannson, Tomasz

2011-09-01

In this paper we describe a new nondestructive evaluation (NDE) technique called Compton Imaging Tomography (CIT) for reconstructing the complete three-dimensional internal structure of an object, based on the registration of multiple two-dimensional Compton-scattered x-ray images of the object. CIT provides high resolution and sensitivity with virtually any material, including lightweight structures and organics, which normally pose problems in conventional x-ray computed tomography because of low contrast. The CIT technique requires only one-sided access to the object, has no limitation on the object's size, and can be applied to high-resolution real-time in situ NDE of large aircraft/spacecraft structures and components. Theoretical and experimental results will be presented.

Sex determination from chest measurements in a sample of Egyptian adults using Multislice Computed Tomography.

PubMed

Darwish, Ragaa T; Abdel-Aziz, Manal H; El Nekiedy, Abdel-Aziz M; Sobh, Zahraa K

2017-11-01

In forensic sciences to determine one's sex is quite important during the identity defining stage. The reliability of sex determination depends on the completeness of the remains and the degree of sexual dimorphism inherent in the population. Computed Tomography is the imaging modality of choice for two- and three-dimensional documentation and analysis of many autopsy findings. The aim of the present work was to assess the reliability of Three-dimensional Multislice Computed Tomography (3D MSCT) to determine sexual dimorphism from certain chest measurements; sternum and fourth rib using the 3D MSCT and to develop equations for sex determination from these bones among adult Egyptians sample. The present study was performed on 60 adult Egyptians. Their age ranged from 21 up to 74 years and they were equally divided between both sexes. Sixty virtual chests (reconstructed Multislice Computed Tomography 3D images) were examined for detection of Sternal measurements; Manubrium length (ML), Sternal body length (BL), Manubrium width (MW), Sternal body widths(BWa&BWb), Sternal area (SA) [(ML + BL) × (MW + BWa + BWb)/3]and Fourth rib width (FRW). All the studied measurements were significantly higher in males than in females. Multiple regression analysis was used to and three significant regression equations were developed for predicting sex using the different studied chest measurements; the sternal measurements, the sternal area and the widths of the right and left fourth ribs with their accuracies 96.67%.95.0%.72.68% respectively. Sterunm and fourth rib width revealed significant metric sex differences with the use of Multislice Computed Tomography 3D images thus provide a great advantage in the analysis of skeletal remains and badly decomposed bodies. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Optical computed tomography in PRESAGE® three-dimensional dosimetry: Challenges and prospective.

PubMed

Khezerloo, Davood; Nedaie, Hassan Ali; Farhood, Bagher; Zirak, Alireza; Takavar, Abbas; Banaee, Nooshin; Ahmadalidokht, Isa; Kron, Tomas

2017-01-01

With the advent of new complex but precise radiotherapy techniques, the demands for an accurate, feasible three-dimensional (3D) dosimetry system have been increased. A 3D dosimeter system generally should not only have accurate and precise results but should also feasible, inexpensive, and time consuming. Recently, one of the new candidates for 3D dosimetry is optical computed tomography (CT) with a radiochromic dosimeter such as PRESAGE®. Several generations of optical CT have been developed since the 90s. At the same time, a large attempt has been also done to introduce the robust dosimeters that compatible with optical CT scanners. In 2004, PRESAGE® dosimeter as a new radiochromic solid plastic dosimeters was introduced. In this decade, a large number of efforts have been carried out to enhance optical scanning methods. This article attempts to review and reflect on the results of these investigations.

Comparison of face types in Chinese women using three-dimensional computed tomography.

PubMed

Zhou, Rong-Rong; Zhao, Qi-Ming; Liu, Miao

2015-04-01

This study compared inverted triangle and square faces of 21 young Chinese Han women (18-25 years old) using three-dimensional computed tomography images retrieved from a records database. In this study, 11 patients had inverted triangle faces and 10 had square faces. The anatomic features were examined and compared. There were significant differences in lower face width, lower face height, masseter thickness, middle/lower face width ratio, and lower face width/height ratio between the two facial types (p < 0.01). Lower face width was positively correlated with masseter thickness and negatively correlated with gonial angle. Lower face height was positively correlated with gonial angle and negatively correlated with masseter thickness, and gonial angle was negatively correlated with masseter thickness. In young Chinese Han women, inverted triangle faces and square faces differ significantly in masseter thickness and lower face height. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

An application framework of three-dimensional reconstruction and measurement for endodontic research.

PubMed

Gao, Yuan; Peters, Ove A; Wu, Hongkun; Zhou, Xuedong

2009-02-01

The purpose of this study was to customize an application framework by using the MeVisLab image processing and visualization platform for three-dimensional reconstruction and assessment of tooth and root canal morphology. One maxillary first molar was scanned before and after preparation with ProTaper by using micro-computed tomography. With a customized application framework based on MeVisLab, internal and external anatomy was reconstructed. Furthermore, the dimensions of root canal and radicular dentin were quantified, and effects of canal preparation were assessed. Finally, a virtual preparation with risk analysis was performed to simulate the removal of a broken instrument. This application framework provided an economical platform and met current requirements of endodontic research. The broad-based use of high-quality free software and the resulting exchange of experience might help to improve the quality of endodontic research with micro-computed tomography.

Into the decomposed body-forensic digital autopsy using multislice-computed tomography.

PubMed

Thali, M J; Yen, K; Schweitzer, W; Vock, P; Ozdoba, C; Dirnhofer, R

2003-07-08

It is impossible to obtain a representative anatomical documentation of an entire body using classical X-ray methods, they subsume three-dimensional bodies into a two-dimensional level. We used the novel multislice-computed tomography (MSCT) technique in order to evaluate a case of homicide with putrefaction of the corpse before performing a classical forensic autopsy. This non-invasive method showed gaseous distension of the decomposing organs and tissues in detail as well as a complex fracture of the calvarium. MSCT also proved useful in screening for foreign matter in decomposing bodies, and full-body scanning took only a few minutes. In conclusion, we believe postmortem MSCT imaging is an excellent vizualisation tool with great potential for forensic documentation and evaluation of decomposed bodies.

The Mundrabilla Meteorite in Three-Dimensions

NASA Technical Reports Server (NTRS)

Gillies, D. C.; Carpenter, P. K.; Engel, H. P.

2003-01-01

Computed tomography (CT) using gamma radiation has revealed the interior structure of the anomalous iron meteorite, Mundrabilla. This meteorite is composed of 25 volume percent of iron sulfide with the remainder being iron-nickel. Both phases have been shown to be contiguous, and three dimensional models have been constructed using rapid prototyping techniques.

Three-dimensional cone-beam computed tomography analysis of enlargement of the pharyngeal airway by the Herbst appliance.

PubMed

Iwasaki, Tomonori; Takemoto, Yoshihiko; Inada, Emi; Sato, Hideo; Saitoh, Issei; Kakuno, Eriko; Kanomi, Ryuzo; Yamasaki, Youichi

2014-12-01

Pharyngeal airway size is increasingly recognized as an important factor in obstructive sleep apnea. However, few studies have examined the changes of pharyngeal airway form after dental procedures for treating obstructive sleep apnea during growth. The purpose of this study was to evaluate the effect of the Herbst appliance on the 3-dimensional form of the pharyngeal airway using cone-beam computed tomography. Twenty-four Class II subjects (ANB, ≥5°; 11 boys; mean age, 11.6 years) who required Herbst therapy with edgewise treatment had cone-beam computed tomography images taken before and after Herbst treatment. Twenty Class I control subjects (9 boys; mean age, 11.5 years) received edgewise treatment only. The volume, depth, and width of the pharyngeal airway were compared between the groups using measurements from 3-dimensional cone-beam computed tomography images of the entire pharyngeal airway. The increase of the oropharyngeal airway volume in the Herbst group (5000.2 mm(3)) was significantly greater than that of the control group (2451.6 mm(3)). Similarly, the increase of the laryngopharyngeal airway volume in the Herbst group (1941.8 mm(3)) was significantly greater than that of the control group (1060.1 mm(3)). The Herbst appliance enlarges the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Morphometric analysis - Cone beam computed tomography to predict bone quality and quantity.

PubMed

Hohlweg-Majert, B; Metzger, M C; Kummer, T; Schulze, D

2011-07-01

Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. MATERIALS AND PROCEDURES: Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality. 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Italian Chapter of the International Society of Cardiovascular Ultrasound expert consensus document on coronary computed tomography angiography: overview and new insights.

PubMed

Sozzi, Fabiola B; Maiello, Maria; Pelliccia, Francesco; Parato, Vito Maurizio; Canetta, Ciro; Savino, Ketty; Lombardi, Federico; Palmiero, Pasquale

2016-09-01

Coronary computed tomography angiography is a noninvasive heart imaging test currently undergoing rapid development and advancement. The high resolution of the three-dimensional pictures of the moving heart and great vessels is performed during a coronary computed tomography to identify coronary artery disease and classify patient risk for atherosclerotic cardiovascular disease. The technique provides useful information about the coronary tree and atherosclerotic plaques beyond simple luminal narrowing and plaque type defined by calcium content. This application will improve image-guided prevention, medical therapy, and coronary interventions. The ability to interpret coronary computed tomography images is of utmost importance as we develop personalized medical care to enable therapeutic interventions stratified on the bases of plaque characteristics. This overview provides available data and expert's recommendations in the utilization of coronary computed tomography findings. We focus on the use of coronary computed tomography to detect coronary artery disease and stratify patients at risk, illustrating the implications of this test on patient management. We describe its diagnostic power in identifying patients at higher risk to develop acute coronary syndrome and its prognostic significance. Finally, we highlight the features of the vulnerable plaques imaged by coronary computed tomography angiography. © 2016, Wiley Periodicals, Inc.

Application of multidetector-row computed tomography in propeller flap planning.

PubMed

Ono, Shimpei; Chung, Kevin C; Hayashi, Hiromitsu; Ogawa, Rei; Takami, Yoshihiro; Hyakusoku, Hiko

2011-02-01

The propeller flap is defined as (1) being island-shaped, (2) having an axis that includes the perforators, and (3) having the ability to be rotated around an axis. The advantage of the propeller flap is that it is a pedicle flap that can be applied to cover defects located at the distal ends of the extremities. The specific aims of the authors' study were (1) to evaluate the usefulness of multidetector-row computed tomography in the planning of propeller flaps and (2) to present a clinical case series of propeller flap reconstructions that were planned preoperatively using multidetector-row computed tomography. The authors retrospectively analyzed all cases between April of 2007 and April of 2010 at Nippon Medical School Hospital in Tokyo, where multidetector-row computed tomography was used preoperatively to plan surgical reconstructions using propeller flaps. Thirteen patients underwent 16 flaps using the propeller flap technique. The perforators were identified accurately by multidetector-row computed tomography preoperatively in all cases. This is the first report describing the application of multidetector-row computed tomography in the planning of propeller flaps. Multidetector-row computed tomography is superior to other imaging methods because it demonstrates more precisely the perforator's position and subcutaneous course using high-resolution three-dimensional images. By using multidetector-row computed tomography to preoperatively identify a flap's perforators, the surgeon can better plan the flap design to efficiently conduct the flap surgery.

Projection matrix acquisition for cone-beam computed tomography iterative reconstruction

NASA Astrophysics Data System (ADS)

Yang, Fuqiang; Zhang, Dinghua; Huang, Kuidong; Shi, Wenlong; Zhang, Caixin; Gao, Zongzhao

2017-02-01

Projection matrix is an essential and time-consuming part in computed tomography (CT) iterative reconstruction. In this article a novel calculation algorithm of three-dimensional (3D) projection matrix is proposed to quickly acquire the matrix for cone-beam CT (CBCT). The CT data needed to be reconstructed is considered as consisting of the three orthogonal sets of equally spaced and parallel planes, rather than the individual voxels. After getting the intersections the rays with the surfaces of the voxels, the coordinate points and vertex is compared to obtain the index value that the ray traversed. Without considering ray-slope to voxel, it just need comparing the position of two points. Finally, the computer simulation is used to verify the effectiveness of the algorithm.

Fractal Dimensionality of Pore and Grain Volume of a Siliciclastic Marine Sand

NASA Astrophysics Data System (ADS)

Reed, A. H.; Pandey, R. B.; Lavoie, D. L.

Three-dimensional (3D) spatial distributions of pore and grain volumes were determined from high-resolution computer tomography (CT) images of resin-impregnated marine sands. Using a linear gradient extrapolation method, cubic three-dimensional samples were constructed from two-dimensional CT images. Image porosity (0.37) was found to be consistent with the estimate of porosity by water weight loss technique (0.36). Scaling of the pore volume (Vp) with the linear size (L), V~LD provides the fractal dimensionalities of the pore volume (D=2.74+/-0.02) and grain volume (D=2.90+/-0.02) typical for sedimentary materials.

Automated Quantification of Pneumothorax in CT

PubMed Central

Do, Synho; Salvaggio, Kristen; Gupta, Supriya; Kalra, Mannudeep; Ali, Nabeel U.; Pien, Homer

2012-01-01

An automated, computer-aided diagnosis (CAD) algorithm for the quantification of pneumothoraces from Multidetector Computed Tomography (MDCT) images has been developed. Algorithm performance was evaluated through comparison to manual segmentation by expert radiologists. A combination of two-dimensional and three-dimensional processing techniques was incorporated to reduce required processing time by two-thirds (as compared to similar techniques). Volumetric measurements on relative pneumothorax size were obtained and the overall performance of the automated method shows an average error of just below 1%. PMID:23082091

Automated method for structural segmentation of nasal airways based on cone beam computed tomography

NASA Astrophysics Data System (ADS)

Tymkovych, Maksym Yu.; Avrunin, Oleg G.; Paliy, Victor G.; Filzow, Maksim; Gryshkov, Oleksandr; Glasmacher, Birgit; Omiotek, Zbigniew; DzierŻak, RóŻa; Smailova, Saule; Kozbekova, Ainur

2017-08-01

The work is dedicated to the segmentation problem of human nasal airways using Cone Beam Computed Tomography. During research, we propose a specialized approach of structured segmentation of nasal airways. That approach use spatial information, symmetrisation of the structures. The proposed stages can be used for construction a virtual three dimensional model of nasal airways and for production full-scale personalized atlases. During research we build the virtual model of nasal airways, which can be used for construction specialized medical atlases and aerodynamics researches.

Three-Dimensional Image Fusion of 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography and Contrast-Enhanced Computed Tomography for Computer-Assisted Planning of Maxillectomy of Recurrent Maxillary Squamous Cell Carcinoma and Defect Reconstruction.

PubMed

Yu, Yao; Zhang, Wen-Bo; Liu, Xiao-Jing; Guo, Chuan-Bin; Yu, Guang-Yan; Peng, Xin

2017-06-01

The purpose of this study was to describe new technology assisted by 3-dimensional (3D) image fusion of 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) for computer planning of a maxillectomy of recurrent maxillary squamous cell carcinoma and defect reconstruction. Treatment of recurrent maxillary squamous cell carcinoma usually includes tumor resection and free flap reconstruction. FDG-PET/CT provided images of regions of abnormal glucose uptake and thus showed metabolic tumor volume to guide tumor resection. CECT data were used to create 3D reconstructed images of vessels to show the vascular diameters and locations, so that the most suitable vein and artery could be selected during anastomosis of the free flap. The data from preoperative maxillofacial CECT scans and FDG-PET/CT imaging were imported into the navigation system (iPlan 3.0; Brainlab, Feldkirchen, Germany). Three-dimensional image fusion between FDG-PET/CT and CECT was accomplished using Brainlab software according to the position of the 2 skulls simulated in the CECT image and PET/CT image, respectively. After verification of the image fusion accuracy, the 3D reconstruction images of the metabolic tumor, vessels, and other critical structures could be visualized within the same coordinate system. These sagittal, coronal, axial, and 3D reconstruction images were used to determine the virtual osteotomy sites and reconstruction plan, which was provided to the surgeon and used for surgical navigation. The average shift of the 3D image fusion between FDG-PET/CT and CECT was less than 1 mm. This technique, by clearly showing the metabolic tumor volume and the most suitable vessels for anastomosis, facilitated resection and reconstruction of recurrent maxillary squamous cell carcinoma. We used 3D image fusion of FDG-PET/CT and CECT to successfully accomplish resection and reconstruction of recurrent maxillary squamous cell carcinoma. This method has the potential to improve the clinical outcomes of these challenging procedures. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Three-dimensional prediction of the human eyeball and canthi for craniofacial reconstruction using cone-beam computed tomography.

PubMed

Kim, Sang-Rok; Lee, Kyung-Min; Cho, Jin-Hyoung; Hwang, Hyeon-Shik

2016-04-01

An anatomical relationship between the hard and soft tissues of the face is mandatory for facial reconstruction. The purpose of this study was to investigate the positions of the eyeball and canthi three-dimensionally from the relationships between the facial hard and soft tissues using cone-beam computed tomography (CBCT). CBCT scan data of 100 living subjects were used to obtain the measurements of facial hard and soft tissues. Stepwise multiple regression analyses were carried out using the hard tissue measurements in the orbit, nasal bone, nasal cavity and maxillary canine to predict the most probable positions of the eyeball and canthi within the orbit. Orbital width, orbital height, and orbital depth were strong predictors of the eyeball and canthi position. Intercanine width was also a predictor of the mediolateral position of the eyeball. Statistically significant regression models for the positions of the eyeball and canthi could be derived from the measurements of orbit and maxillary canine. These results suggest that CBCT data can be useful in predicting the positions of the eyeball and canthi three-dimensionally. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Solving the forward problem of magnetoacoustic tomography with magnetic induction by means of the finite element method

NASA Astrophysics Data System (ADS)

Li, Xun; Li, Xu; Zhu, Shanan; He, Bin

2009-05-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently proposed imaging modality to image the electrical impedance of biological tissue. It combines the good contrast of electrical impedance tomography with the high spatial resolution of sonography. In this paper, a three-dimensional MAT-MI forward problem was investigated using the finite element method (FEM). The corresponding FEM formulae describing the forward problem are introduced. In the finite element analysis, magnetic induction in an object with conductivity values close to biological tissues was first carried out. The stimulating magnetic field was simulated as that generated from a three-dimensional coil. The corresponding acoustic source and field were then simulated. Computer simulation studies were conducted using both concentric and eccentric spherical conductivity models with different geometric specifications. In addition, the grid size for finite element analysis was evaluated for the model calibration and evaluation of the corresponding acoustic field.

Solving the Forward Problem of Magnetoacoustic Tomography with Magnetic Induction by Means of the Finite Element Method

PubMed Central

Li, Xun; Li, Xu; Zhu, Shanan; He, Bin

2010-01-01

Magnetoacoustic Tomography with Magnetic Induction (MAT-MI) is a recently proposed imaging modality to image the electrical impedance of biological tissue. It combines the good contrast of electrical impedance tomography with the high spatial resolution of sonography. In this paper, three-dimensional MAT-MI forward problem was investigated using the finite element method (FEM). The corresponding FEM formulas describing the forward problem are introduced. In the finite element analysis, magnetic induction in an object with conductivity values close to biological tissues was first carried out. The stimulating magnetic field was simulated as that generated from a three-dimensional coil. The corresponding acoustic source and field were then simulated. Computer simulation studies were conducted using both concentric and eccentric spherical conductivity models with different geometric specifications. In addition, the grid size for finite element analysis was evaluated for model calibration and evaluation of the corresponding acoustic field. PMID:19351978

Anthropometry of the Human Scaphoid Waist by Three-Dimensional Computed Tomography.

PubMed

Smith, Jennifer; Hofmeister, Eric P; Renninger, Christopher; Kroonen, Leo T

2015-01-01

Published measurements for the scaphoid are scarce. The purpose of this study is to define anthropometric norms for the waist of the scaphoid to assist in optimizing bone graft quantity and implant use. Computed tomography images of the wrist were reviewed by three surgeons. Anthropometric data were gathered, including the scaphoid waist diameter in two dimensions and the scaphoid waist volume. Each study was measured twice, allowing for determination of inter- and intraobserver reliability. Forty-three studies were examined (23 female and 20 male). Average measurements of the scaphoid waist were 11.28 ± 0.26 mm in the sagittal plane and 8.70 ± 0.17 mm in the coronal plane, and the waist volume was 715 ± 33.0 mm3. Specific measures of the narrowest portion of the scaphoid are provided by this study. Measurements of the scaphoid waist through the use of three-dimensional imaging are an accurate method with good inter- and intraobserver reliability. The measurements obtained from this study can be applied to guide graft and implant selection for treatment of scaphoid waist fractures and nonunions.

Digital dissection - using contrast-enhanced computed tomography scanning to elucidate hard- and soft-tissue anatomy in the Common Buzzard Buteo buteo.

PubMed

Lautenschlager, Stephan; Bright, Jen A; Rayfield, Emily J

2014-04-01

Gross dissection has a long history as a tool for the study of human or animal soft- and hard-tissue anatomy. However, apart from being a time-consuming and invasive method, dissection is often unsuitable for very small specimens and often cannot capture spatial relationships of the individual soft-tissue structures. The handful of comprehensive studies on avian anatomy using traditional dissection techniques focus nearly exclusively on domestic birds, whereas raptorial birds, and in particular their cranial soft tissues, are essentially absent from the literature. Here, we digitally dissect, identify, and document the soft-tissue anatomy of the Common Buzzard (Buteo buteo) in detail, using the new approach of contrast-enhanced computed tomography using Lugol's iodine. The architecture of different muscle systems (adductor, depressor, ocular, hyoid, neck musculature), neurovascular, and other soft-tissue structures is three-dimensionally visualised and described in unprecedented detail. The three-dimensional model is further presented as an interactive PDF to facilitate the dissemination and accessibility of anatomical data. Due to the digital nature of the data derived from the computed tomography scanning and segmentation processes, these methods hold the potential for further computational analyses beyond descriptive and illustrative proposes. © 2013 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.

Virtual Assessment of Sex: Linear and Angular Traits of the Mandibular Ramus Using Three-Dimensional Computed Tomography.

PubMed

Inci, Ercan; Ekizoglu, Oguzhan; Turkay, Rustu; Aksoy, Sema; Can, Ismail Ozgur; Solmaz, Dilek; Sayin, Ibrahim

2016-10-01

Morphometric analysis of the mandibular ramus (MR) provides highly accurate data to discriminate sex. The objective of this study was to demonstrate the utility and accuracy of MR morphometric analysis for sex identification in a Turkish population.Four hundred fifteen Turkish patients (18-60 y; 201 male and 214 female) who had previously had multidetector computed tomography scans of the cranium were included in the study. Multidetector computed tomography images were obtained using three-dimensional reconstructions and a volume-rendering technique, and 8 linear and 3 angular values were measured. Univariate, bivariate, and multivariate discriminant analyses were performed, and the accuracy rates for determining sex were calculated.Mandibular ramus values produced high accuracy rates of 51% to 95.6%. Upper ramus vertical height had the highest rate at 95.6%, and bivariate analysis showed 89.7% to 98.6% accuracy rates with the highest ratios of mandibular flexure upper border and maximum ramus breadth. Stepwise discrimination analysis gave a 99% accuracy rate for all MR variables.Our study showed that the MR, in particular morphometric measures of the upper part of the ramus, can provide valuable data to determine sex in a Turkish population. The method combines both anthropological and radiologic studies.

X-ray phase-contrast computed tomography visualizes the microstructure and degradation profile of implanted biodegradable scaffolds after spinal cord injury

PubMed Central

Takashima, Kenta; Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto; Matsuda, Shojiro; Nakahira, Atsushi; Osumi, Noriko; Kohzuki, Masahiro; Onodera, Hiroshi

2015-01-01

Tissue engineering strategies for spinal cord repair are a primary focus of translational medicine after spinal cord injury (SCI). Many tissue engineering strategies employ three-dimensional scaffolds, which are made of biodegradable materials and have microstructure incorporated with viable cells and bioactive molecules to promote new tissue generation and functional recovery after SCI. It is therefore important to develop an imaging system that visualizes both the microstructure of three-dimensional scaffolds and their degradation process after SCI. Here, X-ray phase-contrast computed tomography imaging based on the Talbot grating interferometer is described and it is shown how it can visualize the polyglycolic acid scaffold, including its microfibres, after implantation into the injured spinal cord. Furthermore, X-ray phase-contrast computed tomography images revealed that degradation occurred from the end to the centre of the braided scaffold in the 28 days after implantation into the injured spinal cord. The present report provides the first demonstration of an imaging technique that visualizes both the microstructure and degradation of biodegradable scaffolds in SCI research. X-ray phase-contrast imaging based on the Talbot grating interferometer is a versatile technique that can be used for a broad range of preclinical applications in tissue engineering strategies. PMID:25537600

[CONE BEAM COMPUTED TOMOGRAPHY IN DIAGNOSTICS OF ODONTOGENIC MAXILLARY SINUSITIS (CASE REPORTS)].

PubMed

Demidova, E; Khurdzidze, G

2017-06-01

Diagnostic studies performed by cone beam computed tomography Morita 3D made possible to obtain high resolution images of hard tissues of upper jawbone and maxillary sinus, to detect bony tissue defects, such as odontogenic cysts, cystogranulomas and granulomas. High-resolution and three dimensional tomographic image reconstructions allowed for optimal and prompt determination of the scope of surgical treatment and planning of effective conservative treatment regimen. Interactive diagnostics helped to estimate cosmetic and functional results of surgical treatment, to prevent the occurrence of surgical complications, and to evaluate the efficacy of conservative treatment. The obtained data contributed to determination of particular applications of cone beam computed tomography in the diagnosis of odontogenic maxillary sinusitis, detection of specific defects with cone beam tomography as the most informative method of diagnosis; as well as to determination of weak and strong sides, and helped to offer mechanisms of x-ray diagnostics to dental surgeons and ENT specialists.

Terahertz computed tomography of NASA thermal protection system materials

NASA Astrophysics Data System (ADS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2012-05-01

A terahertz (THz) axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 m3 (1 ft3) with no safety concerns as for x-ray computed tomography. In this study, the THz-CT system was evaluated for its ability to detect and characterize 1) an embedded void in Space Shuttle external fuel tank thermal protection system (TPS) foam material and 2) impact damage in a TPS configuration under consideration for use in NASA's multi-purpose Orion crew module (CM). Micro-focus X-ray CT is utilized to characterize the flaws and provide a baseline for which to compare the THz CT results.

Registration of planar bioluminescence to magnetic resonance and x-ray computed tomography images as a platform for the development of bioluminescence tomography reconstruction algorithms.

PubMed

Beattie, Bradley J; Klose, Alexander D; Le, Carl H; Longo, Valerie A; Dobrenkov, Konstantine; Vider, Jelena; Koutcher, Jason A; Blasberg, Ronald G

2009-01-01

The procedures we propose make possible the mapping of two-dimensional (2-D) bioluminescence image (BLI) data onto a skin surface derived from a three-dimensional (3-D) anatomical modality [magnetic resonance (MR) or computed tomography (CT)] dataset. This mapping allows anatomical information to be incorporated into bioluminescence tomography (BLT) reconstruction procedures and, when applied using sources visible to both optical and anatomical modalities, can be used to evaluate the accuracy of those reconstructions. Our procedures, based on immobilization of the animal and a priori determined fixed projective transforms, should be more robust and accurate than previously described efforts, which rely on a poorly constrained retrospectively determined warping of the 3-D anatomical information. Experiments conducted to measure the accuracy of the proposed registration procedure found it to have a mean error of 0.36+/-0.23 mm. Additional experiments highlight some of the confounds that are often overlooked in the BLT reconstruction process, and for two of these confounds, simple corrections are proposed.

Three-dimensional imaging modalities in endodontics

PubMed Central

Mao, Teresa

2014-01-01

Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome. PMID:25279337

A simple three-dimensional stent for proper placement of mini-implant

PubMed Central

2013-01-01

Background This paper deals with the fabrication of a three-dimensional stent which is simple in design but provides an accurate placement of a mini-implant in three planes of space, namely, sagittal (root proximity), vertical (attached gingiva/alveolar mucosa) and transverse (angulation). Findings The stent is made of 0.018 × 0.025 in. stainless steel archwire which consists of a ‘u loop’ angulated at 20°, a vertical limb, a horizontal limb and a stop. The angulation of the ‘u’ helps in the placement of the mini-implant at 70° to the long axis of the tooth. The vertical height is determined such that the mini-implant is placed at the mucogingival junction. The mini-implant is placed with the aid of the stent, and its angulation and proximity to the adjacent roots are checked with a cone beam computed tomography image. The cone beam computed tomography image showed the mini-implant at an angle of 70° to the long axis of the tooth. There is no contact between mini-implant and the roots of the adjacent teeth. Conclusion This stent is simple, easy to fabricate, cost-effective, and provides ease of insertion/removal, and three-dimensional orientation of the mini-implant. PMID:24326158

Three-dimensional dynamic thermal imaging of structural flaws by dual-band infrared computed tomography

NASA Astrophysics Data System (ADS)

DelGrande, Nancy; Dolan, Kenneth W.; Durbin, Philip F.; Gorvad, Michael R.; Kornblum, B. T.; Perkins, Dwight E.; Schneberk, Daniel J.; Shapiro, Arthur B.

1993-11-01

We discuss three-dimensional dynamic thermal imaging of structural flaws using dual-band infrared (DBIR) computed tomography. Conventional (single-band) thermal imaging is difficult to interpret. It yields imprecise or qualitative information (e.g., when subsurface flaws produce weak heat flow anomalies masked by surface clutter). We use the DBIR imaging technique to clarify interpretation. We capture the time history of surface temperature difference patterns at the epoxy-glue disbond site of a flash-heated lap joint. This type of flawed structure played a significant role in causing damage to the Aloha Aircraft fuselage on the aged Boeing 737 jetliner. The magnitude of surface-temperature differences versus time for 0.1 mm air layer compared to 0.1 mm glue layer, varies from 0.2 to 1.6 degree(s)C, for simultaneously scanned front and back surfaces. The scans are taken every 42 ms from 0 to 8 s after the heat flash. By ratioing 3 - 5 micrometers and 8 - 12 micrometers DBIR images, we located surface temperature patterns from weak heat flow anomalies at the disbond site and remove the emissivity mask from surface paint of roughness variations. Measurements compare well with calculations based on TOPAX3D, a three-dimensional, finite element computer model. We combine infrared, ultrasound and x-ray imaging methods to study heat transfer, bond quality and material differences associated with the lap joint disbond site.

Using synchrotron-based X-ray micro-computed tomography and high-performance pore-scale simulation to evaluate hydraulic properties in biochar-amended soils

NASA Astrophysics Data System (ADS)

Zhou, H.; Yu, X.; Chen, C.; Zeng, L.; Lu, S.; Wu, L.

2016-12-01

In this research, we combined synchrotron-based X-ray micro-computed tomography (SR-mCT), with three-dimensional lattice Bolzmann (LB) method, to quantify how the change in pore space architecture affected macroscopic hydraulic of two clayey soils amended with biochar. SR-mCT was used to characterize pore structures of the soils before and after biochar addition. The high-resolution soil pore structures were then directly used as internal boundary conditions for three-dimensional water flow simulations with the LB method, which was accelerated by graphics processing unit (GPU) parallel computing. It was shown that, due to the changes in soil pore geometry, the application of biochar increased the soil permeability by at least 1 order of magnitude, and decreased the tortuosity by 20-30%. This work was the first physics based modeling study on the effect of biochar amendment on soil hydraulic properties. The developed theories and techniques have promising potential in understanding the mechanisms of water and nutrient transport in soil at the pore scale.

Three-Dimensional Printing in Orthopedic Surgery.

PubMed

Eltorai, Adam E M; Nguyen, Eric; Daniels, Alan H

2015-11-01

Three-dimensional (3D) printing is emerging as a clinically promising technology for rapid prototyping of surgically implantable products. With this commercially available technology, computed tomography or magnetic resonance images can be used to create graspable objects from 3D reconstructed images. Models can enhance patients' understanding of their pathology and surgeon preoperative planning. Customized implants and casts can be made to match an individual's anatomy. This review outlines 3D printing, its current applications in orthopedics, and promising future directions. Copyright 2015, SLACK Incorporated.

An overview of contemporary nuclear cardiology.

PubMed

Lewin, Howard C; Sciammarella, Maria G; Watters, Thomas A; Alexander, Herbert G

2004-01-01

Myocardial perfusion single photon emission computed tomography (SPECT) is a widely utilized noninvasive imaging modality for the diagnosis, prognosis, and risk stratification of coronary artery disease. It is clearly superior to the traditional planar technique in terms of imaging contrast and consequent diagnostic and prognostic yield. The strength of SPECT images is largely derived from the three-dimensional, volumetric nature of its image. Thus, this modality permits three-dimensional assessment and quantitation of the perfused myocardium and functional assessment through electrocardiographic gating of the perfusion images.

Errors due to the truncation of the computational domain in static three-dimensional electrical impedance tomography.

PubMed

Vauhkonen, P J; Vauhkonen, M; Kaipio, J P

2000-02-01

In electrical impedance tomography (EIT), an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the body. The currents spread out in three dimensions and therefore off-plane structures have a significant effect on the reconstructed images. A question arises: how far from the current carrying electrodes should the discretized model of the object be extended? If the model is truncated too near the electrodes, errors are produced in the reconstructed images. On the other hand if the model is extended very far from the electrodes the computational time may become too long in practice. In this paper the model truncation problem is studied with the extended finite element method. Forward solutions obtained using so-called infinite elements, long finite elements and separable long finite elements are compared to the correct solution. The effects of the truncation of the computational domain on the reconstructed images are also discussed and results from the three-dimensional (3D) sensitivity analysis are given. We show that if the finite element method with ordinary elements is used in static 3D EIT, the dimension of the problem can become fairly large if the errors associated with the domain truncation are to be avoided.

Application of a real-time three-dimensional navigation system to various oral and maxillofacial surgical procedures.

PubMed

Ohba, Seigo; Yoshimura, Hitoshi; Ishimaru, Kyoko; Awara, Kousuke; Sano, Kazuo

2015-09-01

The aim of this study was to confirm the effectiveness of a real-time three-dimensional navigation system for use during various oral and maxillofacial surgeries. Five surgeries were performed with this real-time three-dimensional navigation system. For mandibular surgery, patients wore acrylic surgical splints when they underwent computed tomography examinations and the operation to maintain the mandibular position. The incidence of complications during and after surgery was assessed. No connection with the nasal cavity or maxillary sinus was observed at the maxilla during the operation. The inferior alveolar nerve was not injured directly, and any paresthesia around the lower lip and mental region had disappeared within several days after the surgery. In both maxillary and mandibular cases, there was no abnormal hemorrhage during or after the operation. Real-time three-dimensional computer-navigated surgery allows minimally invasive, safe procedures to be performed with precision. It results in minimal complications and early recovery.

Multifactorial Optimization of Contrast-Enhanced Nanofocus Computed Tomography for Quantitative Analysis of Neo-Tissue Formation in Tissue Engineering Constructs.

PubMed

Sonnaert, Maarten; Kerckhofs, Greet; Papantoniou, Ioannis; Van Vlierberghe, Sandra; Boterberg, Veerle; Dubruel, Peter; Luyten, Frank P; Schrooten, Jan; Geris, Liesbet

2015-01-01

To progress the fields of tissue engineering (TE) and regenerative medicine, development of quantitative methods for non-invasive three dimensional characterization of engineered constructs (i.e. cells/tissue combined with scaffolds) becomes essential. In this study, we have defined the most optimal staining conditions for contrast-enhanced nanofocus computed tomography for three dimensional visualization and quantitative analysis of in vitro engineered neo-tissue (i.e. extracellular matrix containing cells) in perfusion bioreactor-developed Ti6Al4V constructs. A fractional factorial 'design of experiments' approach was used to elucidate the influence of the staining time and concentration of two contrast agents (Hexabrix and phosphotungstic acid) and the neo-tissue volume on the image contrast and dataset quality. Additionally, the neo-tissue shrinkage that was induced by phosphotungstic acid staining was quantified to determine the operating window within which this contrast agent can be accurately applied. For Hexabrix the staining concentration was the main parameter influencing image contrast and dataset quality. Using phosphotungstic acid the staining concentration had a significant influence on the image contrast while both staining concentration and neo-tissue volume had an influence on the dataset quality. The use of high concentrations of phosphotungstic acid did however introduce significant shrinkage of the neo-tissue indicating that, despite sub-optimal image contrast, low concentrations of this staining agent should be used to enable quantitative analysis. To conclude, design of experiments allowed us to define the most optimal staining conditions for contrast-enhanced nanofocus computed tomography to be used as a routine screening tool of neo-tissue formation in Ti6Al4V constructs, transforming it into a robust three dimensional quality control methodology.

High-Resolution Three-Dimensional Computed Tomography for Assessing Complications Related to Intrathecal Drug Delivery.

PubMed

Morgalla, Matthias; Fortunato, Marcos; Azam, Ala; Tatagiba, Marcos; Lepski, Guillherme

2016-07-01

The assessment of the functionality of intrathecal drug delivery (IDD) systems remains difficult and time-consuming. Catheter-related problems are still very common, and sometimes difficult to diagnose. The aim of the present study is to investigate the accuracy of high-resolution three-dimensional computed tomography (CT) in order to detect catheter-related pump dysfunction. An observational, retrospective investigation. Academic medical center in Germany. We used high-resolution three dimensional (3D) computed tomography with volume rendering technique (VRT) or fluoroscopy and conventional axial-CT to assess IDD-related complications in 51 patients from our institution who had IDD systems implanted for the treatment of chronic pain or spasticity. Twelve patients (23.5%) presented a total of 22 complications. The main type of complication in our series was catheter-related (50%), followed by pump failure, infection, and inappropriate refilling. Fluoroscopy and conventional CT were used in 12 cases. High-resolution 3D CT VRT scan was used in 35 instances with suspected yet unclear complications. Using 3D-CT (VRT) the sensitivity was 58.93% - 100% (CI 95%) and the specificity 87.54% - 100% (CI 95%).The positive predictive value was 58.93% - 100% (CI 95%) and the negative predictive value: 87.54% - 100% (CI 95%).Fluoroscopy and axial CT as a combined diagnostic tool had a sensitivity of 8.3% - 91.7% (CI 95%) and a specificity of 62.9% - 100% (CI 95%). The positive predictive value was 19.29% - 100% (CI 95%) and the negative predictive value: 44.43% - 96.89% (CI 95%). This study is limited by its observational design and the small number of cases. High-resolution 3D CT VRT is a non- invasive method that can identify IDD-related complications with more precision than axial CT and fluoroscopy.

Elastic and failure response of imperfect three-dimensional metallic lattices: the role of geometric defects induced by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Liu, Lu; Kamm, Paul; García-Moreno, Francisco; Banhart, John; Pasini, Damiano

2017-10-01

This paper examines three-dimensional metallic lattices with regular octet and rhombicuboctahedron units fabricated with geometric imperfections via Selective Laser Sintering. We use X-ray computed tomography to capture morphology, location, and distribution of process-induced defects with the aim of studying their role in the elastic response, damage initiation, and failure evolution under quasi-static compression. Testing results from in-situ compression tomography show that each lattice exhibits a distinct failure mechanism that is governed not only by cell topology but also by geometric defects induced by additive manufacturing. Extracted from X-ray tomography images, the statistical distributions of three sets of defects, namely strut waviness, strut thickness variation, and strut oversizing, are used to develop numerical models of statistically representative lattices with imperfect geometry. Elastic and failure responses are predicted within 10% agreement from the experimental data. In addition, a computational study is presented to shed light into the relationship between the amplitude of selected defects and the reduction of elastic properties compared to their nominal values. The evolution of failure mechanisms is also explained with respect to strut oversizing, a parameter that can critically cause failure mode transitions that are not visible in defect-free lattices.

Clinical applications of cone beam computed tomography in endodontics: A comprehensive review.

PubMed

Cohenca, Nestor; Shemesh, Hagay

2015-06-01

Cone beam computed tomography (CBCT) is a new technology that produces three-dimensional (3D) digital imaging at reduced cost and less radiation for the patient than traditional CT scans. It also delivers faster and easier image acquisition. By providing a 3D representation of the maxillofacial tissues in a cost- and dose-efficient manner, a better preoperative assessment can be obtained for diagnosis and treatment. This comprehensive review presents current applications of CBCT in endodontics. Specific case examples illustrate the difference in treatment planning with traditional periapical radiography versus CBCT technology.

Evaluation of Orthopedic Metal Artifact Reduction Application in Three-Dimensional Computed Tomography Reconstruction of Spinal Instrumentation: A Single Saudi Center Experience.

PubMed

Ali, Amir Monir

2018-01-01

The aim of the study was to evaluate the commercially available orthopedic metal artifact reduction (OMAR) technique in postoperative three-dimensional computed tomography (3DCT) reconstruction studies after spinal instrumentation and to investigate its clinical application. One hundred and twenty (120) patients with spinal metallic implants were included in the study. All had 3DCT reconstruction examinations using the OMAR software after obtaining the informed consents and approval of the Institution Ethical Committee. The degree of the artifacts, the related muscular density, the clearness of intermuscular fat planes, and definition of the adjacent vertebrae were qualitatively evaluated. The diagnostic satisfaction and quality of the 3D reconstruction images were thoroughly assessed. The majority (96.7%) of 3DCT reconstruction images performed were considered satisfactory to excellent for diagnosis. Only 3.3% of the reconstructed images had rendered unacceptable diagnostic quality. OMAR can effectively reduce metallic artifacts in patients with spinal instrumentation with highly diagnostic 3DCT reconstruction images.

Speckle contrast optical tomography: A new method for deep tissue three-dimensional tomography of blood flow

PubMed Central

Varma, Hari M.; Valdes, Claudia P.; Kristoffersen, Anna K.; Culver, Joseph P.; Durduran, Turgut

2014-01-01

A novel tomographic method based on the laser speckle contrast, speckle contrast optical tomography (SCOT) is introduced that allows us to reconstruct three dimensional distribution of blood flow in deep tissues. This method is analogous to the diffuse optical tomography (DOT) but for deep tissue blood flow. We develop a reconstruction algorithm based on first Born approximation to generate three dimensional distribution of flow using the experimental data obtained from tissue simulating phantoms. PMID:24761306

Compton imaging tomography for nondestructive evaluation of spacecraft thermal protection systems

NASA Astrophysics Data System (ADS)

Romanov, Volodymyr; Burke, Eric; Grubsky, Victor

2017-02-01

Here we present new results of in situ nondestructive evaluation (NDE) of spacecraft thermal protection system materials obtained with POC-developed NDE tool based on a novel Compton Imaging Tomography (CIT) technique recently pioneered and patented by Physical Optics Corporation (POC). In general, CIT provides high-resolution three-dimensional Compton scattered X-ray imaging of the internal structure of evaluated objects, using a set of acquired two-dimensional Compton scattered X-ray images of consecutive cross sections of these objects. Unlike conventional computed tomography, CIT requires only one-sided access to objects, has no limitation on the dimensions and geometry of the objects, and can be applied to large multilayer non-uniform objects with complicated geometries. Also, CIT does not require any contact with the objects being imaged during its application.

Computed tomography image-guided surgery in complex acetabular fractures.

PubMed

Brown, G A; Willis, M C; Firoozbakhsh, K; Barmada, A; Tessman, C L; Montgomery, A

2000-01-01

Eleven complex acetabular fractures in 10 patients were treated by open reduction with internal fixation incorporating computed tomography image guided software intraoperatively. Each of the implants placed under image guidance was found to be accurate and without penetration of the pelvis or joint space. The setup time for the system was minimal. Accuracy in the range of 1 mm was found when registration was precise (eight cases) and was in the range of 3.5 mm when registration was only approximate (three cases). Added benefits included reduced intraoperative fluoroscopic time, less need for more extensive dissection, and obviation of additional surgical approaches in some cases. Compared with a series of similar fractures treated before this image guided series, the reduction in operative time was significant. For patients with complex anterior and posterior combined fractures, the average operation times with and without application of three-dimensional imaging technique were, respectively, 5 hours 15 minutes and 6 hours 14 minutes, revealing 16% less operative time for those who had surgery using image guidance. In the single column fracture group, the operation time for those with three-dimensional imaging application, was 2 hours 58 minutes and for those with traditional surgery, 3 hours 42 minutes, indicating 20% less operative time for those with imaging modality. Intraoperative computed tomography guided imagery was found to be an accurate and suitable method for use in the operative treatment of complex acetabular fractures with substantial displacement.

Endovascular abdominal aortic aneurysm sizing and case planning using the TeraRecon Aquarius workstation.

PubMed

Lee, W Anthony

2007-01-01

The gold standard for preoperative evaluation of an aortic aneurysm is a computed tomography angiogram (CTA). Three-dimensional reconstruction and analysis of the computed tomography data set is enormously helpful, and even sometimes essential, in proper sizing and planning for endovascular stent graft repair. To a large extent, it has obviated the need for conventional angiography for morphologic evaluation. The TeraRecon Aquarius workstation (San Mateo, Calif) represents a highly sophisticated but user-friendly platform utilizing a combination of task-specific hardware and software specifically designed to rapidly manipulate large Digital Imaging and Communications in Medicine (DICOM) data sets and provide surface-shaded and multiplanar renderings in real-time. This article discusses the basics of sizing and planning for endovascular abdominal aortic aneurysm repair and the role of 3-dimensional analysis using the TeraRecon workstation.

Imaging of pharmacokinetic rates of indocyanine green in mouse liver with a hybrid fluorescence molecular tomography/x-ray computed tomography system.

PubMed

Zhang, Guanglei; Liu, Fei; Zhang, Bin; He, Yun; Luo, Jianwen; Bai, Jing

2013-04-01

Pharmacokinetic rates have the potential to provide quantitative physiological and pathological information for biological studies and drug development. Fluorescence molecular tomography (FMT) is an attractive imaging tool for three-dimensionally resolving fluorophore distribution in small animals. In this letter, pharmacokinetic rates of indocyanine green (ICG) in mouse liver are imaged with a hybrid FMT and x-ray computed tomography (XCT) system. A recently developed FMT method using structural priors from an XCT system is adopted to improve the quality of FMT reconstruction. In the in vivo experiments, images of uptake and excretion rates of ICG in mouse liver are obtained, which can be used to quantitatively evaluate liver function. The accuracy of the results is validated by a fiber-based fluorescence measurement system.

Three-Dimensional Printed Prosthesis for Repair of Superior Canal Dehiscence.

PubMed

Kozin, Elliott D; Remenschneider, Aaron K; Cheng, Song; Nakajima, Hideko Heidi; Lee, Daniel J

2015-10-01

Outcomes following repair of superior canal dehiscence (SCD) are variable, and surgery carries a risk of persistent or recurrent SCD symptoms, as well as a risk of hearing loss and vestibulopathy. Poor outcomes may occur from inadequate repair of the SCD or mechanical insult to the membranous labyrinth. Repair of SCD using a customized, fixed-length prosthesis may address current operative limitations and improve surgical outcomes. We aim to 3-dimensionally print customized prostheses to resurface or occlude bony SCD defects. Dehiscences were created along the arcuate eminence of superior semicircular canals in cadaveric temporal bones. Prostheses were designed and created using computed tomography and a 3-dimensional printer. The prostheses occupied the superior semicircular canal defect, reflected in postrepair computed tomography scans. This novel approach to SCD repair could have advantages over current techniques. Refinement of prosthesis design and materials will be important if this approach is translated into clinical use. © American Academy of Otolaryngology-Head and Neck Surgery Foundation 2015.

Effect of therapeutic insoles on the medial longitudinal arch in patients with flatfoot deformity: a three-dimensional loading computed tomography study.

PubMed

Kido, Masamitsu; Ikoma, Kazuya; Hara, Yusuke; Imai, Kan; Maki, Masahiro; Ikeda, Takumi; Fujiwara, Hiroyoshi; Tokunaga, Daisaku; Inoue, Nozomu; Kubo, Toshikazu

2014-12-01

Insoles are frequently used in orthotic therapy as the standard conservative treatment for symptomatic flatfoot deformity to rebuild the arch and stabilize the foot. However, the effectiveness of therapeutic insoles remains unclear. In this study, we assessed the effectiveness of therapeutic insoles for flatfoot deformity using subject-based three-dimensional (3D) computed tomography (CT) models by evaluating the load responses of the bones in the medial longitudinal arch in vivo in 3D. We studied eight individuals (16 feet) with mild flatfoot deformity. CT scans were performed on both feet under non-loaded and full-body-loaded conditions, first with accessory insoles and then with therapeutic insoles under the same conditions. Three-dimensional CT models were constructed for the tibia and the tarsal and metatarsal bones of the medial longitudinal arch (i.e., first metatarsal bone, cuneiforms, navicular, talus, and calcaneus). The rotational angles between the tarsal bones were calculated under loading with accessory insoles or therapeutic insoles and compared. Compared with the accessory insoles, the therapeutic insoles significantly suppressed the eversion of the talocalcaneal joint. This is the first study to precisely verify the usefulness of therapeutic insoles (arch support and inner wedges) in vivo. Copyright © 2014 Elsevier Ltd. All rights reserved.

Using three-dimensional computational modeling to compare the geometrical fitness of two kinds of proximal femoral intramedullary nail for Chinese femur.

PubMed

Zhang, Sheng; Zhang, Kairui; Wang, Yimin; Feng, Wei; Wang, Bowei; Yu, Bin

2013-01-01

The aim of this study was to use three-dimensional (3D) computational modeling to compare the geometric fitness of these two kinds of proximal femoral intramedullary nails in the Chinese femurs. Computed tomography (CT) scans of a total of 120 normal adult Chinese cadaveric femurs were collected for analysis. With the three-dimensional (3D) computational technology, the anatomical fitness between the nail and bone was quantified according to the impingement incidence, maximum thicknesses and lengths by which the nail was protruding into the cortex in the virtual bone model, respectively, at the proximal, middle, and distal portions of the implant in the femur. The results showed that PFNA-II may fit better for the Chinese proximal femurs than InterTan, and the distal portion of InterTan may perform better than that of PFNA-II; the anatomic fitness of both nails for Chinese patients may not be very satisfactory. As a result, both implants need further modifications to meet the needs of the Chinese population.

The impact of different cone beam computed tomography and multi-slice computed tomography scan parameters on virtual three-dimensional model accuracy using a highly precise ex vivo evaluation method.

PubMed

Matta, Ragai-Edward; von Wilmowsky, Cornelius; Neuhuber, Winfried; Lell, Michael; Neukam, Friedrich W; Adler, Werner; Wichmann, Manfred; Bergauer, Bastian

2016-05-01

Multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT) are indispensable imaging techniques in advanced medicine. The possibility of creating virtual and corporal three-dimensional (3D) models enables detailed planning in craniofacial and oral surgery. The objective of this study was to evaluate the impact of different scan protocols for CBCT and MSCT on virtual 3D model accuracy using a software-based evaluation method that excludes human measurement errors. MSCT and CBCT scans with different manufacturers' predefined scan protocols were obtained from a human lower jaw and were superimposed with a master model generated by an optical scan of an industrial noncontact scanner. To determine the accuracy, the mean and standard deviations were calculated, and t-tests were used for comparisons between the different settings. Averaged over 10 repeated X-ray scans per method and 19 measurement points per scan (n = 190), it was found that the MSCT scan protocol 140 kV delivered the most accurate virtual 3D model, with a mean deviation of 0.106 mm compared to the master model. Only the CBCT scans with 0.2-voxel resolution delivered a similar accurate 3D model (mean deviation 0.119 mm). Within the limitations of this study, it was demonstrated that the accuracy of a 3D model of the lower jaw depends on the protocol used for MSCT and CBCT scans. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopatiuk-Tirpak, O.; Langen, K. M.; Meeks, S. L.

2008-09-15

The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to shorter acquisition times are discussed. The spatial resolution, detectable absorbance range, and reproducibility are assessed. An efficient method for calibrating gel dosimeters using the depth-dose relationship is applied, with photon- and electron-based deliveries yielding equivalent results. A procedure involving a preirradiation scan was used to reduce the edge artifacts in reconstructed images, thereby increasing the useful cross-sectional area of the dosimeter by nearly amore » factor of 2. Dose distributions derived from optical density measurements using the calibration coefficient show good agreement with the treatment planning system simulations and radiographic film measurements. The feasibility of use for motion (four-dimensional) dosimetry is demonstrated on an example comparing dose distributions from static and dynamic delivery of a single-field photon plan. The capability to visualize three-dimensional dose distributions is also illustrated.« less

Micro-computed tomography assessment of human alveolar bone: bone density and three-dimensional micro-architecture.

PubMed

Kim, Yoon Jeong; Henkin, Jeffrey

2015-04-01

Micro-computed tomography (micro-CT) is a valuable means to evaluate and secure information related to bone density and quality in human necropsy samples and small live animals. The aim of this study was to assess the bone density of the alveolar jaw bones in human cadaver, using micro-CT. The correlation between bone density and three-dimensional micro architecture of trabecular bone was evaluated. Thirty-four human cadaver jaw bone specimens were harvested. Each specimen was scanned with micro-CT at resolution of 10.5 μm. The bone volume fraction (BV/TV) and the bone mineral density (BMD) value within a volume of interest were measured. The three-dimensional micro architecture of trabecular bone was assessed. All the parameters in the maxilla and the mandible were subject to comparison. The variables for the bone density and the three-dimensional micro architecture were analyzed for nonparametric correlation using Spearman's rho at the significance level of p < .05. A wide range of bone density was observed. There was a significant difference between the maxilla and mandible. All micro architecture parameters were consistently higher in the mandible, up to 3.3 times greater than those in the maxilla. The most linear correlation was observed between BV/TV and BMD, with Spearman's rho = 0.99 (p = .01). Both BV/TV and BMD were highly correlated with all micro architecture parameters with Spearman's rho above 0.74 (p = .01). Two aspects of bone density using micro-CT, the BV/TV and BMD, are highly correlated with three-dimensional micro architecture parameters, which represent the quality of trabecular bone. This noninvasive method may adequately enhance evaluation of the alveolar bone. © 2013 Wiley Periodicals, Inc.

The Relationship of Obesity to Increasing Health-Care Burden in the Setting of Orthopaedic Polytrauma.

PubMed

Licht, Heather; Murray, Mark; Vassaur, John; Jupiter, Daniel C; Regner, Justin L; Chaput, Christopher D

2015-11-18

With the rise of obesity in the American population, there has been a proportionate increase of obesity in the trauma population. The purpose of this study was to use a computed tomography-based measurement of adiposity to determine if obesity is associated with an increased burden to the health-care system in patients with orthopaedic polytrauma. A prospective comprehensive trauma database at a level-I trauma center was utilized to identify 301 patients with polytrauma who had orthopaedic injuries and intensive care unit admission from 2006 to 2011. Routine thoracoabdominal computed tomographic scans allowed for measurement of the truncal adiposity volume. The truncal three-dimensional reconstruction body mass index was calculated from the computed tomography-based volumes based on a previously validated algorithm. A truncal three-dimensional reconstruction body mass index of <30 kg/m(2) denoted non-obese patients and ≥ 30 kg/m(2) denoted obese patients. The need for orthopaedic surgical procedure, in-hospital mortality, length of stay, hospital charges, and discharge disposition were compared between the two groups. Of the 301 patients, 21.6% were classified as obese (truncal three-dimensional reconstruction body mass index of ≥ 30 kg/m(2)). Higher truncal three-dimensional reconstruction body mass index was associated with longer hospital length of stay (p = 0.02), more days spent in the intensive care unit (p = 0.03), more frequent discharge to a long-term care facility (p < 0.0002), higher rate of orthopaedic surgical intervention (p < 0.01), and increased total hospital charges (p < 0.001). Computed tomographic scans, routinely obtained at the time of admission, can be utilized to calculate truncal adiposity and to investigate the impact of obesity on patients with polytrauma. Obese patients were found to have higher total hospital charges, longer hospital stays, discharge to a continuing-care facility, and a higher rate of orthopaedic surgical intervention. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Synchrotron-based X-ray computed tomography during compression loading of cellular materials

DOE PAGES

Cordes, Nikolaus L.; Henderson, Kevin; Stannard, Tyler; ...

2015-04-29

Three-dimensional X-ray computed tomography (CT) of in situ dynamic processes provides internal snapshot images as a function of time. Tomograms are mathematically reconstructed from a series of radiographs taken in rapid succession as the specimen is rotated in small angular increments. In addition to spatial resolution, temporal resolution is important. Thus temporal resolution indicates how close together in time two distinct tomograms can be acquired. Tomograms taken in rapid succession allow detailed analyses of internal processes that cannot be obtained by other means. This article describes the state-of-the-art for such measurements acquired using synchrotron radiation as the X-ray source.

Computed tomography angiography reveals stenosis and aneurysmal dilation of an aberrant right subclavian artery causing systemic blood pressure misreading in an old Pekinese dog

PubMed Central

KIM, Jaehwan; EOM, Kidong; YOON, Hakyoung

2017-01-01

A 14-year-old dog weighing 4 kg presented with hypotension only in the right forelimb. Thoracic radiography revealed a round soft tissue opacity near the aortic arch and below the second thoracic vertebra on a lateral view. Three-dimensional computed tomography angiography clearly revealed stenosis and aneurysmal dilation of an aberrant right subclavian artery. Stenosis and aneurysm of an aberrant subclavian artery should be included as a differential diagnosis in dogs showing a round soft tissue opacity near the aortic arch and below the thoracic vertebra on the lateral thoracic radiograph. PMID:28496026

Computed tomography angiography reveals stenosis and aneurysmal dilation of an aberrant right subclavian artery causing systemic blood pressure misreading in an old Pekinese dog.

PubMed

Kim, Jaehwan; Eom, Kidong; Yoon, Hakyoung

2017-06-16

A 14-year-old dog weighing 4 kg presented with hypotension only in the right forelimb. Thoracic radiography revealed a round soft tissue opacity near the aortic arch and below the second thoracic vertebra on a lateral view. Three-dimensional computed tomography angiography clearly revealed stenosis and aneurysmal dilation of an aberrant right subclavian artery. Stenosis and aneurysm of an aberrant subclavian artery should be included as a differential diagnosis in dogs showing a round soft tissue opacity near the aortic arch and below the thoracic vertebra on the lateral thoracic radiograph.

Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment.

PubMed

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; Motroni, Alessandro; van der Stelt, Paul; Wismeijer, Daniel

2012-01-01

To assess the reliability of cone beam computed tomography (CBCT) voxel gray value measurements using Hounsfield units (HU) derived from multislice computed tomography (MSCT) as a clinical reference (gold standard). Ten partially edentulous human mandibular cadavers were scanned by two types of computed tomography (CT) modalities: multislice CT and cone beam CT. On MSCT scans, eight regions of interest (ROI) designating the site for preoperative implant placement were selected in each mandible. The datasets from both CT systems were matched using a three-dimensional (3D) registration algorithm. The mean voxel gray values of the region around the implant sites were compared between MSCT and CBCT. Significant differences between the mean gray values obtained by CBCT and HU by MSCT were found. In all the selected ROIs, CBCT showed higher mean values than MSCT. A strong correlation (R=0.968) between mean voxel gray values of CBCT and mean HU of MSCT was determined. Voxel gray values from CBCT deviate from actual HU units. However, a strong linear correlation exists, which may permit deriving actual HU units from CBCT using linear regression models.

Failure analysis of fuel cell electrodes using three-dimensional multi-length scale X-ray computed tomography

NASA Astrophysics Data System (ADS)

Pokhrel, A.; El Hannach, M.; Orfino, F. P.; Dutta, M.; Kjeang, E.

2016-10-01

X-ray computed tomography (XCT), a non-destructive technique, is proposed for three-dimensional, multi-length scale characterization of complex failure modes in fuel cell electrodes. Comparative tomography data sets are acquired for a conditioned beginning of life (BOL) and a degraded end of life (EOL) membrane electrode assembly subjected to cathode degradation by voltage cycling. Micro length scale analysis shows a five-fold increase in crack size and 57% thickness reduction in the EOL cathode catalyst layer, indicating widespread action of carbon corrosion. Complementary nano length scale analysis shows a significant reduction in porosity, increased pore size, and dramatically reduced effective diffusivity within the remaining porous structure of the catalyst layer at EOL. Collapsing of the structure is evident from the combination of thinning and reduced porosity, as uniquely determined by the multi-length scale approach. Additionally, a novel image processing based technique developed for nano scale segregation of pore, ionomer, and Pt/C dominated voxels shows an increase in ionomer volume fraction, Pt/C agglomerates, and severe carbon corrosion at the catalyst layer/membrane interface at EOL. In summary, XCT based multi-length scale analysis enables detailed information needed for comprehensive understanding of the complex failure modes observed in fuel cell electrodes.

Recent advances in imaging technologies in dentistry.

PubMed

Shah, Naseem; Bansal, Nikhil; Logani, Ajay

2014-10-28

Dentistry has witnessed tremendous advances in all its branches over the past three decades. With these advances, the need for more precise diagnostic tools, specially imaging methods, have become mandatory. From the simple intra-oral periapical X-rays, advanced imaging techniques like computed tomography, cone beam computed tomography, magnetic resonance imaging and ultrasound have also found place in modern dentistry. Changing from analogue to digital radiography has not only made the process simpler and faster but also made image storage, manipulation (brightness/contrast, image cropping, etc.) and retrieval easier. The three-dimensional imaging has made the complex cranio-facial structures more accessible for examination and early and accurate diagnosis of deep seated lesions. This paper is to review current advances in imaging technology and their uses in different disciplines of dentistry.

Recent advances in imaging technologies in dentistry

PubMed Central

Shah, Naseem; Bansal, Nikhil; Logani, Ajay

2014-01-01

Dentistry has witnessed tremendous advances in all its branches over the past three decades. With these advances, the need for more precise diagnostic tools, specially imaging methods, have become mandatory. From the simple intra-oral periapical X-rays, advanced imaging techniques like computed tomography, cone beam computed tomography, magnetic resonance imaging and ultrasound have also found place in modern dentistry. Changing from analogue to digital radiography has not only made the process simpler and faster but also made image storage, manipulation (brightness/contrast, image cropping, etc.) and retrieval easier. The three-dimensional imaging has made the complex cranio-facial structures more accessible for examination and early and accurate diagnosis of deep seated lesions. This paper is to review current advances in imaging technology and their uses in different disciplines of dentistry. PMID:25349663

Three-dimensional monochromatic x-ray computed tomography using synchrotron radiation

NASA Astrophysics Data System (ADS)

Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Katsuyuki; Uyama, Chikao

1998-08-01

We describe a technique of 3D computed tomography (3D CT) using monochromatic x rays generated by synchrotron radiation, which performs a direct reconstruction of a 3D volume image of an object from its cone-beam projections. For the development, we propose a practical scanning orbit of the x-ray source to obtain complete 3D information on an object, and its corresponding 3D image reconstruction algorithm. The validity and usefulness of the proposed scanning orbit and reconstruction algorithm were confirmed by computer simulation studies. Based on these investigations, we have developed a prototype 3D monochromatic x-ray CT using synchrotron radiation, which provides exact 3D reconstruction and material-selective imaging by using the K-edge energy subtraction technique.

Six dimensional X-ray Tensor Tomography with a compact laboratory setup

NASA Astrophysics Data System (ADS)

Sharma, Y.; Wieczorek, M.; Schaff, F.; Seyyedi, S.; Prade, F.; Pfeiffer, F.; Lasser, T.

2016-09-01

Attenuation based X-ray micro computed tomography (XCT) provides three-dimensional images with micrometer resolution. However, there is a trade-off between the smallest size of the structures that can be resolved and the measurable sample size. In this letter, we present an imaging method using a compact laboratory setup that reveals information about micrometer-sized structures within samples that are several orders of magnitudes larger. We combine the anisotropic dark-field signal obtained in a grating interferometer and advanced tomographic reconstruction methods to reconstruct a six dimensional scattering tensor at every spatial location in three dimensions. The scattering tensor, thus obtained, encodes information about the orientation of micron-sized structures such as fibres in composite materials or dentinal tubules in human teeth. The sparse acquisition schemes presented in this letter enable the measurement of the full scattering tensor at every spatial location and can be easily incorporated in a practical, commercially feasible laboratory setup using conventional X-ray tubes, thus allowing for widespread industrial applications.

Role of post-mapping computed tomography in virtual-assisted lung mapping.

PubMed

Sato, Masaaki; Nagayama, Kazuhiro; Kuwano, Hideki; Nitadori, Jun-Ichi; Anraku, Masaki; Nakajima, Jun

2017-02-01

Background Virtual-assisted lung mapping is a novel bronchoscopic preoperative lung marking technique in which virtual bronchoscopy is used to predict the locations of multiple dye markings. Post-mapping computed tomography is performed to confirm the locations of the actual markings. This study aimed to examine the accuracy of marking locations predicted by virtual bronchoscopy and elucidate the role of post-mapping computed tomography. Methods Automated and manual virtual bronchoscopy was used to predict marking locations. After bronchoscopic dye marking under local anesthesia, computed tomography was performed to confirm the actual marking locations before surgery. Discrepancies between marking locations predicted by the different methods and the actual markings were examined on computed tomography images. Forty-three markings in 11 patients were analyzed. Results The average difference between the predicted and actual marking locations was 30 mm. There was no significant difference between the latest version of the automated virtual bronchoscopy system (30.7 ± 17.2 mm) and manual virtual bronchoscopy (29.8 ± 19.1 mm). The difference was significantly greater in the upper vs. lower lobes (37.1 ± 20.1 vs. 23.0 ± 6.8 mm, for automated virtual bronchoscopy; p < 0.01). Despite this discrepancy, all targeted lesions were successfully resected using 3-dimensional image guidance based on post-mapping computed tomography reflecting the actual marking locations. Conclusions Markings predicted by virtual bronchoscopy were dislocated from the actual markings by an average of 3 cm. However, surgery was accurately performed using post-mapping computed tomography guidance, demonstrating the indispensable role of post-mapping computed tomography in virtual-assisted lung mapping.

A New Volumetric Radiologic Method to Assess Indirect Decompression After Extreme Lateral Interbody Fusion Using High-Resolution Intraoperative Computed Tomography.

PubMed

Navarro-Ramirez, Rodrigo; Berlin, Connor; Lang, Gernot; Hussain, Ibrahim; Janssen, Insa; Sloan, Stephen; Askin, Gulce; Avila, Mauricio J; Zubkov, Micaella; Härtl, Roger

2018-01-01

Two-dimensional radiographic methods have been proposed to evaluate the radiographic outcome after indirect decompression through extreme lateral interbody fusion (XLIF). However, the assessment of neural decompression in a single plane may underestimate the effect of indirect decompression on central canal and foraminal volumes. The present study aimed to assess the reliability and consistency of a novel 3-dimensional radiographic method that assesses neural decompression by volumetric analysis using a new generation of intraoperative fan-beam computed tomography scanner in patients undergoing XLIF. Prospectively collected data from 7 patients (9 levels) undergoing XLIF was retrospectively analyzed. Three independent, blind raters using imaging analysis software performed volumetric measurements pre- and postoperatively to determine central canal and foraminal volumes. Intrarater and Interrater reliability tests were performed to assess the reliability of this novel volumetric method. The interrater reliability between the three raters ranged from 0.800 to 0.952, P < 0.0001. The test-retest analysis on a randomly selected subset of three patients showed good to excellent internal reliability (range of 0.78-1.00) for all 3 raters. There was a significant increase in mean volume ≈20% for right foramen, left foramen, and central canal volumes postoperatively (P = 0.0472; P = 0.0066; P = 0.0003, respectively). Here we demonstrate a new volumetric analysis technique that is feasible, reliable, and reproducible amongst independent raters for central canal and foraminal volumes in the lumbar spine using an intraoperative computed tomography scanner. Copyright © 2017. Published by Elsevier Inc.

Thymopericardial augmented encasement for coronary artery bypass graft surgery: a report of 245 cases.

PubMed

Ohtsuka, Toshiya; Ninomiya, Mikio; Nonaka, Takahiro

2009-07-01

: A pedicled prepericardial fat flap was created to augment the pericardial cavity and applied for patients undergoing coronary artery bypass grafting. The efficacy and durability of this method were investigated. : Between July 2005 and November 2008, the present technique was applied for consecutive 245 patients (165 men and 80 women, aged 67 ± 8.3 years) undergoing isolated coronary artery bypass grafting in which 240 (98.0%) were off-pump cases. The left and/or right internal thoracic artery and the gastroepiploic artery were used in 244 and 160 patients, respectively, and the saphenous vein and the radial artery were used in 51 and 10 patients, respectively. Ninety-seven (40.0%) patients had been diabetic, 18 (7.3%) had had chronic renal failure, and three were redo cases. The prepericardial soft tissue, involving the pedicled thymic gland, was dissected en bloc and sewn with pericardiotomies to wrap the heart and the grafts. Angiography or three-dimensional computed tomography was used to assess the intrapericardial pathways of each graft and a long-term durability of the fat pad. : Early angiography or three-dimensional computed tomography proved that the graft pathways were unaffected by the encasements. Resternotomies in two patients and sternal treatments for infectious dehiscence in two patients were safely achievable. Five-year postoperative computed tomography showed the intact fat pad in the retrosternal space. : The present technique can encase the heart not the least jeopardizing each pathway of the grafts, and the durable fat pad functions protectively when the sternotomy is either reopened or infected.

Reproducibility of three-dimensional cephalometric landmarks in cone-beam and low-dose computed tomography.

PubMed

Olszewski, R; Frison, L; Wisniewski, M; Denis, J M; Vynckier, S; Cosnard, G; Zech, F; Reychler, H

2013-01-01

The purpose of this study is to compare the reproducibility of three-dimensional cephalometric landmarks on three-dimensional computed tomography (3D-CT) surface rendering using clinical protocols based on low-dose (35-mAs) spiral CT and cone-beam CT (I-CAT). The absorbed dose levels for radiosensitive organs in the maxillofacial region during exposure in both 3D-CT protocols were also assessed. The study population consisted of ten human dry skulls examined with low-dose CT and cone-beam CT. Two independent observers identified 24 cephalometric anatomic landmarks at 13 sites on the 3D-CT surface renderings using both protocols, with each observer repeating the identification 1 month later. A total of 1,920 imaging measurements were performed. Thermoluminescent dosimeters were placed at six sites around the thyroid gland, the submandibular glands, and the eyes in an Alderson phantom to measure the absorbed dose levels. When comparing low-dose CT and cone-beam CT protocols, the cone-beam CT protocol proved to be significantly more reproducible for four of the 13 anatomical sites. There was no significant difference between the protocols for the other nine anatomical sites. Both low-dose and cone-beam CT protocols were equivalent in dose absorption to the eyes and submandibular glands. However, thyroid glands were more irradiated with low-dose CT. Cone-beam CT was more reproducible and procured less irradiation to the thyroid gland than low-dose CT. Cone-beam CT should be preferred over low-dose CT for developing three-dimensional bony cephalometric analyses.

Analysis of HRCT-derived xylem network reveals reverse flow in some vessels

USDA-ARS?s Scientific Manuscript database

Flow in xylem vessels is modeled based on constructions of three dimensional xylem networks derived from High Resolution Computed Tomography (HRCT) images of grapevine (Vitis vinifera) stems. Flow in 6-14% of the vessels was found to be oriented in the opposite direction to the bulk flow under norma...

Reduction of metal artifact in three-dimensional computed tomography (3D CT) with dental impression materials.

PubMed

Park, W S; Kim, K D; Shin, H K; Lee, S H

2007-01-01

Metal Artifact still remains one of the main drawbacks in craniofacial Three-Dimensional Computed Tomography (3D CT). In this study, we tried to test the efficacy of additional silicone dental impression materials as a "tooth shield" for the reduction of metal artifact caused by metal restorations and orthodontic appliances. 6 phantoms with 4 teeth were prepared for this in vitro study. Orthodontic bracket, bands and amalgam restorations were placed in each tooth to reproduce various intraoral conditions. Standardized silicone shields were fabricated and placed around the teeth. CT image acquisition was performed with and without silicone shields. Maximum value, mean, and standard deviation of Hounsfield Units (HU) were compared with the presence of silicone shields. In every situation, metal artifacts were reduced in quality and quantity when silicone shields are used. Amalgam restoration made most serious metal artifact. Silicone shields made by dental impression material might be effective way to reduce the metal artifact caused by dental restoration and orthodontic appliances. This will help more excellent 3D image from 3D CT in craniofacial area.

Tortuous pathways: Fundamental characterisation of the anisotropic permeability through clay-rich shales from macro- to nano-scale.

NASA Astrophysics Data System (ADS)

Mitchell, T. M.; Backeberg, N. R.; Iacoviello, F.; Rittner, M.; Jones, A. P.; Wheeler, J.; Day, R.; Vermeesch, P.; Shearing, P. R.; Striolo, A.

2017-12-01

The permeability of shales is important, because it controls where oil and gas resources can migrate to and where in the Earth hydrocarbons are ultimately stored. Shales have a well-known anisotropic directional permeability that is inherited from the depositional layering of sedimentary laminations, where the highest permeability is measured parallel to laminations and the lowest permeability is perpendicular to laminations. We combine state of the art laboratory permeability experiments with high-resolution X-ray computed tomography and for the first time can quantify the three-dimensional interconnected pathways through a rock that define the anisotropic behaviour of shales. Experiments record a physical anisotropy in permeability of one to two orders of magnitude. Two- and three-dimensional analyses of micro- and nano-scale X-ray computed tomography illuminate that the directional anisotropy is fundamentally controlled by the bulk rock mineral geometry, which determines the finite length (or tortuosity) of the interconnected pathways through the porous/permeable phases in shales. Understanding the mineral-scale control on permeability will allow for better estimations of the extent of recoverable reserves in shale gas plays globally.

A case of fetal osteogenesis imperfecta type 2A: longitudinal observation of natural course in utero and pitfalls for prenatal ultrasound diagnosis.

PubMed

Kimura, Ibuki; Araki, Ryota; Yoshizato, Toshiyuki; Miyamoto, Shingo

2015-10-01

We present a case of osteogenesis imperfecta (OI) type 2A in which a natural course in utero was observed from 23 weeks' gestation to term. At 23 weeks' gestation, a sonographic examination showed a cloverleaf skull-like head, a narrow thorax, and marked shortening of the long bones with bowing of the femurs and humeri. Follow-up examinations showed that the cloverleaf skull-like head was not evident at 28 weeks' gestation. Discontinuity of the ribs and femurs was observed at 26 and 30 weeks' gestation, respectively. This finding suggested bone fractures, which were confirmed by three-dimensional computed tomography at 32 weeks' gestation. Ultrasonographic findings of bones, including the long bones and calvarium, changed with advancing gestation during the second trimester. Characteristic features of OI type 2A were evident during the late second to early third trimesters. Repeated ultrasonographic examinations together with three-dimensional computed tomography are necessary for the definitive diagnosis of OI type 2A in the second trimester.

Three dimensional computed tomography lung modeling is useful in simulation and navigation of lung cancer surgery.

PubMed

Ikeda, Norihiko; Yoshimura, Akinobu; Hagiwara, Masaru; Akata, Soichi; Saji, Hisashi

2013-01-01

The number of minimally invasive operations, such as video-assisted thoracoscopic surgery (VATS) lobectomy or segmentectomy, has enormously increased in recent years. These operations require extreme knowledge of the anatomy of pulmonary vessels and bronchi in each patient, and surgeons must carefully dissect the branches of pulmonary vessels during operation. Thus, foreknowledge of the anatomy of each patient would greatly contribute to the safety and accuracy of the operation. The development of multi-detector computed tomography (MDCT) has promoted three dimensional (3D) images of lung structures. It is possible to see the vascular and bronchial structures from the view of the operator; therefore, it is employed for preoperative simulation as well as navigation during operation. Due to advances in software, even small vessels can be accurately imaged, which is useful in performing segmentectomy. Surgical simulation and navigation systems based on high quality 3D lung modeling, including vascular and bronchial structures, can be used routinely to enhance the safety operation, education of junior staff, as well as providing a greater sense of security to the operators.

Morphological imaging and quantification of axial xylem tissue in Fraxinus excelsior L. through X-ray micro-computed tomography.

PubMed

Koddenberg, Tim; Militz, Holger

2018-05-05

The popularity of X-ray based imaging methods has continued to increase in research domains. In wood research, X-ray micro-computed tomography (XμCT) is useful for structural studies examining the three-dimensional and complex xylem tissue of trees qualitatively and quantitatively. In this study, XμCT made it possible to visualize and quantify the spatial xylem organization of the angiosperm species Fraxinus excelsior L. on the microscopic level. Through image analysis, it was possible to determine morphological characteristics of the cellular axial tissue (vessel elements, fibers, and axial parenchyma cells) three-dimensionally. X-ray imaging at high resolutions provides very distinct visual insight into the xylem structure. Numerical analyses performed through semi-automatic procedures made it possible to quickly quantify cell characteristics (length, diameter, and volume of cells). Use of various spatial resolutions (0.87-5 μm) revealed boundaries users should be aware of. Nevertheless, our findings, both qualitative and quantitative, demonstrate XμCT to be a valuable tool for studying the spatial cell morphology of F. excelsior. Copyright © 2018. Published by Elsevier Ltd.

Multifunctional, three-dimensional tomography for analysis of eletrectrohydrodynamic jetting

NASA Astrophysics Data System (ADS)

Nguyen, Xuan Hung; Gim, Yeonghyeon; Ko, Han Seo

2015-05-01

A three-dimensional optical tomography technique was developed to reconstruct three-dimensional objects using a set of two-dimensional shadowgraphic images and normal gray images. From three high-speed cameras, which were positioned at an offset angle of 45° between each other, number, size, and location of electrohydrodynamic jets with respect to the nozzle position were analyzed using shadowgraphic tomography employing multiplicative algebraic reconstruction technique (MART). Additionally, a flow field inside a cone-shaped liquid (Taylor cone) induced under an electric field was observed using a simultaneous multiplicative algebraic reconstruction technique (SMART), a tomographic method for reconstructing light intensities of particles, combined with three-dimensional cross-correlation. Various velocity fields of circulating flows inside the cone-shaped liquid caused by various physico-chemical properties of liquid were also investigated.

Frozen Gaussian approximation for 3D seismic tomography

NASA Astrophysics Data System (ADS)

Chai, Lihui; Tong, Ping; Yang, Xu

2018-05-01

Three-dimensional (3D) wave-equation-based seismic tomography is computationally challenging in large scales and high-frequency regime. In this paper, we apply the frozen Gaussian approximation (FGA) method to compute 3D sensitivity kernels and seismic tomography of high-frequency. Rather than standard ray theory used in seismic inversion (e.g. Kirchhoff migration and Gaussian beam migration), FGA is used to compute the 3D high-frequency sensitivity kernels for travel-time or full waveform inversions. Specifically, we reformulate the equations of the forward and adjoint wavefields for the purpose of convenience to apply FGA, and with this reformulation, one can efficiently compute the Green’s functions whose convolutions with source time function produce wavefields needed for the construction of 3D kernels. Moreover, a fast summation method is proposed based on local fast Fourier transform which greatly improves the speed of reconstruction as the last step of FGA algorithm. We apply FGA to both the travel-time adjoint tomography and full waveform inversion (FWI) on synthetic crosswell seismic data with dominant frequencies as high as those of real crosswell data, and confirm again that FWI requires a more sophisticated initial velocity model for the convergence than travel-time adjoint tomography. We also numerically test the accuracy of applying FGA to local earthquake tomography. This study paves the way to directly apply wave-equation-based seismic tomography methods into real data around their dominant frequencies.

Enabling three-dimensional densitometric measurements using laboratory source X-ray micro-computed tomography

NASA Astrophysics Data System (ADS)

Pankhurst, M. J.; Fowler, R.; Courtois, L.; Nonni, S.; Zuddas, F.; Atwood, R. C.; Davis, G. R.; Lee, P. D.

2018-01-01

We present new software allowing significantly improved quantitative mapping of the three-dimensional density distribution of objects using laboratory source polychromatic X-rays via a beam characterisation approach (c.f. filtering or comparison to phantoms). One key advantage is that a precise representation of the specimen material is not required. The method exploits well-established, widely available, non-destructive and increasingly accessible laboratory-source X-ray tomography. Beam characterisation is performed in two stages: (1) projection data are collected through a range of known materials utilising a novel hardware design integrated into the rotation stage; and (2) a Python code optimises a spectral response model of the system. We provide hardware designs for use with a rotation stage able to be tilted, yet the concept is easily adaptable to virtually any laboratory system and sample, and implicitly corrects the image artefact known as beam hardening.

Role of Cone Beam Computed Tomography in Diagnosis and Treatment Planning in Dentistry: An Update.

PubMed

Shukla, Sagrika; Chug, Ashi; Afrashtehfar, Kelvin I

2017-11-01

Accurate diagnosis and treatment planning are the backbone of any medical therapy; for this reason, cone beam computed tomography (CBCT) was introduced and has been widely used. CBCT technology provides a three-dimensional image viewing, enabling exact location and extent of lesions or any anatomical region. For the very same reason, CBCT can not only be used for surgical fields but also for fields such as endodontics, prosthodontics, and orthodontics for appropriate treatment planning and effective dental care. The aim and clinical significance of this review are to update dental clinicians on the CBCT applications in each dental specialty for an appropriate diagnosis and more predictable treatment.

Feasibility of four-dimensional preoperative simulation for elbow debridement arthroplasty.

PubMed

Yamamoto, Michiro; Murakami, Yukimi; Iwatsuki, Katsuyuki; Kurimoto, Shigeru; Hirata, Hitoshi

2016-04-02

Recent advances in imaging modalities have enabled three-dimensional preoperative simulation. A four-dimensional preoperative simulation system would be useful for debridement arthroplasty of primary degenerative elbow osteoarthritis because it would be able to detect the impingement lesions. We developed a four-dimensional simulation system by adding the anatomical axis to the three-dimensional computed tomography scan data of the affected arm in one position. Eleven patients with primary degenerative elbow osteoarthritis were included. A "two rings" method was used to calculate the flexion-extension axis of the elbow by converting the surface of the trochlea and capitellum into two rings. A four-dimensional simulation movie was created and showed the optimal range of motion and the impingement area requiring excision. To evaluate the reliability of the flexion-extension axis, interobserver and intraobserver reliabilities regarding the assessment of bony overlap volumes were calculated twice for each patient by two authors. Patients were treated by open or arthroscopic debridement arthroplasties. Pre- and postoperative examinations included elbow range of motion measurement, and completion of the patient-rated questionnaire Hand20, Japanese Orthopaedic Association-Japan Elbow Society Elbow Function Score, and the Mayo Elbow Performance Score. Measurement of the bony overlap volume showed an intraobserver intraclass correlation coefficient of 0.93 and 0.90, and an interobserver intraclass correlation coefficient of 0.94. The mean elbow flexion-extension arc significantly improved from 101° to 125°. The mean Hand20 score significantly improved from 52 to 22. The mean Japanese Orthopaedic Association-Japan Elbow Society Elbow Function Score significantly improved from 67 to 88. The mean Mayo Elbow Performance Score significantly improved from 71 to 91 at the final follow-up evaluation. We showed that four-dimensional, preoperative simulation can be generated by adding the rotation axis to the one-position, three-dimensional computed tomography image of the affected arm. This method is feasible for elbow debridement arthroplasty.

Three-dimensional morphology of heel fat pad: an in vivo computed tomography study.

PubMed

Campanelli, Valentina; Fantini, Massimiliano; Faccioli, Niccolò; Cangemi, Alessio; Pozzo, Antonio; Sbarbati, Andrea

2011-11-01

Heel fat pad cushioning efficiency is the result of its structure, shape and thickness. However, while a number of studies have investigated heel fat pad (HFP) anatomy, structural behavior and material properties, no previous study has described its three-dimensional morphology in situ. The assessment of the healthy, unloaded, three-dimensional morphology of heel pad may contribute to deepen the understanding of its role and behavior during locomotion. It is the basis for the assessment of possible HFP morphological modifications due to changes in the amount or distribution of the loads normally sustained by the foot. It may also help in guiding the surgical reconstruction of the pad and in improving footwear design, as well as in developing a correct heel pad geometry for finite element models of the foot. Therefore the purpose of this study was to obtain a complete analysis of HFP three-dimensional morphology in situ. The right foot of nine healthy volunteers was scanned with computed tomography. A methodological approach that maximizes reliability and repeatability of the data was developed by building a device to lock the foot in a neutral position with respect to the scan planes during image acquisition. Scan data were used to reconstruct virtual three-dimensional models for both the calcaneus and HFP. A set of virtual coronal and axial sections were extracted from the three-dimensional model of each HFP and processed to extract a set of one- and two-dimensional morphometrical measurements for a detailed description of heel pad morphology. The tissue exhibited a consistent and sophisticated morphology that may reflect the biomechanics of the foot support. HFP was found to be have a crest on its anterior dorsal surface, flanges on the sides and posteriorly, and a thick portion that reached and covered the posterior surface of the calcaneus and the achilles tendon insertion. Its anterior internal portion was thinner and a lump of fat was consistently present in this region. Finally, HFP was found to be thicker in males than in females. © 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.

Three-dimensional morphology of heel fat pad: an in vivo computed tomography study

PubMed Central

Campanelli, Valentina; Fantini, Massimiliano; Faccioli, Niccolò; Cangemi, Alessio; Pozzo, Antonio; Sbarbati, Andrea

2011-01-01

Heel fat pad cushioning efficiency is the result of its structure, shape and thickness. However, while a number of studies have investigated heel fat pad (HFP) anatomy, structural behavior and material properties, no previous study has described its three-dimensional morphology in situ. The assessment of the healthy, unloaded, three-dimensional morphology of heel pad may contribute to deepen the understanding of its role and behavior during locomotion. It is the basis for the assessment of possible HFP morphological modifications due to changes in the amount or distribution of the loads normally sustained by the foot. It may also help in guiding the surgical reconstruction of the pad and in improving footwear design, as well as in developing a correct heel pad geometry for finite element models of the foot. Therefore the purpose of this study was to obtain a complete analysis of HFP three-dimensional morphology in situ. The right foot of nine healthy volunteers was scanned with computed tomography. A methodological approach that maximizes reliability and repeatability of the data was developed by building a device to lock the foot in a neutral position with respect to the scan planes during image acquisition. Scan data were used to reconstruct virtual three-dimensional models for both the calcaneus and HFP. A set of virtual coronal and axial sections were extracted from the three-dimensional model of each HFP and processed to extract a set of one- and two-dimensional morphometrical measurements for a detailed description of heel pad morphology. The tissue exhibited a consistent and sophisticated morphology that may reflect the biomechanics of the foot support. HFP was found to be have a crest on its anterior dorsal surface, flanges on the sides and posteriorly, and a thick portion that reached and covered the posterior surface of the calcaneus and the achilles tendon insertion. Its anterior internal portion was thinner and a lump of fat was consistently present in this region. Finally, HFP was found to be thicker in males than in females. PMID:21848602

Accelerating electron tomography reconstruction algorithm ICON with GPU.

PubMed

Chen, Yu; Wang, Zihao; Zhang, Jingrong; Li, Lun; Wan, Xiaohua; Sun, Fei; Zhang, Fa

2017-01-01

Electron tomography (ET) plays an important role in studying in situ cell ultrastructure in three-dimensional space. Due to limited tilt angles, ET reconstruction always suffers from the "missing wedge" problem. With a validation procedure, iterative compressed-sensing optimized NUFFT reconstruction (ICON) demonstrates its power in the restoration of validated missing information for low SNR biological ET dataset. However, the huge computational demand has become a major problem for the application of ICON. In this work, we analyzed the framework of ICON and classified the operations of major steps of ICON reconstruction into three types. Accordingly, we designed parallel strategies and implemented them on graphics processing units (GPU) to generate a parallel program ICON-GPU. With high accuracy, ICON-GPU has a great acceleration compared to its CPU version, up to 83.7×, greatly relieving ICON's dependence on computing resource.

Multiple imaging mode X-ray computed tomography for distinguishing active and inactive phases in lithium-ion battery cathodes

NASA Astrophysics Data System (ADS)

Komini Babu, Siddharth; Mohamed, Alexander I.; Whitacre, Jay F.; Litster, Shawn

2015-06-01

This paper presents the use of nanometer scale resolution X-ray computed tomography (nano-CT) in the three-dimensional (3D) imaging of a Li-ion battery cathode, including the separate volumes of active material, binder plus conductive additive, and pore. The different high and low atomic number (Z) materials are distinguished by sequentially imaging the lithium cobalt oxide electrode in absorption and then Zernike phase contrast modes. Morphological parameters of the active material and the additives are extracted from the 3D reconstructions, including the distribution of contact areas between the additives and the active material. This method could provide a better understanding of the electric current distribution and structural integrity of battery electrodes, as well as provide detailed geometries for computational models.

Microvascular anastomosis guidance and evaluation using real-time three-dimensional Fourier-domain Doppler optical coherence tomography

PubMed Central

Ibrahim, Zuhaib; Tong, Dedi; Zhu, Shan; Mao, Qi; Pang, John; Andrew Lee, Wei Ping; Brandacher, Gerald; Kang, Jin U.

2013-01-01

Abstract. Vascular and microvascular anastomoses are critical components of reconstructive microsurgery, vascular surgery, and transplant surgery. Intraoperative surgical guidance using a surgical imaging modality that provides an in-depth view and three-dimensional (3-D) imaging can potentially improve outcome following both conventional and innovative anastomosis techniques. Objective postoperative imaging of the anastomosed vessel can potentially improve the salvage rate when combined with other clinical assessment tools, such as capillary refill, temperature, blanching, and skin turgor. Compared to other contemporary postoperative monitoring modalities—computed tomography angiograms, magnetic resonance (MR) angiograms, and ultrasound Doppler—optical coherence tomography (OCT) is a noninvasive high-resolution (micron-level), high-speed, 3-D imaging modality that has been adopted widely in biomedical and clinical applications. For the first time, to the best of our knowledge, the feasibility of real-time 3-D phase-resolved Doppler OCT (PRDOCT) as an assisted intra- and postoperative imaging modality for microvascular anastomosis of rodent femoral vessels is demonstrated, which will provide new insights and a potential breakthrough to microvascular and supermicrovascular surgery. PMID:23856833

Combined micro computed tomography and histology study of bone augmentation and distraction osteogenesis

NASA Astrophysics Data System (ADS)

Ilgenstein, Bernd; Deyhle, Hans; Jaquiery, Claude; Kunz, Christoph; Stalder, Anja; Stübinger, Stefan; Jundt, Gernot; Beckmann, Felix; Müller, Bert; Hieber, Simone E.

2012-10-01

Bone augmentation is a vital part of surgical interventions of the oral and maxillofacial area including dental implantology. Prior to implant placement, sufficient bone volume is needed to reduce the risk of peri-implantitis. While augmentation using harvested autologous bone is still considered as gold standard, many surgeons prefer bone substitutes to reduce operation time and to avoid donor site morbidity. To assess the osteogenic efficacy of commercially available augmentation materials we analyzed drill cores extracted before implant insertion. In younger patients, distraction osteogenesis is successfully applied to correct craniofacial deformities through targeted bone formation. To study the influence of mesenchymal stem cells on bone regeneration during distraction osteogenesis, human mesenchymal stem cells were injected into the distraction gap of nude rat mandibles immediately after osteotomy. The distraction was performed over eleven days to reach a distraction gap of 6 mm. Both the rat mandibles and the drill cores were scanned using synchrotron radiation-based micro computed tomography. The three-dimensional data were manually registered and compared with corresponding two-dimensional histological sections to assess bone regeneration and its morphology. The analysis of the rat mandibles indicates that bone formation is enhanced by mesenchymal stem cells injected before distraction. The bone substitutes yielded a wide range of bone volume and degree of resorption. The volume fraction of the newly formed bone was determined to 34.4% in the computed tomography dataset for the augmentation material Geistlich Bio-Oss®. The combination of computed tomography and histology allowed a complementary assessment for both bone augmentation and distraction osteogenesis.

Quantification of eggshell microstructure using X-ray micro computed tomography

PubMed Central

Riley, A.; Sturrock, C. J.; Mooney, S. J.

2014-01-01

1. X-ray microcomputed tomography can be used to produce rapid, fully analysable, three-dimensional images of biological and other materials without the need for complex or tedious sample preparation and sectioning. We describe the use of this technique to visualise and analyse the microstructure of fragments of shell taken from three regions of chicken eggs (sharp pole, blunt pole and equatorial region). 2. Two- and three-dimensional images and data were obtained at a resolution of 1.5 microns. The images were analysed to provide measurements of shell thickness, the spacial density of mammillary bodies, the frequency, shape, volume and effective diameter of individual pore spaces, and the intrinsic sponginess (proportion of non-X-ray dense material formed by vesicles) of the shell matrix. Measurements of these parameters were comparable with those derived by traditional methods and reported in the literature. 3. The advantages of using this technology for the quantification of eggshell microstructural parameters and its potential application for commercial, research and other purposes are discussed. PMID:24875292

[Computer-aided method and rapid prototyping for the personalized fabrication of a silicone bandage digital prosthesis].

PubMed

Ventura Ferreira, Nuno; Leal, Nuno; Correia Sá, Inês; Reis, Ana; Marques, Marisa

2014-01-01

The fabrication of digital prostheses has acquired growing importance not only for the possibility for the patient to overcome psychosocial trauma but also to promote grip functionality. An application method of three dimensional-computer-aided design technologies for the production of passive prostheses is presented by means of a fifth finger amputee clinical case following bilateral hand replantation.Three-dimensional-computerized tomography was used for the collection of anthropometric images of the hands. Computer-aided design techniques were used to develop the digital file-based prosthesis from the reconstruction images by inversion and superimposing the contra-lateral finger images. The rapid prototyping manufacturing method was used for the production of a silicone bandage prosthesis prototype. This approach replaces the traditional manual method by a virtual method that is basis for the optimization of a high speed, accurate and innovative process.

Reconstruction 3-dimensional image from 2-dimensional image of status optical coherence tomography (OCT) for analysis of changes in retinal thickness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arinilhaq,; Widita, Rena

2014-09-30

Optical Coherence Tomography is often used in medical image acquisition to diagnose that change due easy to use and low price. Unfortunately, this type of examination produces a two-dimensional retinal image of the point of acquisition. Therefore, this study developed a method that combines and reconstruct 2-dimensional retinal images into three-dimensional images to display volumetric macular accurately. The system is built with three main stages: data acquisition, data extraction and 3-dimensional reconstruction. At data acquisition step, Optical Coherence Tomography produced six *.jpg images of each patient were further extracted with MATLAB 2010a software into six one-dimensional arrays. The six arraysmore » are combined into a 3-dimensional matrix using a kriging interpolation method with SURFER9 resulting 3-dimensional graphics of macula. Finally, system provides three-dimensional color graphs based on the data distribution normal macula. The reconstruction system which has been designed produces three-dimensional images with size of 481 × 481 × h (retinal thickness) pixels.« less

Incremental value of live/real time three-dimensional transesophageal echocardiography over the two-dimensional technique in the assessment of aortic atherosclerotic thrombi and ulcers.

PubMed

Elsayed, Mahmoud; Bulur, Serkan; Kalla, Aditi; Ahmed, Mustafa I; Hsiung, Ming C; Uygur, Begum; Alagic, Nermina; Sungur, Aylin; Singh, Satinder; Nanda, Navin C

2016-08-01

We present two cases in whom live/real time three-dimensional transesophageal echocardiography (3DTEE) provided incremental value in the assessment of atherosclerotic disease in the aorta. In one patient, it identified additional atherosclerotic ulcers as well as thrombi within them which were missed by two-dimensional (2D) TEE. In both cases, the size of the large mobile atherosclerotic plaque was underestimated by 2DTEE as compared with 3DTEE. Furthermore, 3DTEE provided volume quantification of the thrombi and ulcers which is not possible by 2DTEE. The echocardiographic findings of atherosclerotic plaques were confirmed by computed tomography in one patient and by surgery in the other. © 2016, Wiley Periodicals, Inc.

Contours identification of elements in a cone beam computed tomography for investigating maxillary cysts

NASA Astrophysics Data System (ADS)

Chioran, Doina; Nicoarǎ, Adrian; Roşu, Şerban; Cǎrligeriu, Virgil; Ianeş, Emilia

2013-10-01

Digital processing of two-dimensional cone beam computer tomography slicesstarts by identification of the contour of elements within. This paper deals with the collective work of specialists in medicine and applied mathematics in computer science on elaborating and implementation of algorithms in dental 2D imagery.

Computer aided stress analysis of long bones utilizing computer tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marom, S.A.

1986-01-01

A computer aided analysis method, utilizing computed tomography (CT) has been developed, which together with a finite element program determines the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the density and the material properties for the generated finite element model. A three-dimensional finite element model of a tibial shaft is automatically generated from the CT file by a pre-processing procedure for a finite element program. The developed pre-processor includes an edge detection algorithm which determines the boundaries of the reconstructed cross-sectional images of the scanned bone. A mesh generation procedure than automatically generatesmore » a three-dimensional mesh of a user-selected refinement. The elastic properties needed for the stress analysis are individually determined for each model element using the radiographic density (CT number) of each pixel with the elemental borders. The elastic modulus is determined from the CT radiographic density by using an empirical relationship from the literature. The generated finite element model, together with applied loads, determined from existing gait analysis and initial displacements, comprise a formatted input for the SAP IV finite element program. The output of this program, stresses and displacements at the model elements and nodes, are sorted and displayed by a developed post-processor to provide maximum and minimum values at selected locations in the model.« less

Quantification of Wear and Deformation in Different Configurations of Polyethylene Acetabular Cups Using Micro X-ray Computed Tomography

PubMed Central

Affatato, Saverio; Zanini, Filippo; Carmignato, Simone

2017-01-01

Wear is currently quantified as mass loss of the bearing materials measured using gravimetric methods. However, this method does not provide other information, such as volumetric loss or surface deviation. In this work, we validated a technique to quantify polyethylene wear in three different batches of ultrahigh-molecular-polyethylene acetabular cups used for hip implants using nondestructive microcomputed tomography. Three different configurations of polyethylene acetabular cups, previously tested under the ISO 14242 parameters, were tested on a hip simulator for an additional 2 million cycles using a modified ISO 14242 load waveform. In this context, a new approach was proposed in order to simulate, on a hip joint simulator, high-demand activities. In addition, the effects of these activities were analyzed in terms of wear and deformations of those polyethylenes by means of gravimetric method and micro X-ray computed tomography. In particular, while the gravimetric method was used for weight loss assessment, microcomputed tomography allowed for acquisition of additional quantitative information about the evolution of local wear and deformation through three-dimensional surface deviation maps for the entire cups’ surface. Experimental results showed that the wear and deformation behavior of these materials change according to different mechanical simulations. PMID:28772616

Contrast‐enhanced computed tomography with myocardial three‐dimensional printing can guide treatment in symptomatic hypertrophic obstructive cardiomyopathy

PubMed Central

Hamatani, Yasuhiro; Amaki, Makoto; Kanzaki, Hideaki; Yamashita, Kizuku; Nakashima, Yasuteru; Shibata, Atsushi; Okada, Atsushi; Takahama, Hiroyuki; Hasegawa, Takuya; Shimahara, Yusuke; Sugano, Yasuo; Fujita, Tomoyuki; Shiraishi, Isao; Yasuda, Satoshi; Kobayashi, Junjiro

2017-01-01

Abstract Both surgical myectomy and percutaneous transluminal septal myocardial ablation are effective treatments for drug‐refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM). However, in some cases, it is not easy to elucidate the abnormal structure of left ventricular outflow obstruction to adopt these treatments. Here, we presented a young female patient with drug‐refractory symptomatic HOCM. In this case, contrast‐enhanced computed tomography enabled us to assess the suitability of percutaneous transluminal septal myocardial ablation. By creating three‐dimensional printed models using computed tomography data, we could also visualize intracardiac structure and simulate the surgical procedure. A multimodality assessment strategy is useful for evaluating patients complicated with drug‐refractory symptomatic HOCM. PMID:29154429

Full Three-Dimensional Tomography Experiments in the Western Pacific Region

NASA Astrophysics Data System (ADS)

Zhao, L.; Chen, L.; Jordan, T. H.

2001-12-01

Two decades of seismic tomography studies have yielded earth models with three-dimensional (3-D) velocity heterogeneities in the mantle on both global and regional scales. With the continuing improvements in inversion techniques, station coverage and computational facilities, seismic tomography has reached a stage at which higher resolution to the structure can only be achieved reliably by employing accurate descriptions between observables and structural parameters, especially in the upper mantle. With this in mind, we have conducted a tomography experiment for the mantle structure beneath the Western Pacific with a full 3-D approach: imaging the 3-D structure using true 3-D Fréchet kernels. In our experiment, we use nearly 20,000 delay times measured at eight discrete frequencies between 10mHz and 45mHz from three-component regional {S} waves, including its multiple reflections from the surface and the CMB. The 3-D Fréchet kernels for these delay times are computed by a normal-mode approach (Zhao, Jordan & Chapman 2000) in which coupling between each pair of modes is accounted for with the exception of cross coupling between spheroidal and toroidal modes. The algorithm is implemented with MPI on the 192-node (and expanding) dual-processor Linux-PC cluster at the University of Southern California. The 3-D radially anisotropic shear-speed model is obtained through a Gaussian-Bayesian inversion. A full description of features in our model will be given in a separate presentation (Chen, Zhao & Jordan, this meeting). Here we discuss in detail the issues related to the calculation of a large number of coupled-mode 3-D kernels for the frequency-dependent delay times and their inversion. We also examine the efficacy of this full 3-D approach in regional high-resolution tomography studies by comparing the results with those in our previous work in which the 3-D structure was obtained by inverting the same delay-time measurements but using computationally more efficient 2-D Fréchet kernels approximated from 3-D by an asymptotic stationary-phase integration across the great-circle plane.

Cochlear implant-related three-dimensional characteristics determined by micro-computed tomography reconstruction.

PubMed

Ni, Yusu; Dai, Peidong; Dai, Chunfu; Li, Huawei

2017-01-01

To explore the structural characteristics of the cochlea in three-dimensional (3D) detail using 3D micro-computed tomography (mCT) image reconstruction of the osseous labyrinth, with the aim of improving the structural design of electrodes, the selection of stimulation sites, and the effectiveness of cochlear implantation. Three temporal bones were selected from among adult donors' temporal bone specimens. A micro-CT apparatus (GE eXplore) was used to scan three specimens with a voxel resolution of 45 μm. We obtained about 460 slices/specimen, which produced abundant data. The osseous labyrinth images of three specimens were reconstructed from mCT. The cochlea and its spiral characteristics were measured precisely using Able Software 3D-DOCTOR. The 3D images of the osseous labyrinth, including the cochlea, vestibule, and semicircular canals, were reconstructed. The 3D models of the cochlea showed the spatial relationships and surface structural characteristics. Quantitative data concerning the cochlea and its spiral structural characteristics were analyzed with regard to cochlear implantation. The 3D reconstruction of mCT images clearly displayed the detailed spiral structural characteristics of the osseous labyrinth. Quantitative data regarding the cochlea and its spiral structural characteristics could help to improve electrode structural design, signal processing, and the effectiveness of cochlear implantation. Clin. Anat. 30:39-43, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effects of nasal septum perforation repair surgery on three-dimensional airflow: an evaluation using computational fluid dynamics.

PubMed

Nomura, Tsutomu; Ushio, Munetaka; Kondo, Kenji; Yamasoba, Tatsuya

2015-11-01

The purpose of this research is to determine the cause of nasal perforation symptoms and to predict post-operative function after nasal perforation repair surgery. A realistic three-dimensional (3D) model of the nose with a septal perforation was reconstructed using a computed tomography (CT) scan from a patient with nasal septal defect. The numerical simulation was carried out using ANSYS CFX V13.0. Pre- and post-operative models were compared by their velocity, pressure gradient (PG), wall shear (WS), shear strain rate (SSR) and turbulence kinetic energy in three plains. In the post-operative state, the crossflows had disappeared, and stream lines bound to the olfactory cleft area had appeared. After surgery, almost all of high-shear stress areas were disappeared comparing pre-operative model. In conclusion, the effects of surgery to correct nasal septal perforation were evaluated using a three-dimensional airflow evaluation. Following the surgery, crossflows disappeared, and WS, PG and SSR rate were decreased. A high WS.PG and SSR were suspected as causes of nasal perforation symptoms.

Improved Interactive Medical-Imaging System

NASA Technical Reports Server (NTRS)

Ross, Muriel D.; Twombly, Ian A.; Senger, Steven

2003-01-01

An improved computational-simulation system for interactive medical imaging has been invented. The system displays high-resolution, three-dimensional-appearing images of anatomical objects based on data acquired by such techniques as computed tomography (CT) and magnetic-resonance imaging (MRI). The system enables users to manipulate the data to obtain a variety of views for example, to display cross sections in specified planes or to rotate images about specified axes. Relative to prior such systems, this system offers enhanced capabilities for synthesizing images of surgical cuts and for collaboration by users at multiple, remote computing sites.

X-ray Computed Tomography.

ERIC Educational Resources Information Center

Michael, Greg

2001-01-01

Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

3D Surface Reconstruction for Lower Limb Prosthetic Model using Radon Transform

NASA Astrophysics Data System (ADS)

Sobani, S. S. Mohd; Mahmood, N. H.; Zakaria, N. A.; Razak, M. A. Abdul

2018-03-01

This paper describes the idea to realize three-dimensional surfaces of objects with cylinder-based shapes where the techniques adopted and the strategy developed for a non-rigid three-dimensional surface reconstruction of an object from uncalibrated two-dimensional image sequences using multiple-view digital camera and turntable setup. The surface of an object is reconstructed based on the concept of tomography with the aid of performing several digital image processing algorithms on the two-dimensional images captured by a digital camera in thirty-six different projections and the three-dimensional structure of the surface is analysed. Four different objects are used as experimental models in the reconstructions and each object is placed on a manually rotated turntable. The results shown that the proposed method has successfully reconstruct the three-dimensional surface of the objects and practicable. The shape and size of the reconstructed three-dimensional objects are recognizable and distinguishable. The reconstructions of objects involved in the test are strengthened with the analysis where the maximum percent error obtained from the computation is approximately 1.4 % for the height whilst 4.0%, 4.79% and 4.7% for the diameters at three specific heights of the objects.

Analysis of micro computed tomography images; a look inside historic enamelled metal objects

NASA Astrophysics Data System (ADS)

van der Linden, Veerle; van de Casteele, Elke; Thomas, Mienke Simon; de Vos, Annemie; Janssen, Elsje; Janssens, Koen

2010-02-01

In this study the usefulness of micro-Computed Tomography (µ-CT) for the in-depth analysis of enamelled metal objects was tested. Usually investigations of enamelled metal artefacts are restricted to non-destructive surface analysis or analysis of cross sections after destructive sampling. Radiography, a commonly used technique in the field of cultural heritage studies, is limited to providing two-dimensional information about a three-dimensional object (Lang and Middleton, Radiography of Cultural Material, pp. 60-61, Elsevier-Butterworth-Heinemann, Amsterdam-Stoneham-London, 2005). Obtaining virtual slices and information about the internal structure of these objects was made possible by CT analysis. With this technique the underlying metal work was studied without removing the decorative enamel layer. Moreover visible defects such as cracks were measured in both width and depth and as of yet invisible defects and weaker areas are visualised. All these features are of great interest to restorers and conservators as they allow a view inside these objects without so much as touching them.

Feasibility of Clinician-Facilitated Three-Dimensional Printing of Synthetic Cranioplasty Flaps.

PubMed

Panesar, Sandip S; Belo, Joao Tiago A; D'Souza, Rhett N

2018-05-01

Integration of three-dimensional (3D) printing and stereolithography into clinical practice is in its nascence, and concepts may be esoteric to the practicing neurosurgeon. Currently, creation of 3D printed implants involves recruitment of offsite third parties. We explored a range of 3D scanning and stereolithographic techniques to create patient-specific synthetic implants using an onsite, clinician-facilitated approach. We simulated bilateral craniectomies in a single cadaveric specimen. We devised 3 methods of creating stereolithographically viable virtual models from removed bone. First, we used preoperative and postoperative computed tomography scanner-derived bony window models from which the flap was extracted. Second, we used an entry-level 3D light scanner to scan and render models of the individual bone pieces. Third, we used an arm-mounted, 3D laser scanner to create virtual models using a real-time approach. Flaps were printed from the computed tomography scanner and laser scanner models only in a ultraviolet-cured polymer. The light scanner did not produce suitable virtual models for printing. The computed tomography scanner-derived models required extensive postfabrication modification to fit the existing defects. The laser scanner models assumed good fit within the defects without any modification. The methods presented varying levels of complexity in acquisition and model rendering. Each technique required hardware at varying in price points from $0 to approximately $100,000. The laser scanner models produced the best quality parts, which had near-perfect fit with the original defects. Potential neurosurgical applications of this technology are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Pulmonary tumor measurements from x-ray computed tomography in one, two, and three dimensions.

PubMed

Villemaire, Lauren; Owrangi, Amir M; Etemad-Rezai, Roya; Wilson, Laura; O'Riordan, Elaine; Keller, Harry; Driscoll, Brandon; Bauman, Glenn; Fenster, Aaron; Parraga, Grace

2011-11-01

We evaluated the accuracy and reproducibility of three-dimensional (3D) measurements of lung phantoms and patient tumors from x-ray computed tomography (CT) and compared these to one-dimensional (1D) and two-dimensional (2D) measurements. CT images of three spherical and three irregularly shaped tumor phantoms were evaluated by three observers who performed five repeated measurements. Additionally, three observers manually segmented 29 patient lung tumors five times each. Follow-up imaging was performed for 23 tumors and response criteria were compared. For a single subject, imaging was performed on nine occasions over 2 years to evaluate multidimensional tumor response. To evaluate measurement accuracy, we compared imaging measurements to ground truth using analysis of variance. For estimates of precision, intraobserver and interobserver coefficients of variation and intraclass correlations (ICC) were used. Linear regression and Pearson correlations were used to evaluate agreement and tumor response was descriptively compared. For spherical shaped phantoms, all measurements were highly accurate, but for irregularly shaped phantoms, only 3D measurements were in high agreement with ground truth measurements. All phantom and patient measurements showed high intra- and interobserver reproducibility (ICC >0.900). Over a 2-year period for a single patient, there was disagreement between tumor response classifications based on 3D measurements and those generated using 1D and 2D measurements. Tumor volume measurements were highly reproducible and accurate for irregular, spherical phantoms and patient tumors with nonuniform dimensions. Response classifications obtained from multidimensional measurements suggest that 3D measurements provide higher sensitivity to tumor response. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

Diagnostic significance of three-dimensional echocardiography in asymptomatic unicuspid aortic valve.

PubMed

Mladenovic, Zorica; Vranes, Danijela; Obradovic, Slobodan; Dzudovic, Boris; Angelkov Ristic, Andjelka; Ratkovic, Nenad; Jovic, Zoran; Spasic, Marijan; Maric Kocijancic, Jelena; Djruic, Predrag

2018-06-04

Unicuspid aortic valve (UAV) is a rare congenital anomaly of aorta associated with a faster progress of valvular dysfunction, aortic dilatation and with necessity for more frequent controls and precise evaluation Asymptomatic 35 year old man had abnormal systolic diastolic murmur on aortic valve during routine examination. Initial diagnostic with transthoracic echocardiography (TTE) supposed bicuspid aortic valve, while three-dimensional transesophageal echocardiography (3D TEE) and multidetector computed tomography defined unicuspid, unicomissural aortic valve with moderate aortic stenosis and regurgitation. This case report confirmed that 3D TEE gives us opportunity for early, improved and precise diagnosis of UAV. © 2018 Wiley Periodicals, Inc.

Take Away Body Parts! An Investigation into the Use of 3D-Printed Anatomical Models in Undergraduate Anatomy Education

ERIC Educational Resources Information Center

Smith, Claire F.; Tollemache, Nicholas; Covill, Derek; Johnston, Malcolm

2018-01-01

Understanding the three-dimensional (3D) nature of the human form is imperative for effective medical practice and the emergence of 3D printing creates numerous opportunities to enhance aspects of medical and healthcare training. A recently deceased, un-embalmed donor was scanned through high-resolution computed tomography. The scan data underwent…

Visualization of Stereoscopic Anatomic Models of the Paranasal Sinuses and Cervical Vertebrae from the Surgical and Procedural Perspective

ERIC Educational Resources Information Center

Chen, Jian; Smith, Andrew D.; Khan, Majid A.; Sinning, Allan R.; Conway, Marianne L.; Cui, Dongmei

2017-01-01

Recent improvements in three-dimensional (3D) virtual modeling software allows anatomists to generate high-resolution, visually appealing, colored, anatomical 3D models from computed tomography (CT) images. In this study, high-resolution CT images of a cadaver were used to develop clinically relevant anatomic models including facial skull, nasal…

The feasibility study on 3-dimensional fluorescent x-ray computed tomography using the pinhole effect for biomedical applications.

PubMed

Sunaguchi, Naoki; Yuasa, Tetsuya; Hyodo, Kazuyuki; Zeniya, Tsutomu

2013-01-01

We propose a 3-dimensional fluorescent x-ray computed tomography (CT) pinhole collimator, aimed at providing molecular imaging with quantifiable measures and sub-millimeter spatial resolution. In this study, we demonstrate the feasibility of this concept and investigate imaging properties such as spatial resolution, contrast resolution and quantifiable measures, by imaging physical phantoms using a preliminary imaging system developed with monochromatic synchrotron x rays constructed at the BLNE-7A experimental line at KEK, Japan.

Model studies of laser absorption computed tomography for remote air pollution measurement

NASA Technical Reports Server (NTRS)

Wolfe, D. C., Jr.; Byer, R. L.

1982-01-01

Model studies of the potential of laser absorption-computed tomography are presented which demonstrate the possibility of sensitive remote atmospheric pollutant measurements, over kilometer-sized areas, with two-dimensional resolution, at modest laser source powers. An analysis of this tomographic reconstruction process as a function of measurement SNR, laser power, range, and system geometry, shows that the system is able to yield two-dimensional maps of pollutant concentrations at ranges and resolutions superior to those attainable with existing, direct-detection laser radars.

Utilisation of three-dimensional printed heart models for operative planning of complex congenital heart defects.

PubMed

Olejník, Peter; Nosal, Matej; Havran, Tomas; Furdova, Adriana; Cizmar, Maros; Slabej, Michal; Thurzo, Andrej; Vitovic, Pavol; Klvac, Martin; Acel, Tibor; Masura, Jozef

2017-01-01

To evaluate the accuracy of the three-dimensional (3D) printing of cardiovascular structures. To explore whether utilisation of 3D printed heart replicas can improve surgical and catheter interventional planning in patients with complex congenital heart defects. Between December 2014 and November 2015 we fabricated eight cardiovascular models based on computed tomography data in patients with complex spatial anatomical relationships of cardiovascular structures. A Bland-Altman analysis was used to assess the accuracy of 3D printing by comparing dimension measurements at analogous anatomical locations between the printed models and digital imagery data, as well as between printed models and in vivo surgical findings. The contribution of 3D printed heart models for perioperative planning improvement was evaluated in the four most representative patients. Bland-Altman analysis confirmed the high accuracy of 3D cardiovascular printing. Each printed model offered an improved spatial anatomical orientation of cardiovascular structures. Current 3D printers can produce authentic copies of patients` cardiovascular systems from computed tomography data. The use of 3D printed models can facilitate surgical or catheter interventional procedures in patients with complex congenital heart defects due to better preoperative planning and intraoperative orientation.

Three-dimensional computed tomography reconstruction for operative planning in robotic segmentectomy: a pilot study

PubMed Central

Le Moal, Julien; Peillon, Christophe; Dacher, Jean-Nicolas

2018-01-01

Background The objective of our pilot study was to assess if three-dimensional (3D) reconstruction performed by Visible Patient™ could be helpful for the operative planning, efficiency and safety of robot-assisted segmentectomy. Methods Between 2014 and 2015, 3D reconstructions were provided by the Visible Patient™ online service and used for the operative planning of robotic segmentectomy. To obtain 3D reconstruction, the surgeon uploaded the anonymized computed tomography (CT) image of the patient to the secured Visible Patient™ server and then downloaded the model after completion. Results Nine segmentectomies were performed between 2014 and 2015 using a pre-operative 3D model. All 3D reconstructions met our expectations: anatomical accuracy (bronchi, arteries, veins, tumor, and the thoracic wall with intercostal spaces), accurate delimitation of each segment in the lobe of interest, margin resection, free space rotation, portability (smartphone, tablet) and time saving technique. Conclusions We have shown that operative planning by 3D CT using Visible Patient™ reconstruction is useful in our practice of robot-assisted segmentectomy. The main disadvantage is the high cost. Its impact on reducing complications and improving surgical efficiency is the object of an ongoing study. PMID:29600049

Three-dimensional computed tomography reconstruction for operative planning in robotic segmentectomy: a pilot study.

PubMed

Le Moal, Julien; Peillon, Christophe; Dacher, Jean-Nicolas; Baste, Jean-Marc

2018-01-01

The objective of our pilot study was to assess if three-dimensional (3D) reconstruction performed by Visible Patient™ could be helpful for the operative planning, efficiency and safety of robot-assisted segmentectomy. Between 2014 and 2015, 3D reconstructions were provided by the Visible Patient™ online service and used for the operative planning of robotic segmentectomy. To obtain 3D reconstruction, the surgeon uploaded the anonymized computed tomography (CT) image of the patient to the secured Visible Patient™ server and then downloaded the model after completion. Nine segmentectomies were performed between 2014 and 2015 using a pre-operative 3D model. All 3D reconstructions met our expectations: anatomical accuracy (bronchi, arteries, veins, tumor, and the thoracic wall with intercostal spaces), accurate delimitation of each segment in the lobe of interest, margin resection, free space rotation, portability (smartphone, tablet) and time saving technique. We have shown that operative planning by 3D CT using Visible Patient™ reconstruction is useful in our practice of robot-assisted segmentectomy. The main disadvantage is the high cost. Its impact on reducing complications and improving surgical efficiency is the object of an ongoing study.

Multi-mounted X-ray cone-beam computed tomography

NASA Astrophysics Data System (ADS)

Fu, Jian; Wang, Jingzheng; Guo, Wei; Peng, Peng

2018-04-01

As a powerful nondestructive inspection technique, X-ray computed tomography (X-CT) has been widely applied to clinical diagnosis, industrial production and cutting-edge research. Imaging efficiency is currently one of the major obstacles for the applications of X-CT. In this paper, a multi-mounted three dimensional cone-beam X-CT (MM-CBCT) method is reported. It consists of a novel multi-mounted cone-beam scanning geometry and the corresponding three dimensional statistical iterative reconstruction algorithm. The scanning geometry is the most iconic design and significantly different from the current CBCT systems. Permitting the cone-beam scanning of multiple objects simultaneously, the proposed approach has the potential to achieve an imaging efficiency orders of magnitude greater than the conventional methods. Although multiple objects can be also bundled together and scanned simultaneously by the conventional CBCT methods, it will lead to the increased penetration thickness and signal crosstalk. In contrast, MM-CBCT avoids substantially these problems. This work comprises a numerical study of the method and its experimental verification using a dataset measured with a developed MM-CBCT prototype system. This technique will provide a possible solution for the CT inspection in a large scale.

[Three-dimensional tooth model reconstruction based on fusion of dental computed tomography images and laser-scanned images].

PubMed

Zhang, Dongxia; Gan, Yangzhou; Xiong, Jing; Xia, Zeyang

2017-02-01

Complete three-dimensional(3D) tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography(CT) images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs, i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete3 D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.

Clinical application of three-dimensional reconstruction and rapid prototyping technology of multislice spiral computed tomography angiography for the repair of ventricular septal defect of tetralogy of Fallot.

PubMed

Ma, X J; Tao, L; Chen, X; Li, W; Peng, Z Y; Chen, Y; Jin, J; Zhang, X L; Xiong, Q F; Zhong, Z L; Chen, X F

2015-02-13

Three-dimensional (3D) reconstruction and rapid prototyping technology (RPT) of multislice spiral computed tomography angiography (CTA) was applied to prepare physical models of the heart and ventricular septal defects of tetralogy of Fallot (ToF) patients in order to explore their applications in the diagnosis and treatment of this complex heart disease. CTA data of 35 ToF patients were collected to prepare l:l 3D solid models using digital 3D reconstruction and RPT, and the resultant models were used intraoperatively as reference. The operations of all 35 patients were completed under the guidance of the 3D solid model, without difficulty. Intraoperative findings of the patients were consistent with the morphological and size changes of the 3D solid model, and no significant differences were found between the patches obtained from the 3D solid model and the actual intraoperative measurements (t = 0.83, P = 0.412). 3D reconstruction and RPT of multislice spiral CTA can accurately and intuitively reflect the anatomy of ventricular septal defects in ToF patients, providing the foundation for a solid model of the complex congenital heart.

Imaging of cellular spread on a three-dimensional scaffold by means of a novel cell-labeling technique for high-resolution computed tomography.

PubMed

Thimm, Benjamin W; Hofmann, Sandra; Schneider, Philipp; Carretta, Roberto; Müller, Ralph

2012-03-01

Computed tomography (CT) represents a truly three-dimensional (3D) imaging technique that can provide high-resolution images on the cellular level. Thus, one approach to detect single cells is X-ray absorption-based CT, where cells are labeled with a dense, opaque material providing the required contrast for CT imaging. Within the present work, a novel cell-labeling method has been developed showing the feasibility of labeling fixed cells with iron oxide (FeO) particles for subsequent CT imaging and quantitative morphometry. A biotin-streptavidin detection system was exploited to bind FeO particles to its target endothelial cells. The binding of the particles was predominantly close to the cell centers on 2D surfaces as shown by light microscopy, scanning electron microscopy, and CT. When cells were cultured on porous, 3D polyurethane surfaces, significantly more FeO particles were detected compared with surfaces without cells and FeO particle labeling using CT. Here, we report on the implementation and evaluation of a novel cell detection method based on high-resolution CT. This system has potential in cell tracking for 3D in vitro imaging in the future.

Technical note: a landmark-based approach to the study of the ear ossicles using ultra-high-resolution X-ray computed tomography data.

PubMed

Schmidt, Jodi L; Cole, Theodore M; Silcox, Mary T

2011-08-01

Previous study of the ear ossicles in Primates has demonstrated that they vary on both functional and phylogenetic bases. Such studies have generally employed two-dimensional linear measurements rather than three-dimensional data. The availability of Ultra- high-resolution X-ray computed tomography (UhrCT) has made it possible to accurately image the ossicles so that broadly accepted methodologies for acquiring and studying morphometric data can be applied. Using UhrCT data also allows for the ossicular chain to be studied in anatomical position, so that it is possible to consider the spatial and size relationships of all three bones. One issue impeding the morphometric study of the ear ossicles is a lack of broadly recognized landmarks. Distinguishing landmarks on the ossicles is difficult in part because there are only two areas of articulation in the ossicular chain, one of which (the malleus/incus articulation) has a complex three-dimensional form. A measurement error study is presented demonstrating that a suite of 16 landmarks can be precisely located on reconstructions of the ossicles from UhrCT data. Estimates of measurement error showed that most landmarks were highly replicable, with an average CV for associated interlandmark distances of less than 3%. The positions of these landmarks are chosen to reflect not only the overall shape of the bones in the chain and their relative positions, but also functional parameters. This study should provide a basis for further examination of the smallest bones in the body in three dimensions. Copyright © 2011 Wiley-Liss, Inc.

Computed tomographic analysis of deformity and dimensional changes in the eyeball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborne, D.R.; Foulks, G.N.

1984-12-01

Computed tomography (CT) was performed in 40 patients with a confirmed ophthalmic diagnosis and a change in the dimensions or configuration of the eyeball. Abnormalities studied included coloboma, microphthalmus, buphthalmos, axial myopia, macrophthalmus, phthisis bulbi, trauma, neoplasm, posterior staphyloma, granuloma, pseudotumor, and surgicalscleral banding for retinal detachment. CT findings could be grouped into three categories depending upon whether the eye was small, large, or normal in size, with the findings in each group allowing distinction of most disease processes.

Robotics in neurosurgery: which tools for what?

PubMed

Benabid, A L; Hoffmann, D; Seigneuret, E; Chabardes, S

2006-01-01

Robots are the tools for taking advantage of the skills of computers in achieving complicated tasks. This has been made possible owing to the "numerical image explosion" which allowed us to easily obtain spatial coordinates, three dimensional reconstruction, multimodality imaging including digital subtraction angiography (DSA), computed tomography (CT), magnetic resonance imaging (MRI) and magneto encephalography (MEG), with high resolution in space, time, and tissue density. Neurosurgical robots currently available at the operating level are being described. Future evolutions, indications and ethical aspects are examined.

Computer tomography of flows external to test models

NASA Technical Reports Server (NTRS)

Prikryl, I.; Vest, C. M.

1982-01-01

Computer tomographic techniques for reconstruction of three-dimensional aerodynamic density fields, from interferograms recorded from several different viewing directions were studied. Emphasis is on the case in which an opaque object such as a test model in a wind tunnel obscures significant regions of the interferograms (projection data). A method called the Iterative Convolution Method (ICM), existing methods in which the field is represented by a series expansions, and analysis of real experimental data in the form of aerodynamic interferograms are discussed.

Computed tomography-guided tissue engineering of upper airway cartilage.

PubMed

Brown, Bryan N; Siebenlist, Nicholas J; Cheetham, Jonathan; Ducharme, Norm G; Rawlinson, Jeremy J; Bonassar, Lawrence J

2014-06-01

Normal laryngeal function has a large impact on quality of life, and dysfunction can be life threatening. In general, airway obstructions arise from a reduction in neuromuscular function or a decrease in mechanical stiffness of the structures of the upper airway. These reductions decrease the ability of the airway to resist inspiratory or expiratory pressures, causing laryngeal collapse. We propose to restore airway patency through methods that replace damaged tissue and improve the stiffness of airway structures. A number of recent studies have utilized image-guided approaches to create cell-seeded constructs that reproduce the shape and size of the tissue of interest with high geometric fidelity. The objective of the present study was to establish a tissue engineering approach to the creation of viable constructs that approximate the shape and size of equine airway structures, in particular the epiglottis. Computed tomography images were used to create three-dimensional computer models of the cartilaginous structures of the larynx. Anatomically shaped injection molds were created from the three-dimensional models and were seeded with bovine auricular chondrocytes that were suspended within alginate before static culture. Constructs were then cultured for approximately 4 weeks post-seeding and evaluated for biochemical content, biomechanical properties, and histologic architecture. Results showed that the three-dimensional molded constructs had the approximate size and shape of the equine epiglottis and that it is possible to seed such constructs while maintaining 75%+ cell viability. Extracellular matrix content was observed to increase with time in culture and was accompanied by an increase in the mechanical stiffness of the construct. If successful, such an approach may represent a significant improvement on the currently available treatments for damaged airway cartilage and may provide clinical options for replacement of damaged tissue during treatment of obstructive airway disease.

Implementation of a computationally efficient least-squares algorithm for highly under-determined three-dimensional diffuse optical tomography problems.

PubMed

Yalavarthy, Phaneendra K; Lynch, Daniel R; Pogue, Brian W; Dehghani, Hamid; Paulsen, Keith D

2008-05-01

Three-dimensional (3D) diffuse optical tomography is known to be a nonlinear, ill-posed and sometimes under-determined problem, where regularization is added to the minimization to allow convergence to a unique solution. In this work, a generalized least-squares (GLS) minimization method was implemented, which employs weight matrices for both data-model misfit and optical properties to include their variances and covariances, using a computationally efficient scheme. This allows inversion of a matrix that is of a dimension dictated by the number of measurements, instead of by the number of imaging parameters. This increases the computation speed up to four times per iteration in most of the under-determined 3D imaging problems. An analytic derivation, using the Sherman-Morrison-Woodbury identity, is shown for this efficient alternative form and it is proven to be equivalent, not only analytically, but also numerically. Equivalent alternative forms for other minimization methods, like Levenberg-Marquardt (LM) and Tikhonov, are also derived. Three-dimensional reconstruction results indicate that the poor recovery of quantitatively accurate values in 3D optical images can also be a characteristic of the reconstruction algorithm, along with the target size. Interestingly, usage of GLS reconstruction methods reduces error in the periphery of the image, as expected, and improves by 20% the ability to quantify local interior regions in terms of the recovered optical contrast, as compared to LM methods. Characterization of detector photo-multiplier tubes noise has enabled the use of the GLS method for reconstructing experimental data and showed a promise for better quantification of target in 3D optical imaging. Use of these new alternative forms becomes effective when the ratio of the number of imaging property parameters exceeds the number of measurements by a factor greater than 2.

Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.

PubMed

Lee, Jong-Ki; Ha, Byung-Hyun; Choi, Jeong-Ho; Heo, Seok-Mo; Perinpanayagam, Hiran

2006-10-01

In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.

Validation of cone beam computed tomography-based tooth printing using different three-dimensional printing technologies.

PubMed

Khalil, Wael; EzEldeen, Mostafa; Van De Casteele, Elke; Shaheen, Eman; Sun, Yi; Shahbazian, Maryam; Olszewski, Raphael; Politis, Constantinus; Jacobs, Reinhilde

2016-03-01

Our aim was to determine the accuracy of 3-dimensional reconstructed models of teeth compared with the natural teeth by using 4 different 3-dimensional printers. This in vitro study was carried out using 2 intact, dry adult human mandibles, which were scanned with cone beam computed tomography. Premolars were selected for this study. Dimensional differences between natural teeth and the printed models were evaluated directly by using volumetric differences and indirectly through optical scanning. Analysis of variance, Pearson correlation, and Bland Altman plots were applied for statistical analysis. Volumetric measurements from natural teeth and fabricated models, either by the direct method (the Archimedes principle) or by the indirect method (optical scanning), showed no statistical differences. The mean volume difference ranged between 3.1 mm(3) (0.7%) and 4.4 mm(3) (1.9%) for the direct measurement, and between -1.3 mm(3) (-0.6%) and 11.9 mm(3) (+5.9%) for the optical scan. A surface part comparison analysis showed that 90% of the values revealed a distance deviation within the interval 0 to 0.25 mm. Current results showed a high accuracy of all printed models of teeth compared with natural teeth. This outcome opens perspectives for clinical use of cost-effective 3-dimensional printed teeth for surgical procedures, such as tooth autotransplantation. Copyright © 2016 Elsevier Inc. All rights reserved.

Simulating the influence of scatter and beam hardening in dimensional computed tomography

NASA Astrophysics Data System (ADS)

Lifton, J. J.; Carmignato, S.

2017-10-01

Cone-beam x-ray computed tomography (XCT) is a radiographic scanning technique that allows the non-destructive dimensional measurement of an object’s internal and external features. XCT measurements are influenced by a number of different factors that are poorly understood. This work investigates how non-linear x-ray attenuation caused by beam hardening and scatter influences XCT-based dimensional measurements through the use of simulated data. For the measurement task considered, both scatter and beam hardening are found to influence dimensional measurements when evaluated using the ISO50 surface determination method. On the other hand, only beam hardening is found to influence dimensional measurements when evaluated using an advanced surface determination method. Based on the results presented, recommendations on the use of beam hardening and scatter correction for dimensional XCT are given.

Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

PubMed

Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

2014-10-01

The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Analysis of eletrectrohydrodynamic jetting using multifunctional and three-dimensional tomography

NASA Astrophysics Data System (ADS)

Ko, Han Seo; Nguyen, Xuan Hung; Lee, Soo-Hong; Kim, Young Hyun

2013-11-01

Three-dimensional optical tomography technique was developed to reconstruct three-dimensional flow fields using a set of two-dimensional shadowgraphic images and normal gray images. From three high speed cameras, which were positioned at an offset angle of 45° relative to one another, number, size and location of electrohydrodynamic jets with respect to the nozzle position were analyzed using shadowgraphic tomography employing a multiplicative algebraic reconstruction technique (MART). Additionally, a flow field inside cone-shaped liquid (Taylor cone) which was induced under electric field was also observed using a simultaneous multiplicative algebraic reconstruction technique (SMART) for reconstructing intensities of particle light and combining with a three-dimensional cross correlation. Various velocity fields of a circulating flow inside the cone-shaped liquid due to different physico-chemical properties of liquid and applied voltages were also investigated. This work supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. S-2011-0023457).

Three-Dimensional Modeling May Improve Surgical Education and Clinical Practice.

PubMed

Jones, Daniel B; Sung, Robert; Weinberg, Crispin; Korelitz, Theodore; Andrews, Robert

2016-04-01

Three-dimensional (3D) printing has been used in the manufacturing industry for rapid prototyping and product testing. The aim of our study was to assess the feasibility of creating anatomical 3D models from a digital image using 3D printers. Furthermore, we sought face validity of models and explored potential opportunities for using 3D printing to enhance surgical education and clinical practice. Computed tomography and magnetic resonance images were reviewed, converted to computer models, and printed by stereolithography to create near exact replicas of human organs. Medical students and surgeons provided feedback via survey at the 2014 Surgical Education Week conference. There were 51 respondents, and 95.8% wanted these models for their patients. Cost was a concern, but 82.6% found value in these models at a price less than $500. All respondents thought the models would be useful for integration into the medical school curriculum. Three-dimensional printing is a potentially disruptive technology to improve both surgical education and clinical practice. As the technology matures and cost decreases, we envision 3D models being increasingly used in surgery. © The Author(s) 2015.

Computer-aided endovascular aortic repair using fully automated two- and three-dimensional fusion imaging.

PubMed

Panuccio, Giuseppe; Torsello, Giovanni Federico; Pfister, Markus; Bisdas, Theodosios; Bosiers, Michel J; Torsello, Giovanni; Austermann, Martin

2016-12-01

To assess the usability of a fully automated fusion imaging engine prototype, matching preinterventional computed tomography with intraoperative fluoroscopic angiography during endovascular aortic repair. From June 2014 to February 2015, all patients treated electively for abdominal and thoracoabdominal aneurysms were enrolled prospectively. Before each procedure, preoperative planning was performed with a fully automated fusion engine prototype based on computed tomography angiography, creating a mesh model of the aorta. In a second step, this three-dimensional dataset was registered with the two-dimensional intraoperative fluoroscopy. The main outcome measure was the applicability of the fully automated fusion engine. Secondary outcomes were freedom from failure of automatic segmentation or of the automatic registration as well as accuracy of the mesh model, measuring deviations from intraoperative angiography in millimeters, if applicable. Twenty-five patients were enrolled in this study. The fusion imaging engine could be used in successfully 92% of the cases (n = 23). Freedom from failure of automatic segmentation was 44% (n = 11). The freedom from failure of the automatic registration was 76% (n = 19), the median error of the automatic registration process was 0 mm (interquartile range, 0-5 mm). The fully automated fusion imaging engine was found to be applicable in most cases, albeit in several cases a fully automated data processing was not possible, requiring manual intervention. The accuracy of the automatic registration yielded excellent results and promises a useful and simple to use technology. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Bayesian reconstruction and use of anatomical a priori information for emission tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowsher, J.E.; Johnson, V.E.; Turkington, T.G.

1996-10-01

A Bayesian method is presented for simultaneously segmenting and reconstructing emission computed tomography (ECT) images and for incorporating high-resolution, anatomical information into those reconstructions. The anatomical information is often available from other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). The Bayesian procedure models the ECT radiopharmaceutical distribution as consisting of regions, such that radiopharmaceutical activity is similar throughout each region. It estimates the number of regions, the mean activity of each region, and the region classification and mean activity of each voxel. Anatomical information is incorporated by assigning higher prior probabilities to ECT segmentations inmore » which each ECT region stays within a single anatomical region. This approach is effective because anatomical tissue type often strongly influences radiopharmaceutical uptake. The Bayesian procedure is evaluated using physically acquired single-photon emission computed tomography (SPECT) projection data and MRI for the three-dimensional (3-D) Hoffman brain phantom. A clinically realistic count level is used. A cold lesion within the brain phantom is created during the SPECT scan but not during the MRI to demonstrate that the estimation procedure can detect ECT structure that is not present anatomically.« less

Role of computed tomography angiography in detection and staging of small bowel carcinoid tumors

PubMed Central

Bonekamp, David; Raman, Siva P; Horton, Karen M; Fishman, Elliot K

2015-01-01

Small-bowel carcinoid tumors are the most common form (42%) of gastrointestinal carcinoids, which by themselves comprise 70% of neuroendocrine tumors. Although primary small bowel neoplasms are overall rare (3%-6% of all gastrointestinal neoplasms), carcinoids still represent the second most common (20%-30%) primary small-bowel malignancy after small bowel adenocarcinoma. Their imaging evaluation is often challenging. State-of-the-art high-resolution multiphasic computed tomography together with advanced postprocessing methods provides an excellent tool for their depiction. The manifold interactive parameter choices however require knowledge of when to use which technique. Here, we discuss the imaging appearance and evaluation of duodenal, jejunal and ileal carcinoid tumors, including the imaging features of the primary tumor, locoregional mesenteric nodal metastases, and distant metastatic disease. A protocol for optimal lesion detection is presented, including the use of computed tomography enterography, volume acquisition, computed tomography angiography and three-dimensional mapping. Imaging findings are illustrated with a series of challenging cases which illustrate the spectrum of possible disease in the small bowel and mesentery, the range of possible appearances in the bowel itself on multiphase data and extraluminal findings such as the desmoplastic reaction in mesentery and hypervascular liver metastases. Typical imaging pitfalls and pearls are illustrated. PMID:26435774

Evaluation of the Root and Canal Morphology of Maxillary Permanent Molars and the Incidence of the Second Mesiobuccal Root Canal in Greek Population Using Cone-beam Computed Tomography

PubMed Central

Nikoloudaki, Georgia E.; Kontogiannis, Taxiarchis G.; Kerezoudis, Nikolaos P.

2015-01-01

Objectives: Cone-Beam Computed Tomography is an alternative imaging technique which has been recently introduced in the field of Oral & Maxillofacial Radiology. It has rapidly gained great popularity among clinicians due to its ability to detect lesions and defects of the orofacial region and provide three-dimensional information about them. In the field of Endodontics, CBCT can be a useful tool to reveal tooth morphology irregularities, additional root canals and vertical root fractures. The objective of this study is to evaluate the root and root canal morphology of the maxillary permanent molars in Greek population using Cone-Beam Computed Tomography. Materials and Methods : 273 cone-beam computed tomography (CBCT) images were examined. The number of roots and root canals of the first and second maxillary molars were evaluated. Root canal configuration was classified according to Weine’s classification by two independent examiners and statistical analysis was performed. Results : A total of 812 molars (410 first and 402 second ones) were evaluated. The vast majority of both first and second molars had three roots (89.26% and 85.07%, respectively). Most first molars had four canals, while most second molars had three. In the mesiobuccal roots, one foramen was recorded in 80.91% of all teeth. Other rare morphologic variations were also found, such as fusion of a maxillary second molar with a supernumerary tooth. Conclusion : Within the limitations of this study, it can be concluded that more attention should be given to the detection of additional canals during root canal treatment in maxillary permanent molars. Towards this effort, CBCT can provide the clinician with supplemental information about the different root canal configurations for successful Root Canal Treatment. PMID:26464594

Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

PubMed

Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

2013-12-01

The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime scene.

Construction of three-dimensional tooth model by micro-computed tomography and application for data sharing.

PubMed

Kato, A; Ohno, N

2009-03-01

The study of dental morphology is essential in terms of phylogeny. Advances in three-dimensional (3D) measurement devices have enabled us to make 3D images of teeth without destruction of samples. However, raw fundamental data on tooth shape requires complex equipment and techniques. An online database of 3D teeth models is therefore indispensable. We aimed to explore the basic methodology for constructing 3D teeth models, with application for data sharing. Geometric information on the human permanent upper left incisor was obtained using micro-computed tomography (micro-CT). Enamel, dentine, and pulp were segmented by thresholding of different gray-scale intensities. Segmented data were separately exported in STereo-Lithography Interface Format (STL). STL data were converted to Wavefront OBJ (OBJect), as many 3D computer graphics programs support the Wavefront OBJ format. Data were also applied to Quick Time Virtual Reality (QTVR) format, which allows the image to be viewed from any direction. In addition to Wavefront OBJ and QTVR data, the original CT series were provided as 16-bit Tag Image File Format (TIFF) images on the website. In conclusion, 3D teeth models were constructed in general-purpose data formats, using micro-CT and commercially available programs. Teeth models that can be used widely would benefit all those who study dental morphology.

Three-Dimensional Analysis of Voids in AM60B Magnesium Tensile Bars Using Computed Tomography Imagery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waters, A M

2001-05-01

In an effort to increase automobile fuel efficiency as well as decrease the output of harmful greenhouse gases, the automotive industry has recently shown increased interest in cast light metals such as magnesium alloys in an effort to increase weight savings. Currently several magnesium alloys such as AZ91 and AM60B are being used in structural applications for automobiles. However, these magnesium alloys are not as well characterized as other commonly used structural metals such as aluminum. This dissertation presents a methodology to nondestructively quantify damage accumulation due to void behavior in three dimensions in die-cast magnesium AM60B tensile bars asmore » a function of mechanical load. Computed tomography data was acquired after tensile bars were loaded up to and including failure, and analyzed to characterize void behavior as it relates to damage accumulation. Signal and image processing techniques were used along with a cluster labeling routine to nondestructively quantify damage parameters in three dimensions. Void analyses were performed including void volume distribution characterization, nearest neighbor distance calculations, shape parameters, and volumetric renderings of voids in the alloy. The processed CT data was used to generate input files for use in finite element simulations, both two- and three-dimensional. The void analyses revealed that the overwhelming source of failure in each tensile bar was a ring of porosity within each bar, possibly due to a solidification front inherent to the casting process. The measured damage parameters related to void nucleation, growth, and coalescence were shown to contribute significantly to total damage accumulation. Void volume distributions were characterized using a Weibull function, and the spatial distributions of voids were shown to be clustered. Two-dimensional finite element analyses of the tensile bars were used to fine-tune material damage models and a three-dimensional mesh of an extracted portion of one tensile bar including voids was generated from CT data and used as input to a finite element analysis.« less

Real-time three-dimensional optical coherence tomography image-guided core-needle biopsy system.

PubMed

Kuo, Wei-Cheng; Kim, Jongsik; Shemonski, Nathan D; Chaney, Eric J; Spillman, Darold R; Boppart, Stephen A

2012-06-01

Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed that incorporates both three-dimensional OCT imaging and tissue biopsy within the same needle for true OCT-guided core-needle biopsy. We have developed and demonstrate an integrated core-needle biopsy system that utilizes catheter-based 3-D OCT for real-time image-guidance for target tissue localization, imaging of tissue immediately prior to physical biopsy, and subsequent OCT imaging of the biopsied specimen for immediate assessment at the point-of-care. OCT images of biopsied ex vivo tumor specimens acquired during core-needle placement are correlated with corresponding histology, and computational visualization of arbitrary planes within the 3-D OCT volumes enables feedback on specimen tissue type and biopsy quality. These results demonstrate the potential for using real-time 3-D OCT for needle biopsy guidance by imaging within the needle and tissue during biopsy procedures.

Positron emission tomography

NASA Astrophysics Data System (ADS)

Yamamoto, Y. Lucas; Thompson, Christopher J.; Diksic, Mirko; Meyer, Ernest; Feindel, William H.

One of the most exciting new technologies introduced in the last 10 yr is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body. This approach is analogous to quantitative in-vivo autoradiography but has the added advantage of permitting non-invasive in vivo studies. PET scanning requires a small cyclotron to produce short-lived positron emitting isotopes such as oxygen-15, carbon-11, nitrogen-13 and fluorine-18. Proper radiochemical facilities and advanced computer equipment are also needed. Most important, PET requires a multidisciplinary scientific team of physicists, radiochemists, mathematicians, biochemists and physicians. This review analyzes the most recent trends in the imaging technology, radiochemistry, methodology and clinical applications of positron emission tomography.

Three-dimensional multifunctional optical coherence tomography for skin imaging

NASA Astrophysics Data System (ADS)

Li, En; Makita, Shuichi; Hong, Young-Joo; Kasaragod, Deepa; Sasaoka, Tomoko; Yamanari, Masahiro; Sugiyama, Satoshi; Yasuno, Yoshiaki

2016-02-01

Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by a single scan. They respectively contrast the structure and morphology, vasculature, melanin content and collagen traits of the tissue.

Determination of strain fields in porous shape memory alloys using micro-computed tomography

NASA Astrophysics Data System (ADS)

Bormann, Therese; Friess, Sebastian; de Wild, Michael; Schumacher, Ralf; Schulz, Georg; Müller, Bert

2010-09-01

Shape memory alloys (SMAs) belong to 'intelligent' materials since the metal alloy can change its macroscopic shape as the result of the temperature-induced, reversible martensite-austenite phase transition. SMAs are often applied for medical applications such as stents, hinge-less instruments, artificial muscles, and dental braces. Rapid prototyping techniques, including selective laser melting (SLM), allow fabricating complex porous SMA microstructures. In the present study, the macroscopic shape changes of the SMA test structures fabricated by SLM have been investigated by means of micro computed tomography (μCT). For this purpose, the SMA structures are placed into the heating stage of the μCT system SkyScan 1172™ (SkyScan, Kontich, Belgium) to acquire three-dimensional datasets above and below the transition temperature, i.e. at room temperature and at about 80°C, respectively. The two datasets were registered on the basis of an affine registration algorithm with nine independent parameters - three for the translation, three for the rotation and three for the scaling in orthogonal directions. Essentially, the scaling parameters characterize the macroscopic deformation of the SMA structure of interest. Furthermore, applying the non-rigid registration algorithm, the three-dimensional strain field of the SMA structure on the micrometer scale comes to light. The strain fields obtained will serve for the optimization of the SLM-process and, more important, of the design of the complex shaped SMA structures for tissue engineering and medical implants.

Recent Inferior Myocardial Infarction Complicated with a Right Ventricular Thrombus Detected by Three Cardiac Imaging Modalities.

PubMed

Kuno, Toshiki; Imaeda, Syohei; Hashimoto, Kenji; Ryuzaki, Toshinobu; Saito, Tetsuya; Yamazaki, Hiroyuki; Tabei, Ryota; Kodaira, Masaki; Hase, Manabu; Numasawa, Yohei

2018-03-01

We report the case of a 71-year-old woman diagnosed with recent inferior myocardial infarction complicated with right ventricular infarction and a right ventricular thrombus. Three-dimensional transthoracic echocardiography, contrast-enhanced computed tomography, and cardiac magnetic resonance imaging clearly detected a thrombus. We consider cases with a recent right ventricular infarction to require assessment for thrombus formations in the right ventricle. Fortunately, vigorous anticoagulation therapy resolved the thrombi in both the right ventricle and right coronary artery.

Direct Numerical Simulation of Liquid Nozzle Spray with Comparison to Shadowgraphy and X-Ray Computed Tomography Experimental Results

NASA Astrophysics Data System (ADS)

van Poppel, Bret; Owkes, Mark; Nelson, Thomas; Lee, Zachary; Sowell, Tyler; Benson, Michael; Vasquez Guzman, Pablo; Fahrig, Rebecca; Eaton, John; Kurman, Matthew; Kweon, Chol-Bum; Bravo, Luis

2014-11-01

In this work, we present high-fidelity Computational Fluid Dynamics (CFD) results of liquid fuel injection from a pressure-swirl atomizer and compare the simulations to experimental results obtained using both shadowgraphy and phase-averaged X-ray computed tomography (CT) scans. The CFD and experimental results focus on the dense near-nozzle region to identify the dominant mechanisms of breakup during primary atomization. Simulations are performed using the NGA code of Desjardins et al (JCP 227 (2008)) and employ the volume of fluid (VOF) method proposed by Owkes and Desjardins (JCP 270 (2013)), a second order accurate, un-split, conservative, three-dimensional VOF scheme providing second order density fluxes and capable of robust and accurate high density ratio simulations. Qualitative features and quantitative statistics are assessed and compared for the simulation and experimental results, including the onset of atomization, spray cone angle, and drop size and distribution.

[Three-dimensional evaluation of condylar morphology remodeling after orthognathic surgery in mandibular retrognathism by cone-beam computed tomography].

PubMed

Chen, Shuo; Liu, Xiao-jing; Li, Zi-li; Liang, Cheng; Wang, Xiao-xia; Fu, Kai-yuan; Yi, Biao

2015-08-18

To evaluate the effect of orthognathic surgery on condylar morphology changes by comparing three-dimension surface reconstructions of condyles using cone-beam computed tomography (CBCT) data. In the study, 18 patients with mandible retrognathism deformities were included and CBCT data of 36 temporomandibular joints were collected before surgery and 12 months after surgery. Condyles were reconstructed and superimposed pre- and post-operatively to compare the changes of condylar surfaces. One-sample t test and χ2 test were performed for the analysis of three-dimension metric measurement and condylar head remodeling signs. P<0.05 was considered significant. The root-mean-square (RMS) of condylar surface changes before and after the surgery was (0.37±0.11) mm, which was significant statistically (P<0.05). The distribution of condylar remodeling signs showed significant difference (P<0.05). Bone resorption occurred predominantly in the posterior area of condylar head and bone formation occurred mainly in the anterior area. Three-dimension superimposition method based on CBCT data showed that condylar morphology had undergone remodeling after mandibular advancement.

Quantification of pericardial effusions by echocardiography and computed tomography.

PubMed

Leibowitz, David; Perlman, Gidon; Planer, David; Gilon, Dan; Berman, Philip; Bogot, Naama

2011-01-15

Echocardiography is a well-accepted tool for the diagnosis and quantification of pericardial effusion (PEff). Given the increasing use of computed tomographic (CT) scanning, more PEffs are being initially diagnosed by computed tomography. No study has compared quantification of PEff by computed tomography and echocardiography. The objective of this study was to assess the accuracy of quantification of PEff by 2-dimensional echocardiography and computed tomography compared to the amount of pericardial fluid drained at pericardiocentesis. We retrospectively reviewed an institutional database to identify patients who underwent chest computed tomography and echocardiography before percutaneous pericardiocentesis with documentation of the amount of fluid withdrawn. Digital 2-dimensional echocardiographic and CT images were retrieved and quantification of PEff volume was performed by applying the formula for the volume of a prolate ellipse, π × 4/3 × maximal long-axis dimension/2 × maximal transverse dimension/2 × maximal anteroposterior dimension/2, to the pericardial sac and to the heart. Nineteen patients meeting study qualifications were entered into the study. The amount of PEff drained was 200 to 1,700 ml (mean 674 ± 340). Echocardiographically calculated pericardial effusion volume correlated relatively well with PEff volume (r = 0.73, p <0.001, mean difference -41 ± 225 ml). There was only moderate correlation between CT volume quantification and actual volume drained (r = 0.4, p = 0.004, mean difference 158 ± 379 ml). In conclusion, echocardiography appears a more accurate imaging technique than computed tomography in quantitative assessment of nonloculated PEffs and should continue to be the primary imaging in these patients. Copyright © 2011 Elsevier Inc. All rights reserved.

Microscale reconstruction of biogeochemical substrates using multimode X-ray tomography and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Miller, M.; Miller, E.; Liu, J.; Lund, R. M.; McKinley, J. P.

2012-12-01

X-ray computed tomography (CT), scanning electron microscopy (SEM), electron microprobe analysis (EMP), and computational image analysis are mature technologies used in many disciplines. Cross-discipline combination of these imaging and image-analysis technologies is the focus of this research, which uses laboratory and light-source resources in an iterative approach. The objective is to produce images across length scales, taking advantage of instrumentation that is optimized for each scale, and to unify them into a single compositional reconstruction. Initially, CT images will be collected using both x-ray absorption and differential phase contrast modes. The imaged sample will then be physically sectioned and the exposed surfaces imaged and characterized via SEM/EMP. The voxel slice corresponding to the physical sample surface will be isolated computationally, and the volumetric data will be combined with two-dimensional SEM images along CT image planes. This registration step will take advantage of the similarity between the X-ray absorption (CT) and backscattered electron (SEM) coefficients (both proportional to average atomic number in the interrogated volume) as well as the images' mutual information. Elemental and solid-phase distributions on the exposed surfaces, co-registered with SEM images, will be mapped using EMP. The solid-phase distribution will be propagated into three-dimensional space using computational methods relying on the estimation of compositional distributions derived from the CT data. If necessary, solid-phase and pore-space boundaries will be resolved using X-ray differential phase contrast tomography, x-ray fluorescence tomography, and absorption-edge microtomography at a light-source facility. Computational methods will be developed to register and model images collected over varying scales and data types. Image resolution, physically and dynamically, is qualitatively different for the electron microscopy and CT methodologies. Routine CT images are resolved at 10-20 μm, while SEM images are resolved at 10-20 nm; grayscale values vary according to collection time and instrument sensitivity; and compositional sensitivities via EMP vary in interrogation volume and scale. We have so far successfully registered SEM imagery within a multimode tomographic volume and have used standard methods to isolate pore space within the volume. We are developing a three-dimensional solid-phase identification and registration method that is constrained by bulk-sample X-ray diffraction Rietveld refinements. The results of this project will prove useful in fields that require the fine-scale definition of solid-phase distributions and relationships, and could replace more inefficient methods for making these estimations.

Novel Treatment Planning of Hemimandibular Hyperplasia by the Use of Three-Dimensional Computer-Aided-Design and Computer-Aided-Manufacturing Technologies.

PubMed

Hatamleh, Muhanad M; Yeung, Elizabeth; Osher, Jonas; Huppa, Chrisopher

2017-05-01

Hemimandibular hyperplasia is characterized by an obvious overgrowth in the size of the mandible on one side, which can extend up to the midline causing facial asymmetry. Surgical resection of the overgrowth depends heavily on the skill and experience of the surgeon. This report describes a novel methodology of applying three-dimensional computer-aided-design and computer-aided-manufacturing principles in improving the outcome of surgery in 2 mandibular hyperplasia patients. Both patients had their cone beam computer tomography (CBCT) scan performed. CMF Pro Plan software (v. 2.1) was used to process the scan data into virtual 3-dimensional models of the maxilla and mandible. Head tilt was adjusted manually by following horizontal reference. Facial asymmetry secondary to mandibular hypertrophy was obvious on frontal and lateral views. Simulation functions were followed including mirror imaging of the unaffected mandibular side into the hyperplastic side and position was optimized by translation and orientation functions. Reconstruction of virtual symmetry was assessed and checked by running 3-dimensional measurements. Then, subtraction functions were used to create a 3-dimensional template defining the outline of the lower mandibular osteotomy needed. Precision of mandibular teeth was enhanced by amalgamating the CBCT scan with e-cast scan of the patient lower teeth. 3-Matic software (v. 10.0) was used in designing cutting guide(s) that define the amount of overgrowth to be resected. The top section of the guide was resting on the teeth hence ensuring stability and accuracy while positioning it. The guide design was exported as an .stl file and printed using in-house 3-dimensional printer in biocompatible resin. Three-dimensional technologies of both softwares (CMF Pro Plan and 3-Matic) are accurate and reliable methods in the diagnosis, treatment planning, and designing of cutting guides that optimize surgical correction of hemimandibular hyperplasia at timely and cost-effect manner.

Transmission mode terahertz computed tomography

DOEpatents

Ferguson, Bradley Stuart; Wang, Shaohong; Zhang, Xi-Cheng

2006-10-10

A method of obtaining a series of images of a three-dimensional object by transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a scanning spot. The object is placed within the Rayleigh range of the focused THz beam and a focusing system is used to transfer the imaging plane from adjacent the object to a desired distance away from the object. A related system is also disclosed.

[Leonardo da Vinci the first human body imaging specialist. A brief communication on the thorax oseum images].

PubMed

Cicero, Raúl; Criales, José Luis; Cardoso, Manuel

2009-01-01

The impressive development of computed tomography (CT) techniques such as the three dimensional helical CT produces a spatial image of the thoracic skull. At the beginning of the 16th century Leonardo da Vinci drew with great precision the thorax oseum. These drawings show an outstanding similarity with the images obtained by three dimensional helical CT. The cumbersome task of the Renaissance genius is a prime example of the careful study of human anatomy. Modern imaging techniques require perfect anatomic knowledge of the human body in order to generate exact interpretations of images. Leonardo's example is alive for anybody devoted to modern imaging studies.

Computer-Aided Design and Computer-Aided Manufacturing Hydroxyapatite/Epoxide Acrylate Maleic Compound Construction for Craniomaxillofacial Bone Defects.

PubMed

Zhang, Lei; Shen, Shunyao; Yu, Hongbo; Shen, Steve Guofang; Wang, Xudong

2015-07-01

The aim of this study was to investigate the use of computer-aided design and computer-aided manufacturing hydroxyapatite (HA)/epoxide acrylate maleic (EAM) compound construction artificial implants for craniomaxillofacial bone defects. Computed tomography, computer-aided design/computer-aided manufacturing and three-dimensional reconstruction, as well as rapid prototyping were performed in 12 patients between 2008 and 2013. The customized HA/EAM compound artificial implants were manufactured through selective laser sintering using a rapid prototyping machine into the exact geometric shapes of the defect. The HA/EAM compound artificial implants were then implanted during surgical reconstruction. Color-coded superimpositions demonstrated the discrepancy between the virtual plan and achieved results using Geomagic Studio. As a result, the HA/EAM compound artificial bone implants were perfectly matched with the facial areas that needed reconstruction. The postoperative aesthetic and functional results were satisfactory. The color-coded superimpositions demonstrated good consistency between the virtual plan and achieved results. The three-dimensional maximum deviation is 2.12 ± 0.65  mm and the three-dimensional mean deviation is 0.27 ± 0.07  mm. No facial nerve weakness or pain was observed at the follow-up examinations. Only 1 implant had to be removed 2 months after the surgery owing to severe local infection. No other complication was noted during the follow-up period. In conclusion, computer-aided, individually fabricated HA/EAM compound construction artificial implant was a good craniomaxillofacial surgical technique that yielded improved aesthetic results and functional recovery after reconstruction.

Fundamentals of cone beam computed tomography for a prosthodontist

PubMed Central

John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R. B.

2015-01-01

Cone beam computed tomography (CBCT, also referred to as C-arm computed tomography [CT], cone beam volume CT, or flat panel CT) is a medical imaging technique of X-ray CT where the X-rays are divergent, forming a cone.[1] CBCT systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimeter resolution in images of high diagnostic quality, with short scanning times (10–70 s) and radiation dosages reportedly up to 15–100 times lower than those of conventional CT scans. Increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. The aim of this article is to sensitize the Prosthodontist to CBCT technology, provide an overview of currently available maxillofacial CBCT systems and review the specific application of various CBCT display modes to clinical Prosthodontic practice. A MEDLINE search for relevant articles in this specific area of interest was conducted. The selected articles were critically reviewed and the data acquired were systematically compiled. PMID:26929479

Quantitative features in the computed tomography of healthy lungs.

PubMed Central

Fromson, B H; Denison, D M

1988-01-01

This study set out to determine whether quantitative features of lung computed tomography scans could be identified that would lead to a tightly defined normal range for use in assessing patients. Fourteen normal subjects with apparently healthy lungs were studied. A technique was developed for rapid and automatic extraction of lung field data from the computed tomography scans. The Hounsfield unit histograms were constructed and, when normalised for predicted lung volumes, shown to be consistent in shape for all the subjects. A three dimensional presentation of the data in the form of a "net plot" was devised, and from this a logarithmic relationship between the area of each lung slice and its mean density was derived (r = 0.9, n = 545, p less than 0.0001). The residual density, calculated as the difference between measured density and density predicted from the relationship with area, was shown to be normally distributed with a mean of 0 and a standard deviation of 25 Hounsfield units (chi 2 test: p less than 0.05). A presentation combining this residual density with the net plot is described. PMID:3353883

Cone beam computed tomography: basics and applications in dentistry.

PubMed

Venkatesh, Elluru; Elluru, Snehal Venkatesh

2017-01-01

The introduction of cone beam computed tomography (CBCT) devices, changed the way oral and maxillofacial radiology is practiced. CBCT was embraced into the dental settings very rapidly due to its compact size, low cost, low ionizing radiation exposure when compared to medical computed tomography. Alike medical CT, 3 dimensional evaluation of the maxillofacial region with minimal distortion is offered by the CBCT. This article provides an overview of basics of CBCT technology and reviews the specific application of CBCT technology to oral and maxillofacial region with few illustrations.

Human vocal tract resonances and the corresponding mode shapes investigated by three-dimensional finite-element modelling based on CT measurement.

PubMed

Vampola, Tomáš; Horáček, Jaromír; Laukkanen, Anne-Maria; Švec, Jan G

2015-04-01

Resonance frequencies of the vocal tract have traditionally been modelled using one-dimensional models. These cannot accurately represent the events in the frequency region of the formant cluster around 2.5-4.5 kHz, however. Here, the vocal tract resonance frequencies and their mode shapes are studied using a three-dimensional finite element model obtained from computed tomography measurements of a subject phonating on vowel [a:]. Instead of the traditional five, up to eight resonance frequencies of the vocal tract were found below the prominent antiresonance around 4.7 kHz. The three extra resonances were found to correspond to modes which were axially asymmetric and involved the piriform sinuses, valleculae, and transverse vibrations in the oral cavity. The results therefore suggest that the phenomenon of speaker's and singer's formant clustering may be more complex than originally thought.

Mineralization of collagen may occur on fibril surfaces: evidence from conventional and high-voltage electron microscopy and three-dimensional imaging

NASA Technical Reports Server (NTRS)

Landis, W. J.; Hodgens, K. J.; Song, M. J.; Arena, J.; Kiyonaga, S.; Marko, M.; Owen, C.; McEwen, B. F.

1996-01-01

The interaction between collagen and mineral crystals in the normally calcifying leg tendons from the domestic turkey, Meleagris gallopavo, has been investigated at an ultrastructural level with conventional and high-voltage electron microscopy, computed tomography, and three-dimensional image reconstruction methods. Specimens treated by either aqueous or anhydrous techniques and resin-embedded were appropriately sectioned and regions of early tendon mineralization were photographed. On the basis of individual photomicrographs, stereoscopic pairs of images, and tomographic three-dimensional image reconstructions, platelet-shaped crystals may be demonstrated for the first time in association with the surface of collagen fibrils. Mineral is also observed in closely parallel arrays within collagen hole and overlap zones. The mineral deposition at these spatially distinct locations in the tendon provides insight into possible means by which calcification is mediated by collagen as a fundamental event in skeletal and dental formation among vertebrates.

[Nasolabial muscle finite-element study and clinical application].

PubMed

Yin, Ningbei; Wu, Jiajun; Chen, Bo; Wang, Yongqian; Song, Tao; Ma, Hengyuan

2015-05-01

To investigate the nasolabial muscle anatomy and biomechanical characteristics. Micro-computed tomography scan was performed in 8 cases of spontaneous abortion fetus lip nasal specimens to construct a three-dimensional model. The nasolabial muscle structure was analyzed using Mimics software. The three-dimensional configuration model of nasolabial muscle was established based on local anatomy and tissue section, and compared with tissue section. Three dimensional finite element analysis was performed on lip nasal muscle related biomechanics and surface deformation in Application verification was carried out in 263 cases of microform cleft lip surgery. There was close relationship between nasolabial muscle. The nasolabial muscle tension system was constituted, based on which a new cleft lip repair surgery was designed and satisfied results were achieved. There is close relationship among nasolabial muscle in anatomy, histology and biomechanics. To obtain better effect, cleft lip repair should be performed on the basis of recovering muscle tension system.

Three-dimensional printing of complex biological structures by freeform reversible embedding of suspended hydrogels

PubMed Central

Hinton, Thomas J.; Jallerat, Quentin; Palchesko, Rachelle N.; Park, Joon Hyung; Grodzicki, Martin S.; Shue, Hao-Jan; Ramadan, Mohamed H.; Hudson, Andrew R.; Feinberg, Adam W.

2015-01-01

We demonstrate the additive manufacturing of complex three-dimensional (3D) biological structures using soft protein and polysaccharide hydrogels that are challenging or impossible to create using traditional fabrication approaches. These structures are built by embedding the printed hydrogel within a secondary hydrogel that serves as a temporary, thermoreversible, and biocompatible support. This process, termed freeform reversible embedding of suspended hydrogels, enables 3D printing of hydrated materials with an elastic modulus <500 kPa including alginate, collagen, and fibrin. Computer-aided design models of 3D optical, computed tomography, and magnetic resonance imaging data were 3D printed at a resolution of ~200 μm and at low cost by leveraging open-source hardware and software tools. Proof-of-concept structures based on femurs, branched coronary arteries, trabeculated embryonic hearts, and human brains were mechanically robust and recreated complex 3D internal and external anatomical architectures. PMID:26601312

Three-dimensional analysis of the microstructure and bio-corrosion of Mg–Zn and Mg–Zn–Ca alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Y.; Chiu, Y.L.; Jones, I.P.

2016-02-15

The effects of the morphology and the distribution of secondary phases on the bio-corrosion properties of magnesium (Mg) alloys are significant. Focused Ion Beam (FIB) tomography and Micro X-Ray computed tomography (Micro-CT) have been used to characterise the morphology and distribution of (α-Mg + MgZn) and (α-Mg + Ca{sub 2} + Mg{sub 6} + Zn{sub 3}) eutectic phase mixtures in as-cast Mg–3Zn and Mg–3Zn–0.3Ca alloys, respectively. There were two different 3D distributions: (i) an interconnected network and (ii) individual spheres. The tomography informed our understanding of the relationship between the distribution of secondary phases and the development of localized corrosionmore » in magnesium alloys. - Highlights: • Multi-scale tomography was used to characterise the morphology and distribution of secondary phases in Mg alloys. • The development of localized corrosion was investigated using tomography. • An improved understanding of the microstructure and corrosion was achieved using Micro-CT tomography.« less

Morphologic evaluation of remnant anterior cruciate ligament bundles after injury with three-dimensional computed tomography.

PubMed

Adachi, Nobuo; Ochi, Mitsuo; Takazawa, Kobun; Ishifuro, Minoru; Deie, Masataka; Nakamae, Atsuo; Kamei, Goki

2016-01-01

This study aimed to investigate the morphological patterns of remnant anterior cruciate ligament bundles after injury (ACL remnant) on three-dimensional computed tomography (3DCT) and compare them with those on arthroscopy. Sixty-three patients (33 males and 30 females; mean age 25.2 ± 10.1 years) who had undergone primary ACL reconstruction between March 2011 and December 2012 were included in this study. The average durations between traumas and 3DCT and between 3DCT and surgery were 101.7 ± 87.2 and 38.2 ± 38.7 days, respectively. ACL remnants were classified into four morphological patterns on 3DCT. 3DCT findings were compared with arthroscopic findings with and without probing. The morphological patterns of the ACL remnants on 3DCT were well matched with those on arthroscopy without probing (the concordance rate was 77.8%). However, the concordance rate was reduced to 49.2% when arthroscopic probing was used to confirm the femoral attachment of ACL remnants (p ≤ 0.05). This study demonstrates that the morphological patterns of ACL remnants on 3DCT were well matched with those on arthroscopy without probing. Therefore, the technique can be useful for preoperative planning of the ACL reconstruction or informed consent to the patients. However, for definitive diagnosis, arthroscopic probing is required. IV.

Quantitative evaluation of maxillary bone deformation by computed tomography in patients with leprosy

PubMed Central

Kondo, Osamu; Suzuki, Koichi; Aoki, Yoshinori; Ishii, Norihisa

2018-01-01

Background Facial deformation as a sequela of leprosy is caused not only by a saddle nose but also by regression of the maxilla, as well documented in paleopathological observations of excavated skeletal remains of patients with leprosy. However, maxillary changes in living patients have been evaluated only by the subjective visual grading. Here, we attempted to evaluate maxillary bone deformation in patients with leprosy using three-dimensional computed tomography (3D-CT). Methods Three-dimensional images centered on the maxilla were reconstructed using multiplanar reconstruction methods in former patients with leprosy (n = 10) and control subjects (n = 5); the anterior-posterior length of the maxilla (MA-P) was then measured. The difference between the MA-P of the patients and those of controls was evaluated after compensating for individual skull size. These findings were also compared with those from previous paleopathological studies. Findings Three former patients with lepromatous leprosy showed marked atrophy of the maxilla at the prosthion (-8.6, -11.1 and -17.9 mm) which corresponded with the visual appearance of the maxillary deformity, and these results were consistent with paleopathological findings of excavated skeletal remains. Additionally, the precise bone defects of the maxilla could be individually calculated for accurate reconstructive surgery. Interpretation We have successfully illustrated maxillary bone deformities in living patients with leprosy. This study also confirmed the maxillary regression described in paleopathological studies. PMID:29522533

Quantitative 3D reconstruction of airway and pulmonary vascular trees using HRCT

NASA Astrophysics Data System (ADS)

Wood, Susan A.; Hoford, John D.; Hoffman, Eric A.; Zerhouni, Elias A.; Mitzner, Wayne A.

1993-07-01

Accurate quantitative measurements of airway and vascular dimensions are essential to evaluate function in the normal and diseased lung. In this report, a novel method is described for three-dimensional extraction and analysis of pulmonary tree structures using data from High Resolution Computed Tomography (HRCT). Serially scanned two-dimensional slices of the lower left lobe of isolated dog lungs were stacked to create a volume of data. Airway and vascular trees were three-dimensionally extracted using a three dimensional seeded region growing algorithm based on difference in CT number between wall and lumen. To obtain quantitative data, we reduced each tree to its central axis. From the central axis, branch length is measured as the distance between two successive branch points, branch angle is measured as the angle produced by two daughter branches, and cross sectional area is measured from a plane perpendicular to the central axis point. Data derived from these methods can be used to localize and quantify structural differences both during changing physiologic conditions and in pathologic lungs.

A micro-CL system and its applications

NASA Astrophysics Data System (ADS)

Wei, Zenghui; Yuan, Lulu; Liu, Baodong; Wei, Cunfeng; Sun, Cuili; Yin, Pengfei; Wei, Long

2017-11-01

The computed laminography (CL) method is preferable to computed tomography for the non-destructive testing of plate-like objects. A micro-CL system is developed for three-dimensional imaging of plate-like objects. The details of the micro-CL system are described, including the system architecture, scanning modes, and reconstruction algorithm. The experiment results of plate-like fossils, insulated gate bipolar translator module, ball grid array packaging, and printed circuit board are also presented to demonstrate micro-CL's ability for 3D imaging of flat specimens and universal applicability in various fields.

A micro-CL system and its applications.

PubMed

Wei, Zenghui; Yuan, Lulu; Liu, Baodong; Wei, Cunfeng; Sun, Cuili; Yin, Pengfei; Wei, Long

2017-11-01

The computed laminography (CL) method is preferable to computed tomography for the non-destructive testing of plate-like objects. A micro-CL system is developed for three-dimensional imaging of plate-like objects. The details of the micro-CL system are described, including the system architecture, scanning modes, and reconstruction algorithm. The experiment results of plate-like fossils, insulated gate bipolar translator module, ball grid array packaging, and printed circuit board are also presented to demonstrate micro-CL's ability for 3D imaging of flat specimens and universal applicability in various fields.

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation.

PubMed

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe; Kim, Tae-Il; Yi, Won-Jin

2015-03-01

We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

Addressing the computational cost of large EIT solutions.

PubMed

Boyle, Alistair; Borsic, Andrea; Adler, Andy

2012-05-01

Electrical impedance tomography (EIT) is a soft field tomography modality based on the application of electric current to a body and measurement of voltages through electrodes at the boundary. The interior conductivity is reconstructed on a discrete representation of the domain using a finite-element method (FEM) mesh and a parametrization of that domain. The reconstruction requires a sequence of numerically intensive calculations. There is strong interest in reducing the cost of these calculations. An improvement in the compute time for current problems would encourage further exploration of computationally challenging problems such as the incorporation of time series data, wide-spread adoption of three-dimensional simulations and correlation of other modalities such as CT and ultrasound. Multicore processors offer an opportunity to reduce EIT computation times but may require some restructuring of the underlying algorithms to maximize the use of available resources. This work profiles two EIT software packages (EIDORS and NDRM) to experimentally determine where the computational costs arise in EIT as problems scale. Sparse matrix solvers, a key component for the FEM forward problem and sensitivity estimates in the inverse problem, are shown to take a considerable portion of the total compute time in these packages. A sparse matrix solver performance measurement tool, Meagre-Crowd, is developed to interface with a variety of solvers and compare their performance over a range of two- and three-dimensional problems of increasing node density. Results show that distributed sparse matrix solvers that operate on multiple cores are advantageous up to a limit that increases as the node density increases. We recommend a selection procedure to find a solver and hardware arrangement matched to the problem and provide guidance and tools to perform that selection.

On-Line Use of Three-Dimensional Marker Trajectory Estimation From Cone-Beam Computed Tomography Projections for Precise Setup in Radiotherapy for Targets With Respiratory Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worm, Esben S., E-mail: esbeworm@rm.dk; Department of Medical Physics, Aarhus University Hospital, Aarhus; Hoyer, Morten

2012-05-01

Purpose: To develop and evaluate accurate and objective on-line patient setup based on a novel semiautomatic technique in which three-dimensional marker trajectories were estimated from two-dimensional cone-beam computed tomography (CBCT) projections. Methods and Materials: Seven treatment courses of stereotactic body radiotherapy for liver tumors were delivered in 21 fractions in total to 6 patients by a linear accelerator. Each patient had two to three gold markers implanted close to the tumors. Before treatment, a CBCT scan with approximately 675 two-dimensional projections was acquired during a full gantry rotation. The marker positions were segmented in each projection. From this, the three-dimensionalmore » marker trajectories were estimated using a probability based method. The required couch shifts for patient setup were calculated from the mean marker positions along the trajectories. A motion phantom moving with known tumor trajectories was used to examine the accuracy of the method. Trajectory-based setup was retrospectively used off-line for the first five treatment courses (15 fractions) and on-line for the last two treatment courses (6 fractions). Automatic marker segmentation was compared with manual segmentation. The trajectory-based setup was compared with setup based on conventional CBCT guidance on the markers (first 15 fractions). Results: Phantom measurements showed that trajectory-based estimation of the mean marker position was accurate within 0.3 mm. The on-line trajectory-based patient setup was performed within approximately 5 minutes. The automatic marker segmentation agreed with manual segmentation within 0.36 {+-} 0.50 pixels (mean {+-} SD; pixel size, 0.26 mm in isocenter). The accuracy of conventional volumetric CBCT guidance was compromised by motion smearing ({<=}21 mm) that induced an absolute three-dimensional setup error of 1.6 {+-} 0.9 mm (maximum, 3.2) relative to trajectory-based setup. Conclusions: The first on-line clinical use of trajectory estimation from CBCT projections for precise setup in stereotactic body radiotherapy was demonstrated. Uncertainty in the conventional CBCT-based setup procedure was eliminated with the new method.« less

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

DTIC Science & Technology

2011-01-01

solution from DI water (or PBS). For the second model, a 5 mm cube of cortical bone tissue was embedded in polymethylmethacrylate and sectioned...radiography1 and as a radiopacifer in polymethylmethacrylate bone cement.2 Current commercial products for either application use microscale BaSO4 particles... polymethylmethacrylate bone cement (Lewis, 1997). The objective of this study was to non-destructively and three-dimensionally image microdamage

Characterizing Multiple Wireless Sensor Networks for Large-Scale Radio Tomography

DTIC Science & Technology

2015-03-01

with other transceivers over a wireless frequency. A base station transceiver collects the information and processes the information into something...or most other obstructions in between the two links [4]. A base station transceiver is connected to a processing computer to collect the RSS of each... transceivers at four different heights to create a Three-Dimensional (3-D) RTI network. Using shadowing- based RTI, this research demonstrated that RTI

Vertical facial height and its correlation with facial width and depth: Three dimensional cone beam computed tomography evaluation based on dry skulls.

PubMed

Wang, Ming Feng; Otsuka, Takero; Akimoto, Susumu; Sato, Sadao

2013-01-01

The aim of the present study was to evaluate how vertical facial height correlates with mandibular plane angle, facial width and depth from a three dimensional (3D) viewing angle. In this study 3D cephalometric landmarks were identified and measurements from 43 randomly selected cone beam computed tomography (CBCT) images of dry skulls from the Weisbach collection of Vienna Natural History Museum were analyzed. Pearson correlation coefficients of facial height measurements and mandibular plane angle and the correlation coefficients of height-width and height-depth were calculated, respectively. The mandibular plane angle (MP-SN) significantly correlated with ramus height (Co-Go) and posterior facial height (PFH) but not with anterior lower face height (ALFH) or anterior total face height (ATFH). The ALFH and ATFH showed significant correlation with anterior cranial base length (S-N), whereas PFH showed significant correlation with the mandible (S-B) and maxilla (S-A) anteroposterior position. High or low mandibular plane angle might not necessarily be accompanied by long or short anterior face height, respectively. The PFH rather than AFH is assumed to play a key role in the vertical facial type whereas AFH seems to undergo relatively intrinsic growth.

Three-dimensional forward solver and its performance analysis for magnetic resonance electrical impedance tomography (MREIT) using recessed electrodes.

PubMed

Lee, Byung Il; Oh, Suk Hoon; Woo, Eung Je; Lee, Soo Yeol; Cho, Min Hyoung; Kwon, Ohin; Seo, Jin Keun; Lee, June-Yub; Baek, Woon Sik

2003-07-07

In magnetic resonance electrical impedance tomography (MREIT), we try to reconstruct a cross-sectional resistivity (or conductivity) image of a subject. When we inject a current through surface electrodes, it generates a magnetic field. Using a magnetic resonance imaging (MRI) scanner, we can obtain the induced magnetic flux density from MR phase images of the subject. We use recessed electrodes to avoid undesirable artefacts near electrodes in measuring magnetic flux densities. An MREIT image reconstruction algorithm produces cross-sectional resistivity images utilizing the measured internal magnetic flux density in addition to boundary voltage data. In order to develop such an image reconstruction algorithm, we need a three-dimensional forward solver. Given injection currents as boundary conditions, the forward solver described in this paper computes voltage and current density distributions using the finite element method (FEM). Then, it calculates the magnetic flux density within the subject using the Biot-Savart law and FEM. The performance of the forward solver is analysed and found to be enough for use in MREIT for resistivity image reconstructions and also experimental designs and validations. The forward solver may find other applications where one needs to compute voltage, current density and magnetic flux density distributions all within a volume conductor.

Three-dimensional airways reconstruction in syndromic pedriatric patients following mandibular distraction osteogenesis.

PubMed

Spinelli, Giuseppe; Agostini, Tommaso; Arcuri, Francesco; Conti, Marco; Raffaini, Mirco

2015-05-01

Airway obstruction, associated with mandibular hypoplasia, is a frequent complication in syndromic pediatric patients. The clinical signs of airway obstruction change from mild positional obstruction to severe respiratory distress with cyanosis. The young age of the patients makes medical management extremely complex. The purpose was to evaluate the success of surgery, evaluating the expansion of the respiratory volumes measured by computer tomography analyzed through a software (SimPlant Pro 15). Twelve patients with mandibular hypoplasia and respiratory distress were treated between December 2010 and December 2013. Eleven of them had tracheostomy in the preoperative period. The goal of surgery was to prevent permanent tracheostomy or to remove it, if present. Volume and surface area increased by an average of 279.2% and 89.4%, respectively. Tracheostomy was avoided in 1 patient who underwent surgery precociously, and it was removed in 10 patients. Only 1 case failed in volume airway augmentation, and tracheostomy was not removed. Computer tomography can calculate the cross-sectional areas of the airway in 3 planes of space: coronal, sagittal, and axial. In most patients, changes in airways have been accompanied by improvements in sleep and breathing, allowing for the removal of tracheostomy with an improved quality of life. Three-dimensional reconstruction of airways revealed a useful tool to better understand the success of surgery. IV.

Soft, hard-tissues and pharyngeal airway volume changes following maxillomandibular transverse osteodistraction: Computed tomography and three-dimensional laser scanner evaluation.

PubMed

Bianchi, Francesca Antonella; Gerbino, Giovanni; Corsico, Marina; Schellino, Eleonora; Barla, Niccolò; Verzè, Laura; Ramieri, Guglielmo

2017-01-01

Maxillomandibular transverse osteodistraction (MMTOD) is an alternative approach to the traditional treatment for transverse maxillary and mandibular deficiencies and crowding. The aim was to report soft and hard-tissues changes and airway volume variation. In this study, skeletally mature, non-syndromic patients with transverse maxillary and mandibular hypoplasia, who underwent a MMTOD between 2010 and 2012, were included. Surgical changes were analysed using clinical evaluation, three-dimensional facial surface data and computed tomography analysis before (T0) and after the completion of post-op orthodontic treatment (T1). Nineteen patients (eight males and eleven females; average age: 26.3 years) were enrolled. MMTOD produces facial changes in the cheek, paranasal areas, nasal base and chin. Facial changes are mostly explained by the underlying skeletal movements, which are essentially represented by the transverse enlargement of both the maxilla and the mandible. Following MMTOD, the airway volume and the lateral dimension of the cross-sectional airway increased significantly. MMTOD is a technique that allows an increase in airway volume and in both maxillary and mandibular arch perimeters simultaneously by increasing skeletal width. Facial appearance is improved and a stable occlusion is obtained. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Three-dimensional visualization of the microvasculature of bile duct ligation-induced liver fibrosis in rats by x-ray phase-contrast imaging computed tomography

NASA Astrophysics Data System (ADS)

Xuan, Ruijiao; Zhao, Xinyan; Hu, Doudou; Jian, Jianbo; Wang, Tailing; Hu, Chunhong

2015-07-01

X-ray phase-contrast imaging (PCI) can substantially enhance contrast, and is particularly useful in differentiating biological soft tissues with small density differences. Combined with computed tomography (CT), PCI-CT enables the acquisition of accurate microstructures inside biological samples. In this study, liver microvasculature was visualized without contrast agents in vitro with PCI-CT using liver fibrosis samples induced by bile duct ligation (BDL) in rats. The histological section examination confirmed the correspondence of CT images with the microvascular morphology of the samples. By means of the PCI-CT and three-dimensional (3D) visualization technique, 3D microvascular structures in samples from different stages of liver fibrosis were clearly revealed. Different types of blood vessels, including portal veins and hepatic veins, in addition to ductular proliferation and bile ducts, could be distinguished with good sensitivity, excellent specificity and excellent accuracy. The study showed that PCI-CT could assess the morphological changes in liver microvasculature that result from fibrosis and allow characterization of the anatomical and pathological features of the microvasculature. With further development of PCI-CT technique, it may become a novel noninvasive imaging technique for the auxiliary analysis of liver fibrosis.

Breast sentinel lymph node navigation with three-dimensional computed tomography-lymphography: a 12-year study.

PubMed

Yamamoto, Shigeru; Suga, Kazuyoshi; Maeda, Kazunari; Maeda, Noriko; Yoshimura, Kiyoshi; Oka, Masaaki

2016-05-01

To evaluate the utility of three-dimensional (3D) computed tomography (CT)-lymphography (LG) breast sentinel lymph node navigation in our institute. Between 2002 and 2013, we preoperatively identified sentinel lymph nodes (SLNs) in 576 clinically node-negative breast cancer patients with T1 and T2 breast cancer using 3D CT-LG method. SLN biopsy (SLNB) was performed in 557 of 576 patients using both the images of 3D CT-LG for guidance and the blue dye method. Using 3D CT-LG, SLNs were visualized in 569 (99%) of 576 patients. Of 569 patients, both lymphatic draining ducts and SLNs from the peritumoral and periareolar areas were visualized in 549 (96%) patients. Only SLNs without lymphatic draining ducts were visualized in 20 patients. Drainage lymphatic pathways visualized with 3D CT-LG (549 cases) were classified into four patterns: single route/single SLN (355 cases, 65%), multiple routes/single SLN (59 cases, 11%) single route/multiple SLNs (62 cases, 11%) and multiple routes/multiple SLNs (73 cases, 13%). SLNs were detected in 556 (99.8%) of 557 patients during SLNB. CT-LG is useful for preoperative visualization of SLNs and breast lymphatic draining routes. This preoperative method should contribute greatly to the easy detection of SLNs during SLNB.

Three-dimensional DNA image cytometry by optical projection tomographic microscopy for early cancer diagnosis.

PubMed

Agarwal, Nitin; Biancardi, Alberto M; Patten, Florence W; Reeves, Anthony P; Seibel, Eric J

2014-04-01

Aneuploidy is typically assessed by flow cytometry (FCM) and image cytometry (ICM). We used optical projection tomographic microscopy (OPTM) for assessing cellular DNA content using absorption and fluorescence stains. OPTM combines some of the attributes of both FCM and ICM and generates isometric high-resolution three-dimensional (3-D) images of single cells. Although the depth of field of the microscope objective was in the submicron range, it was extended by scanning the objective's focal plane. The extended depth of field image is similar to a projection in a conventional x-ray computed tomography. These projections were later reconstructed using computed tomography methods to form a 3-D image. We also present an automated method for 3-D nuclear segmentation. Nuclei of chicken, trout, and triploid trout erythrocyte were used to calibrate OPTM. Ratios of integrated optical densities extracted from 50 images of each standard were compared to ratios of DNA indices from FCM. A comparison of mean square errors with thionin, hematoxylin, Feulgen, and SYTOX green was done. Feulgen technique was preferred as it showed highest stoichiometry, least variance, and preserved nuclear morphology in 3-D. The addition of this quantitative biomarker could further strengthen existing classifiers and improve early diagnosis of cancer using 3-D microscopy.

Evaluation of emphysema using three-dimensional computed tomography: association with postoperative complications in lung cancer patients.

PubMed

Kawakami, Kenichi; Iwano, Shingo; Hashimoto, Naozumi; Hasegawa, Yoshinori; Naganawa, Shinji

2015-02-01

Three-dimensional computed tomography (3D-CT) enables in vivo volumetry of total lung volume (TLV) and emphysematous low-attenuation volume (LAV) in patients with chronic obstructive pulmonary disease (COPD). We retrospectively investigated the correlation between preoperative 3D-CT volumetry and postoperative complications in lung cancer patients. We searched our institution's surgical records from December 2006 to December 2009 and selected patients who had undergone pulmonary lobectomy for primary lung cancer. From 3D-CT data, TLV and LAV <-950 HU of thresholds were retrospectively measured. The LAV% was calculated as follows: LAV% = LAV/TLV*100. The associations between the seven independent variables (LAV%, age, gender, body mass index, smoking history, forced expiratory volume in 1 second as percent forced vital capacity [FEV1%], and resected lobe) and the two outcomes (postoperative complications and prolonged postoperative stay [PPS]) were compared using logistic regression analysis. A total of 309 patients (222 males, 87 females; mean age, 67 years; range, 40-87 years) were evaluated. On multivariate analysis, age and LAV% were significantly correlated with postoperative complications (p = 0.006 and p = 0.006, respectively), and LAV% was significantly correlated with PPS (p = 0.031). LAV% measured using 3D-CT is more sensitive for predicting complications after lobectomy for lung cancer than FEV1%.

Computational adaptive optics for broadband optical interferometric tomography of biological tissue

NASA Astrophysics Data System (ADS)

Boppart, Stephen A.

2015-03-01

High-resolution real-time tomography of biological tissues is important for many areas of biological investigations and medical applications. Cellular level optical tomography, however, has been challenging because of the compromise between transverse imaging resolution and depth-of-field, the system and sample aberrations that may be present, and the low imaging sensitivity deep in scattering tissues. The use of computed optical imaging techniques has the potential to address several of these long-standing limitations and challenges. Two related techniques are interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO). Through three-dimensional Fourierdomain resampling, in combination with high-speed OCT, ISAM can be used to achieve high-resolution in vivo tomography with enhanced depth sensitivity over a depth-of-field extended by more than an order-of-magnitude, in realtime. Subsequently, aberration correction with CAO can be performed in a tomogram, rather than to the optical beam of a broadband optical interferometry system. Based on principles of Fourier optics, aberration correction with CAO is performed on a virtual pupil using Zernike polynomials, offering the potential to augment or even replace the more complicated and expensive adaptive optics hardware with algorithms implemented on a standard desktop computer. Interferometric tomographic reconstructions are characterized with tissue phantoms containing sub-resolution scattering particles, and in both ex vivo and in vivo biological tissue. This review will collectively establish the foundation for high-speed volumetric cellular-level optical interferometric tomography in living tissues.

Comparison of Conventional Versus Spiral Computed Tomography with Three Dimensional Reconstruction in Chronic Otitis Media with Ossicular Chain Destruction.

PubMed

Naghibi, Saeed; Seifirad, Sirous; Adami Dehkordi, Mahboobeh; Einolghozati, Sasan; Ghaffarian Eidgahi Moghadam, Nafiseh; Akhavan Rezayat, Amir; Seifirad, Soroush

2016-01-01

Chronic otitis media (COM) can be treated with tympanoplasty with or without mastoidectomy. In patients who have undergone middle ear surgery, three-dimensional spiral computed tomography (CT) scan plays an important role in optimizing surgical planning. This study was performed to compare the findings of three-dimensional reconstructed spiral and conventional CT scan of ossicular chain study in patients with COM. Fifty patients enrolled in the study underwent plane and three dimensional CT scan (PHILIPS-MX 8000). Ossicles changes, mastoid cavity, tympanic cavity, and presence of cholesteatoma were evaluated. Results of the two methods were then compared and interpreted by a radiologist, recorded in questionnaires, and analyzed. Logistic regression test and Kappa coefficient of agreement were used for statistical analyses. Sixty two ears with COM were found in physical examination. A significant difference was observed between the findings of the two methods in ossicle erosion (11.3% in conventional CT vs. 37.1% in spiral CT, P = 0.0001), decrease of mastoid air cells (82.3% in conventional CT vs. 93.5% in spiral CT, P = 0.001), and tympanic cavity opacity (12.9% in conventional CT vs. 40.3% in spiral CT, P=0.0001). No significant difference was observed between the findings of the two methods in ossicle destruction (6.5% conventional CT vs. 56.4% in spiral CT, P = 0.125), and presence of cholesteatoma (3.2% in conventional CT vs. 42% in spiral CT, P = 0.172). In this study, spiral CT scan demonstrated ossicle dislocation in 9.6%, decrease of mastoid air cells in 4.8%, and decrease of volume in the tympanic cavity in 1.6%; whereas, none of these findings were reported in the patients' conventional CT scans. Spiral-CT scan is superior to conventional CT in the diagnosis of lesions in COM before operation. It can be used for detailed evaluation of ossicular chain in such patients.

Plant light interception can be explained via computed tomography scanning: demonstration with pyramidal cedar (Thuja occidentalis, Fastigiata).

PubMed

Dutilleul, Pierre; Han, Liwen; Smith, Donald L

2008-01-01

Light interception by the leaf canopy is a key aspect of plant photosynthesis, which helps mitigate the greenhouse effect via atmospheric CO(2) recycling. The relationship between plant light interception and leaf area was traditionally modelled with the Beer-Lambert law, until the spatial distribution of leaves was incorporated through the fractal dimension of leafless plant structure photographed from the side allowing maximum appearance of branches and petioles. However, photographs of leafless plants are two-dimensional projections of three-dimensional structures, and sampled plants were cut at the stem base before leaf blades were detached manually, so canopy development could not be followed for individual plants. Therefore, a new measurement and modelling approach were developed to explain plant light interception more completely and precisely, based on appropriate processing of computed tomography (CT) scanning data collected for developing canopies. Three-dimensional images of canopies were constructed from CT scanning data. Leaf volumes (LV) were evaluated from complete canopy images, and fractal dimensions (FD) were estimated from skeletonized leafless images. The experimental plant species is pyramidal cedar (Thuja occidentalis, Fastigiata). The three-dimensional version of the Beer-Lambert law based on FD alone provided a much better explanation of plant light interception (R(2) = 0.858) than those using the product LV*FD (0.589) or LV alone (0.548). While values of all three regressors were found to increase over time, FD in the Beer-Lambert law followed the increase in light interception the most closely. The delayed increase of LV reflected the appearance of new leaves only after branches had lengthened and ramified. The very strong correlation obtained with FD demonstrates that CT scanning data contain fundamental information about the canopy architecture geometry. The model can be used to identify crops and plantation trees with improved light interception and productivity.

Plant Light Interception Can Be Explained via Computed Tomography Scanning: Demonstration with Pyramidal Cedar (Thuja occidentalis, Fastigiata)

PubMed Central

Dutilleul, Pierre; Han, Liwen; Smith, Donald L.

2008-01-01

Background and Aims Light interception by the leaf canopy is a key aspect of plant photosynthesis, which helps mitigate the greenhouse effect via atmospheric CO2 recycling. The relationship between plant light interception and leaf area was traditionally modelled with the Beer–Lambert law, until the spatial distribution of leaves was incorporated through the fractal dimension of leafless plant structure photographed from the side allowing maximum appearance of branches and petioles. However, photographs of leafless plants are two-dimensional projections of three-dimensional structures, and sampled plants were cut at the stem base before leaf blades were detached manually, so canopy development could not be followed for individual plants. Therefore, a new measurement and modelling approach were developed to explain plant light interception more completely and precisely, based on appropriate processing of computed tomography (CT) scanning data collected for developing canopies. Methods Three-dimensional images of canopies were constructed from CT scanning data. Leaf volumes (LV) were evaluated from complete canopy images, and fractal dimensions (FD) were estimated from skeletonized leafless images. The experimental plant species is pyramidal cedar (Thuja occidentalis, Fastigiata). Key Results The three-dimensional version of the Beer–Lambert law based on FD alone provided a much better explanation of plant light interception (R2 = 0·858) than those using the product LV*FD (0·589) or LV alone (0·548). While values of all three regressors were found to increase over time, FD in the Beer–Lambert law followed the increase in light interception the most closely. The delayed increase of LV reflected the appearance of new leaves only after branches had lengthened and ramified. Conclusions The very strong correlation obtained with FD demonstrates that CT scanning data contain fundamental information about the canopy architecture geometry. The model can be used to identify crops and plantation trees with improved light interception and productivity. PMID:17981879

Laser interference fringe tomography: a novel 3D imaging technique for pathology

NASA Astrophysics Data System (ADS)

Kazemzadeh, Farnoud; Haylock, Thomas M.; Chifman, Lev M.; Hajian, Arsen R.; Behr, Bradford B.; Cenko, Andrew T.; Meade, Jeff T.; Hendrikse, Jan

2011-03-01

Laser interference fringe tomography (LIFT) is within the class of optical imaging devices designed for in vivo and ex vivo medical imaging applications. LIFT is a very simple and cost-effective three-dimensional imaging device with performance rivaling some of the leading three-dimensional imaging devices used for histology. Like optical coherence tomography (OCT), it measures the reflectivity as a function of depth within a sample and is capable of producing three-dimensional images from optically scattering media. LIFT has the potential capability to produce high spectral resolution, full-color images. The optical design of LIFT along with the planned iterations for improvements and miniaturization are presented and discussed in addition to the theoretical concepts and preliminary imaging results of the device.

Evaluation of a Multicore-Optimized Implementation for Tomographic Reconstruction

PubMed Central

Agulleiro, Jose-Ignacio; Fernández, José Jesús

2012-01-01

Tomography allows elucidation of the three-dimensional structure of an object from a set of projection images. In life sciences, electron microscope tomography is providing invaluable information about the cell structure at a resolution of a few nanometres. Here, large images are required to combine wide fields of view with high resolution requirements. The computational complexity of the algorithms along with the large image size then turns tomographic reconstruction into a computationally demanding problem. Traditionally, high-performance computing techniques have been applied to cope with such demands on supercomputers, distributed systems and computer clusters. In the last few years, the trend has turned towards graphics processing units (GPUs). Here we present a detailed description and a thorough evaluation of an alternative approach that relies on exploitation of the power available in modern multicore computers. The combination of single-core code optimization, vector processing, multithreading and efficient disk I/O operations succeeds in providing fast tomographic reconstructions on standard computers. The approach turns out to be competitive with the fastest GPU-based solutions thus far. PMID:23139768

Diffuse optical correlation tomography of cerebral blood flow during cortical spreading depression in rat brain

NASA Astrophysics Data System (ADS)

Zhou, Chao; Yu, Guoqiang; Furuya, Daisuke; Greenberg, Joel; Yodh, Arjun; Durduran, Turgut

2006-02-01

Diffuse optical correlation methods were adapted for three-dimensional (3D) tomography of cerebral blood flow (CBF) in small animal models. The image reconstruction was optimized using a noise model for diffuse correlation tomography which enabled better data selection and regularization. The tomographic approach was demonstrated with simulated data and during in-vivo cortical spreading depression (CSD) in rat brain. Three-dimensional images of CBF were obtained through intact skull in tissues(~4mm) deep below the cortex.

Comparison of three-dimensional surface-imaging systems.

PubMed

Tzou, Chieh-Han John; Artner, Nicole M; Pona, Igor; Hold, Alina; Placheta, Eva; Kropatsch, Walter G; Frey, Manfred

2014-04-01

In recent decades, three-dimensional (3D) surface-imaging technologies have gained popularity worldwide, but because most published articles that mention them are technical, clinicians often have difficulties gaining a proper understanding of them. This article aims to provide the reader with relevant information on 3D surface-imaging systems. In it, we compare the most recent technologies to reveal their differences. We have accessed five international companies with the latest technologies in 3D surface-imaging systems: 3dMD, Axisthree, Canfield, Crisalix and Dimensional Imaging (Di3D; in alphabetical order). We evaluated their technical equipment, independent validation studies and corporate backgrounds. The fastest capturing devices are the 3dMD and Di3D systems, capable of capturing images within 1.5 and 1 ms, respectively. All companies provide software for tissue modifications. Additionally, 3dMD, Canfield and Di3D can fuse computed tomography (CT)/cone-beam computed tomography (CBCT) images into their 3D surface-imaging data. 3dMD and Di3D provide 4D capture systems, which allow capturing the movement of a 3D surface over time. Crisalix greatly differs from the other four systems as it is purely web based and realised via cloud computing. 3D surface-imaging systems are becoming important in today's plastic surgical set-ups, taking surgeons to a new level of communication with patients, surgical planning and outcome evaluation. Technologies used in 3D surface-imaging systems and their intended field of application vary within the companies evaluated. Potential users should define their requirements and assignment of 3D surface-imaging systems in their clinical as research environment before making the final decision for purchase. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Extracting three-dimensional orientation and tractography of myofibers using optical coherence tomography

PubMed Central

Gan, Yu; Fleming, Christine P.

2013-01-01

Abnormal changes in orientation of myofibers are associated with various cardiac diseases such as arrhythmia, irregular contraction, and cardiomyopathy. To extract fiber information, we present a method of quantifying fiber orientation and reconstructing three-dimensional tractography of myofibers using optical coherence tomography (OCT). A gradient based algorithm was developed to quantify fiber orientation in three dimensions and particle filtering technique was employed to track myofibers. Prior to image processing, three-dimensional image data set were acquired from all cardiac chambers and ventricular septum of swine hearts using OCT system without optical clearing. The algorithm was validated through rotation test and comparison with manual measurements. The experimental results demonstrate that we are able to visualize three-dimensional fiber tractography in myocardium tissues. PMID:24156071

Simulation of FIB-SEM images for analysis of porous microstructures.

PubMed

Prill, Torben; Schladitz, Katja

2013-01-01

Focused ion beam nanotomography-scanning electron microscopy tomography yields high-quality three-dimensional images of materials microstructures at the nanometer scale combining serial sectioning using a focused ion beam with SEM. However, FIB-SEM tomography of highly porous media leads to shine-through artifacts preventing automatic segmentation of the solid component. We simulate the SEM process in order to generate synthetic FIB-SEM image data for developing and validating segmentation methods. Monte-Carlo techniques yield accurate results, but are too slow for the simulation of FIB-SEM tomography requiring hundreds of SEM images for one dataset alone. Nevertheless, a quasi-analytic description of the specimen and various acceleration techniques, including a track compression algorithm and an acceleration for the simulation of secondary electrons, cut down the computing time by orders of magnitude, allowing for the first time to simulate FIB-SEM tomography. © Wiley Periodicals, Inc.

A novel forward projection-based metal artifact reduction method for flat-detector computed tomography.

PubMed

Prell, Daniel; Kyriakou, Yiannis; Beister, Marcel; Kalender, Willi A

2009-11-07

Metallic implants generate streak-like artifacts in flat-detector computed tomography (FD-CT) reconstructed volumetric images. This study presents a novel method for reducing these disturbing artifacts by inserting discarded information into the original rawdata using a three-step correction procedure and working directly with each detector element. Computation times are minimized by completely implementing the correction process on graphics processing units (GPUs). First, the original volume is corrected using a three-dimensional interpolation scheme in the rawdata domain, followed by a second reconstruction. This metal artifact-reduced volume is then segmented into three materials, i.e. air, soft-tissue and bone, using a threshold-based algorithm. Subsequently, a forward projection of the obtained tissue-class model substitutes the missing or corrupted attenuation values directly for each flat detector element that contains attenuation values corresponding to metal parts, followed by a final reconstruction. Experiments using tissue-equivalent phantoms showed a significant reduction of metal artifacts (deviations of CT values after correction compared to measurements without metallic inserts reduced typically to below 20 HU, differences in image noise to below 5 HU) caused by the implants and no significant resolution losses even in areas close to the inserts. To cover a variety of different cases, cadaver measurements and clinical images in the knee, head and spine region were used to investigate the effectiveness and applicability of our method. A comparison to a three-dimensional interpolation correction showed that the new approach outperformed interpolation schemes. Correction times are minimized, and initial and corrected images are made available at almost the same time (12.7 s for the initial reconstruction, 46.2 s for the final corrected image compared to 114.1 s and 355.1 s on central processing units (CPUs)).

Applied anatomic site study of palatal anchorage implants using cone beam computed tomography.

PubMed

Lai, Ren-fa; Zou, Hui; Kong, Wei-dong; Lin, Wei

2010-06-01

The purpose of this study was to conduct quantitative research on bone height and bone mineral density of palatal implant sites for implantation, and to provide reference sites for safe and stable palatal implants. Three-dimensional reformatting images were reconstructed by cone beam computed tomography (CBCT) in 34 patients, aged 18 to 35 years, using EZ Implant software. Bone height was measured at 20 sites of interest on the palate. Bone mineral density was measured at the 10 sites with the highest implantation rate, classified using K-mean cluster analysis based on bone height and bone mineral density. According to the cluster analysis, 10 sites were classified into three clusters. Significant differences in bone height and bone mineral density were detected between these three clusters (P<0.05). The greatest bone height was obtained in cluster 2, followed by cluster 1 and cluster 3. The highest bone mineral density was found in cluster 3, followed by cluster 1 and cluster 2. CBCT plays an important role in pre-surgical treatment planning. CBCT is helpful in identifying safe and stable implantation sites for palatal anchorage.

Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis.

PubMed

Rai, Arpita; Acharya, Ashith B; Naikmasur, Venkatesh G

2016-01-01

Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Sixty subjects aged 20-85 years were included in the study. For each tooth, mid-sagittal, mid-coronal, and three axial sections-cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root-were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. All statistical analyses were performed using an SPSS 17.0 software program. Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation ( r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level.

Comparison of in vivo 3D cone-beam computed tomography tooth volume measurement protocols.

PubMed

Forst, Darren; Nijjar, Simrit; Flores-Mir, Carlos; Carey, Jason; Secanell, Marc; Lagravere, Manuel

2014-12-23

The objective of this study is to analyze a set of previously developed and proposed image segmentation protocols for precision in both intra- and inter-rater reliability for in vivo tooth volume measurements using cone-beam computed tomography (CBCT) images. Six 3D volume segmentation procedures were proposed and tested for intra- and inter-rater reliability to quantify maxillary first molar volumes. Ten randomly selected maxillary first molars were measured in vivo in random order three times with 10 days separation between measurements. Intra- and inter-rater agreement for all segmentation procedures was attained using intra-class correlation coefficient (ICC). The highest precision was for automated thresholding with manual refinements. A tooth volume measurement protocol for CBCT images employing automated segmentation with manual human refinement on a 2D slice-by-slice basis in all three planes of space possessed excellent intra- and inter-rater reliability. Three-dimensional volume measurements of the entire tooth structure are more precise than 3D volume measurements of only the dental roots apical to the cemento-enamel junction (CEJ).

Computed Tomography Studies of Lung Mechanics

PubMed Central

Simon, Brett A.; Christensen, Gary E.; Low, Daniel A.; Reinhardt, Joseph M.

2005-01-01

The study of lung mechanics has progressed from global descriptions of lung pressure and volume relationships to the high-resolution, three-dimensional, quantitative measurement of dynamic regional mechanical properties and displacements. X-ray computed tomography (CT) imaging is ideally suited to the study of regional lung mechanics in intact subjects because of its high spatial and temporal resolution, correlation of functional data with anatomic detail, increasing volumetric data acquisition, and the unique relationship between CT density and lung air content. This review presents an overview of CT measurement principles and limitations for the study of regional mechanics, reviews some of the early work that set the stage for modern imaging approaches and impacted the understanding and management of patients with acute lung injury, and presents evolving novel approaches for the analysis and application of dynamic volumetric lung image data. PMID:16352757

Comparison of competing segmentation standards for X-ray computed topographic imaging using Lattice Boltzmann techniques

NASA Astrophysics Data System (ADS)

Larsen, J. D.; Schaap, M. G.

2013-12-01

Recent advances in computing technology and experimental techniques have made it possible to observe and characterize fluid dynamics at the micro-scale. Many computational methods exist that can adequately simulate fluid flow in porous media. Lattice Boltzmann methods provide the distinct advantage of tracking particles at the microscopic level and returning macroscopic observations. While experimental methods can accurately measure macroscopic fluid dynamics, computational efforts can be used to predict and gain insight into fluid dynamics by utilizing thin sections or computed micro-tomography (CMT) images of core sections. Although substantial effort have been made to advance non-invasive imaging methods such as CMT, fluid dynamics simulations, and microscale analysis, a true three dimensional image segmentation technique has not been developed until recently. Many competing segmentation techniques are utilized in industry and research settings with varying results. In this study lattice Boltzmann method is used to simulate stokes flow in a macroporous soil column. Two dimensional CMT images were used to reconstruct a three dimensional representation of the original sample. Six competing segmentation standards were used to binarize the CMT volumes which provide distinction between solid phase and pore space. The permeability of the reconstructed samples was calculated, with Darcy's Law, from lattice Boltzmann simulations of fluid flow in the samples. We compare simulated permeability from differing segmentation algorithms to experimental findings.

Electrical Capacitance Volume Tomography: Design and Applications

PubMed Central

Wang, Fei; Marashdeh, Qussai; Fan, Liang-Shih; Warsito, Warsito

2010-01-01

This article reports recent advances and progress in the field of electrical capacitance volume tomography (ECVT). ECVT, developed from the two-dimensional electrical capacitance tomography (ECT), is a promising non-intrusive imaging technology that can provide real-time three-dimensional images of the sensing domain. Images are reconstructed from capacitance measurements acquired by electrodes placed on the outside boundary of the testing vessel. In this article, a review of progress on capacitance sensor design and applications to multi-phase flows is presented. The sensor shape, electrode configuration, and the number of electrodes that comprise three key elements of three-dimensional capacitance sensors are illustrated. The article also highlights applications of ECVT sensors on vessels of various sizes from 1 to 60 inches with complex geometries. Case studies are used to show the capability and validity of ECVT. The studies provide qualitative and quantitative real-time three-dimensional information of the measuring domain under study. Advantages of ECVT render it a favorable tool to be utilized for industrial applications and fundamental multi-phase flow research. PMID:22294905

The virtual craniofacial patient: 3D jaw modeling and animation.

PubMed

Enciso, Reyes; Memon, Ahmed; Fidaleo, Douglas A; Neumann, Ulrich; Mah, James

2003-01-01

In this paper, we present new developments in the area of 3D human jaw modeling and animation. CT (Computed Tomography) scans have traditionally been used to evaluate patients with dental implants, assess tumors, cysts, fractures and surgical procedures. More recently this data has been utilized to generate models. Researchers have reported semi-automatic techniques to segment and model the human jaw from CT images and manually segment the jaw from MRI images. Recently opto-electronic and ultrasonic-based systems (JMA from Zebris) have been developed to record mandibular position and movement. In this research project we introduce: (1) automatic patient-specific three-dimensional jaw modeling from CT data and (2) three-dimensional jaw motion simulation using jaw tracking data from the JMA system (Zebris).

Growth oscillation in larger foraminifera.

PubMed

Briguglio, Antonino; Hohenegger, Johann

2014-01-01

This work shows the potential for applying three-dimensional biometry to studying cell growth in larger benthic foraminifera. The volume of each test chamber was measured from the three-dimensional model obtained by means of computed tomography. Analyses of cell growth based on the sequence of chamber volumes revealed constant and significant oscillations for all investigated specimens, characterized by periods of approximately 15, 30, 90, and 360 days. Possible explanations for these periods are connected to tides, lunar cycles, and seasonality. The potential to record environmental oscillations or fluctuations during the lifetime of larger foraminifera is pivotal for reconstructing short-term paleoenvironmental variations or for gaining insight into the influence of tides or tidal current on the shallow-water benthic fauna in both recent and fossil environments.

Reconstruction of a three-dimensional, transonic rotor flow field from holographic interferogram data

NASA Technical Reports Server (NTRS)

Kittleson, John K.; Yu, Yung H.

1987-01-01

Holographic interferometry and computerized aided tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia view field near the model rotor blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting the fringe order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in several planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three dimensional transonic rotor flow studies.

Assessment of Myocardial Infarct Size by Three-Dimensional and Two-Dimensional Speckle Tracking Echocardiography: A Comparative Study to Single Photon Emission Computed Tomography.

PubMed

Wang, Qiushuang; Huang, Dangsheng; Zhang, Liwei; Shen, Dong; Ouyang, Qiaohong; Duan, Zhongxiang; An, Xiuzhi; Zhang, Meiqing; Zhang, Chunhong; Yang, Feifei; Zhi, Guang

2015-10-01

To compare three-dimensional (3D) and two-dimensional (2D) speckle tracking echocardiography (STE) techniques in the assessment of left ventricular function and myocardial infarct size (MIS). Thirty-two patients diagnosed with ST elevation myocardial infarction and 18 healthy control patients underwent 2D echocardiography, 3D echocardiography, and single photon emission computed tomography (SPECT). 3D left ventricular global area strain (GAS), 2D and 3D global longitudinal strain (GLS), global radial strain (GRS) as well as global circumferential strain (GCS) were analyzed to correlate with myocardial infarct size detected by SPECT. 2D and 3D left ventricular ejection fraction (LVEF) as well as 2D and 3D wall motion score index (WMSI) also were measured using conventional echocardiography. The 2D-GLS values were significantly higher than that of 3D-GLS, while 2D-GCS and GRS were significantly lower than 3D-GCS and GRS, respectively. However, no significant differences in LVEF and WMSI could be observed between 2D and 3D echocardiography. Myocardial strain indices, LVEF, and WMSI using 2D and 3D echocardiography also had good correlations with MIS as measured by SPECT. ROC curve analysis showed that the 3D and 2D myocardial indices, LVEF, and WMSI could distinguish between small and large MIS, while 2D-GLS had the highest AUC. The 2D and 3D myocardial strain indices correlated well with MIS by SPECT. Among them, the 2D-GLS showed the highest diagnostic value, while 3D-GRS and GCS had better diagnostic value than 2D-GRS and GCS. © 2015, Wiley Periodicals, Inc.

Multidetector Computed Tomography for Congenital Anomalies of the Aortic Arch: Vascular Rings.

PubMed

García-Guereta, Luis; García-Cerro, Estefanía; Bret-Zurita, Montserrat

2016-07-01

The development of multidetector computed tomography has triggered a revolution in the study of the aorta and other large vessels and has replaced angiography in the diagnosis of congenital anomalies of the aortic arch, particularly vascular rings. The major advantage of multidetector computed tomography is that it permits clear 3-dimensional assessment of not only vascular structures, but also airway and esophageal compression. The current update aims to summarize the embryonic development of the aortic arch and the developmental anomalies leading to vascular ring formation and to discuss the current diagnostic and therapeutic role of multidetector computed tomography in this field. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Reconstruction of a Three-Dimensional Transonic Rotor Flow Field from Holographical Interferogram Data.

DTIC Science & Technology

1985-03-01

interferometry and computer- R - spanwise coordinate, ft assisted tomography ( CAT ) are used to determine the transonic velocity field of a model rotor...and extracting fringe-order functions, the c data are transferred to a CAT code.- The CAT code Ui transmitted wave complex amplitude then calculates...the perturbation velocity in sev- eral planes above the blade surface. The values Ur reference wave complex amplitude from the holography- CAT method

Recent advances in electron tomography: TEM and HAADF-STEM tomography for materials science and semiconductor applications.

PubMed

Kübel, Christian; Voigt, Andreas; Schoenmakers, Remco; Otten, Max; Su, David; Lee, Tan-Chen; Carlsson, Anna; Bradley, John

2005-10-01

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1-2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

Cranioplasty Enhanced by Three-Dimensional Printing: Custom-Made Three-Dimensional-Printed Titanium Implants for Skull Defects.

PubMed

Park, Eun-Kyung; Lim, Jun-Young; Yun, In-Sik; Kim, Ju-Seong; Woo, Su-Heon; Kim, Dong-Seok; Shim, Kyu-Won

2016-06-01

The authors studied to demonstrate the efficacy of custom-made three-dimensional (3D)-printed titanium implants for reconstructing skull defects. From 2013 to 2015, 21 patients (8-62 years old, mean = 28.6-year old; 11 females and 10 males) with skull defects were treated. Total disease duration ranged from 6 to 168 months (mean = 33.6 months). The size of skull defects ranged from 84 × 104 to 154 × 193 mm. Custom-made implants were manufactured by Medyssey Co, Ltd (Jecheon, South Korea) using 3D computed tomography data, Mimics software, and an electron beam melting machine. The team reviewed several different designs and simulated surgery using a 3D skull model. During the operation, the implant was fit to the defect without dead space. Operation times ranged from 85 to 180 minutes (mean = 115.7 minutes). Operative sites healed without any complications except for 1 patient who had red swelling with exudation at the skin defect, which was a skin infection and defect at the center of the scalp flap reoccurring since the initial head injury. This patient underwent reoperation for skin defect revision and replacement of the implant. Twenty-one patients were followed for 6 to 24 months (mean = 14.1 months). The patients were satisfied and had no recurrent wound problems. Head computed tomography after operation showed good fixation of titanium implants and satisfactory skull-shape symmetry. For the reconstruction of skull defects, the use of autologous bone grafts has been the treatment of choice. However, bone use depends on availability, defect size, and donor morbidity. As 3D printing techniques are further advanced, it is becoming possible to manufacture custom-made 3D titanium implants for skull reconstruction.

A fully 3D approach for metal artifact reduction in computed tomography.

PubMed

Kratz, Barbel; Weyers, Imke; Buzug, Thorsten M

2012-11-01

In computed tomography imaging metal objects in the region of interest introduce inconsistencies during data acquisition. Reconstructing these data leads to an image in spatial domain including star-shaped or stripe-like artifacts. In order to enhance the quality of the resulting image the influence of the metal objects can be reduced. Here, a metal artifact reduction (MAR) approach is proposed that is based on a recomputation of the inconsistent projection data using a fully three-dimensional Fourier-based interpolation. The success of the projection space restoration depends sensitively on a sensible continuation of neighboring structures into the recomputed area. Fortunately, structural information of the entire data is inherently included in the Fourier space of the data. This can be used for a reasonable recomputation of the inconsistent projection data. The key step of the proposed MAR strategy is the recomputation of the inconsistent projection data based on an interpolation using nonequispaced fast Fourier transforms (NFFT). The NFFT interpolation can be applied in arbitrary dimension. The approach overcomes the problem of adequate neighborhood definitions on irregular grids, since this is inherently given through the usage of higher dimensional Fourier transforms. Here, applications up to the third interpolation dimension are presented and validated. Furthermore, prior knowledge may be included by an appropriate damping of the transform during the interpolation step. This MAR method is applicable on each angular view of a detector row, on two-dimensional projection data as well as on three-dimensional projection data, e.g., a set of sequential acquisitions at different spatial positions, projection data of a spiral acquisition, or cone-beam projection data. Results of the novel MAR scheme based on one-, two-, and three-dimensional NFFT interpolations are presented. All results are compared in projection data space and spatial domain with the well-known one-dimensional linear interpolation strategy. In conclusion, it is recommended to include as much spatial information into the recomputation step as possible. This is realized by increasing the dimension of the NFFT. The resulting image quality can be enhanced considerably.

[Diagnostic possibilities of digital volume tomography].

PubMed

Lemkamp, Michael; Filippi, Andreas; Berndt, Dorothea; Lambrecht, J Thomas

2006-01-01

Cone beam computed tomography allows high quality 3D images of cranio-facial structures. Although detail resolution is increased, x-ray exposition is reduced compared to classic computer tomography. The volume is analysed in three orthogonal plains, which can be rotated independently without quality loss. Cone beam computed tomography seems to be a less expensive and less x-ray exposing alternative to classic computer tomography.

Differentiation of Benign and Malignant Breast Tumors by In-Vivo Three-Dimensional Parallel-Plate Diffuse Optical Tomography

PubMed Central

Choe, Regine; Konecky, Soren D.; Corlu, Alper; Lee, Kijoon; Durduran, Turgut; Busch, David R.; Pathak, Saurav; Czerniecki, Brian J.; Tchou, Julia; Fraker, Douglas L.; DeMichele, Angela; Chance, Britton; Arridge, Simon R.; Schweiger, Martin; Culver, Joseph P.; Schnall, Mitchell D.; Putt, Mary E.; Rosen, Mark A.; Yodh, Arjun G.

2009-01-01

We have developed a novel parallel-plate diffuse optical tomography (DOT) system for three-dimensional in vivo imaging of human breast tumor based on large optical data sets. Images of oxy-, deoxy-, total-hemoglobin concentration, blood oxygen saturation, and tissue scattering were reconstructed. Tumor margins were derived using the optical data with guidance from radiology reports and Magnetic Resonance Imaging. Tumor-to-normal ratios of these endogenous physiological parameters and an optical index were computed for 51 biopsy-proven lesions from 47 subjects. Malignant cancers (N=41) showed statistically significant higher total hemoglobin, oxy-hemoglobin concentration, and scattering compared to normal tissue. Furthermore, malignant lesions exhibited a two-fold average increase in optical index. The influence of core biopsy on DOT results was also explored; the difference between the malignant group measured before core biopsy and the group measured more than one week after core biopsy was not significant. Benign tumors (N=10) did not exhibit statistical significance in the tumor-to-normal ratios of any parameter. Optical index and tumor-to-normal ratios of total hemoglobin, oxy-hemoglobin concentration, and scattering exhibited high area under the receiver operating characteristic curve values from 0.90 to 0.99, suggesting good discriminatory power. The data demonstrate that benign and malignant lesions can be distinguished by quantitative three-dimensional DOT. PMID:19405750

3D visualization of Thoraco-Lumbar Spinal Lesions in German Shepherd Dog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azpiroz, J.; Krafft, J.; Cadena, M.

2006-09-08

Computed tomography (CT) has been found to be an excellent imaging modality due to its sensitivity to characterize the morphology of the spine in dogs. This technique is considered to be particularly helpful for diagnosing spinal cord atrophy and spinal stenosis. The three-dimensional visualization of organs and bones can significantly improve the diagnosis of certain diseases in dogs. CT images were acquired of a German shepherd's dog spinal cord to generate stacks and digitally process them to arrange them in a volume image. All imaging experiments were acquired using standard clinical protocols on a clinical CT scanner. The three-dimensional visualizationmore » allowed us to observe anatomical structures that otherwise are not possible to observe with two-dimensional images. The combination of an imaging modality like CT together with imaging processing techniques can be a powerful tool for the diagnosis of a number of animal diseases.« less

From tissue to silicon to plastic: three-dimensional printing in comparative anatomy and physiology

PubMed Central

Lauridsen, Henrik; Hansen, Kasper; Nørgård, Mathias Ørum; Wang, Tobias; Pedersen, Michael

2016-01-01

Comparative anatomy and physiology are disciplines related to structures and mechanisms in three-dimensional (3D) space. For the past centuries, scientific reports in these fields have relied on written descriptions and two-dimensional (2D) illustrations, but in recent years 3D virtual modelling has entered the scene. However, comprehending complex anatomical structures is hampered by reproduction on flat inherently 2D screens. One way to circumvent this problem is in the production of 3D-printed scale models. We have applied computed tomography and magnetic resonance imaging to produce digital models of animal anatomy well suited to be printed on low-cost 3D printers. In this communication, we report how to apply such technology in comparative anatomy and physiology to aid discovery, description, comprehension and communication, and we seek to inspire fellow researchers in these fields to embrace this emerging technology. PMID:27069653

A Three-Dimensional Mediastinal Model Created with Rapid Prototyping in a Patient with Ectopic Thymoma

PubMed Central

Nakada, Takeo; Inagaki, Takuya

2014-01-01

Preoperative three-dimensional (3D) imaging of a mediastinal tumor using two-dimensional (2D) axial computed tomography is sometimes difficult, and an unexpected appearance of the tumor may be encountered during surgery. In order to evaluate the preoperative feasibility of a 3D mediastinal model that used the rapid prototyping technique, we created a model and report its results. The 2D image showed some of the relationship between the tumor and the pericardium, but the 3D mediastinal model that was created using the rapid prototyping technique showed the 3D lesion in the outer side of the extrapericardium. The patient underwent a thoracoscopic resection of the tumor, and the pathological examination showed a rare middle mediastinal ectopic thymoma. We believe that the construction of mediastinal models is useful for thoracoscopic surgery and other complicated surgeries of the chest diseases. PMID:24633133

A three-dimensional mediastinal model created with rapid prototyping in a patient with ectopic thymoma.

PubMed

Akiba, Tadashi; Nakada, Takeo; Inagaki, Takuya

2015-01-01

Preoperative three-dimensional (3D) imaging of a mediastinal tumor using two-dimensional (2D) axial computed tomography is sometimes difficult, and an unexpected appearance of the tumor may be encountered during surgery. In order to evaluate the preoperative feasibility of a 3D mediastinal model that used the rapid prototyping technique, we created a model and report its results. The 2D image showed some of the relationship between the tumor and the pericardium, but the 3D mediastinal model that was created using the rapid prototyping technique showed the 3D lesion in the outer side of the extrapericardium. The patient underwent a thoracoscopic resection of the tumor, and the pathological examination showed a rare middle mediastinal ectopic thymoma. We believe that the construction of mediastinal models is useful for thoracoscopic surgery and other complicated surgeries of the chest diseases.

3D visualization of Thoraco-Lumbar Spinal Lesions in German Shepherd Dog

NASA Astrophysics Data System (ADS)

Azpiroz, J.; Krafft, J.; Cadena, M.; Rodríguez, A. O.

2006-09-01

Computed tomography (CT) has been found to be an excellent imaging modality due to its sensitivity to characterize the morphology of the spine in dogs. This technique is considered to be particularly helpful for diagnosing spinal cord atrophy and spinal stenosis. The three-dimensional visualization of organs and bones can significantly improve the diagnosis of certain diseases in dogs. CT images were acquired of a German shepherd's dog spinal cord to generate stacks and digitally process them to arrange them in a volume image. All imaging experiments were acquired using standard clinical protocols on a clinical CT scanner. The three-dimensional visualization allowed us to observe anatomical structures that otherwise are not possible to observe with two-dimensional images. The combination of an imaging modality like CT together with imaging processing techniques can be a powerful tool for the diagnosis of a number of animal diseases.

Single-lens computed tomography imaging spectrometer and method of capturing spatial and spectral information

NASA Technical Reports Server (NTRS)

Wilson, Daniel W. (Inventor); Johnson, William R. (Inventor); Bearman, Gregory H. (Inventor)

2011-01-01

Computed tomography imaging spectrometers ("CTISs") employing a single lens are provided. The CTISs may be either transmissive or reflective, and the single lens is either configured to transmit and receive uncollimated light (in transmissive systems), or is configured to reflect and receive uncollimated light (in reflective systems). An exemplary transmissive CTIS includes a focal plane array detector, a single lens configured to transmit and receive uncollimated light, a two-dimensional grating, and a field stop aperture. An exemplary reflective CTIS includes a focal plane array detector, a single mirror configured to reflect and receive uncollimated light, a two-dimensional grating, and a field stop aperture.

Three-dimensional structural dynamics and fluctuations of DNA-nanogold conjugates by individual-particle electron tomography

NASA Astrophysics Data System (ADS)

Zhang, Lei; Lei, Dongsheng; Smith, Jessica M.; Zhang, Meng; Tong, Huimin; Zhang, Xing; Lu, Zhuoyang; Liu, Jiankang; Alivisatos, A. Paul; Ren, Gang

2016-03-01

DNA base pairing has been used for many years to direct the arrangement of inorganic nanocrystals into small groupings and arrays with tailored optical and electrical properties. The control of DNA-mediated assembly depends crucially on a better understanding of three-dimensional structure of DNA-nanocrystal-hybridized building blocks. Existing techniques do not allow for structural determination of these flexible and heterogeneous samples. Here we report cryo-electron microscopy and negative-staining electron tomography approaches to image, and three-dimensionally reconstruct a single DNA-nanogold conjugate, an 84-bp double-stranded DNA with two 5-nm nanogold particles for potential substrates in plasmon-coupling experiments. By individual-particle electron tomography reconstruction, we obtain 14 density maps at ~2-nm resolution. Using these maps as constraints, we derive 14 conformations of dsDNA by molecular dynamics simulations. The conformational variation is consistent with that from liquid solution, suggesting that individual-particle electron tomography could be an expected approach to study DNA-assembling and flexible protein structure and dynamics.

The structure of gallery networks in the nests of termite Cubitermes spp. revealed by X-ray tomography

NASA Astrophysics Data System (ADS)

Perna, Andrea; Jost, Christian; Couturier, Etienne; Valverde, Sergi; Douady, Stéphane; Theraulaz, Guy

2008-09-01

Recent studies have introduced computer tomography (CT) as a tool for the visualisation and characterisation of insect architectures. Here, we use CT to map the three-dimensional networks of galleries inside Cubitermes nests in order to analyse them with tools from graph theory. The structure of these networks indicates that connections inside the nest are rearranged during the whole nest life. The functional analysis reveals that the final network topology represents an excellent compromise between efficient connectivity inside the nest and defence against attacking predators. We further discuss and illustrate the usefulness of CT to disentangle environmental and specific influences on nest architecture.

Computer tomographic assessment of postoperative peripancreatic collections after distal pancreatectomy.

PubMed

Uchida, Yuichiro; Masui, Toshihiko; Sato, Asahi; Nagai, Kazuyuki; Anazawa, Takayuki; Takaori, Kyoichi; Uemoto, Shinji

2018-03-27

Peripancreatic collections occur frequently after distal pancreatectomy. However, the sequelae of peripancreatic collections vary from case to case, and their clinical impact is uncertain. In this study, the correlations between CT findings of peripancreatic collections and complications after distal pancreatectomy were investigated. Ninety-six consecutive patients who had undergone distal pancreatectomy between 2010 and 2015 were retrospectively investigated. The extent and heterogeneity of peripancreatic collections and background clinicopathological characteristics were analyzed. The extent of peripancreatic collections was calculated based on three-dimensional computed tomography images, and the degree of heterogeneity of peripancreatic collections was assessed based on the standard deviation of their density on computed tomography. Of 85 patients who underwent postoperative computed tomography imaging, a peripancreatic collection was detected in 77 (91%). Patients with either a large extent or a high degree of heterogeneity of peripancreatic collection had a significantly higher rate of clinically relevant pancreatic fistula than those without (odds ratio 5.95, 95% confidence interval 2.12-19.72, p = 0.001; odds ratio 8.0, 95% confidence interval 2.87-24.19, p = 0.0001, respectively). A large and heterogeneous peripancreatic collection was significantly associated with postoperative complications, especially clinically relevant postoperative pancreatic fistula. A small and homogenous peripancreatic collection could be safely observed.

The application of X-ray microtomography for the assessement of root resorption caused by the orthodontic treatment of premolars.

PubMed

Sawicka, Monika; Bedini, Rossella; Pecci, Raffaella; Pameijer, Cornelis Hans; Kmiec, Zbigniew

2012-01-01

The purpose of this study was to demonstrate potential application of micro-computed tomography in the morphometric analysis of the root resorption in extracted human first premolars subjected to the orthodontic force. In one patient treated in the orthodontic clinic two mandibular first premolars subjected to orthodontic force for 4 weeks and one control tooth were selected for micro-computed tomographic analysis. The hardware device used in this study was a desktop X-ray microfocus CT scanner (SkyScan 1072). The morphology of root's surfaces was assessed by TView and Computer Tomography Analyzer (CTAn) softwares (SkyScan, bvba) which allowed analysis of all microscans, identification of root resorption craters and measurement of their length, width and volume. Microscans showed in details the surface morphology of the investigated teeth. The analysis of microscans allowed to detect 3 root resorption cavities in each of the orthodontically moved tooth and only one resorption crater in the control tooth. The volumes of the resorption craters in orthodontically-treated teeth were much larger than in a control tooth. Micro-computed tomography is a reproducible technique for the three-dimensional non-invasive assessment of root's morphology ex vivo. TView and CTan softwares are useful in accurate morphometric measurements of root's resorption.

Three dimensional morphological studies of Larger Benthic Foraminifera at the population level using micro computed tomography

NASA Astrophysics Data System (ADS)

Kinoshita, Shunichi; Eder, Wolfgang; Woeger, Julia; Hohenegger, Johann; Briguglio, Antonino; Ferrandez-Canadell, Carles

2015-04-01

Symbiont-bearing larger benthic Foraminifera (LBF) are long-living marine (at least 1 year), single-celled organisms with complex calcium carbonate shells. Their morphology has been intensively studied since the middle of the nineteenth century. This led to a broad spectrum of taxonomic results, important from biostratigraphy to ecology in shallow water tropical to warm temperate marine palaeo-environments. However, it was necessary for the traditional investigation methods to cut or destruct specimens for analysing the taxonomically important inner structures. X-ray micro-computed tomography (microCT) is one of the newest techniques used in morphological studies. The greatest advantage is the non-destructive acquisition of inner structures. Furthermore, the running improve of microCT scanners' hard- and software provides high resolution and short time scans well-suited for LBF. Three-dimensional imaging techniques allow to select and extract each chamber and to measure easily its volume, surface and several form parameters used for morphometric analyses. Thus, 3-dimensional visualisation of LBF-tests is a very big step forward from traditional morphology based on 2-dimensional data. The quantification of chamber form is a great opportunity to tackle LBF structures, architectures and the bauplan geometry. The micrometric digital resolution is the only way to solve many controversies in phylogeny and evolutionary trends of LBF. For the present study we used micro-computed tomography to easily investigate the chamber number of every specimen from statistically representative part of populations to estimate population dynamics. Samples of living individuals are collected at monthly intervals from fixed locations. Specific preparation allows to scan up to 35 specimens per scan within 2 hours and to obtain the complete digital dataset for each specimen of the population. MicroCT enables thus a fast and precise count of all chambers built by the foraminifer from its birth until the time of collection and to extract selected chambers for further studies. The variation in chamber number during the sampling period (in this study limited at 15 months) will allow the estimation of the mean chamber building rate for each investigated species. However, a number of morphological aberrations within the population can be observed: often multiple proloculi are present; their orientation to the equatorial plane (or planes) respectively the spatial position of the foramina between proloculus (or proloculi) to the reniform deuteroloculi, the geometry of septa and septula and their variation trough ontogeny and several other ontogenetic variation need further attention. Many new insights into the biology of living and fossil LBF will be obtained when the three dimensional morphology of the complete foraminiferal shell is raised to the population level.

Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

2003-01-01

Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans and the experimental data. Furthermore, modeling of the voids collected via NDE offered an analytical advantage that resulted in more accurate assessments of the material s structural strength. The top figure shows a CT scan image of the specimen test section illustrating various hidden structural entities in the material and an optical image of the test specimen considered in this study. The bottom figure represents the stress response predicted from the finite element analyses (ref .3 ) for a selected CT slice where it clearly illustrates the correspondence of the high stress risers due to voids in the material with those predicted by the NDE. This study is continuing, and efforts are concentrated on improving the modeling capabilities to imitate the structural anomalies as detected.

Role of virtual bronchoscopy in children with a vegetable foreign body in the tracheobronchial tree.

PubMed

Behera, G; Tripathy, N; Maru, Y K; Mundra, R K; Gupta, Y; Lodha, M

2014-12-01

Multidetector computed tomography virtual bronchoscopy is a non-invasive diagnostic tool which provides a three-dimensional view of the tracheobronchial airway. This study aimed to evaluate the usefulness of virtual bronchoscopy in cases of vegetable foreign body aspiration in children. The medical records of patients with a history of foreign body aspiration from August 2006 to August 2010 were reviewed. Data were collected regarding their clinical presentation and chest X-ray, virtual bronchoscopy and rigid bronchoscopy findings. Cases of metallic and other non-vegetable foreign bodies were excluded from the analysis. Patients with multidetector computed tomography virtual bronchoscopy showing features of vegetable foreign body were included in the analysis. For each patient, virtual bronchoscopy findings were reviewed and compared with those of rigid bronchoscopy. A total of 60 patients; all children ranging from 1 month to 8 years of age, were included. The mean age at presentation was 2.01 years. Rigid bronchoscopy confirmed the results of multidetector computed tomography virtual bronchoscopy (i.e. presence of foreign body, site of lodgement, and size and shape) in 59 patients. In the remaining case, a vegetable foreign body identified by virtual bronchoscopy was revealed by rigid bronchoscopy to be a thick mucus plug. Thus, the positive predictive value of virtual bronchoscopy was 98.3 per cent. Multidetector computed tomography virtual bronchoscopy is a sensitive and specific diagnostic tool for identifying radiolucent vegetable foreign bodies in the tracheobronchial tree. It can also provide a useful pre-operative road map for rigid bronchoscopy. Patients suspected of having an airway foreign body or chronic unexplained respiratory symptoms should undergo multidetector computed tomography virtual bronchoscopy to rule out a vegetable foreign body in the tracheobronchial tree and avoid general anaesthesia and invasive rigid bronchoscopy.

Rapid prototyping to design a customized locking plate for pancarpal arthrodesis in a giant breed dog.

PubMed

Petazzoni, M; Nicetto, T

2014-01-01

This report describes the treatment of traumatic carpal hyperextension in a giant breed dog by pancarpal arthrodesis using a custom-made Fixin locking plate, created with the aid of a three-dimensional plastic model of the bones of the antebrachium produced by rapid prototyping technology. A three-year-old 104 kg male Mastiff dog was admitted for treatment of carpal hyperextension injury. After diagnosis of carpal instability, surgery was recommended. Computed tomography images were used to create a life-size three-dimensional plastic model of the forelimb. The model was used as the basis for constructing a customized 12-hole Fixin locking plate. The plate was used to attain successful pancarpal arthrodesis in the animal. Radiographic examination after 74 and 140 days revealed signs of osseous union of the arthrodesis. Further clinical and radiographic follow-up examination three years later did not reveal any changes in implant position or complications.

Femoral articular shape and geometry. A three-dimensional computerized analysis of the knee.

PubMed

Siu, D; Rudan, J; Wevers, H W; Griffiths, P

1996-02-01

An average, three-dimensional anatomic shape and geometry of the distal femur were generated from x-ray computed tomography data of five fresh asymptomatic cadaver knees using AutoCAD (AutoDesk, Sausalito, CA), a computer-aided design and drafting software. Each femur model was graphically repositioned to a standardized orientation using a series of alignment templates and scaled to a nominal size of 85 mm in mediolateral and 73 mm in anteroposterior dimensions. An average generic shape of the distal femur was synthesized by combining these pseudosolid models and reslicing the composite structure at different elevations using clipping and smoothing techniques in interactive computer graphics. The resulting distal femoral geometry was imported into a computer-aided manufacturing system, and anatomic prototypes of the distal femur were produced. Quantitative geometric analyses of the generic femur in the coronal and transverse planes revealed definite condylar camber (3 degrees-6 degrees) and toe-in (8 degrees-10 degrees) with an oblique patellofemoral groove (15 degrees) with respect to the mechanical axis of the femur. In the sagittal plane, each condyle could be approximated by three concatenated circular arcs (anterior, distal, and posterior) with slope continuity and a single arc for the patellofemoral groove. The results of this study may have important implications in future femoral prosthesis design and clinical applications.

A simulation-based study on the influence of beam hardening in X-ray computed tomography for dimensional metrology.

PubMed

Lifton, Joseph J; Malcolm, Andrew A; McBride, John W

2015-01-01

X-ray computed tomography (CT) is a radiographic scanning technique for visualising cross-sectional images of an object non-destructively. From these cross-sectional images it is possible to evaluate internal dimensional features of a workpiece which may otherwise be inaccessible to tactile and optical instruments. Beam hardening is a physical process that degrades the quality of CT images and has previously been suggested to influence dimensional measurements. Using a validated simulation tool, the influence of spectrum pre-filtration and beam hardening correction are evaluated for internal and external dimensional measurements. Beam hardening is shown to influence internal and external dimensions in opposition, and to have a greater influence on outer dimensions compared to inner dimensions. The results suggest the combination of spectrum pre-filtration and a local gradient-based surface determination method are able to greatly reduce the influence of beam hardening in X-ray CT for dimensional metrology.

Facial soft-tissue asymmetry in three-dimensional cone-beam computed tomography images of children with surgically corrected unilateral clefts.

PubMed

Starbuck, John Marlow; Ghoneima, Ahmed; Kula, Katherine

2014-03-01

Cleft lip with or without cleft palate (CL/P) is a relatively common craniofacial malformation involving bony and soft-tissue disruptions of the nasolabial and dentoalveolar regions. The combination of CL/P and subsequent craniofacial surgeries to close the cleft and improve appearance of the cutaneous upper lip and nose can cause scarring and muscle pull, possibly resulting in soft-tissue depth asymmetries across the face. We tested the hypothesis that tissue depths in children with unilateral CL/P exhibit differences in symmetry across the sides of the face. Twenty-eight tissue depths were measured on cone-beam computed tomography images of children with unilateral CL/P (n = 55), aged 7 to 17 years, using Dolphin software (version 11.5). Significant differences in tissue depth symmetry were found around the cutaneous upper lip and nose in patients with unilateral CL/P.

Guide-star-based computational adaptive optics for broadband interferometric tomography

PubMed Central

Adie, Steven G.; Shemonski, Nathan D.; Graf, Benedikt W.; Ahmad, Adeel; Scott Carney, P.; Boppart, Stephen A.

2012-01-01

We present a method for the numerical correction of optical aberrations based on indirect sensing of the scattered wavefront from point-like scatterers (“guide stars”) within a three-dimensional broadband interferometric tomogram. This method enables the correction of high-order monochromatic and chromatic aberrations utilizing guide stars that are revealed after numerical compensation of defocus and low-order aberrations of the optical system. Guide-star-based aberration correction in a silicone phantom with sparse sub-resolution-sized scatterers demonstrates improvement of resolution and signal-to-noise ratio over a large isotome. Results in highly scattering muscle tissue showed improved resolution of fine structure over an extended volume. Guide-star-based computational adaptive optics expands upon the use of image metrics for numerically optimizing the aberration correction in broadband interferometric tomography, and is analogous to phase-conjugation and time-reversal methods for focusing in turbid media. PMID:23284179

X-ray computed tomography library of shark anatomy and lower jaw surface models.

PubMed

Kamminga, Pepijn; De Bruin, Paul W; Geleijns, Jacob; Brazeau, Martin D

2017-04-11

The cranial diversity of sharks reflects disparate biomechanical adaptations to feeding. In order to be able to investigate and better understand the ecomorphology of extant shark feeding systems, we created a x-ray computed tomography (CT) library of shark cranial anatomy with three-dimensional (3D) lower jaw reconstructions. This is used to examine and quantify lower jaw disparity in extant shark species in a separate study. The library is divided in a dataset comprised of medical CT scans of 122 sharks (Selachimorpha, Chondrichthyes) representing 73 extant species, including digitized morphology of entire shark specimens. This CT dataset and additional data provided by other researchers was used to reconstruct a second dataset containing 3D models of the left lower jaw for 153 individuals representing 94 extant shark species. These datasets form an extensive anatomical record of shark skeletal anatomy, necessary for comparative morphological, biomechanical, ecological and phylogenetic studies.

The dynamic micro computed tomography at SSRF

NASA Astrophysics Data System (ADS)

Chen, R.; Xu, L.; Du, G.; Deng, B.; Xie, H.; Xiao, T.

2018-05-01

Synchrotron radiation micro-computed tomography (SR-μCT) is a critical technique for quantitative characterizing the 3D internal structure of samples, recently the dynamic SR-μCT has been attracting vast attention since it can evaluate the three-dimensional structure evolution of a sample. A dynamic μCT method, which is based on monochromatic beam, was developed at the X-ray Imaging and Biomedical Application Beamline at Shanghai Synchrotron Radiation Facility, by combining the compressed sensing based CT reconstruction algorithm and hardware upgrade. The monochromatic beam based method can achieve quantitative information, and lower dose than the white beam base method in which the lower energy beam is absorbed by the sample rather than contribute to the final imaging signal. The developed method is successfully used to investigate the compression of the air sac during respiration in a bell cricket, providing new knowledge for further research on the insect respiratory system.

[Reconstruction of an air-gun injury track in the neck region--a case report].

PubMed

Woźniak, Krzysztof; Nowaczek-Dziocha, Elzbieta; Moskała, Artur; Urbanik, Andrzej; Pohl, Jerzy

2009-01-01

The authors present a case of an air-gun injury of the neck region with a foreign body left in situ. The DICOM files obtained during clinical CT examination (including computed tomography angiography) gave the opportunity for three-dimensional reconstructions of the location of the pellet, neighboring blood vessels and the bullet track--essential for a successful analysis of a possible version according to the testimonies related to the critical event.

A synchrotron-based local computed tomography combined with data-constrained modelling approach for quantitative analysis of anthracite coal microstructure

PubMed Central

Chen, Wen Hao; Yang, Sam Y. S.; Xiao, Ti Qiao; Mayo, Sherry C.; Wang, Yu Dan; Wang, Hai Peng

2014-01-01

Quantifying three-dimensional spatial distributions of pores and material compositions in samples is a key materials characterization challenge, particularly in samples where compositions are distributed across a range of length scales, and where such compositions have similar X-ray absorption properties, such as in coal. Consequently, obtaining detailed information within sub-regions of a multi-length-scale sample by conventional approaches may not provide the resolution and level of detail one might desire. Herein, an approach for quantitative high-definition determination of material compositions from X-ray local computed tomography combined with a data-constrained modelling method is proposed. The approach is capable of dramatically improving the spatial resolution and enabling finer details within a region of interest of a sample larger than the field of view to be revealed than by using conventional techniques. A coal sample containing distributions of porosity and several mineral compositions is employed to demonstrate the approach. The optimal experimental parameters are pre-analyzed. The quantitative results demonstrated that the approach can reveal significantly finer details of compositional distributions in the sample region of interest. The elevated spatial resolution is crucial for coal-bed methane reservoir evaluation and understanding the transformation of the minerals during coal processing. The method is generic and can be applied for three-dimensional compositional characterization of other materials. PMID:24763649

Evaluation of the three-dimensional bony coverage before and after rotational acetabular osteotomy.

PubMed

Tanaka, Takeyuki; Moro, Toru; Takatori, Yoshio; Oshima, Hirofumi; Ito, Hideya; Sugita, Naohiko; Mitsuishi, Mamoru; Tanaka, Sakae

2018-02-26

Rotational acetabular osteotomy is a type of pelvic osteotomy that involves rotation of the acetabular bone to improve the bony coverage of the femoral head for patients with acetabular dysplasia. Favourable post-operative long-term outcomes have been reported in previous studies. However, there is a paucity of published data regarding three-dimensional bony coverage. The present study investigated the three-dimensional bony coverage of the acetabulum covering the femoral head in hips before and after rotational acetabular osteotomy and in normal hips. The computed tomography data of 40 hip joints (12 joints before and after rotational acetabular osteotomy; 16 normal joints) were analyzed. The three-dimensional bony coverage of each joint was evaluated using original software. The post-operative bony coverage improved significantly compared with pre-operative values. In particular, the anterolateral aspect of the acetabulum tended to be dysplastic in patients with acetabular dysplasia compared to those with normal hip joints. However, greater bony coverage at the anterolateral aspect was obtained after rotational acetabular osteotomy. Meanwhile, the results of the present study may indicate that the bony coverage in the anterior aspect may be excessive. Three-dimensional analysis indicated that rotational acetabular osteotomy achieved favorable bony coverage. Further investigations are necessary to determine the ideal bony coverage after rotational acetabular osteotomy.

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation

PubMed Central

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe

2015-01-01

Purpose We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). Materials and Methods The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. Results VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). Conclusion It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method. PMID:25793178

False ankylosis of the temporomandibular joint in a cat. Correction by partial zygomatic arch resection.

PubMed

Larguier, L; Jamet, N

2015-01-01

To describe the use of two-dimensional computer-assisted tomography (CT) with three-dimensional (3D) reconstruction in the diagnosis and planning of surgical treatment of a case of false ankylosis of the temporomandibular joint. A young European Shorthaired cat was presented with the complaint of inability to eat and open its jaws. A CT scan with 3D reconstruction allowed visualization of the lesion which was causing extra-articular ankylosis of the temporomandibular joint. Surgery was performed to resect an osseous lesion of the zygomatic arch, thus freeing the temporomandibular joint. Postoperative physical therapy was initiated immediately following surgery, and then carried out by the owner with a one year follow-up. Clinical examination of the cat was performed during regular office visits (at 1 month and 3 months following surgery), which allowed objective assessment of postoperative recuperation. At the end of a year, the owners reported that the cat had maintained sufficient jaw opening without any signs consistent with chronic pain. Computed tomography scan with 3D reconstruction allowed planning of the surgical correction of extra-articular ankylosis of the temporomandibular joint, and in this case condylectomy was avoided, since temporomandibular joint range-of-motion was maintained.

X-ray micro computed tomography for the visualization of an atherosclerotic human coronary artery

NASA Astrophysics Data System (ADS)

Matviykiv, Sofiya; Buscema, Marzia; Deyhle, Hans; Pfohl, Thomas; Zumbuehl, Andreas; Saxer, Till; Müller, Bert

2017-06-01

Atherosclerosis refers to narrowing or blocking of blood vessels that can lead to a heart attack, chest pain or stroke. Constricted segments of diseased arteries exhibit considerably increased wall shear stress, compared to the healthy ones. One of the possibilities to improve patient’s treatment is the application of nano-therapeutic approaches, based on shear stress sensitive nano-containers. In order to tailor the chemical composition and subsequent physical properties of such liposomes, one has to know precisely the morphology of critically stenosed arteries at micrometre resolution. It is often obtained by means of histology, which has the drawback of offering only two-dimensional information. Additionally, it requires the artery to be decalcified before sectioning, which might lead to deformations within the tissue. Micro computed tomography (μCT) enables the three-dimensional (3D) visualization of soft and hard tissues at micrometre level. μCT allows lumen segmentation that is crucial for subsequent flow simulation analysis. In this communication, tomographic images of a human coronary artery before and after decalcification are qualitatively and quantitatively compared. We analyse the cross section of the diseased human coronary artery before and after decalcification, and calculate the lumen area of both samples.

Three-dimensional surgical simulation.

PubMed

Cevidanes, Lucia H C; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

2010-09-01

In this article, we discuss the development of methods for computer-aided jaw surgery, which allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3-dimensional surface models from cone-beam computed tomography, dynamic cephalometry, semiautomatic mirroring, interactive cutting of bone, and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intraoperative guidance. The system provides further intraoperative assistance with a computer display showing jaw positions and 3-dimensional positioning guides updated in real time during the surgical procedure. The computer-aided surgery system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training, and assessing the difficulties of the surgical procedures before the surgery. Computer-aided surgery can make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Computer-assisted virtual preoperative planning in orthopedic surgery for acetabular fractures based on actual computed tomography data.

PubMed

Wang, Guang-Ye; Huang, Wen-Jun; Song, Qi; Qin, Yun-Tian; Liang, Jin-Feng

2016-12-01

Acetabular fractures have always been very challenging for orthopedic surgeons; therefore, appropriate preoperative evaluation and planning are particularly important. This study aimed to explore the application methods and clinical value of preoperative computer simulation (PCS) in treating pelvic and acetabular fractures. Spiral computed tomography (CT) was performed on 13 patients with pelvic and acetabular fractures, and Digital Imaging and Communications in Medicine (DICOM) data were then input into Mimics software to reconstruct three-dimensional (3D) models of actual pelvic and acetabular fractures for preoperative simulative reduction and fixation, and to simulate each surgical procedure. The times needed for virtual surgical modeling and reduction and fixation were also recorded. The average fracture-modeling time was 45 min (30-70 min), and the average time for bone reduction and fixation was 28 min (16-45 min). Among the surgical approaches planned for these 13 patients, 12 were finally adopted; 12 cases used the simulated surgical fixation, and only 1 case used a partial planned fixation method. PCS can provide accurate surgical plans and data support for actual surgeries.

Echocardiography in the Era of Multimodality Cardiovascular Imaging

PubMed Central

Shah, Benoy Nalin

2013-01-01

Echocardiography remains the most frequently performed cardiac imaging investigation and is an invaluable tool for detailed and accurate evaluation of cardiac structure and function. Echocardiography, nuclear cardiology, cardiac magnetic resonance imaging, and cardiovascular-computed tomography comprise the subspeciality of cardiovascular imaging, and these techniques are often used together for a multimodality, comprehensive assessment of a number of cardiac diseases. This paper provides the general cardiologist and physician with an overview of state-of-the-art modern echocardiography, summarising established indications as well as highlighting advances in stress echocardiography, three-dimensional echocardiography, deformation imaging, and contrast echocardiography. Strengths and limitations of echocardiography are discussed as well as the growing role of real-time three-dimensional echocardiography in the guidance of structural heart interventions in the cardiac catheter laboratory. PMID:23878804

Three-dimensional virtual operations can facilitate complicated surgical planning for the treatment of patients with jaw deformities associated with facial asymmetry: a case report.

PubMed

Hara, Shingo; Mitsugi, Masaharu; Kanno, Takahiro; Nomachi, Akihiko; Wajima, Takehiko; Tatemoto, Yukihiro

2013-09-01

This article describes a case we experienced in which good postsurgical facial profiles were obtained for a patient with jaw deformities associated with facial asymmetry, by implementing surgical planning with SimPlant OMS. Using this method, we conducted LF1 osteotomy, intraoral vertical ramus osteotomy (IVRO), sagittal split ramus osteotomy (SSRO), mandibular constriction and mandibular border genioplasty. Not only did we obtain a class I occlusal relationship, but the complicated surgery also improved the asymmetry of the frontal view, as well as of the profile view, of the patient. The virtual operation using three-dimensional computed tomography (3D-CT) could be especially useful for the treatment of patients with jaw deformities associated with facial asymmetry.

Three-dimensional virtual operations can facilitate complicated surgical planning for the treatment of patients with jaw deformities associated with facial asymmetry: a case report

PubMed Central

Hara, Shingo; Mitsugi, Masaharu; Kanno, Takahiro; Nomachi, Akihiko; Wajima, Takehiko; Tatemoto, Yukihiro

2013-01-01

This article describes a case we experienced in which good postsurgical facial profiles were obtained for a patient with jaw deformities associated with facial asymmetry, by implementing surgical planning with SimPlant OMS. Using this method, we conducted LF1 osteotomy, intraoral vertical ramus osteotomy (IVRO), sagittal split ramus osteotomy (SSRO), mandibular constriction and mandibular border genioplasty. Not only did we obtain a class I occlusal relationship, but the complicated surgery also improved the asymmetry of the frontal view, as well as of the profile view, of the patient. The virtual operation using three-dimensional computed tomography (3D-CT) could be especially useful for the treatment of patients with jaw deformities associated with facial asymmetry. PMID:23907678

Evaluation of mini-implant sites in the posterior maxilla using traditional radiographs and cone-beam computed tomography

PubMed Central

Abbassy, Mona A.; Sabban, Hanady M.; Hassan, Ali H.; Zawawi, Khalid H.

2015-01-01

Objectives: To evaluate the accuracy of using routine 2-dimensional (2D) radiographs (panoramic and periapical) when evaluating the position of orthodontic temporary anchorage devices (mini-implants) in the maxilla, and to compare the results to 3-dimensional cone-beam computed tomography (CBCT). Methods: This cross-sectional study was conducted at King Abdulaziz University, Faculty of Dentistry, Jeddah, Kingdom of Saudi Arabia from February 2014 to January 2015. Panoramic and periapical radiographs were used to examine the position of mini-implants in relation to the adjacent roots. Rating of mini-implants position was performed by 82 dentists from different specialties, using 2 D images according to the following criteria: 1) away from the root; 2) mini-implant tip appears touching the lamina dura; and 3) mini-implant overlays the lamina dura. The results were compared with CBCT findings. Results: There was no difference between dentists from different specialties when rating the position of the mini-implants (Cronbach’s alpha=0.956). The accuracy of the periapical images was 45.1%, while the panoramic images 33.6%. However, both panoramic and periapical radiographs were significantly inaccurate when assessing the mini-implant position when compared with the CBCT findings (p=0.0001). Conclusion: Three-dimensional CBCT technology allows better visualization of mini-implant placement. The use of CBCT when assessing the position of mini-implants is recommended. PMID:26593168

A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography.

PubMed

Dunlop, Jason A; Wirth, Stefan; Penney, David; McNeil, Andrew; Bradley, Robert S; Withers, Philip J; Preziosi, Richard F

2012-06-23

High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44-49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers.

Cone-beam computed tomography analysis of curved root canals after mechanical preparation with three nickel-titanium rotary instruments

PubMed Central

Elsherief, Samia M.; Zayet, Mohamed K.; Hamouda, Ibrahim M.

2013-01-01

Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes (surface area, changes in curvature and transportation) during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files (P = 0.226). During preparation there was failure of only one file (the protaper group). In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems. PMID:23885273

Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data.

PubMed

Suresh, Niraj; Stephens, Sean A; Adams, Lexor; Beck, Anthon N; McKinney, Adriana L; Varga, Tamas

2016-04-26

Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB(1), to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm(2)) and the volume (in mm(3)). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation.

Comparing the Use of 3D Photogrammetry and Computed Tomography in Assessing the Severity of Single-Suture Nonsyndromic Craniosynostosis

PubMed Central

Ho, Olivia A.; Saber, Nikoo; Stephens, Derek; Clausen, April; Drake, James; Forrest, Christopher

2017-01-01

Purpose: Single-suture nonsyndromic craniosynostosis is diagnosed using clinical assessment and computed tomography (CT). With increasing awareness of the associated risks of radiation exposure, the use of CT is particularly concerning in patients with craniosynostosis since they are exposed at a younger age and more frequently than the average child. Three-dimensional (3D) photogrammetry is advantageous—it involves no radiation, is conveniently obtainable within clinic, and does not require general anaesthesia. This study aims to assess how 3D photogrammetry compares to CT in the assessment of craniosynostosis severity, to quantify surgical outcomes, and analyze the validity of 3D photogrammetry in craniosynostosis. Methods: Computed tomography images and 3D photographs of patients who underwent craniosynostosis surgery were assessed and aligned to best fit. The intervening area between the CT and 3D photogrammetry curves at the supraorbital bar (bandeau) level in axial view was calculated. Statistical analysis was performed using Student t test. Ninety-five percent confidence intervals were determined and equivalence margins were applied. Results: In total, 41 pairs of CTs and 3D photographs were analyzed. The 95% confidence interval was 198.16 to 264.18 mm2 and the mean was 231.17 mm2. When comparisons were made in the same bandeau region omitting the temporalis muscle, the 95% confidence interval was 108.94 to 147.38 mm2, and the mean was 128.16 mm2. Although statistically significant difference between the modalities was found, they can be attributable to the dampening effect of soft tissue. Conclusion: Within certain error margins, 3D photogrammetry is comparable to CT in assessing the severity of single-suture nonsyndromic craniosynostosis. However, a dampening effect can be attributable to the soft tissue. Three-dimensional photogrammetry may be more applicable for severe cases of craniosynostosis but not milder deformity. It may also be beneficial for assessing the overall appearance and aesthetics but not for determining underlying bony severity. PMID:29026817

Comparing the Use of 3D Photogrammetry and Computed Tomography in Assessing the Severity of Single-Suture Nonsyndromic Craniosynostosis.

PubMed

Ho, Olivia A; Saber, Nikoo; Stephens, Derek; Clausen, April; Drake, James; Forrest, Christopher; Phillips, John

2017-05-01

Single-suture nonsyndromic craniosynostosis is diagnosed using clinical assessment and computed tomography (CT). With increasing awareness of the associated risks of radiation exposure, the use of CT is particularly concerning in patients with craniosynostosis since they are exposed at a younger age and more frequently than the average child. Three-dimensional (3D) photogrammetry is advantageous-it involves no radiation, is conveniently obtainable within clinic, and does not require general anaesthesia. This study aims to assess how 3D photogrammetry compares to CT in the assessment of craniosynostosis severity, to quantify surgical outcomes, and analyze the validity of 3D photogrammetry in craniosynostosis. Computed tomography images and 3D photographs of patients who underwent craniosynostosis surgery were assessed and aligned to best fit. The intervening area between the CT and 3D photogrammetry curves at the supraorbital bar (bandeau) level in axial view was calculated. Statistical analysis was performed using Student t test. Ninety-five percent confidence intervals were determined and equivalence margins were applied. In total, 41 pairs of CTs and 3D photographs were analyzed. The 95% confidence interval was 198.16 to 264.18 mm 2 and the mean was 231.17 mm 2 . When comparisons were made in the same bandeau region omitting the temporalis muscle, the 95% confidence interval was 108.94 to 147.38 mm 2 , and the mean was 128.16 mm 2 . Although statistically significant difference between the modalities was found, they can be attributable to the dampening effect of soft tissue. Within certain error margins, 3D photogrammetry is comparable to CT in assessing the severity of single-suture nonsyndromic craniosynostosis. However, a dampening effect can be attributable to the soft tissue. Three-dimensional photogrammetry may be more applicable for severe cases of craniosynostosis but not milder deformity. It may also be beneficial for assessing the overall appearance and aesthetics but not for determining underlying bony severity.

Computational cell quantification in the human brain tissues based on hard x-ray phase-contrast tomograms

NASA Astrophysics Data System (ADS)

Hieber, Simone E.; Bikis, Christos; Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Chicherova, Natalia; Rack, Alexander; Zdora, Marie-Christine; Zanette, Irene; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

2016-10-01

Cell visualization and counting plays a crucial role in biological and medical research including the study of neurodegenerative diseases. The neuronal cell loss is typically determined to measure the extent of the disease. Its characterization is challenging because the cell density and size already differs by more than three orders of magnitude in a healthy cerebellum. Cell visualization is commonly performed by histology and fluorescence microscopy. These techniques are limited to resolve complex microstructures in the third dimension. Phase- contrast tomography has been proven to provide sufficient contrast in the three-dimensional imaging of soft tissue down to the cell level and, therefore, offers the basis for the three-dimensional segmentation. Within this context, a human cerebellum sample was embedded in paraffin and measured in local phase-contrast mode at the beamline ID19 (ESRF, Grenoble, France) and the Diamond Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK). After the application of Frangi-based filtering the data showed sufficient contrast to automatically identify the Purkinje cells and to quantify their density to 177 cells per mm3 within the volume of interest. Moreover, brain layers were segmented in a region of interest based on edge detection. Subsequently performed histological analysis validated the presence of the cells, which required a mapping from the two- dimensional histological slices to the three-dimensional tomogram. The methodology can also be applied to further tissue types and shows potential for the computational tissue analysis in health and disease.

Reconstruction of three-dimensional porous media using generative adversarial neural networks

NASA Astrophysics Data System (ADS)

Mosser, Lukas; Dubrule, Olivier; Blunt, Martin J.

2017-10-01

To evaluate the variability of multiphase flow properties of porous media at the pore scale, it is necessary to acquire a number of representative samples of the void-solid structure. While modern x-ray computer tomography has made it possible to extract three-dimensional images of the pore space, assessment of the variability in the inherent material properties is often experimentally not feasible. We present a method to reconstruct the solid-void structure of porous media by applying a generative neural network that allows an implicit description of the probability distribution represented by three-dimensional image data sets. We show, by using an adversarial learning approach for neural networks, that this method of unsupervised learning is able to generate representative samples of porous media that honor their statistics. We successfully compare measures of pore morphology, such as the Euler characteristic, two-point statistics, and directional single-phase permeability of synthetic realizations with the calculated properties of a bead pack, Berea sandstone, and Ketton limestone. Results show that generative adversarial networks can be used to reconstruct high-resolution three-dimensional images of porous media at different scales that are representative of the morphology of the images used to train the neural network. The fully convolutional nature of the trained neural network allows the generation of large samples while maintaining computational efficiency. Compared to classical stochastic methods of image reconstruction, the implicit representation of the learned data distribution can be stored and reused to generate multiple realizations of the pore structure very rapidly.

Use of 3-dimensional computed tomography to detect a barium-masked fish bone causing esophageal perforation.

PubMed

Tsukiyama, Atsushi; Tagami, Takashi; Kim, Shiei; Yokota, Hiroyuki

2014-01-01

Computed tomography (CT) is useful for evaluating esophageal foreign bodies and detecting perforation. However, when evaluation is difficult owing to the previous use of barium as a contrast medium, 3-dimensional CT may facilitate accurate diagnosis. A 49-year-old man was transferred to our hospital with the diagnosis of esophageal perforation. Because barium had been used as a contrast medium for an esophagram performed at a previous hospital, horizontal CT and esophageal endoscopy could not be able to identify the foreign body or characterize the lesion. However, 3-dimensional CT clearly revealed an L-shaped foreign body and its anatomical relationships in the mediastinum. Accordingly, we removed the foreign body using an upper gastrointestinal endoscope. The foreign body was the premaxillary bone of a sea bream. The patient was discharged without complications.

Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water.

PubMed

Glaser, Adam K; Andreozzi, Jacqueline M; Zhang, Rongxiao; Pogue, Brian W; Gladstone, David J

2015-07-01

To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp-Davis-Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm(3) volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%-99% pass fraction depending on the chosen threshold dose. The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.

Three-dimensional fine structure of the organization of microtubules in neurite varicosities by ultra-high voltage electron microscope tomography.

PubMed

Nishida, Tomoki; Yoshimura, Ryoichi; Endo, Yasuhisa

2017-09-01

Neurite varicosities are highly specialized compartments that are involved in neurotransmitter/ neuromodulator release and provide a physiological platform for neural functions. However, it remains unclear how microtubule organization contributes to the form of varicosity. Here, we examine the three-dimensional structure of microtubules in varicosities of a differentiated PC12 neural cell line using ultra-high voltage electron microscope tomography. Three-dimensional imaging showed that a part of the varicosities contained an accumulation of organelles that were separated from parallel microtubule arrays. Further detailed analysis using serial sections and whole-mount tomography revealed microtubules running in a spindle shape of swelling in some other types of varicosities. These electron tomographic results showed that the structural diversity and heterogeneity of microtubule organization supported the form of varicosities, suggesting that a different distribution pattern of microtubules in varicosities is crucial to the regulation of varicosities development.

Do Three-dimensional Visualization and Three-dimensional Printing Improve Hepatic Segment Anatomy Teaching? A Randomized Controlled Study.

PubMed

Kong, Xiangxue; Nie, Lanying; Zhang, Huijian; Wang, Zhanglin; Ye, Qiang; Tang, Lei; Li, Jianyi; Huang, Wenhua

2016-01-01

Hepatic segment anatomy is difficult for medical students to learn. Three-dimensional visualization (3DV) is a useful tool in anatomy teaching, but current models do not capture haptic qualities. However, three-dimensional printing (3DP) can produce highly accurate complex physical models. Therefore, in this study we aimed to develop a novel 3DP hepatic segment model and compare the teaching effectiveness of a 3DV model, a 3DP model, and a traditional anatomical atlas. A healthy candidate (female, 50-years old) was recruited and scanned with computed tomography. After three-dimensional (3D) reconstruction, the computed 3D images of the hepatic structures were obtained. The parenchyma model was divided into 8 hepatic segments to produce the 3DV hepatic segment model. The computed 3DP model was designed by removing the surrounding parenchyma and leaving the segmental partitions. Then, 6 experts evaluated the 3DV and 3DP models using a 5-point Likert scale. A randomized controlled trial was conducted to evaluate the educational effectiveness of these models compared with that of the traditional anatomical atlas. The 3DP model successfully displayed the hepatic segment structures with partitions. All experts agreed or strongly agreed that the 3D models provided good realism for anatomical instruction, with no significant differences between the 3DV and 3DP models in each index (p > 0.05). Additionally, the teaching effects show that the 3DV and 3DP models were significantly better than traditional anatomical atlas in the first and second examinations (p < 0.05). Between the first and second examinations, only the traditional method group had significant declines (p < 0.05). A novel 3DP hepatic segment model was successfully developed. Both the 3DV and 3DP models could improve anatomy teaching significantly. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Three-Dimensional Liver Surgery Simulation: Computer-Assisted Surgical Planning with Three-Dimensional Simulation Software and Three-Dimensional Printing^.

PubMed

Oshiro, Yukio; Ohkohchi, Nobuhiro

2017-06-01

To perform accurate hepatectomy without injury, it is necessary to understand the anatomical relationship among the branches of Glisson's sheath, hepatic veins, and tumor. In Japan, three-dimensional (3D) preoperative simulation for liver surgery is becoming increasingly common, and liver 3D modeling and 3D hepatectomy simulation by 3D analysis software for liver surgery have been covered by universal healthcare insurance since 2012. Herein, we review the history of virtual hepatectomy using computer-assisted surgery (CAS) and our research to date, and we discuss the future prospects of CAS. We have used the SYNAPSE VINCENT medical imaging system (Fujifilm Medical, Tokyo, Japan) for 3D visualization and virtual resection of the liver since 2010. We developed a novel fusion imaging technique combining 3D computed tomography (CT) with magnetic resonance imaging (MRI). The fusion image enables us to easily visualize anatomic relationships among the hepatic arteries, portal veins, bile duct, and tumor in the hepatic hilum. In 2013, we developed an original software, called Liversim, which enables real-time deformation of the liver using physical simulation, and a randomized control trial has recently been conducted to evaluate the use of Liversim and SYNAPSE VINCENT for preoperative simulation and planning. Furthermore, we developed a novel hollow 3D-printed liver model whose surface is covered with frames. This model is useful for safe liver resection, has better visibility, and the production cost is reduced to one-third of a previous model. Preoperative simulation and navigation with CAS in liver resection are expected to help planning and conducting a surgery and surgical education. Thus, a novel CAS system will contribute to not only the performance of reliable hepatectomy but also to surgical education.

Intensity-modulated radiation therapy: a review with a physics perspective.

PubMed

Cho, Byungchul

2018-03-01

Intensity-modulated radiation therapy (IMRT) has been considered the most successful development in radiation oncology since the introduction of computed tomography into treatment planning that enabled three-dimensional conformal radiotherapy in 1980s. More than three decades have passed since the concept of inverse planning was first introduced in 1982, and IMRT has become the most important and common modality in radiation therapy. This review will present developments in inverse IMRT treatment planning and IMRT delivery using multileaf collimators, along with the associated key concepts. Other relevant issues and future perspectives are also presented.

Four-dimensional computed tomography-based treatment planning for intensity-modulated radiation therapy and proton therapy for distal esophageal cancer.

PubMed

Zhang, Xiaodong; Zhao, Kuai-le; Guerrero, Thomas M; McGuire, Sean E; Yaremko, Brian; Komaki, Ritsuko; Cox, James D; Hui, Zhouguang; Li, Yupeng; Newhauser, Wayne D; Mohan, Radhe; Liao, Zhongxing

2008-09-01

To compare three-dimensional (3D) and four-dimensional (4D) computed tomography (CT)-based treatment plans for proton therapy or intensity-modulated radiation therapy (IMRT) for esophageal cancer in terms of doses to the lung, heart, and spinal cord and variations in target coverage and normal tissue sparing. The IMRT and proton plans for 15 patients with distal esophageal cancer were designed from the 3D average CT scans and then recalculated on 10 4D CT data sets. Dosimetric data were compared for tumor coverage and normal tissue sparing. Compared with IMRT, median lung volumes exposed to 5, 10, and 20 Gy and mean lung dose were reduced by 35.6%, 20.5%, 5.8%, and 5.1 Gy for a two-beam proton plan and by 17.4%, 8.4%, 5%, and 2.9 Gy for a three-beam proton plan. The greater lung sparing in the two-beam proton plan was achieved at the expense of less conformity to the target (conformity index [CI], 1.99) and greater irradiation of the heart (heart-V40, 41.8%) compared with the IMRT plan(CI, 1.55, heart-V40, 35.7%) or the three-beam proton plan (CI, 1.46, heart-V40, 27.7%). Target coverage differed by more than 2% between the 3D and 4D plans for patients with substantial diaphragm motion in the three-beam proton and IMRT plans. The difference in spinal cord maximum dose between 3D and 4D plans could exceed 5 Gy for the proton plans partly owing to variations in stomach gas filling. Proton therapy provided significantly better sparing of lung than did IMRT. Diaphragm motion and stomach gas-filling must be considered in evaluating target coverage and cord doses.

Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

PubMed Central

Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

2016-01-01

Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

Analysis of Facial Asymmetry in Deformational Plagiocephaly Using Three-Dimensional Computed Tomographic Review

PubMed Central

Moon, Il Yung; Oh, Kap Sung

2014-01-01

Background Infants with deformational plagiocephaly (DP) usually present with cranial vault deformities as well as facial asymmetry. The purpose of this study was to use three-dimensional anthropometric data to evaluate the influence of cranial deformities on facial asymmetry. Methods We analyzed three-dimensional computed tomography data for infants with DP (n=48) and without DP (n=30, control). Using 16 landmarks and 3 reference planes, 22 distance parameters and 2 angular parameters were compared. This cephalometric assessment focused on asymmetry of the orbits, nose, ears, maxilla, and mandible. We then assessed the correlation between 23 of the measurements and cranial vault asymmetry (CVA) for statistical significance using relative differences and correlation analysis. Results With the exception of few orbital asymmetry variables, most measurements indicated that the facial asymmetry was greater in infants with DP. Mandibular and nasal asymmetry was correlated highly with severity of CVA. Shortening of the ipsilateral mandibular body was particularly significant. There was no significant deformity in the maxilla or ear. Conclusion This study demonstrated that the cranial vault deformity in DP is associated with facial asymmetry. Compared with the control group, the infants with DP were found to have prominent asymmetry of the nose and mandible. PMID:28913202

Simultaneous reconstruction of 3D refractive index, temperature, and intensity distribution of combustion flame by double computed tomography technologies based on spatial phase-shifting method

NASA Astrophysics Data System (ADS)

Guo, Zhenyan; Song, Yang; Yuan, Qun; Wulan, Tuya; Chen, Lei

2017-06-01

In this paper, a transient multi-parameter three-dimensional (3D) reconstruction method is proposed to diagnose and visualize a combustion flow field. Emission and transmission tomography based on spatial phase-shifted technology are combined to reconstruct, simultaneously, the various physical parameter distributions of a propane flame. Two cameras triggered by the internal trigger mode capture the projection information of the emission and moiré tomography, respectively. A two-step spatial phase-shifting method is applied to extract the phase distribution in the moiré fringes. By using the filtered back-projection algorithm, we reconstruct the 3D refractive-index distribution of the combustion flow field. Finally, the 3D temperature distribution of the flame is obtained from the refractive index distribution using the Gladstone-Dale equation. Meanwhile, the 3D intensity distribution is reconstructed based on the radiation projections from the emission tomography. Therefore, the structure and edge information of the propane flame are well visualized.

Effects of lung disease on the three-dimensional structure and air flow pattern in the human airway tree

NASA Astrophysics Data System (ADS)

van de Moortele, Tristan; Nemes, Andras; Wendt, Christine; Coletti, Filippo

2016-11-01

The morphological features of the airway tree directly affect the air flow features during breathing, which determines the gas exchange and inhaled particle transport. Lung disease, Chronic Obstructive Pulmonary Disease (COPD) in this study, affects the structural features of the lungs, which in turn negatively affects the air flow through the airways. Here bronchial tree air volume geometries are segmented from Computed Tomography (CT) scans of healthy and diseased subjects. Geometrical analysis of the airway centerlines and corresponding cross-sectional areas provide insight into the specific effects of COPD on the airway structure. These geometries are also used to 3D print anatomically accurate, patient specific flow models. Three-component, three-dimensional velocity fields within these models are acquired using Magnetic Resonance Imaging (MRI). The three-dimensional flow fields provide insight into the change in flow patterns and features. Additionally, particle trajectories are determined using the velocity fields, to identify the fate of therapeutic and harmful inhaled aerosols. Correlation between disease-specific and patient-specific anatomical features with dysfunctional airflow patterns can be achieved by combining geometrical and flow analysis.

Computed Tomography and Thermography Increases CMC Material and Process Development Efficiency and Testing Effectiveness

NASA Technical Reports Server (NTRS)

Effinger, Michael; Beshears, Ron; Hufnagle, David; Walker, James; Russell, Sam; Stowell, Bob; Myers, David

2002-01-01

Nondestructive characterization techniques have been used to steer development and testing of CMCs. Computed tomography is used to determine the volumetric integrity of the CMC plates and components. Thermography is used to determine the near surface integrity of the CMC plates and components. For process and material development, information such as density uniformity, part delamination, and dimensional tolerance conformity is generated. The information from the thermography and computed tomography is correlated and then specimen cutting maps are superimposed on the thermography images. This enables for tighter data and potential explanation of off nominal test data. Examples of nondestructive characterization utilization to make decisions in process and material development and testing are presented.

Compensating the intensity fall-off effect in cone-beam tomography by an empirical weight formula.

PubMed

Chen, Zikuan; Calhoun, Vince D; Chang, Shengjiang

2008-11-10

The Feldkamp-David-Kress (FDK) algorithm is widely adopted for cone-beam reconstruction due to its one-dimensional filtered backprojection structure and parallel implementation. In a reconstruction volume, the conspicuous cone-beam artifact manifests as intensity fall-off along the longitudinal direction (the gantry rotation axis). This effect is inherent to circular cone-beam tomography due to the fact that a cone-beam dataset acquired from circular scanning fails to meet the data sufficiency condition for volume reconstruction. Upon observations of the intensity fall-off phenomenon associated with the FDK reconstruction of a ball phantom, we propose an empirical weight formula to compensate for the fall-off degradation. Specifically, a reciprocal cosine can be used to compensate the voxel values along longitudinal direction during three-dimensional backprojection reconstruction, in particular for boosting the values of voxels at positions with large cone angles. The intensity degradation within the z plane, albeit insignificant, can also be compensated by using the same weight formula through a parameter for radial distance dependence. Computer simulations and phantom experiments are presented to demonstrate the compensation effectiveness of the fall-off effect inherent in circular cone-beam tomography.

Complex branchial fistula: a variant arch anomaly.

PubMed

De Caluwé, D; Hayes, R; McDermott, M; Corbally, M T

2001-07-01

A 5-year-old boy presented with an infected left-sided branchial fistula. Despite antibiotic treatment and repeated excision of the fistula, purulent discharge from the wound persisted. Three-dimensional computed tomography (3D CT) reconstruction greatly facilitated the diagnosis and management of this case by showing the course of the fistulous tract. The complexity of the tract suggests that this represents a variant arch anomaly because it contains features of first, second, third, and fourth arch remnants. Copyright 2001 by W.B. Saunders Company.

Rapid Prototyping Integrated With Nondestructive Evaluation and Finite Element Analysis

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Baaklini, George Y.

2001-01-01

Most reverse engineering approaches involve imaging or digitizing an object then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. Rapid prototyping (RP) refers to the practical ability to build high-quality physical prototypes directly from computer aided design (CAD) files. Using rapid prototyping, full-scale models or patterns can be built using a variety of materials in a fraction of the time required by more traditional prototyping techniques (refs. 1 and 2). Many software packages have been developed and are being designed to tackle the reverse engineering and rapid prototyping issues just mentioned. For example, image processing and three-dimensional reconstruction visualization software such as Velocity2 (ref. 3) are being used to carry out the construction process of three-dimensional volume models and the subsequent generation of a stereolithography file that is suitable for CAD applications. Producing three-dimensional models of objects from computed tomography (CT) scans is becoming a valuable nondestructive evaluation methodology (ref. 4). Real components can be rendered and subjected to temperature and stress tests using structural engineering software codes. For this to be achieved, accurate high-resolution images have to be obtained via CT scans and then processed, converted into a traditional file format, and translated into finite element models. Prototyping a three-dimensional volume of a composite structure by reading in a series of two-dimensional images generated via CT and by using and integrating commercial software (e.g. Velocity2, MSC/PATRAN (ref. 5), and Hypermesh (ref. 6)) is being applied successfully at the NASA Glenn Research Center. The building process from structural modeling to the analysis level is outlined in reference 7. Subsequently, a stress analysis of a composite cooling panel under combined thermomechanical loading conditions was performed to validate this process.

Three-dimensional structural dynamics and fluctuations of DNA-nanogold conjugates by individual-particle electron tomography

DOE PAGES

Zhang, Lei; Lei, Dongsheng; Smith, Jessica M.; ...

2016-03-30

DNA base pairing has been used for many years to direct the arrangement of inorganic nanocrystals into small groupings and arrays with tailored optical and electrical properties. The control of DNA-mediated assembly depends crucially on a better understanding of three-dimensional structure of DNA-nanocrystal-hybridized building blocks. Existing techniques do not allow for structural determination of these flexible and heterogeneous samples. Here we report cryo-electron microscopy and negative-staining electron tomography approaches to image, and three-dimensionally reconstruct a single DNA-nanogold conjugate, an 84-bp double-stranded DNA with two 5-nm nanogold particles for potential substrates in plasmon-coupling experiments. By individual-particle electron tomography reconstruction, we obtainmore » 14 density maps at ~ 2-nm resolution . Using these maps as constraints, we derive 14 conformations of dsDNA by molecular dynamics simulations. The conformational variation is consistent with that from liquid solution, suggesting that individual-particle electron tomography could be an expected approach to study DNA-assembling and flexible protein structure and dynamics.« less

High-speed upper-airway imaging using full-range optical coherence tomography

NASA Astrophysics Data System (ADS)

Jing, Joseph; Zhang, Jun; Loy, Anthony Chin; Wong, Brian J. F.; Chen, Zhongping

2012-11-01

Obstruction in the upper airway can often cause reductions in breathing or gas exchange efficiency and lead to rest disorders such as sleep apnea. Imaging diagnosis of the obstruction region has been accomplished using computed tomography (CT) and magnetic resonance imaging (MRI). However CT requires the use of ionizing radiation, and MRI typically requires sedation of the patient to prevent motion artifacts. Long-range optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images with high resolution and without the use of ionizing radiation. In this paper, we present work on the development of a long-range OCT endoscopic probe with 1.2 mm OD and 20 mm working distance used in conjunction with a modified Fourier domain swept source OCT system to acquire structural and anatomical datasets of the human airway. Imaging from the bottom of the larynx to the end of the nasal cavity is completed within 40 s.

Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Guanglei, E-mail: guangleizhang@bjtu.edu.cn; Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044; Pu, Huangsheng

2015-02-23

Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but alsomore » make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.« less

Three-dimensional plotting and printing of an implant drilling guide: simplifying guided implant surgery.

PubMed

Flügge, Tabea Viktoria; Nelson, Katja; Schmelzeisen, Rainer; Metzger, Marc Christian

2013-08-01

To present an efficient workflow for the production of implant drilling guides using virtual planning tools. For this purpose, laser surface scanning, cone beam computed tomography, computer-aided design and manufacturing, and 3-dimensional (3D) printing were combined. Intraoral optical impressions (iTero, Align Technologies, Santa Clara, CA) and digital 3D radiographs (cone beam computed tomography) were performed at the first consultation of 1 exemplary patient. With image processing techniques, the intraoral surface data, acquired using an intraoral scanner, and radiologic 3D data were fused. The virtual implant planning process (using virtual library teeth) and the in-office production of the implant drilling guide was performed after only 1 clinical consultation of the patient. Implant surgery with a computer-aided design and manufacturing produced implant drilling guide was performed during the second consultation. The production of a scan prosthesis and multiple preoperative consultations of the patient were unnecessary. The presented procedure offers another step in facilitating the production of drilling guides in dental implantology. Four main advantages are realized with this procedure. First, no additional scan prosthesis is needed. Second, data acquisition can be performed during the first consultation. Third, the virtual planning is directly transferred to the drilling guide without a loss of accuracy. Finally, the treatment cost and time required are reduced with this facilitated production process. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Review: Polymeric-Based 3D Printing for Tissue Engineering.

PubMed

Wu, Geng-Hsi; Hsu, Shan-Hui

Three-dimensional (3D) printing, also referred to as additive manufacturing, is a technology that allows for customized fabrication through computer-aided design. 3D printing has many advantages in the fabrication of tissue engineering scaffolds, including fast fabrication, high precision, and customized production. Suitable scaffolds can be designed and custom-made based on medical images such as those obtained from computed tomography. Many 3D printing methods have been employed for tissue engineering. There are advantages and limitations for each method. Future areas of interest and progress are the development of new 3D printing platforms, scaffold design software, and materials for tissue engineering applications.

Medical physics: some recollections in diagnostic X-ray imaging and therapeutic radiology.

PubMed

Gray, J E; Orton, C G

2000-12-01

Medical physics has changed dramatically since 1895. There was a period of slow evolutionary change during the first 70 years after Roentgen's discovery of x rays. With the advent of the computer, however, both diagnostic and therapeutic radiology have undergone rapid growth and changes. Technologic advances such as computed tomography and magnetic resonance imaging in diagnostic imaging and three-dimensional treatment planning systems, stereotactic radiosurgery, and intensity modulated radiation therapy in radiation oncology have resulted in substantial changes in medical physics. These advances have improved diagnostic imaging and radiation therapy while expanding the need for better educated and experienced medical physics staff.

Three-dimensional monochromatic x-ray CT

NASA Astrophysics Data System (ADS)

Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Ktsuyuki; Uyama, Chikao

1995-08-01

In this paper, we describe a 3D computed tomography (3D CT) using monochromatic x-rays generated by synchrotron radiation, which performs a direct reconstruction of 3D volume image of an object from its cone-beam projections. For the develpment of 3D CT, scanning orbit of x-ray source to obtain complete 3D information about an object and corresponding 3D image reconstruction algorithm are considered. Computer simulation studies demonstrate the validities of proposed scanning method and reconstruction algorithm. A prototype experimental system of 3D CT was constructed. Basic phantom examinations and specific material CT image by energy subtraction obtained in this experimental system are shown.

Interdisciplinary Study of Egyptian Mummies from the Pushkin State Museum of Fine Arts Collection at the National Research Centre ``Kurchatov Institute''

NASA Astrophysics Data System (ADS)

Yatsishina, E. B.; Kovalchuk, M. V.; Loshak, M. D.; Vasilyev, S. V.; Vasilieva, O. A.; Dyuzheva, O. P.; Pojidaev, V. M.; Ushakov, V. L.

2018-05-01

Nine ancient Egyptian mummies (dated preliminarily to the period from the 1st mill. BCE to the first centuries CE) from the collection of the State Pushkin Museum of Fine Arts have been studied at the National Research Centre "Kurchatov Institute" (NRC KI) on the base of the complex of NBICS technologies. Tomographic scanning is performed using a magneto-resonance tomograph (3 T) and a hybrid positron emission tomography/computed tomography (PET-CT) scanner. Three-dimensional reconstructions of mummies and their anthropological measurements are carried out. Some medical conclusions are drawn based on the tomographic data. In addition, the embalming composition and tissue of one of the mummies are preliminarily analyzed.

Assessing the morphology of selective laser melted NiTi-scaffolds for a three-dimensional quantification of the one-way shape memory effect

NASA Astrophysics Data System (ADS)

Bormann, Therese; de Wild, Michael; Beckmann, Felix; Müller, Bert

2013-04-01

NiTi is promising for the use as bone scaffold, because the pseudoelasticity or the one- and two-way shape memory effect in the physiological window can mechanically stimulate the adherent cells. Such stimuli can enhance osseointegration and might reduce stress shielding associated with load bearing implants. The present study is based on the additive manufacturing technique of selective laser melting (SLM) to fabricate three-dimensional NiTi scaffolds. We demonstrate that the morphology of the scaffolds can be quantified using synchrotron radiation-based micro computed tomography (SRμCT) and sophisticated registration software. Comparing the CAD file with the SLM scaffolds, quality factors are derived. With respect to the CAD file, the overlap corresponds to (92.5 +/- 0.6) %. (7.4 +/- 0.42) % of material was missing and (48.9 +/- 2.3) % of excess material found. This means that the actual scaffold is less porous than expected, a fact that has to be considered for the scaffold design. In order to quantify the shape memory effect during the shape recovery process, we acquired radiographs rotating an initially deformed scaffold in angular steps of 0.2 degree during controlled heating. The continuously acquired radiographs were combined to tomography data, showing that the quality factors evolved with temperature as the scaffold height, measured by conventional thermo-mechanical analysis. Furthermore, the data comprise the presence of compressive and tensile local strains in the three-dimensional scaffolds to be compared with the physiological situation.

Serial 3-dimensional computed tomography and a novel method of volumetric analysis for the evaluation of the osteo-odonto-keratoprosthesis.

PubMed

Sipkova, Zuzana; Lam, Fook Chang; Francis, Ian; Herold, Jim; Liu, Christopher

2013-04-01

To assess the use of serial computed tomography (CT) in the detection of osteo-odonto-lamina resorption in osteo-odonto-keratoprosthesis (OOKP) and to investigate the use of new volumetric software, Advanced Lung Analysis software (3D-ALA; GE Healthcare), for detecting changes in OOKP laminar volume. A retrospective assessment of the radiological databases and hospital records was performed for 22 OOKP patients treated at the National OOKP referral center in Brighton, United Kingdom. Three-dimensional surface reconstructions of the OOKP laminae were performed using stored CT data. For the 2-dimensional linear analysis, the linear dimensions of the reconstructed laminae were measured, compared with original measurements taken at the time of surgery, and then assigned a CT grade based on a predetermined resorption grading scale. The volumetric analysis involved calculating the laminar volumes using 3D-ALA. The effectiveness of 2-dimensional linear analysis, volumetric analysis, and clinical examination in detecting laminar resorption was compared. The mean change in laminar volume between the first and second scans was -6.67% (range, +10.13% to -24.86%). CT grades assigned to patients based on laminar dimension measurements remained the same, despite significant changes in laminar volumes. Clinical examination failed to identify 60% of patients who were found to have resorption on volumetric analysis. Currently, the detection of laminar resorption relies on clinical examination and the measurement of laminar dimensions on the 2- and 3-dimensional radiological images. Laminar volume measurement is a useful new addition to the armamentarium. It provides an objective tool that allows for a precise and reproducible assessment of laminar resorption.

Detection of marginal leakage of Class V restorations in vitro by micro-computed tomography.

PubMed

Zhao, X Y; Li, S B; Gu, L J; Li, Y

2014-01-01

This in vitro study evaluated the efficacy of micro-computed tomography (CT) in marginal leakage detection of Class V restorations. Standardized Class V preparations with cervical margins in dentin and occlusal margins in enamel were made in 20 extracted human molars and restored with dental bonding agents and resin composite. All teeth were then immersed in 50% ammoniacal silver nitrate solution for 12 hours, followed by a developing solution for eight hours. Each restoration was scanned by micro-CT, the depth of marginal silver leakage in the central scanning section was measured, and the three-dimensional images of the silver leakage around each restoration were reconstructed. Afterward, all restorations were cut through the center and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by the micro-CT and the microscope were compared for equivalency. The silver leakage depth in cervical walls observed by micro-CT and microscope showed no significant difference; however, in certain cases the judgment of leakage depth in the occlusal wall in micro-CT image was affected by adjacent enamel structure, providing less leakage depth than was observed with the microscope (p<0.01). Micro-CT displayed the three-dimensional image of the leakage around the Class V restorations with clear borders only in the dentin region. It can be concluded that micro-CT can detect nondestructively the leakage around a resin composite restoration in two and three dimensions, with accuracy comparable to that of the conventional microscope method in the dentin region but with inferior accuracy in the enamel region.

Three-dimensional printing of X-ray computed tomography datasets with multiple materials using open-source data processing.

PubMed

Sander, Ian M; McGoldrick, Matthew T; Helms, My N; Betts, Aislinn; van Avermaete, Anthony; Owers, Elizabeth; Doney, Evan; Liepert, Taimi; Niebur, Glen; Liepert, Douglas; Leevy, W Matthew

2017-07-01

Advances in three-dimensional (3D) printing allow for digital files to be turned into a "printed" physical product. For example, complex anatomical models derived from clinical or pre-clinical X-ray computed tomography (CT) data of patients or research specimens can be constructed using various printable materials. Although 3D printing has the potential to advance learning, many academic programs have been slow to adopt its use in the classroom despite increased availability of the equipment and digital databases already established for educational use. Herein, a protocol is reported for the production of enlarged bone core and accurate representation of human sinus passages in a 3D printed format using entirely consumer-grade printers and a combination of free-software platforms. The comparative resolutions of three surface rendering programs were also determined using the sinuses, a human body, and a human wrist data files to compare the abilities of different software available for surface map generation of biomedical data. Data shows that 3D Slicer provided highest compatibility and surface resolution for anatomical 3D printing. Generated surface maps were then 3D printed via fused deposition modeling (FDM printing). In conclusion, a methodological approach that explains the production of anatomical models using entirely consumer-grade, fused deposition modeling machines, and a combination of free software platforms is presented in this report. The methods outlined will facilitate the incorporation of 3D printed anatomical models in the classroom. Anat Sci Educ 10: 383-391. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.

Maxillary distraction osteogenesis in the adolescent cleft patient: three-dimensional computed tomography analysis of linear and volumetric changes over five years.

PubMed

Chen, Philip Kuo-Ting; Por, Yong-Chen; Liou, Eric Jein-Wein; Chang, Frank Chun-Shin

2011-07-01

To assess the results of maxillary distraction osteogenesis with the Rigid External Distraction System using three-dimensional computed tomography scan volume-rendered images with respect to stability and facial growth at three time frames: preoperative (T0), 1-year postoperative (T1), and 5-years postoperative (T2). Retrospective analysis. Tertiary. A total of 12 patients with severe cleft maxillary hypoplasia were treated between June 30, 1997, and July 15, 1998. The mean age at surgery was 11 years 1 month. Le Fort I maxillary distraction osteogenesis. Distraction was started 2 to 5 days postsurgery at a rate of 1 mm per day. The consolidation period was 3 months. No face mask was used. A paired t test was used for statistical analysis. Overjet, ANB, and SNA and maxillary, pterygoid, and mandibular volumes. From T0 to T1, there were statistically significant increments of overjet, ANB, and SNA and maxillary, pterygoid, and mandibular volumes. The T1 to T2 period demonstrated a reduction of overjet (30.07%) and ANB (54.42%). The maxilla showed a stable SNA and a small but statistically significant advancement of the ANS point. There was a significant increase in the mandibular volume. However, there was no significant change in the maxillary and pterygoid volumes. Maxillary distraction osteogenesis demonstrated linear and volumetric maxillary growth during the distraction phase without clinically significant continued growth thereafter. Overcorrection is required to take into account recurrence of midface retrusion over the long term.

Representative volume element model of lithium-ion battery electrodes based on X-ray nano-tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashkooli, Ali Ghorbani; Amirfazli, Amir; Farhad, Siamak

For this, a new model that keeps all major advantages of the single-particle model of lithium-ion batteries (LIBs) and includes three-dimensional structure of the electrode was developed. Unlike the single spherical particle, this model considers a small volume element of an electrode, called the Representative Volume Element (RVE), which represent the real electrode structure. The advantages of using RVE as the model geometry was demonstrated for a typical LIB electrode consisting of nano-particle LiFePO 4 (LFP) active material. The three-dimensional morphology of the LFP electrode was reconstructed using a synchrotron X-ray nano-computed tomography at the Advanced Photon Source of themore » Argonne National. A 27 μm 3 cube from reconstructed structure was chosen as the RVE for the simulation purposes. The model was employed to predict the voltage curve in a half-cell during galvanostatic operations and validated with experimental data. The simulation results showed that the distribution of lithium inside the electrode microstructure is very different from the results obtained based on the single-particle model. The range of lithium concentration is found to be much greater, successfully illustrates the effect of microstructure heterogeneity.« less

Representative volume element model of lithium-ion battery electrodes based on X-ray nano-tomography

DOE PAGES

Kashkooli, Ali Ghorbani; Amirfazli, Amir; Farhad, Siamak; ...

2017-01-28

For this, a new model that keeps all major advantages of the single-particle model of lithium-ion batteries (LIBs) and includes three-dimensional structure of the electrode was developed. Unlike the single spherical particle, this model considers a small volume element of an electrode, called the Representative Volume Element (RVE), which represent the real electrode structure. The advantages of using RVE as the model geometry was demonstrated for a typical LIB electrode consisting of nano-particle LiFePO 4 (LFP) active material. The three-dimensional morphology of the LFP electrode was reconstructed using a synchrotron X-ray nano-computed tomography at the Advanced Photon Source of themore » Argonne National. A 27 μm 3 cube from reconstructed structure was chosen as the RVE for the simulation purposes. The model was employed to predict the voltage curve in a half-cell during galvanostatic operations and validated with experimental data. The simulation results showed that the distribution of lithium inside the electrode microstructure is very different from the results obtained based on the single-particle model. The range of lithium concentration is found to be much greater, successfully illustrates the effect of microstructure heterogeneity.« less

Introduction to Seismic Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Charlotte Anne

2017-11-21

Tomography is a method of obtaining an image of a 3d object by observing the behavior of energy transmissions through the object. The image is obtained by Interrogating the object with Energy sources at a variety of Locations and observing the Object’s effects on the energy at a Variety of sensors. Tomography was first Used to build 3-dimensional Scans through Human bodies. These Are called computed Tomographic (ct) scans.

The application of rapid prototyping technique in chin augmentation.

PubMed

Li, Min; Lin, Xin; Xu, Yongchen

2010-04-01

This article discusses the application of computer-aided design and rapid prototyping techniques in prosthetic chin augmentation for mild microgenia. Nine cases of mild microgenia underwent an electrobeam computer tomography scan. Then we performed three-dimensional reconstruction and operative design using computer software. According to the design, we determined the shape and size of the prostheses and made an individualized prosthesis for each chin augmentation with the rapid prototyping technique. With the application of computer-aided design and a rapid prototyping technique, we could determine the shape, size, and embedding location accurately. Prefabricating the individual prosthesis model is useful in improving the accuracy of treatment. In the nine cases of mild microgenia, three received a silicone implant, four received an ePTFE implant, and two received a Medpor implant. All patients were satisfied with the results. During follow-up at 6-12 months, all patients remained satisfied. The application of computer-aided design and rapid prototyping techniques can offer surgeons the ability to design an individualized ideal prosthesis for each patient.

Quantification of the kV X-ray imaging dose during real-time tumor tracking and from three- and four-dimensional cone-beam computed tomography in lung cancer patients using a Monte Carlo simulation.

PubMed

Nakamura, Mitsuhiro; Ishihara, Yoshitomo; Matsuo, Yukinori; Iizuka, Yusuke; Ueki, Nami; Iramina, Hiraku; Hirashima, Hideaki; Mizowaki, Takashi

2018-03-01

Knowledge of the imaging doses delivered to patients and accurate dosimetry of the radiation to organs from various imaging procedures is becoming increasingly important for clinicians. The purposes of this study were to calculate imaging doses delivered to the organs of lung cancer patients during real-time tumor tracking (RTTT) with three-dimensional (3D), and four-dimensional (4D) cone-beam computed tomography (CBCT), using Monte Carlo techniques to simulate kV X-ray dose distributions delivered using the Vero4DRT. Imaging doses from RTTT, 3D-CBCT and 4D-CBCT were calculated with the planning CT images for nine lung cancer patients who underwent stereotactic body radiotherapy (SBRT) with RTTT. With RTTT, imaging doses from correlation modeling and from monitoring of imaging during beam delivery were calculated. With CBCT, doses from 3D-CBCT and 4D-CBCT were also simulated. The doses covering 2-cc volumes (D2cc) in correlation modeling were up to 9.3 cGy for soft tissues and 48.4 cGy for bone. The values from correlation modeling and monitoring were up to 11.0 cGy for soft tissues and 59.8 cGy for bone. Imaging doses in correlation modeling were larger with RTTT. On a single 4D-CBCT, the skin and bone D2cc values were in the ranges of 7.4-10.5 cGy and 33.5-58.1 cGy, respectively. The D2cc from 4D-CBCT was approximately double that from 3D-CBCT. Clinicians should Figure that the imaging dose increases the cumulative doses to organs.

Evaluation of three-dimensional computed tomography processing for deep inferior epigastric perforator flap breast reconstruction.

PubMed

Teoh, Raymond; Johnson, Raleigh F; Nishino, Thomas K; Ethridge, Richard T

2007-01-01

The deep inferior epigastric perforator flap procedure has become a popular alternative for women who require breast reconstruction. One of the difficulties with this procedure is identifying perforator arteries large enough to ensure that the harvested tissue is well vascularized. Current techniques involve imaging the perforator arteries with computed tomography (CT) to produce a grid mapping the locations of the perforator arteries relative to the umbilicus. To compare the time it takes to produce a map of the perforators using either two-dimensional (2D) or three-dimensional (3D) CT, and to see whether there is a benefit in using a 3D model. Patient CT abdomen and pelvis scans were acquired from a GE 64-slice scanner. CT image processing was performed with the GE 3D Advantage Workstation v4.2 software. Maps of the perforators were generated both as 2D and 3D representations. Perforators within a region 5 cm rostral and 7 cm caudal to the umbilicus were measured and the times to perform these measurements using both 2D and 3D images were recorded by a stopwatch. Although the 3D method took longer than the 2D method (mean [+/- SD] time 1:51+/-0:35 min versus 1:08+/-0:16 min per perforator artery, respectively), producing a 3D image provides much more information than the 2D images alone. Additionally, an actual-sized 3D image can be printed out, removing the need to make measurements and producing a grid. Although it took less time to create a grid of the perforators using 2D axial CT scans, the 3D reconstruction of the abdomen allows the plastic surgeons to better visualize the patient's anatomy and has definite clinical utility.

Quantification of the kV X-ray imaging dose during real-time tumor tracking and from three- and four-dimensional cone-beam computed tomography in lung cancer patients using a Monte Carlo simulation

PubMed Central

Nakamura, Mitsuhiro; Ishihara, Yoshitomo; Matsuo, Yukinori; Iizuka, Yusuke; Ueki, Nami; Iramina, Hiraku; Hirashima, Hideaki; Mizowaki, Takashi

2018-01-01

Abstract Knowledge of the imaging doses delivered to patients and accurate dosimetry of the radiation to organs from various imaging procedures is becoming increasingly important for clinicians. The purposes of this study were to calculate imaging doses delivered to the organs of lung cancer patients during real-time tumor tracking (RTTT) with three-dimensional (3D), and four-dimensional (4D) cone-beam computed tomography (CBCT), using Monte Carlo techniques to simulate kV X-ray dose distributions delivered using the Vero4DRT. Imaging doses from RTTT, 3D-CBCT and 4D-CBCT were calculated with the planning CT images for nine lung cancer patients who underwent stereotactic body radiotherapy (SBRT) with RTTT. With RTTT, imaging doses from correlation modeling and from monitoring of imaging during beam delivery were calculated. With CBCT, doses from 3D-CBCT and 4D-CBCT were also simulated. The doses covering 2-cc volumes (D2cc) in correlation modeling were up to 9.3 cGy for soft tissues and 48.4 cGy for bone. The values from correlation modeling and monitoring were up to 11.0 cGy for soft tissues and 59.8 cGy for bone. Imaging doses in correlation modeling were larger with RTTT. On a single 4D-CBCT, the skin and bone D2cc values were in the ranges of 7.4–10.5 cGy and 33.5–58.1 cGy, respectively. The D2cc from 4D-CBCT was approximately double that from 3D-CBCT. Clinicians should Figure that the imaging dose increases the cumulative doses to organs. PMID:29385514

Applications of cone beam computed tomography for a prosthodontist.

PubMed

John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R B

2016-01-01

Cone beam computed tomography (CBCT) is a medical imaging technique of X-ray computed tomography where the X-rays are divergent, forming a cone. CBCT systems have been designed for imaging hard tissues of the maxillofacial region. The increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. This article is intended to elaborate and enunciate on the various applications and benefits of CBCT, in the realm of maxillofacial prosthodontics, over and beyond its obvious benefits in the rehabilitation of patients with implants. With the onus of meticulous reconstruction of near ideal occlusion resting on the prosthodontist, CBCT provides a unique imaging option, which can be a boon in various aspects of prosthodontic practice - from imaging of the temporomandibular joint for accurate movement simulation, to template assisted maxillofacial reconstruction or even over denture therapy. CBCT could play a crucial role in lessening the burden of a hectic prosthodontic routine for the clinician and critically contribute to accurate and effective treatment for the patient. Apart from the authors' clinical experiences shared here, a web-based search for relevant articles in this specific area of interest was also conducted. The selected articles were critically reviewed and the data acquired were systematically compiled.

High-resolution x-ray computed tomography to understand ruminant phylogeny

NASA Astrophysics Data System (ADS)

Costeur, Loic; Schulz, Georg; Müller, Bert

2014-09-01

High-resolution X-ray computed tomography has become a vital technique to study fossils down to the true micrometer level. Paleontological research requires the non-destructive analysis of internal structures of fossil specimens. We show how X-ray computed tomography enables us to visualize the inner ear of extinct and extant ruminants without skull destruction. The inner ear, a sensory organ for hearing and balance has a rather complex three-dimensional morphology and thus provides relevant phylogenetical information what has been to date essentially shown in primates. We made visible the inner ears of a set of living and fossil ruminants using the phoenix x-ray nanotom®m (GE Sensing and Inspection Technologies GmbH). Because of the high absorbing objects a tungsten target was used and the experiments were performed with maximum accelerating voltage of 180 kV and a beam current of 30 μA. Possible stem ruminants of the living families are known in the fossil record but extreme morphological convergences in external structures such as teeth is a strong limitation to our understanding of the evolutionary history of this economically important group of animals. We thus investigate the inner ear to assess its phylogenetical potential for ruminants and our first results show strong family-level morphological differences.

Applications of cone beam computed tomography for a prosthodontist

PubMed Central

John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R. B.

2016-01-01

Cone beam computed tomography (CBCT) is a medical imaging technique of X-ray computed tomography where the X-rays are divergent, forming a cone. CBCT systems have been designed for imaging hard tissues of the maxillofacial region. The increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. This article is intended to elaborate and enunciate on the various applications and benefits of CBCT, in the realm of maxillofacial prosthodontics, over and beyond its obvious benefits in the rehabilitation of patients with implants. With the onus of meticulous reconstruction of near ideal occlusion resting on the prosthodontist, CBCT provides a unique imaging option, which can be a boon in various aspects of prosthodontic practice – from imaging of the temporomandibular joint for accurate movement simulation, to template assisted maxillofacial reconstruction or even over denture therapy. CBCT could play a crucial role in lessening the burden of a hectic prosthodontic routine for the clinician and critically contribute to accurate and effective treatment for the patient. Apart from the authors’ clinical experiences shared here, a web-based search for relevant articles in this specific area of interest was also conducted. The selected articles were critically reviewed and the data acquired were systematically compiled. PMID:27134420

Differential diagnosis of endodontic-related inferior alveolar nerve paraesthesia with cone beam computed tomography: a case report.

PubMed

Gambarini, G; Plotino, G; Grande, N M; Testarelli, L; Prencipe, M; Messineo, D; Fratini, L; D'Ambrosio, F

2011-02-01

To discuss the use of cone-beam computed tomography (CBCT) in the differential diagnosis of a case of labiomandibular paraesthesia caused by extrusion of endodontic sealer into the mandibular canal. A 59-year-old woman suffering from a paraesthesia on the left posterior mandible and numbness on the left side of the lower lip was referred to an endodontic specialist 1 month after multiple root canal treatments. A panoramic radiograph revealed the presence of extruded root filling material beyond the apex of the mesial root of the mandibular left second molar and also beyond the apex of the first premolar. A cone beam computed tomography examination was undertaken, which confirmed the presence of radiopaque root canal filling material in the periapical area of the second molar, and revealed that the material was inside the mandibular canal. No extruded filling material was found inside the mental foramen beyond the apex of the first premolar tooth. Small field of view CBCT (where possible) can be considered an effective radiographic diagnostic device when endodontic-related inferior alveolar nerve or mental foramen paraesthesia are suspected. CBCT is able to provide detailed three-dimensional images of the tooth, the root canal system and the surrounding tissue. © 2010 International Endodontic Journal.

Direct integration of the inverse Radon equation for X-ray computed tomography.

PubMed

Libin, E E; Chakhlov, S V; Trinca, D

2016-11-22

A new mathematical appoach using the inverse Radon equation for restoration of images in problems of linear two-dimensional x-ray tomography is formulated. In this approach, Fourier transformation is not used, and it gives the chance to create the practical computing algorithms having more reliable mathematical substantiation. Results of software implementation show that for especially for low number of projections, the described approach performs better than standard X-ray tomographic reconstruction algorithms.

3D noninvasive ultrasound Joule heat tomography based on acousto-electric effect using unipolar pulses: a simulation study

PubMed Central

Yang, Renhuan; Li, Xu; Song, Aiguo; He, Bin; Yan, Ruqiang

2012-01-01

Electrical properties of biological tissues are highly sensitive to their physiological and pathological status. Thus it is of importance to image electrical properties of biological tissues. However, spatial resolution of conventional electrical impedance tomography (EIT) is generally poor. Recently, hybrid imaging modalities combining electric conductivity contrast and ultrasonic resolution based on acouto-electric effect has attracted considerable attention. In this study, we propose a novel three-dimensional (3D) noninvasive ultrasound Joule heat tomography (UJHT) approach based on acouto-electric effect using unipolar ultrasound pulses. As the Joule heat density distribution is highly dependent on the conductivity distribution, an accurate and high resolution mapping of the Joule heat density distribution is expected to give important information that is closely related to the conductivity contrast. The advantages of the proposed ultrasound Joule heat tomography using unipolar pulses include its simple inverse solution, better performance than UJHT using common bipolar pulses and its independence of any priori knowledge of the conductivity distribution of the imaging object. Computer simulation results show that using the proposed method, it is feasible to perform a high spatial resolution Joule heat imaging in an inhomogeneous conductive media. Application of this technique on tumor scanning is also investigated by a series of computer simulations. PMID:23123757

Dual-modal three-dimensional imaging of single cells with isometric high resolution using an optical projection tomography microscope

NASA Astrophysics Data System (ADS)

Miao, Qin; Rahn, J. Richard; Tourovskaia, Anna; Meyer, Michael G.; Neumann, Thomas; Nelson, Alan C.; Seibel, Eric J.

2009-11-01

The practice of clinical cytology relies on bright-field microscopy using absorption dyes like hematoxylin and eosin in the transmission mode, while the practice of research microscopy relies on fluorescence microscopy in the epi-illumination mode. The optical projection tomography microscope is an optical microscope that can generate 3-D images of single cells with isometric high resolution both in absorption and fluorescence mode. Although the depth of field of the microscope objective is in the submicron range, it can be extended by scanning the objective's focal plane. The extended depth of field image is similar to a projection in a conventional x-ray computed tomography. Cells suspended in optical gel flow through a custom-designed microcapillary. Multiple pseudoprojection images are taken by rotating the microcapillary. After these pseudoprojection images are further aligned, computed tomography methods are applied to create 3-D reconstruction. 3-D reconstructed images of single cells are shown in both absorption and fluorescence mode. Fluorescence spatial resolution is measured at 0.35 μm in both axial and lateral dimensions. Since fluorescence and absorption images are taken in two different rotations, mechanical error may cause misalignment of 3-D images. This mechanical error is estimated to be within the resolution of the system.

Single photon emission computed tomography-guided Cerenkov luminescence tomography

NASA Astrophysics Data System (ADS)

Hu, Zhenhua; Chen, Xueli; Liang, Jimin; Qu, Xiaochao; Chen, Duofang; Yang, Weidong; Wang, Jing; Cao, Feng; Tian, Jie

2012-07-01

Cerenkov luminescence tomography (CLT) has become a valuable tool for preclinical imaging because of its ability of reconstructing the three-dimensional distribution and activity of the radiopharmaceuticals. However, it is still far from a mature technology and suffers from relatively low spatial resolution due to the ill-posed inverse problem for the tomographic reconstruction. In this paper, we presented a single photon emission computed tomography (SPECT)-guided reconstruction method for CLT, in which a priori information of the permissible source region (PSR) from SPECT imaging results was incorporated to effectively reduce the ill-posedness of the inverse reconstruction problem. The performance of the method was first validated with the experimental reconstruction of an adult athymic nude mouse implanted with a Na131I radioactive source and an adult athymic nude mouse received an intravenous tail injection of Na131I. A tissue-mimic phantom based experiment was then conducted to illustrate the ability of the proposed method in resolving double sources. Compared with the traditional PSR strategy in which the PSR was determined by the surface flux distribution, the proposed method obtained much more accurate and encouraging localization and resolution results. Preliminary results showed that the proposed SPECT-guided reconstruction method was insensitive to the regularization methods and ignored the heterogeneity of tissues which can avoid the segmentation procedure of the organs.

Toward atomic-scale bright-field electron tomography for the study of fullerene-like nanostructures.

PubMed

Bar Sadan, Maya; Houben, Lothar; Wolf, Sharon G; Enyashin, Andrey; Seifert, Gotthard; Tenne, Reshef; Urban, Knut

2008-03-01

We present the advancement of electron tomography for three-dimensional structure reconstruction of fullerene-like particles toward atomic-scale resolution. The three-dimensional reconstruction of nested molybdenum disulfide nanooctahedra is achieved by the combination of low voltage operation of the electron microscope with aberration-corrected phase contrast imaging. The method enables the study of defects and irregularities in the three-dimensional structure of individual fullerene-like particles on the scale of 2-3 A. Control over shape, size, and atomic architecture is a key issue in synthesis and design of functional nanoparticles. Transmission electron microscopy (TEM) is the primary technique to characterize materials down to the atomic level, albeit the images are two-dimensional projections of the studied objects. Recent advancements in aberration-corrected TEM have demonstrated single atom sensitivity for light elements at subångström resolution. Yet, the resolution of tomographic schemes for three-dimensional structure reconstruction has not surpassed 1 nm3, preventing it from becoming a powerful tool for characterization in the physical sciences on the atomic scale. Here we demonstrate that negative spherical aberration imaging at low acceleration voltage enables tomography down to the atomic scale at reduced radiation damage. First experimental data on the three-dimensional reconstruction of nested molybdenum disulfide nanooctahedra is presented. The method is applicable to the analysis of the atomic architecture of a wide range of nanostructures where strong electron channeling is absent, in particular to carbon fullerenes and inorganic fullerenes.

Effects of nasal septum perforation repair on nasal airflow: An analysis using computational fluid dynamics on preoperative and postoperative three-dimensional models.

PubMed

Nomura, Tsutomu; Ushio, Munetaka; Kondo, Kenji; Kikuchi, Shigeru

2018-10-01

The purpose of this research is to examine the changes in nasal airflow dynamics before and after the nasal perforation repair. Three dimensional (3D) models of the nasal cavity before and after septal perforation repair was reconstructed using preoperative and postoperative computed tomography (CT) images of a patient. The numerical simulation was carried out using ANSYS CFX V15.0. Pre- and post-operative models were compared by their velocity, pressure (P), pressure gradient (PG), wall shear (WS), shear strain rate (SSR) and turbulence kinetic energy (TKE) in three plains. In the post-operative state, the cross flows disappeared. In preoperative state, there were areas showing high PG, WS, SSR at the posterior border of the perforation, which exactly correspond to the area showing erosive mucosa on endoscopic inspection of the patient. In postoperative state, such high PG, WS and SSR areas disappeared. High TKEs also disappeared after surgery. The effects of septal perforation repair on airflow dynamics were evaluated using computer fluid dynamics (CFD). High WS, PG and SSR observed at the edge of the septal perforation may be related to the clinical symptom such as nasal bleeding and pain. TKE was considered to cause nasal symptom. Copyright © 2018 Elsevier B.V. All rights reserved.

Ultra-high resolution computed tomography imaging

DOEpatents

Paulus, Michael J.; Sari-Sarraf, Hamed; Tobin, Jr., Kenneth William; Gleason, Shaun S.; Thomas, Jr., Clarence E.

2002-01-01

A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

In-Situ Observations of Longitudinal Compression Damage in Carbon-Epoxy Cross Ply Laminates Using Fast Synchrotron Radiation Computed Tomography

NASA Technical Reports Server (NTRS)

Bergan, Andrew C.; Garcea, Serafina C.

2017-01-01

The role of longitudinal compressive failure mechanisms in notched cross-ply laminates is studied experimentally with in-situ synchrotron radiation based computed tomography. Carbon/epoxy specimens loaded monotonically in uniaxial compression exhibited a quasi-stable failure process, which was captured with computed tomography scans recorded continuously with a temporal resolutions of 2.4 seconds and a spatial resolution of 1.1 microns per voxel. A detailed chronology of the initiation and propagation of longitudinal matrix splitting cracks, in-plane and out-of-plane kink bands, shear-driven fiber failure, delamination, and transverse matrix cracks is provided with a focus on kink bands as the dominant failure mechanism. An automatic segmentation procedure is developed to identify the boundary surfaces of a kink band. The segmentation procedure enables 3-dimensional visualization of the kink band and conveys the orientation, inclination, and spatial variation of the kink band. The kink band inclination and length are examined using the segmented data revealing tunneling and spatial variations not apparent from studying the 2-dimensional section data.

Kinematic reconstruction in cardiovascular imaging.

PubMed

Bastarrika, G; Huebra Rodríguez, I J González de la; Calvo-Imirizaldu, M; Suárez Vega, V M; Alonso-Burgos, A

2018-05-17

Advances in clinical applications of computed tomography have been accompanied by improvements in advanced post-processing tools. In addition to multiplanar reconstructions, curved planar reconstructions, maximum intensity projections, and volumetric reconstructions, very recently kinematic reconstruction has been developed. This new technique, based on mathematical models that simulate the propagation of light beams through a volume of data, makes it possible to obtain very realistic three dimensional images. This article illustrates examples of kinematic reconstructions and compares them with classical volumetric reconstructions in patients with cardiovascular disease in a way that makes it easy to establish the differences between the two types of reconstruction. Kinematic reconstruction is a new method for representing three dimensional images that facilitates the explanation and comprehension of the findings. Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Small-angle X-ray scattering tensor tomography: model of the three-dimensional reciprocal-space map, reconstruction algorithm and angular sampling requirements.

PubMed

Liebi, Marianne; Georgiadis, Marios; Kohlbrecher, Joachim; Holler, Mirko; Raabe, Jörg; Usov, Ivan; Menzel, Andreas; Schneider, Philipp; Bunk, Oliver; Guizar-Sicairos, Manuel

2018-01-01

Small-angle X-ray scattering tensor tomography, which allows reconstruction of the local three-dimensional reciprocal-space map within a three-dimensional sample as introduced by Liebi et al. [Nature (2015), 527, 349-352], is described in more detail with regard to the mathematical framework and the optimization algorithm. For the case of trabecular bone samples from vertebrae it is shown that the model of the three-dimensional reciprocal-space map using spherical harmonics can adequately describe the measured data. The method enables the determination of nanostructure orientation and degree of orientation as demonstrated previously in a single momentum transfer q range. This article presents a reconstruction of the complete reciprocal-space map for the case of bone over extended ranges of q. In addition, it is shown that uniform angular sampling and advanced regularization strategies help to reduce the amount of data required.

Stereolithography: a potential new tool in forensic medicine.

PubMed

Dolz, M S; Cina, S J; Smith, R

2000-06-01

Stereolithography is a computer-mediated method that can be used to quickly create anatomically correct three-dimensional epoxy and acrylic resin models from various types of medical data. Multiple imaging modalities can be exploited, including computed tomography and magnetic resonance imaging. The technology was first developed and used in 1986 to overcome limitations in previous computer-aided manufacturing/milling techniques. Stereolithography is presently used to accurately reproduce both the external and internal anatomy of body structures. Current medical uses of stereolithography include preoperative planning of orthopedic and maxillofacial surgeries, the fabrication of custom prosthetic devices; and the assessment of the degree of bony and soft-tissue injury caused by trauma. We propose that there is a useful, as yet untapped, potential for this technology in forensic medicine.

Study of Image Qualities From 6D Robot-Based CBCT Imaging System of Small Animal Irradiator.

PubMed

Sharma, Sunil; Narayanasamy, Ganesh; Clarkson, Richard; Chao, Ming; Moros, Eduardo G; Zhang, Xin; Yan, Yulong; Boerma, Marjan; Paudel, Nava; Morrill, Steven; Corry, Peter; Griffin, Robert J

2017-01-01

To assess the quality of cone beam computed tomography images obtained by a robotic arm-based and image-guided small animal conformal radiation therapy device. The small animal conformal radiation therapy device is equipped with a 40 to 225 kV X-ray tube mounted on a custom made gantry, a 1024 × 1024 pixels flat panel detector (200 μm resolution), a programmable 6 degrees of freedom robot for cone beam computed tomography imaging and conformal delivery of radiation doses. A series of 2-dimensional radiographic projection images were recorded in cone beam mode by placing and rotating microcomputed tomography phantoms on the "palm' of the robotic arm. Reconstructed images were studied for image quality (spatial resolution, image uniformity, computed tomography number linearity, voxel noise, and artifacts). Geometric accuracy was measured to be 2% corresponding to 0.7 mm accuracy on a Shelley microcomputed tomography QA phantom. Qualitative resolution of reconstructed axial computed tomography slices using the resolution coils was within 200 μm. Quantitative spatial resolution was found to be 3.16 lp/mm. Uniformity of the system was measured within 34 Hounsfield unit on a QRM microcomputed tomography water phantom. Computed tomography numbers measured using the linearity plate were linear with material density ( R 2 > 0.995). Cone beam computed tomography images of the QRM multidisk phantom had minimal artifacts. Results showed that the small animal conformal radiation therapy device is capable of producing high-quality cone beam computed tomography images for precise and conformal small animal dose delivery. With its high-caliber imaging capabilities, the small animal conformal radiation therapy device is a powerful tool for small animal research.

A computationally inexpensive model for estimating dimensional measurement uncertainty due to x-ray computed tomography instrument misalignments

NASA Astrophysics Data System (ADS)

Ametova, Evelina; Ferrucci, Massimiliano; Chilingaryan, Suren; Dewulf, Wim

2018-06-01

The recent emergence of advanced manufacturing techniques such as additive manufacturing and an increased demand on the integrity of components have motivated research on the application of x-ray computed tomography (CT) for dimensional quality control. While CT has shown significant empirical potential for this purpose, there is a need for metrological research to accelerate the acceptance of CT as a measuring instrument. The accuracy in CT-based measurements is vulnerable to the instrument geometrical configuration during data acquisition, namely the relative position and orientation of x-ray source, rotation stage, and detector. Consistency between the actual instrument geometry and the corresponding parameters used in the reconstruction algorithm is critical. Currently available procedures provide users with only estimates of geometrical parameters. Quantification and propagation of uncertainty in the measured geometrical parameters must be considered to provide a complete uncertainty analysis and to establish confidence intervals for CT dimensional measurements. In this paper, we propose a computationally inexpensive model to approximate the influence of errors in CT geometrical parameters on dimensional measurement results. We use surface points extracted from a computer-aided design (CAD) model to model discrepancies in the radiographic image coordinates assigned to the projected edges between an aligned system and a system with misalignments. The efficacy of the proposed method was confirmed on simulated and experimental data in the presence of various geometrical uncertainty contributors.

Online service for monitoring the ionosphere based on data from the global navigation satellite system

NASA Astrophysics Data System (ADS)

Aleshin, I. M.; Alpatov, V. V.; Vasil'ev, A. E.; Burguchev, S. S.; Kholodkov, K. I.; Budnikov, P. A.; Molodtsov, D. A.; Koryagin, V. N.; Perederin, F. V.

2014-07-01

A service is described that makes possible the effective construction of a three-dimensional ionospheric model based on the data of ground receivers of signals from global navigation satellite positioning systems (GNSS). The obtained image has a high resolution, mainly because data from the IPG GNSS network of the Federal Service for Hydrometeorology and Environmental Monitoring (Rosgidromet) are used. A specially developed format and its implementation in the form of SQL structures are used to collect, transmit, and store data. The method of high-altitude radio tomography is used to construct the three-dimensional model. The operation of all system components (from registration point organization to the procedure for constructing the electron density three-dimensional distribution and publication of the total electron content map on the Internet) has been described in detail. The three-dimensional image of the ionosphere, obtained automatically, is compared with the ionosonde measurements, calculated using the two-dimensional low-altitude tomography method and averaged by the ionospheric model.

Representation of photon limited data in emission tomography using origin ensembles

NASA Astrophysics Data System (ADS)

Sitek, A.

2008-06-01

Representation and reconstruction of data obtained by emission tomography scanners are challenging due to high noise levels in the data. Typically, images obtained using tomographic measurements are represented using grids. In this work, we define images as sets of origins of events detected during tomographic measurements; we call these origin ensembles (OEs). A state in the ensemble is characterized by a vector of 3N parameters Y, where the parameters are the coordinates of origins of detected events in a three-dimensional space and N is the number of detected events. The 3N-dimensional probability density function (PDF) for that ensemble is derived, and we present an algorithm for OE image estimation from tomographic measurements. A displayable image (e.g. grid based image) is derived from the OE formulation by calculating ensemble expectations based on the PDF using the Markov chain Monte Carlo method. The approach was applied to computer-simulated 3D list-mode positron emission tomography data. The reconstruction errors for a 10 000 000 event acquisition for simulated ranged from 0.1 to 34.8%, depending on object size and sampling density. The method was also applied to experimental data and the results of the OE method were consistent with those obtained by a standard maximum-likelihood approach. The method is a new approach to representation and reconstruction of data obtained by photon-limited emission tomography measurements.

Recent advances in Optical Computed Tomography (OCT) imaging system for three dimensional (3D) radiotherapy dosimetry

NASA Astrophysics Data System (ADS)

Rahman, Ahmad Taufek Abdul; Farah Rosli, Nurul; Zain, Shafirah Mohd; Zin, Hafiz M.

2018-01-01

Radiotherapy delivery techniques for cancer treatment are becoming more complex and highly focused, to enable accurate radiation dose delivery to the cancerous tissue and minimum dose to the healthy tissue adjacent to tumour. Instrument to verify the complex dose delivery in radiotherapy such as optical computed tomography (OCT) measures the dose from a three-dimensional (3D) radiochromic dosimeter to ensure the accuracy of the radiotherapy beam delivery to the patient. OCT measures the optical density in radiochromic material that changes predictably upon exposure to radiotherapy beams. OCT systems have been developed using a photodiode and charged coupled device (CCD) as the detector. The existing OCT imaging systems have limitation in terms of the accuracy and the speed of the measurement. Advances in on-pixel intelligence CMOS image sensor (CIS) will be exploited in this work to replace current detector in OCT imaging systems. CIS is capable of on-pixel signal processing at a very fast imaging speed (over several hundred images per second) that will allow improvement in the 3D measurement of the optical density. The paper will review 3D radiochromic dosimeters and OCT systems developed and discuss how CMOS based OCT imaging will provide accurate and fast optical density measurements in 3D. The paper will also discuss the configuration of the CMOS based OCT developed in this work and how it may improve the existing OCT system.

The use of cone beam computed tomography and three dimensional printing technology in the restoration of a maxillectomy patient using a dental implant retained obturator.

PubMed

Michelinakis, George

2017-01-01

This case report presents an alternative method for fabricating an obturator for patients that develop xerostomia and mild trismus following radiation to the Head and Neck region. Multiple initial impression stages are avoided leading to less irritation to soft tissues and less discomfort to the patient. A 69-year-old male patient was referred to our dental practice by the Maxillofacial Surgery Department of the local General Hospital. The patient had undergone a right maxillectomy for removal of a Squamous Cell Carcinoma 2 weeks prior. Four endosseous dental implants were placed in the remaining upper jaw and 2 implants were inserted into the canine region of his edentulous mandible 3 weeks after ablative surgery. Five months following completion of radiotherapy and chemotherapy, a cone beam computed tomography of the maxilla was obtained, and a three dimensional model was constructed using an appropriate resin. Using the model as the detailed primary cast, a custom acrylic special tray was fabricated for the final impression of the remaining maxilla and the maxillary defect. An implant retained maxillary obturator and an implant retained mandibular overdenture were constructed to restore patient's speech, mastication and deglutition. The method presented here can limit the impression stages needed for construction of a maxillary obturator prosthesis to a single impression procedure advocating a partial digital workflow process. This can be very beneficial to the patient suffering from postradiation side-effects such as trismus, mucositis, and xerostomia.

[In vivo anatomical study of inferior attachment of renal fascia in adult with acute pancreatitis as shown on multidetector computed tomography].

PubMed

Qi, Rui; Zhou, Xiangping; Yu, Jianqun; Li, Zhenlin

2014-04-01

This study aims to explore the inferior adhesion of the renal fascia (RF), and the inferior connectivity of the perirenal spaces (PS) with multidetector computed tomography (MDCT), and to investigate the diagnostic value of CT for showing this anatomy. From May to July 2012, eighty-two patients with acute pancreatitis presented in our hospital were enrolled into this study and underwent contrast-enhanced CT scans. All the image data were used to perform three dimensional reconstruction to show the inferior attachment of RF and the inferior connectivity of PS. The fusion of anterior renal fascia (ARF) and posterior renal fascia (PRF) next to the plane of iliac fossa were found on the left in 71.95% (59/82) cases, and on the right in 75.61% (62/82). In these cases, bilateral perirenal spaces, and anterior and posterior pararenal spaces were not found to be connected with each other. No fusion of ARF and PRF below the level of bilateral kidneys occurred on the left side in 28.05% (23/82) cases and on the right side in 24.39% (20/82). In these patients, the PS extended to the extraperitoneal space of the pelvic cavity and further to the inguinal region, and bilateral anterior and posterior pararenal spaces were not found to be connected with each other. Three-dimensional reconstruction on contrast-enhanced MDCT could be a valuable procedure for depicting inferior attachment of RF, and the inferior connectivity of PS.

Three-dimensional representation of the human cochlea using micro-computed tomography data: presenting an anatomical model for further numerical calculations.

PubMed

Braun, Katharina; Böhnke, Frank; Stark, Thomas

2012-06-01

We present a complete geometric model of the human cochlea, including the segmentation and reconstruction of the fluid-filled chambers scala tympani and scala vestibuli, the lamina spiralis ossea and the vibrating structure (cochlear partition). Future fluid-structure coupled simulations require a reliable geometric model of the cochlea. The aim of this study was to present an anatomical model of the human cochlea, which can be used for further numerical calculations. Using high resolution micro-computed tomography (µCT), we obtained images of a cut human temporal bone with a spatial resolution of 5.9 µm. Images were manually segmented to obtain the three-dimensional reconstruction of the cochlea. Due to the high resolution of the µCT data, a detailed examination of the geometry of the twisted cochlear partition near the oval and the round window as well as the precise illustration of the helicotrema was possible. After reconstruction of the lamina spiralis ossea, the cochlear partition and the curved geometry of the scala vestibuli and the scala tympani were presented. The obtained data sets were exported as standard lithography (stl) files. These files represented a complete framework for future numerical simulations of mechanical (acoustic) wave propagation on the cochlear partition in the form of mathematical mechanical cochlea models. Additional quantitative information concerning heights, lengths and volumes of the scalae was found and compared with previous results.

Three-dimensional radiation dosimetry using polymer gel and solid radiochromic polymer: From basics to clinical applications

PubMed Central

Watanabe, Yoichi; Warmington, Leighton; Gopishankar, N

2017-01-01

Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the material property in response to radiation. These are available in the gel form as polymer gel dosimeter (PGD) and ferrous gel dosimeter (FGD) and in the solid form as solid plastic dosimeter (SPD). Those are made of a continuous uniform medium which polymerizes upon irradiation. Hence, the intrinsic spatial resolution of those dosimeters is very high, and it is only limited by the method by which one converts the dose information recorded by the medium to the absorbed dose. The current standard methods of the dose quantification are magnetic resonance imaging, optical computed tomography, and X-ray computed tomography. In particular, magnetic resonance imaging is well established as a method for obtaining clinically relevant dosimetric data by PGD and FGD. Despite the likely possibility of doing 3D dosimetry by PGD, FGD or SPD, the tools are still lacking wider usages for clinical applications. In this review article, we summarize the current status of PGD, FGD, and SPD and discuss the issue faced by these for wider acceptance in radiation oncology clinic and propose some directions for future development. PMID:28396725

Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: a phantom study.

PubMed

Hwang, Sung Ho; Oh, Yu-Whan; Ham, Soo-Youn; Kang, Eun-Young; Lee, Ki Yeol

2015-01-01

To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 ± 5.3%), with an IVV of 13.1 ± 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

Multimodality 3D Superposition and Automated Whole Brain Tractography: Comprehensive Printing of the Functional Brain

PubMed Central

Brimley, Cameron J; Sublett, Jesna Mathew; Stefanowicz, Edward; Flora, Sarah; Mongelluzzo, Gino; Schirmer, Clemens M

2017-01-01

Whole brain tractography using diffusion tensor imaging (DTI) sequences can be used to map cerebral connectivity; however, this can be time-consuming due to the manual component of image manipulation required, calling for the need for a standardized, automated, and accurate fiber tracking protocol with automatic whole brain tractography (AWBT). Interpreting conventional two-dimensional (2D) images, such as computed tomography (CT) and magnetic resonance imaging (MRI), as an intraoperative three-dimensional (3D) environment is a difficult task with recognized inter-operator variability. Three-dimensional printing in neurosurgery has gained significant traction in the past decade, and as software, equipment, and practices become more refined, trainee education, surgical skills, research endeavors, innovation, patient education, and outcomes via valued care is projected to improve. We describe a novel multimodality 3D superposition (MMTS) technique, which fuses multiple imaging sequences alongside cerebral tractography into one patient-specific 3D printed model. Inferences on cost and improved outcomes fueled by encouraging patient engagement are explored. PMID:29201580

Real-time three-dimensional ultrasound-assisted axillary plexus block defines soft tissue planes.

PubMed

Clendenen, Steven R; Riutort, Kevin; Ladlie, Beth L; Robards, Christopher; Franco, Carlo D; Greengrass, Roy A

2009-04-01

Two-dimensional (2D) ultrasound is commonly used for regional block of the axillary brachial plexus. In this technical case report, we described a real-time three-dimensional (3D) ultrasound-guided axillary block. The difference between 2D and 3D ultrasound is similar to the difference between plain radiograph and computer tomography. Unlike 2D ultrasound that captures a planar image, 3D ultrasound technology acquires a 3D volume of information that enables multiple planes of view by manipulating the image without movement of the ultrasound probe. Observation of the brachial plexus in cross-section demonstrated distinct linear hyperechoic tissue structures (loose connective tissue) that initially inhibited the flow of the local anesthesia. After completion of the injection, we were able to visualize the influence of arterial pulsation on the spread of the local anesthesia. Possible advantages of this novel technology over current 2D methods are wider image volume and the capability to manipulate the planes of the image without moving the probe.

Multimodality 3D Superposition and Automated Whole Brain Tractography: Comprehensive Printing of the Functional Brain.

PubMed

Konakondla, Sanjay; Brimley, Cameron J; Sublett, Jesna Mathew; Stefanowicz, Edward; Flora, Sarah; Mongelluzzo, Gino; Schirmer, Clemens M

2017-09-29

Whole brain tractography using diffusion tensor imaging (DTI) sequences can be used to map cerebral connectivity; however, this can be time-consuming due to the manual component of image manipulation required, calling for the need for a standardized, automated, and accurate fiber tracking protocol with automatic whole brain tractography (AWBT). Interpreting conventional two-dimensional (2D) images, such as computed tomography (CT) and magnetic resonance imaging (MRI), as an intraoperative three-dimensional (3D) environment is a difficult task with recognized inter-operator variability. Three-dimensional printing in neurosurgery has gained significant traction in the past decade, and as software, equipment, and practices become more refined, trainee education, surgical skills, research endeavors, innovation, patient education, and outcomes via valued care is projected to improve. We describe a novel multimodality 3D superposition (MMTS) technique, which fuses multiple imaging sequences alongside cerebral tractography into one patient-specific 3D printed model. Inferences on cost and improved outcomes fueled by encouraging patient engagement are explored.

Forensic microradiology: micro-computed tomography (Micro-CT) and analysis of patterned injuries inside of bone.

PubMed

Thali, Michael J; Taubenreuther, Ulrike; Karolczak, Marek; Braun, Marcel; Brueschweiler, Walter; Kalender, Willi A; Dirnhofer, Richard

2003-11-01

When a knife is stabbed in bone, it leaves an impression in the bone. The characteristics (shape, size, etc.) may indicate the type of tool used to produce the patterned injury in bone. Until now it has been impossible in forensic sciences to document such damage precisely and non-destructively. Micro-computed tomography (Micro-CT) offers an opportunity to analyze patterned injuries of tool marks made in bone. Using high-resolution Micro-CT and computer software, detailed analysis of three-dimensional (3D) architecture has recently become feasible and allows microstructural 3D bone information to be collected. With adequate viewing software, data from 2D slice of an arbitrary plane can be extracted from 3D datasets. Using such software as a "digital virtual knife," the examiner can interactively section and analyze the 3D sample. Analysis of the bone injury revealed that Micro-CT provides an opportunity to correlate a bone injury to an injury-causing instrument. Even broken knife tips can be graphically and non-destructively assigned to a suspect weapon.

Accuracy of Cup Positioning With the Computed Tomography-Based Two-dimensional to Three-Dimensional Matched Navigation System: A Prospective, Randomized Controlled Study.

PubMed

Yamada, Kazuki; Endo, Hirosuke; Tetsunaga, Tomonori; Miyake, Takamasa; Sanki, Tomoaki; Ozaki, Toshifumi

2018-01-01

The accuracy of various navigation systems used for total hip arthroplasty has been described, but no publications reported the accuracy of cup orientation in computed tomography (CT)-based 2D-3D (two-dimensional to three-dimensional) matched navigation. In a prospective, randomized controlled study, 80 hips including 44 with developmental dysplasia of the hips were divided into a CT-based 2D-3D matched navigation group (2D-3D group) and a paired-point matched navigation group (PPM group). The accuracy of cup orientation (absolute difference between the intraoperative record and the postoperative measurement) was compared between groups. Additionally, multiple logistic regression analysis was performed to evaluate patient factors affecting the accuracy of cup orientation in each navigation. The accuracy of cup inclination was 2.5° ± 2.2° in the 2D-3D group and 4.6° ± 3.3° in the PPM group (P = .0016). The accuracy of cup anteversion was 2.3° ± 1.7° in the 2D-3D group and 4.4° ± 3.3° in the PPM group (P = .0009). In the PPM group, the presence of roof osteophytes decreased the accuracy of cup inclination (odds ratio 8.27, P = .0140) and the absolute value of pelvic tilt had a negative influence on the accuracy of cup anteversion (odds ratio 1.27, P = .0222). In the 2D-3D group, patient factors had no effect on the accuracy of cup orientation. The accuracy of cup positioning in CT-based 2D-3D matched navigation was better than in paired-point matched navigation, and was not affected by patient factors. It is a useful system for even severely deformed pelvises such as developmental dysplasia of the hips. Copyright © 2017 Elsevier Inc. All rights reserved.

Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery.

PubMed

Pasricha, Neel D; Bhullar, Paramjit K; Shieh, Christine; Carrasco-Zevallos, Oscar M; Keller, Brenton; Izatt, Joseph A; Toth, Cynthia A; Freedman, Sharon F; Kuo, Anthony N

2017-02-14

The authors report the use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT), capable of live four-dimensional (three-dimensional across time) intraoperative imaging, to directly visualize suture depth during lateral rectus resection. Key surgical steps visualized in this report included needle depth during partial and full-thickness muscle passes along with scleral passes. [J Pediatr Ophthalmol Strabismus. 2017;54:e1-e5.]. Copyright 2017, SLACK Incorporated.

[Pulmonary atelectasis in patients with neurological or muscular disease; gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position].

PubMed

Toyoshima, Mitsuo; Maeoka, Yukinori; Kawahara, Hitoshi; Maegaki, Yoshihiro; Ohno, Kousaku

2006-11-01

We report 10 cases of pulmonary atelectasis diagnosed by chest computed tomography in patients with neurological or muscular disease. Atelectasis was frequently seen in hypotonic patients who could not roll over on their own. The atelectases located mostly in the dorsal bronchopulmonary segments, adjacent to the heart or diaphragm. Atelectasis diminished in two patients after they became able to roll themselves over. Gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position can cause pulmonary atelectasis in patients with neurological or muscular disease who can not roll over by their own power. To confirm that the prone position reduces compression of the lungs, chest computed tomography was performed in both the supine and the prone position in three patients. Sagittal images with three-dimensional computed tomographic reconstruction revealed significant sternad displacements of the heart and caudal displacements of the dorsal portion of the diaphragm on prone position compared with supine position. The prone position, motor exercises for rolling over, and biphasic cuirass ventilation are effective in reducing gravity-related lung compression. Some patients with intellectual disabilities were also able to cooperate in chest physiotherapy. Chest physiotherapy is useful in preventing atelectasis in patients with neurological or muscular disease.

Cone-Beam Computed Tomography Evaluation of Horizontal and Vertical Dimensional Changes in Buccal Peri-Implant Alveolar Bone and Soft Tissue: A 1-Year Prospective Clinical Study.

PubMed

Kaminaka, Akihiro; Nakano, Tamaki; Ono, Shinji; Kato, Tokinori; Yatani, Hirofumi

2015-10-01

This study evaluated changes in the horizontal and vertical dimensions of the buccal alveolar bone and soft tissue over a 1-year period following implant prosthesis. Thirty-three participants with no history of guided bone regeneration or soft tissue augmentation underwent dental implant placement with different types of connections. The dimensions of the buccal alveolar bone and soft tissue were evaluated immediately and at 1 year after prosthesis from reconstructions of cross-sectional cone-beam computed tomography images. The vertical and horizontal loss of buccal bone and soft tissue around implants with conical connections were lower than around those with external or internal connections. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone and soft tissue height (p < .05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (p < .05). Implants with a conical connection preserve peri-implant alveolar bone and soft tissue more effectively than other connection types. Furthermore, the initial buccal alveolar bone and soft tissue thickness around the implant platform may influence their vertical dimensional changes at 1 year after implant prosthesis. © 2014 Wiley Periodicals, Inc.

3D printing from microfocus computed tomography (micro-CT) in human specimens: education and future implications.

PubMed

Shelmerdine, Susan C; Simcock, Ian C; Hutchinson, John Ciaran; Aughwane, Rosalind; Melbourne, Andrew; Nikitichev, Daniil I; Ong, Ju-Ling; Borghi, Alessandro; Cole, Garrard; Kingham, Emilia; Calder, Alistair D; Capelli, Claudio; Akhtar, Aadam; Cook, Andrew C; Schievano, Silvia; David, Anna; Ourselin, Sebastian; Sebire, Neil J; Arthurs, Owen J

2018-06-14

Microfocus CT (micro-CT) is an imaging method that provides three-dimensional digital data sets with comparable resolution to light microscopy. Although it has traditionally been used for non-destructive testing in engineering, aerospace industries and in preclinical animal studies, new applications are rapidly becoming available in the clinical setting including post-mortem fetal imaging and pathological specimen analysis. Printing three-dimensional models from imaging data sets for educational purposes is well established in the medical literature, but typically using low resolution (0.7 mm voxel size) data acquired from CT or MR examinations. With higher resolution imaging (voxel sizes below 1 micron, <0.001 mm) at micro-CT, smaller structures can be better characterised, and data sets post-processed to create accurate anatomical models for review and handling. In this review, we provide examples of how three-dimensional printing of micro-CT imaged specimens can provide insight into craniofacial surgical applications, developmental cardiac anatomy, placental imaging, archaeological remains and high-resolution bone imaging. We conclude with other potential future usages of this emerging technique.

Novel Arch Bar Fabricated With a Computer-Aided Design and Three-Dimensional Printing: A Feasibility Study.

PubMed

He, Wei; Sun, Yuchun; Tian, Kaiyue; Xie, Xiaoyan; Wang, Xiaoxia; Li, Zili

2015-11-01

The aim of the present study was to evaluate the feasibility of the design and fabrication of a novel arch bar using 3-dimensional printing. Furthermore, the study assessed its use in a preliminary clinical study of intermaxillary fixation. Seven patients who met the inclusion criteria were enrolled in the present study. Plaster dental casts were created of each patient and scanned using cone-beam computed tomography to obtain digital casts. Computer-aided design software was then used to complete the virtual building of the arch bars, which were manufactured using 3-dimensional printing and a cobalt-chrome alloy. The clinical results were observed after the arch bars were fixed to the dentition with steel wires. The arch bar contacted the dentition with a "surface-to-surface" pattern. The utility of these novel arch bars was verified by successfully fitting them to the dental arches of the patients. All the patients achieved their desired occlusion. The results of the present study have illustrated that this digital method is feasible for constructing a novel arch bar, showing promise for clinical use. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Computed tomography-based finite element analysis to assess fracture risk and osteoporosis treatment

PubMed Central

Imai, Kazuhiro

2015-01-01

Finite element analysis (FEA) is a computer technique of structural stress analysis and developed in engineering mechanics. FEA has developed to investigate structural behavior of human bones over the past 40 years. When the faster computers have acquired, better FEA, using 3-dimensional computed tomography (CT) has been developed. This CT-based finite element analysis (CT/FEA) has provided clinicians with useful data. In this review, the mechanism of CT/FEA, validation studies of CT/FEA to evaluate accuracy and reliability in human bones, and clinical application studies to assess fracture risk and effects of osteoporosis medication are overviewed. PMID:26309819

Diagnostic tools in maxillofacial fractures: Is there really a need of three-dimensional computed tomography?

PubMed Central

Shah, Sheerin; Uppal, Sanjeev K.; Mittal, Rajinder K.; Garg, Ramneesh; Saggar, Kavita; Dhawan, Rishi

2016-01-01

Introduction: Because of its functional and cosmetic importance, facial injuries, especially bony fractures are clinically very significant. Missed and maltreated fractures might result in malocclusion and disfigurement of the face, thus making accurate diagnosis of the fracture very essential. In earlier times, conventional radiography along with clinical examination played a major role in diagnosis of maxillofacial fractures. However, it was noted that the overlapping nature of bones and the inability to visualise soft tissue swelling and fracture displacement, especially in face, makes radiography less reliable and useful. Computed tomography (CT), also called as X-ray computed radiography, has helped in solving this problem. This clinical study is to compare three-dimensional (3D) CT reconstruction with conventional radiography in evaluating the maxillofacial fractures preoperatively and effecting the surgical management, accordingly. Materials and Methods: Fifty patients, with suspected maxillofacial fractures on clinical examination, were subjected to conventional radiography and CT face with 3D reconstruction. The number and site of fractures in zygoma, maxilla, mandible and nose, detected by both the methods, were enumerated and compared. The final bearing of these additional fractures, on the management protocol, was analysed. Results: CT proved superior to conventional radiography in diagnosing additional number of fractures in zygoma, maxilla, mandible (subcondylar) and nasal bone. Coronal and axial images were found to be significantly more diagnostic in fracture sites such as zygomaticomaxillary complex, orbital floor, arch, lateral maxillary wall and anterior maxillary wall. Conclusion: 3D images gave an inside out picture of the actual sites of fractures. It acted as mind's eye for pre-operative planning and intra-operative execution of surgery. Better surgical treatment could be given to 33% of the cases because of better diagnostic ability of CT. PMID:27833286

Diagnostic tools in maxillofacial fractures: Is there really a need of three-dimensional computed tomography?

PubMed

Shah, Sheerin; Uppal, Sanjeev K; Mittal, Rajinder K; Garg, Ramneesh; Saggar, Kavita; Dhawan, Rishi

2016-01-01

Because of its functional and cosmetic importance, facial injuries, especially bony fractures are clinically very significant. Missed and maltreated fractures might result in malocclusion and disfigurement of the face, thus making accurate diagnosis of the fracture very essential. In earlier times, conventional radiography along with clinical examination played a major role in diagnosis of maxillofacial fractures. However, it was noted that the overlapping nature of bones and the inability to visualise soft tissue swelling and fracture displacement, especially in face, makes radiography less reliable and useful. Computed tomography (CT), also called as X-ray computed radiography, has helped in solving this problem. This clinical study is to compare three-dimensional (3D) CT reconstruction with conventional radiography in evaluating the maxillofacial fractures preoperatively and effecting the surgical management, accordingly. Fifty patients, with suspected maxillofacial fractures on clinical examination, were subjected to conventional radiography and CT face with 3D reconstruction. The number and site of fractures in zygoma, maxilla, mandible and nose, detected by both the methods, were enumerated and compared. The final bearing of these additional fractures, on the management protocol, was analysed. CT proved superior to conventional radiography in diagnosing additional number of fractures in zygoma, maxilla, mandible (subcondylar) and nasal bone. Coronal and axial images were found to be significantly more diagnostic in fracture sites such as zygomaticomaxillary complex, orbital floor, arch, lateral maxillary wall and anterior maxillary wall. 3D images gave an inside out picture of the actual sites of fractures. It acted as mind's eye for pre-operative planning and intra-operative execution of surgery. Better surgical treatment could be given to 33% of the cases because of better diagnostic ability of CT.

A Method for Identifying Contours in Processing Digital Images from Computer Tomograph

NASA Astrophysics Data System (ADS)

Roşu, Şerban; Pater, Flavius; Costea, Dan; Munteanu, Mihnea; Roşu, Doina; Fratila, Mihaela

2011-09-01

The first step in digital processing of two-dimensional computed tomography images is to identify the contour of component elements. This paper deals with the collective work of specialists in medicine and applied mathematics in computer science on elaborating new algorithms and methods in medical 2D and 3D imagery.

[Three-dimensional reconstruction of functional brain images].

PubMed

Inoue, M; Shoji, K; Kojima, H; Hirano, S; Naito, Y; Honjo, I

1999-08-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: 1) routine images by SPM, 2) three-dimensional static images, and 3) three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface model is the most common method of three-dimensional display. However, the volume rendering method may be more effective for imaging regions such as the brain.

A forward-adjoint operator pair based on the elastic wave equation for use in transcranial photoacoustic computed tomography

PubMed Central

Mitsuhashi, Kenji; Poudel, Joemini; Matthews, Thomas P.; Garcia-Uribe, Alejandro; Wang, Lihong V.; Anastasio, Mark A.

2017-01-01

Photoacoustic computed tomography (PACT) is an emerging imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to an inverse source problem in which the initial pressure distribution is recovered from measurements of the radiated wavefield. A major challenge in transcranial PACT brain imaging is compensation for aberrations in the measured data due to the presence of the skull. Ultrasonic waves undergo absorption, scattering and longitudinal-to-shear wave mode conversion as they propagate through the skull. To properly account for these effects, a wave-equation-based inversion method should be employed that can model the heterogeneous elastic properties of the skull. In this work, a forward model based on a finite-difference time-domain discretization of the three-dimensional elastic wave equation is established and a procedure for computing the corresponding adjoint of the forward operator is presented. Massively parallel implementations of these operators employing multiple graphics processing units (GPUs) are also developed. The developed numerical framework is validated and investigated in computer19 simulation and experimental phantom studies whose designs are motivated by transcranial PACT applications. PMID:29387291

3D printing from cardiovascular CT: a practical guide and review

PubMed Central

Birbara, Nicolette S.; Hussain, Tarique; Greil, Gerald; Foley, Thomas A.; Pather, Nalini

2017-01-01

Current cardiovascular imaging techniques allow anatomical relationships and pathological conditions to be captured in three dimensions. Three-dimensional (3D) printing, or rapid prototyping, has also become readily available and made it possible to transform virtual reconstructions into physical 3D models. This technology has been utilised to demonstrate cardiovascular anatomy and disease in clinical, research and educational settings. In particular, 3D models have been generated from cardiovascular computed tomography (CT) imaging data for purposes such as surgical planning and teaching. This review summarises applications, limitations and practical steps required to create a 3D printed model from cardiovascular CT. PMID:29255693

Visualization of subcutaneous insulin injections by x-ray computed tomography

NASA Astrophysics Data System (ADS)

Thomsen, M.; Poulsen, M.; Bech, M.; Velroyen, A.; Herzen, J.; Beckmann, F.; Feidenhans'l, R.; Pfeiffer, F.

2012-11-01

We report how the three-dimensional structure of subcutaneous injections of soluble insulin can be visualized by x-ray computed tomography using an iodine based contrast agent. The injections investigated are performed ex vivo in porcine adipose tissue. Full tomography scans carried out at a laboratory x-ray source with a total acquisition time of about 1 min yield CT-images with an effective pixel size of 109 × 109 μm2. The depots are segmented using a modified Chan-Vese algorithm and we are able to observe differences in the shape of the injection depot and the position of the depot in the skin among equally performed injections. To overcome the beam hardening artefacts, which affect the quantitative prediction of the volume injected, we additionally present results concerning the visualization of two injections using synchrotron radiation. The spatial concentration distribution of iodine is calculated to show the dilution of the insulin drug inside the depot. Characterisation of the shape of the depot and the spatial concentration profile of the injected fluid is important knowledge when improving the clinical formulation of an insulin drug, the performance of injection devices and when predicting the effect of the drug through biomedical simulations.

X-ray computed tomography applied to investigate ancient manuscripts

NASA Astrophysics Data System (ADS)

Bettuzzi, Matteo; Albertin, Fauzia; Brancaccio, Rosa; Casali, Franco; Pia Morigi, Maria; Peccenini, Eva

2017-03-01

I will describe in this paper the first results of a series of X-ray tomography applications, with different system setups, running on some ancient manuscripts containing iron-gall ink. The purpose is to verify the optimum measurement conditions with a laboratory instrumentation -that is also in fact portable- in order to recognize the text from the inside of the documents, without opening them. This becomes possible by exploiting the X-rays absorption contrast of iron-based ink and the three-dimensional reconstruction potential provided by computed tomography that overcomes problems that appear in simple radiograph practice. This work is part of a larger project of EPFL (Ecole Polytechnique Fédérale de Lausanne, Switzerland), the "Venice Time Machine" project (EPEL, Digital Heritage Venice, http://dhvenice.eu/, 2015) aimed at digitizing, transcribing and sharing in an open database all the information of the State Archives of Venice, exploiting traditional digitization technologies and innovative methods of acquisition. In this first measurement campaign I investigated a manuscript of the seventeenth century made of a folded sheet; a couple of unopened ancient wills kept in the State Archives in Venice and a handwritten book of several hundred pages of notes of Physics of the nineteenth century.

Comparison of diffraction-enhanced computed tomography and monochromatic synchrotron radiation computed tomography of human trabecular bone.

PubMed

Connor, D M; Hallen, H D; Lalush, D S; Sumner, D R; Zhong, Z

2009-10-21

Diffraction-enhanced imaging (DEI) is an x-ray-based medical imaging modality that, when used in tomography mode (DECT), can generate a three-dimensional map of both the apparent absorption coefficient and the out-of-plane gradient of the index of refraction of the sample. DECT is known to have contrast gains over monochromatic synchrotron radiation CT (SRCT) for soft tissue structures. The goal of this experiment was to compare contrast-to-noise ratio (CNR) and resolution in images of human trabecular bone acquired using SRCT with images acquired using DECT. All images were acquired at the National Synchrotron Light Source (Upton, NY, USA) at beamline X15 A at an x-ray energy of 40 keV and the silicon [3 3 3] reflection. SRCT, apparent absorption DECT and refraction DECT slice images of the trabecular bone were created. The apparent absorption DECT images have significantly higher spatial resolution and CNR than the corresponding SRCT images. Thus, DECT will prove to be a useful tool for imaging applications in which high contrast and high spatial resolution are required for both soft tissue features and bone.

External cervical resorption: an analysis using cone beam and microfocus computed tomography and scanning electron microscopy.

PubMed

Gunst, V; Mavridou, A; Huybrechts, B; Van Gorp, G; Bergmans, L; Lambrechts, P

2013-09-01

To provide a three-dimensional representation of external cervical resorption (ECR) with microscopy, stereo microscopy, cone beam computed tomography (CT), microfocus CT and scanning electron microscopy (SEM). External cervical resorption is an aggressive form of root resorption, leading to a loss of dental hard tissues. This is due to clastic action, activated by a damage of the covering cementum and stimulated probably by infection. Clinically, it is a challenging situation as it is characterized by a late symptomatology. This is due to the pericanalar protection from a resorption-resistant sheet, composed of pre-dentine and surrounding dentine. The clastic activity is often associated with an attempt to repair, seen by the formation of osteoid tissue. Cone beam CT is extremely useful in the diagnoses and treatment planning of ECR. SEM analyses provide a better insight into the activity of osteoclasts. The root canal is surrounded by a layer of dentine that is resistant to resorption. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Analysis of sintered polymer scaffolds using concomitant synchrotron computed tomography and in situ mechanical testing.

PubMed

Dhillon, A; Schneider, P; Kuhn, G; Reinwald, Y; White, L J; Levchuk, A; Rose, F R A J; Müller, R; Shakesheff, K M; Rahman, C V

2011-12-01

The mechanical behaviour of polymer scaffolds plays a vital role in their successful use in bone tissue engineering. The present study utilised novel sintered polymer scaffolds prepared using temperature-sensitive poly(DL-lactic acid-co-glycolic acid)/poly(ethylene glycol) particles. The microstructure of these scaffolds was monitored under compressive strain by image-guided failure assessment (IGFA), which combined synchrotron radiation computed tomography (SR CT) and in situ micro-compression. Three-dimensional CT data sets of scaffolds subjected to a strain rate of 0.01%/s illustrated particle movement within the scaffolds with no deformation or cracking. When compressed using a higher strain rate of 0.02%/s particle movement was more pronounced and cracks between sintered particles were observed. The results from this study demonstrate that IGFA based on simultaneous SR CT imaging and micro-compression testing is a useful tool for assessing structural and mechanical scaffold properties, leading to further insight into structure-function relationships in scaffolds for bone tissue engineering applications.

3D Printing of Plant Golgi Stacks from Their Electron Tomographic Models.

PubMed

Mai, Keith Ka Ki; Kang, Madison J; Kang, Byung-Ho

2017-01-01

Three-dimensional (3D) printing is an effective tool for preparing tangible 3D models from computer visualizations to assist in scientific research and education. With the recent popularization of 3D printing processes, it is now possible for individual laboratories to convert their scientific data into a physical form suitable for presentation or teaching purposes. Electron tomography is an electron microscopy method by which 3D structures of subcellular organelles or macromolecular complexes are determined at nanometer-level resolutions. Electron tomography analyses have revealed the convoluted membrane architectures of Golgi stacks, chloroplasts, and mitochondria. But the intricacy of their 3D organizations is difficult to grasp from tomographic models illustrated on computer screens. Despite the rapid development of 3D printing technologies, production of organelle models based on experimental data with 3D printing has rarely been documented. In this chapter, we present a simple guide to creating 3D prints of electron tomographic models of plant Golgi stacks using the two most accessible 3D printing technologies.

Ultrasonic image analysis and image-guided interventions.

PubMed

Noble, J Alison; Navab, Nassir; Becher, H

2011-08-06

The fields of medical image analysis and computer-aided interventions deal with reducing the large volume of digital images (X-ray, computed tomography, magnetic resonance imaging (MRI), positron emission tomography and ultrasound (US)) to more meaningful clinical information using software algorithms. US is a core imaging modality employed in these areas, both in its own right and used in conjunction with the other imaging modalities. It is receiving increased interest owing to the recent introduction of three-dimensional US, significant improvements in US image quality, and better understanding of how to design algorithms which exploit the unique strengths and properties of this real-time imaging modality. This article reviews the current state of art in US image analysis and its application in image-guided interventions. The article concludes by giving a perspective from clinical cardiology which is one of the most advanced areas of clinical application of US image analysis and describing some probable future trends in this important area of ultrasonic imaging research.

Advances in imaging: impact on studying craniofacial bone structure.

PubMed

Majumdar, S

2003-01-01

Methods for measuring the structure of craniofacial bones are discussed in this paper. In addition to the three-dimensional macro-structure of the craniofacial skeleton, there is considerable interest in imaging the bone at a microscopic resolution in order to depict the micro-architecture of the trabecular bone itself. In addition to the density of the bone, the microarchitecture reflects bone quality. An understanding of bone quality and density changes has implications for a number of craniofacial pathologies, as well as for implant design and understanding the biomechanical function and loading of the jaw. Trabecular bone micro-architecture has been recently imaged using imaging methods such as micro-computed tomography, magnetic resonance imaging, and the images have been used in finite element models to assess bone mechanical properties. In this paper, some of the recent advances in micro-computed tomography and magnetic resonance imaging are reviewed, and their potential for imaging the trabecular bone in mandibular bones is presented. Examples of in vitro and in vivo images are presented.

Electromagnetic navigated positioning of the maxilla after Le Fort I osteotomy in preclinical orthognathic surgery cases.

PubMed

Berger, Moritz; Nova, Igor; Kallus, Sebastian; Ristow, Oliver; Eisenmann, Urs; Freudlsperger, Christian; Seeberger, Robin; Hoffmann, Jürgen; Dickhaus, Hartmut

2017-03-01

Inaccuracies in orthognathic surgery can be caused during face-bow registration, model surgery on plaster models, and intermaxillary splint manufacturing. Electromagnetic (EM) navigation is a promising method for splintless digitized maxillary positioning. After performing Le Fort I osteotomy on 10 plastic skulls, the target position of the maxilla was guided by an EM navigation system. Specially implemented software illustrated the target position by real-time multistage colored three-dimensional imaging. Accuracy was determined by using pre- and postoperative cone beam computed tomography. The high accuracy of the EM system was underlined by the fact that it had a navigated maxilla position discrepancy of only 0.4 mm, which was verified by postoperative cone beam computed tomography. This preclinical study demonstrates a precise digitized approach for splintless maxillary repositioning after Le Fort I osteotomy. The accuracy and intuitive illustration of the introduced EM navigation system is promising for potential daily use in orthognathic surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Apical root resorption due to orthodontic treatment detected by cone beam computed tomography.

PubMed

Castro, Iury O; Alencar, Ana H G; Valladares-Neto, José; Estrela, Carlos

2013-03-01

To determine the frequency of apical root resorption (ARR) due to orthodontic treatment using cone beam computed tomography (CBCT) in a sample of 1256 roots from 30 patients. All patients had Class I malocclusion with crowding. Of the 30 patients evaluated, 11 were boys and 19 were girls; their mean age was 13 years (11 to 16 years). Orthodontic treatment followed the nonextraction treatment. CBCT images were obtained before and after orthodontic treatment, and ARR was determined using Axial Guided Navigation of CBCT images. All patients had ARR. No statistically significant association was found between resorption frequency, gender, and age. ARR was detected using CBCT in 46% of all roots that underwent orthodontic treatment. CBCT was effective for detecting in vivo even minimal degrees of ARR due to orthodontic treatment and allowed three-dimensional evaluation of dental roots and visualization of palatine roots of maxillary molars. The highest frequencies and the most significant ARR occurred in incisors and distal roots of first maxillary and mandibular molars.

X-Ray Computed Tomography Reveals the Response of Root System Architecture to Soil Texture1[OPEN

PubMed Central

Rogers, Eric D.; Monaenkova, Daria; Mijar, Medhavinee; Goldman, Daniel I.

2016-01-01

Root system architecture (RSA) impacts plant fitness and crop yield by facilitating efficient nutrient and water uptake from the soil. A better understanding of the effects of soil on RSA could improve crop productivity by matching roots to their soil environment. We used x-ray computed tomography to perform a detailed three-dimensional quantification of changes in rice (Oryza sativa) RSA in response to the physical properties of a granular substrate. We characterized the RSA of eight rice cultivars in five different growth substrates and determined that RSA is the result of interactions between genotype and growth environment. We identified cultivar-specific changes in RSA in response to changing growth substrate texture. The cultivar Azucena exhibited low RSA plasticity in all growth substrates, whereas cultivar Bala root depth was a function of soil hardness. Our imaging techniques provide a framework to study RSA in different growth environments, the results of which can be used to improve root traits with agronomic potential. PMID:27208237

Using additive manufacturing in accuracy evaluation of reconstructions from computed tomography.

PubMed

Smith, Erin J; Anstey, Joseph A; Venne, Gabriel; Ellis, Randy E

2013-05-01

Bone models derived from patient imaging and fabricated using additive manufacturing technology have many potential uses including surgical planning, training, and research. This study evaluated the accuracy of bone surface reconstruction of two diarthrodial joints, the hip and shoulder, from computed tomography. Image segmentation of the tomographic series was used to develop a three-dimensional virtual model, which was fabricated using fused deposition modelling. Laser scanning was used to compare cadaver bones, printed models, and intermediate segmentations. The overall bone reconstruction process had a reproducibility of 0.3 ± 0.4 mm. Production of the model had an accuracy of 0.1 ± 0.1 mm, while the segmentation had an accuracy of 0.3 ± 0.4 mm, indicating that segmentation accuracy was the key factor in reconstruction. Generally, the shape of the articular surfaces was reproduced accurately, with poorer accuracy near the periphery of the articular surfaces, particularly in regions with periosteum covering and where osteophytes were apparent.

Anatomical and metabolic small-animal whole-body imaging using ring-shaped confocal photoacoustic computed tomography

NASA Astrophysics Data System (ADS)

Xia, Jun; Chatni, Muhammad; Maslov, Konstantin; Wang, Lihong V.

2013-03-01

Due to the wide use of animals for human disease studies, small animal whole-body imaging plays an increasingly important role in biomedical research. Currently, none of the existing imaging modalities can provide both anatomical and glucose metabolic information, leading to higher costs of building dual-modality systems. Even with image coregistration, the spatial resolution of the metabolic imaging modality is not improved. We present a ring-shaped confocal photoacoustic computed tomography (RC-PACT) system that can provide both assessments in a single modality. Utilizing the novel design of confocal full-ring light delivery and ultrasound transducer array detection, RC-PACT provides full-view cross-sectional imaging with high spatial resolution. Scanning along the orthogonal direction provides three-dimensional imaging. While the mouse anatomy was imaged with endogenous hemoglobin contrast, the glucose metabolism was imaged with a near-infrared dye-labeled 2-deoxyglucose. Through mouse tumor models, we demonstrate that RC-PACT may be a paradigm shifting imaging method for preclinical research.

Characterizing the Three-Dimensional Structure of Block Copolymers via Sequential Infiltration Synthesis and Scanning Transmission Electron Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Segal-Peretz, Tamar; Winterstein, Jonathan; Doxastakis, Manolis

Understanding and controlling the three-dimensional structure of block copolymer (BCP) thin films is critical for utilizing these materials for sub-20 nm nanopatterning in semiconductor devices, as well as in membranes and solar cell applications. Combining an atomic layer deposition (ALD) based technique for enhancing the contrast of BCPs in transmission electron microscopy (TEM) together with scanning TEM (STEM) tomography reveals and characterizes the three-dimensional structures of poly(styrene-block-methyl methacrylate) (PS-b-PMMA) thin films with great clarity. Sequential infiltration synthesis (SIS), a block-selective technique for growing inorganic materials in BCPs films in ALD, and an emerging tool for enhancing the etch contrast ofmore » BCPs, was harnessed to significantly enhance the high-angle scattering from the polar domains of BCP films in the TEM. The power of combining SIS and STEM tomography for three dimensional (3D) characterization of BCPs films was demonstrated with the following cases: self-assembled cylindrical, lamellar, and spherical PS-PMMA thin films. In all cases, STEM tomography has revealed 3D structures that were hidden underneath the surface, including: 1) the 3D structure of defects in cylindrical and lamellar phases, 2) non-perpendicular 3D surface of grain boundaries in the cylindrical phase, and 3) the 3D arrangement of spheres in body centered cubic (BCC) and hexagonal closed pack (HCP) morphologies in the spherical phase. The 3D data of the spherical morphologies was compared to coarse-grained simulations and assisted in validating the simulations’ parameters. STEM tomography of SIS-treated BCP films enables the characterization of the exact structure used for pattern transfer, and can lead to better understating of the physics which is utilized in BCP lithography.« less

Image matrix processor for fast multi-dimensional computations

DOEpatents

Roberson, George P.; Skeate, Michael F.

1996-01-01

An apparatus for multi-dimensional computation which comprises a computation engine, including a plurality of processing modules. The processing modules are configured in parallel and compute respective contributions to a computed multi-dimensional image of respective two dimensional data sets. A high-speed, parallel access storage system is provided which stores the multi-dimensional data sets, and a switching circuit routes the data among the processing modules in the computation engine and the storage system. A data acquisition port receives the two dimensional data sets representing projections through an image, for reconstruction algorithms such as encountered in computerized tomography. The processing modules include a programmable local host, by which they may be configured to execute a plurality of different types of multi-dimensional algorithms. The processing modules thus include an image manipulation processor, which includes a source cache, a target cache, a coefficient table, and control software for executing image transformation routines using data in the source cache and the coefficient table and loading resulting data in the target cache. The local host processor operates to load the source cache with a two dimensional data set, loads the coefficient table, and transfers resulting data out of the target cache to the storage system, or to another destination.

Comparison of patient-specific internal gross tumor volume for radiation treatment of primary esophageal cancer based separately on three-dimensional and four-dimensional computed tomography images.

PubMed

Wang, W; Li, J; Zhang, Y; Li, F; Xu, M; Fan, T; Shao, Q; Shang, D

2014-01-01

To compare the target volume, position and matching index of the patient-specific internal gross tumor volume (IGTV) based on three-dimensional (3D) and four-dimensional (4D) computed tomography (CT) images for primary esophageal cancer. Twenty-nine patients with primary thoracic esophageal cancer underwent 3DCT and 4DCT scans during free breathing. IGTVs were constructed using three approaches: combining the gross target volumes from the 10 respiratory phases of the 4DCT dataset to produce IGTV10 ; IGTV2 was acquired by combining the two extreme phases; and IGTV3D was created from the 3DCT-based gross target volume by enlarging the 95th percentile of motion in each direction measured by the 4DCT. 0.16 cm lateral (LR), 0.14 cm anteroposterior (AP) and 0.29 cm superoinferior (SI) in the upper; 0.18 cm LR, 0.10 cm AP and 0.63 cm SI in the middle; and 0.40 cm LR, 0.58 cm AP and 0.82 cm in the lower thoracic esophagus could account for 95% of respiratory-induced tumor motion. The centroid position shift between IGTV10 and IGTV2 was all below 0.10 cm, and less than 0.20 cm between IGTV10 and IGTV3D . IGTV10 was bigger than IGTV2 ; the mean value of matching index for IGTV2 to IGTV10 was 0.87 ± 0.05, 0.85 ± 0.06 and 0.83 ± 0.05 for upper, middle and distal thoracic esophageal tumors, respectively, and just 0.57 ± 0.11, 0.56 ± 0.13 and 0.40 ± 0.03 between IGTV3D and IGTV10 . 4DCT-based IGTV10 is a reasonable patient-specific IGTV for primary thoracic esophageal cancer, and IGTV2 is considered as an acceptable alternative to IGTV10 . However, it seems unreasonable to use IGTV3D substitute IGTV10 . © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

From Solidification Processing to Microstructure to Mechanical Properties: A Multi-scale X-ray Study of an Al-Cu Alloy Sample

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tourret, D.; Mertens, J. C. E.; Lieberman, E.

We follow an Al-12 at. pct Cu alloy sample from the liquid state to mechanical failure, using in situ X-ray radiography during directional solidification and tensile testing, as well as three-dimensional computed tomography of the microstructure before and after mechanical testing. The solidification processing stage is simulated with a multi-scale dendritic needle network model, and the micromechanical behavior of the solidified microstructure is simulated using voxelized tomography data and an elasto-viscoplastic fast Fourier transform model. This study demonstrates the feasibility of direct in situ monitoring of a metal alloy microstructure from the liquid processing stage up to its mechanical failure,more » supported by quantitative simulations of microstructure formation and its mechanical behavior.« less

Simultaneous K-edge subtraction tomography for tracing strontium using parametric X-ray radiation

NASA Astrophysics Data System (ADS)

Hayakawa, Y.; Hayakawa, K.; Kaneda, T.; Nogami, K.; Sakae, T.; Sakai, T.; Sato, I.; Takahashi, Y.; Tanaka, T.

2017-07-01

The X-ray source based on parametric X-ray radiation (PXR) has been regularly providing a coherent X-ray beam for application studies at Nihon University. Recently, three dimensional (3D) computed tomography (CT) has become one of the most important applications of the PXR source. The methodology referred to as K-edge subtraction (KES) imaging is a particularly successful application utilizing the energy selectivity of PXR. In order to demonstrate the applicability of PXR-KES, a simultaneous KES experiment for a specimen containing strontium was performed using a PXR beam having an energy near the Sr K-edge of 16.1 keV. As a result, the 3D distribution of Sr was obtained by subtraction between the two simultaneously acquired tomographic images.

From Solidification Processing to Microstructure to Mechanical Properties: A Multi-scale X-ray Study of an Al-Cu Alloy Sample

DOE PAGES

Tourret, D.; Mertens, J. C. E.; Lieberman, E.; ...

2017-09-13

We follow an Al-12 at. pct Cu alloy sample from the liquid state to mechanical failure, using in situ X-ray radiography during directional solidification and tensile testing, as well as three-dimensional computed tomography of the microstructure before and after mechanical testing. The solidification processing stage is simulated with a multi-scale dendritic needle network model, and the micromechanical behavior of the solidified microstructure is simulated using voxelized tomography data and an elasto-viscoplastic fast Fourier transform model. This study demonstrates the feasibility of direct in situ monitoring of a metal alloy microstructure from the liquid processing stage up to its mechanical failure,more » supported by quantitative simulations of microstructure formation and its mechanical behavior.« less

From Solidification Processing to Microstructure to Mechanical Properties: A Multi-scale X-ray Study of an Al-Cu Alloy Sample

NASA Astrophysics Data System (ADS)

Tourret, D.; Mertens, J. C. E.; Lieberman, E.; Imhoff, S. D.; Gibbs, J. W.; Henderson, K.; Fezzaa, K.; Deriy, A. L.; Sun, T.; Lebensohn, R. A.; Patterson, B. M.; Clarke, A. J.

2017-11-01

We follow an Al-12 at. pct Cu alloy sample from the liquid state to mechanical failure, using in situ X-ray radiography during directional solidification and tensile testing, as well as three-dimensional computed tomography of the microstructure before and after mechanical testing. The solidification processing stage is simulated with a multi-scale dendritic needle network model, and the micromechanical behavior of the solidified microstructure is simulated using voxelized tomography data and an elasto-viscoplastic fast Fourier transform model. This study demonstrates the feasibility of direct in situ monitoring of a metal alloy microstructure from the liquid processing stage up to its mechanical failure, supported by quantitative simulations of microstructure formation and its mechanical behavior.

High-performance image reconstruction in fluorescence tomography on desktop computers and graphics hardware.

PubMed

Freiberger, Manuel; Egger, Herbert; Liebmann, Manfred; Scharfetter, Hermann

2011-11-01

Image reconstruction in fluorescence optical tomography is a three-dimensional nonlinear ill-posed problem governed by a system of partial differential equations. In this paper we demonstrate that a combination of state of the art numerical algorithms and a careful hardware optimized implementation allows to solve this large-scale inverse problem in a few seconds on standard desktop PCs with modern graphics hardware. In particular, we present methods to solve not only the forward but also the non-linear inverse problem by massively parallel programming on graphics processors. A comparison of optimized CPU and GPU implementations shows that the reconstruction can be accelerated by factors of about 15 through the use of the graphics hardware without compromising the accuracy in the reconstructed images.

Comparison of Skeletal and Dental Reference Planes with the Hamulus-Incisive-Papilla Plane: A Pilot Study on 3D Reconstructed Tomographies of the Skull.

PubMed

Pittschieler, Elisabeth; Foltin, Andrea; Falkensammer, Frank; Figl, Michael; Birkfellner, Wolfgang; Jonke, Erwin; Bantleon, Hans-Peter

2016-01-01

The aim of this study was to investigate the hamulus-incisive-papilla (HIP) plane as an alternative for transferring the three-dimensional position of a patient's maxilla to an articulator. Camper, Frankfurt horizontal, occlusal, and HIP planes were evaluated in 21 patients' computed tomography scans and compared to one another. Analysis of variance showed significant differences between all planes, with the HIP plane being closest to the occlusal plane (HIP-OP: 0.6 ± 4.0 degrees). Frankfurt and Camper planes, being more peripheral, showed higher geometric asymmetries. The HIP plane, when used for articulator mounting, results in a closer and more technically reliable patient relationship in a clinical and laboratory context.

The use of microtomography in bone tissue and biomaterial three-dimensional analysis.

PubMed

Bedini, Rossella; Meleo, Deborah; Pecci, Raffaella; Pacifici, Luciano

2009-01-01

X-ray computed microtomography (micro-CT, microComputerised Tomography) is a miniaturized form of conventional computerized axial tomography (CAT ). This sophisticated technology enables 3D riconstruction of the internal structure of small X-ray opaque objects without sample destruction or preparation. The aim of this study is to show the possible applications of micro-CT in the analysis of bone graft materials of different origins (i.e. homologous, heterologous, alloplastic) in order to define their morphometric properties by means of SkyScan 1072 3D microtomography system. Since there is a close relationship between the properties of the materials and their microstructure, it is necessary to examine them using the highest levels of resolution before being able to improve existing materials or create new products.

Analysis of x-ray tomography data of an extruded low density styrenic foam: an image analysis study

NASA Astrophysics Data System (ADS)

Lin, Jui-Ching; Heeschen, William

2016-10-01

Extruded styrenic foams are low density foams that are widely used for thermal insulation. It is difficult to precisely characterize the structure of the cells in low density foams by traditional cross-section viewing due to the frailty of the walls of the cells. X-ray computed tomography (CT) is a non-destructive, three dimensional structure characterization technique that has great potential for structure characterization of styrenic foams. Unfortunately the intrinsic artifacts of the data and the artifacts generated during image reconstruction are often comparable in size and shape to the thin walls of the foam, making robust and reliable analysis of cell sizes challenging. We explored three different image processing methods to clean up artifacts in the reconstructed images, thus allowing quantitative three dimensional determination of cell size in a low density styrenic foam. Three image processing approaches - an intensity based approach, an intensity variance based approach, and a machine learning based approach - are explored in this study, and the machine learning image feature classification method was shown to be the best. Individual cells are segmented within the images after the images were cleaned up using the three different methods and the cell sizes are measured and compared in the study. Although the collected data with the image analysis methods together did not yield enough measurements for a good statistic of the measurement of cell sizes, the problem can be resolved by measuring multiple samples or increasing imaging field of view.

Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

NASA Astrophysics Data System (ADS)

Zhang, Haifeng; Mao, Xiyuan; Du, Zijing; Jiang, Wenbo; Han, Xiuguo; Zhao, Danyang; Han, Dong; Li, Qingfeng

2016-01-01

We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo. The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.

Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model.

PubMed

Zhang, Haifeng; Mao, Xiyuan; Du, Zijing; Jiang, Wenbo; Han, Xiuguo; Zhao, Danyang; Han, Dong; Li, Qingfeng

2016-01-01

We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo . The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.

Characterization of dilute species within CVD-grown silicon nanowires doped using trimethylboron: protected lift-out specimen preparation for atom probe tomography.

PubMed

Prosa, T J; Alvis, R; Tsakalakos, L; Smentkowski, V S

2010-08-01

Three-dimensional quantitative compositional analysis of nanowires is a challenge for standard techniques such as secondary ion mass spectrometry because of specimen size and geometry considerations; however, it is precisely the size and geometry of nanowires that makes them attractive candidates for analysis via atom probe tomography. The resulting boron composition of various trimethylboron vapour-liquid-solid grown silicon nanowires were measured both with time-of-flight secondary ion mass spectrometry and pulsed-laser atom probe tomography. Both characterization techniques yielded similar results for relative composition. Specialized specimen preparation for pulsed-laser atom probe tomography was utilized and is described in detail whereby individual silicon nanowires are first protected, then lifted out, trimmed, and finally wet etched to remove the protective layer for subsequent three-dimensional analysis.

A Freeware Path to Neutron Computed Tomography

NASA Astrophysics Data System (ADS)

Schillinger, Burkhard; Craft, Aaron E.

Neutron computed tomography has become a routine method at many neutron sources due to the availability of digital detection systems, powerful computers and advanced software. The commercial packages Octopus by Inside Matters and VGStudio by Volume Graphics have been established as a quasi-standard for high-end computed tomography. However, these packages require a stiff investment and are available to the users only on-site at the imaging facility to do their data processing. There is a demand from users to have image processing software at home to do further data processing; in addition, neutron computed tomography is now being introduced even at smaller and older reactors. Operators need to show a first working tomography setup before they can obtain a budget to build an advanced tomography system. Several packages are available on the web for free; however, these have been developed for X-rays or synchrotron radiation and are not immediately useable for neutron computed tomography. Three reconstruction packages and three 3D-viewers have been identified and used even for Gigabyte datasets. This paper is not a scientific publication in the classic sense, but is intended as a review to provide searchable help to make the described packages usable for the tomography community. It presents the necessary additional preprocessing in ImageJ, some workarounds for bugs in the software, and undocumented or badly documented parameters that need to be adapted for neutron computed tomography. The result is a slightly complicated, but surprisingly high-quality path to neutron computed tomography images in 3D, but not a replacement for the even more powerful commercial software mentioned above.

Three-dimensional imaging of adherent cells using FIB/SEM and STEM.

PubMed

Villinger, Clarissa; Schauflinger, Martin; Gregorius, Heiko; Kranz, Christine; Höhn, Katharina; Nafeey, Soufi; Walther, Paul

2014-01-01

In this chapter we describe three different approaches for three-dimensional imaging of electron microscopic samples: serial sectioning transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) tomography, and focused ion beam/scanning electron microscopy (FIB/SEM) tomography. With these methods, relatively large volumes of resin-embedded biological structures can be analyzed at resolutions of a few nm within a reasonable expenditure of time. The traditional method is serial sectioning and imaging the same area in all sections. Another method is TEM tomography that involves tilting a section in the electron beam and then reconstruction of the volume by back projection of the images. When the scanning transmission (STEM) mode is used, thicker sections (up to 1 μm) can be analyzed. The third approach presented here is focused ion beam/scanning electron microscopy (FIB/SEM) tomography, in which a sample is repeatedly milled with a focused ion beam (FIB) and each newly produced block face is imaged with the scanning electron microscope (SEM). This process can be repeated ad libitum in arbitrary small increments allowing 3D analysis of relatively large volumes such as eukaryotic cells. We show that resolution of this approach is considerably improved when the secondary electron signal is used. However, the most important prerequisite for three-dimensional imaging is good specimen preparation. For all three imaging methods, cryo-fixed (high-pressure frozen) and freeze-substituted samples have been used.

First-in-Man Computed Tomography-Guided Percutaneous Revascularization of Coronary Chronic Total Occlusion Using a Wearable Computer: Proof of Concept.

PubMed

Opolski, Maksymilian P; Debski, Artur; Borucki, Bartosz A; Szpak, Marcin; Staruch, Adam D; Kepka, Cezary; Witkowski, Adam

2016-06-01

We report a case of successful computed tomography-guided percutaneous revascularization of a chronically occluded right coronary artery using a wearable, hands-free computer with a head-mounted display worn by interventional cardiologists in the catheterization laboratory. The projection of 3-dimensional computed tomographic reconstructions onto the screen of virtual reality glass allowed the operators to clearly visualize the distal coronary vessel, and verify the direction of the guide wire advancement relative to the course of the occluded vessel segment. This case provides proof of concept that wearable computers can improve operator comfort and procedure efficiency in interventional cardiology. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Reduction effect of the quantity of radiation exposure and contrast media by image support system in transarterial chemoembolization for the treatment of hepatocellular carcinoma.

PubMed

Tamai, Tsutomu; Taniyama, Oki; Oda, Kohei; Kasai, Ai; Ijyuin, Syo; Sakae, Haruka; Onishi, Hiroka; Tabu, Kazuaki; Kumagai, Kotaro; Mawatari, Seiichi; Moriuchi, Akihiro; Uto, Hirofumi; Ido, Akio

2018-05-01

We confirmed the clinical utility of a three-dimensional navigation system during transarterial chemoembolization. We evaluated 128 tumors in 91 patients enrolled between May 2015 and August 2016. We evaluated the accuracy of the three-dimensional navigation imaging system for all tumors. We compared the patients who were able to undergo route detection using three-dimensional navigation with previously treated patients who underwent transarterial chemoembolization without using three-dimensional navigation (n = 21). For 38 patients who underwent super-selective microcatheter insertion after a feeding artery was identified by three-dimensional navigation, we confirmed the relationship between the tumors and contrasted liver parenchyma and divided the computed tomography hepatic arteriography findings into four grades. Grade 1: an overlap of > 5 mm, grade 2: an overlap between 0 and 5 mm, grade 3: the borders of the tumor within the liver parenchyma but in contact with the edges, and grade 4: a tumor outside the borders of the liver parenchyma. Using the three-dimensional navigation system, we identified a tumor-feeding artery in 125/128 tumors (97.6%). Furthermore, this system allowed us to significantly reduce the volume of contrast media and the radiation exposure dose in patients undergoing an evaluation. We identified 15 grade 1 tumors (39.5%), 3 grade 2 tumors (7.9%), 11 grade 3 tumors (28.9%), and 9 grade 4 tumors (23.7%) according to our definitions. The three-dimensional navigation is useful not only for patients but also for surgeons who have relatively little experience. © 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Three dimensional Cone Beam Computed Tomography Study of Pharyngeal Airway Dimensions in Different Anteroposterior Skeletal Classification Patients

DTIC Science & Technology

2015-07-10

this far. Thank you to my beautiful wife, Mary, for walking beside me every step of the way through the hard work of dental school and residency...Your encouragement and love has meant so much to me. Thank you to Laura and Daniel for always putting a smile on my face when I come home each day...Thank you to my mother for her countless hours of hard work and sacrifice while educating and raising me. Thank you to my father for providing an

Virtual autopsy using imaging: bridging radiologic and forensic sciences. A review of the Virtopsy and similar projects.

PubMed

Bolliger, Stephan A; Thali, Michael J; Ross, Steffen; Buck, Ursula; Naether, Silvio; Vock, Peter

2008-02-01

The transdisciplinary research project Virtopsy is dedicated to implementing modern imaging techniques into forensic medicine and pathology in order to augment current examination techniques or even to offer alternative methods. Our project relies on three pillars: three-dimensional (3D) surface scanning for the documentation of body surfaces, and both multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) to visualise the internal body. Three-dimensional surface scanning has delivered remarkable results in the past in the 3D documentation of patterned injuries and of objects of forensic interest as well as whole crime scenes. Imaging of the interior of corpses is performed using MSCT and/or MRI. MRI, in addition, is also well suited to the examination of surviving victims of assault, especially choking, and helps visualise internal injuries not seen at external examination of the victim. Apart from the accuracy and three-dimensionality that conventional documentations lack, these techniques allow for the re-examination of the corpse and the crime scene even decades later, after burial of the corpse and liberation of the crime scene. We believe that this virtual, non-invasive or minimally invasive approach will improve forensic medicine in the near future.

Improved tomographic reconstructions using adaptive time-dependent intensity normalization.

PubMed

Titarenko, Valeriy; Titarenko, Sofya; Withers, Philip J; De Carlo, Francesco; Xiao, Xianghui

2010-09-01

The first processing step in synchrotron-based micro-tomography is the normalization of the projection images against the background, also referred to as a white field. Owing to time-dependent variations in illumination and defects in detection sensitivity, the white field is different from the projection background. In this case standard normalization methods introduce ring and wave artefacts into the resulting three-dimensional reconstruction. In this paper the authors propose a new adaptive technique accounting for these variations and allowing one to obtain cleaner normalized data and to suppress ring and wave artefacts. The background is modelled by the product of two time-dependent terms representing the illumination and detection stages. These terms are written as unknown functions, one scaled and shifted along a fixed direction (describing the illumination term) and one translated by an unknown two-dimensional vector (describing the detection term). The proposed method is applied to two sets (a stem Salix variegata and a zebrafish Danio rerio) acquired at the parallel beam of the micro-tomography station 2-BM at the Advanced Photon Source showing significant reductions in both ring and wave artefacts. In principle the method could be used to correct for time-dependent phenomena that affect other tomographic imaging geometries such as cone beam laboratory X-ray computed tomography.

Design and Construction of an Optical Computed Tomography Scanner for Polymer Gel Dosimetry Application

PubMed Central

Zakariaee, Seyed Salman; Mesbahi, Asghar; Keshtkar, Ahmad; Azimirad, Vahid

2014-01-01

Polymer gel dosimeter is the only accurate three dimensional (3D) dosimeter that can measure the absorbed dose distribution in a perfect 3D setting. Gel dosimetry by using optical computed tomography (OCT) has been promoted by several researches. In the current study, we designed and constructed a prototype OCT system for gel dosimetry. First, the electrical system for optical scanning of the gel container using a Helium-Neon laser and a photocell was designed and constructed. Then, the mechanical part for two rotational and translational motions was designed and step motors were assembled to it. The data coming from photocell was grabbed by the home-built interface and sent to a personal computer. Data processing was carried out using MATLAB software. To calibrate the system and tune up the functionality of it, different objects was designed and scanned. Furthermore, the spatial and contrast resolution of the system was determined. The system was able to scan the gel dosimeter container with a diameter up to 11 cm inside the water phantom. The standard deviation of the pixels within water flask image was considered as the criteria for image uniformity. The uniformity of the system was about ±0.05%. The spatial resolution of the system was approximately 1 mm and contrast resolution was about 0.2%. Our primary results showed that this system is able to obtain two-dimensional, cross-sectional images from polymer gel samples. PMID:24761377

Modeling and analysis of visual digital impact model for a Chinese human thorax.

PubMed

Zhu, Jin; Wang, Kai-Ming; Li, Shu; Liu, Hai-Yan; Jing, Xiao; Li, Xiao-Fang; Liu, Yi-He

2017-01-01

To establish a three-dimensional finite element model of the human chest for engineering research on individual protection. Computed tomography (CT) scanning data were used for three-dimensional reconstruction with the medical image reconstruction software Mimics. The finite element method (FEM) preprocessing software ANSYS ICEM CFD was used for cell mesh generation, and the relevant material behavior parameters of all of the model's parts were specified. The finite element model was constructed with the FEM software, and the model availability was verified based on previous cadaver experimental data. A finite element model approximating the anatomical structure of the human chest was established, and the model's simulation results conformed to the results of the cadaver experiment overall. Segment data of the human body and specialized software can be utilized for FEM model reconstruction to satisfy the need for numerical analysis of shocks to the human chest in engineering research on body mechanics.

Influence of Thickness and Contact Surface Geometry of Condylar Stem of TMJ Implant on Its Stability

NASA Astrophysics Data System (ADS)

Arabshahi, Zohreh; Kashani, Jamal; Kadir, Mohammed Rafiq Abdul; Azari, Abbas

The aim of this study is to examine the effect thickness and contact surface geometry of condylar stem of TMJ implant on its stability in total reconstruction system and evaluate the micro strain resulted in bone at fixation screw holes in jaw bone embedded with eight different designs of temporomandibular joint implants. A three dimensional model of a lower mandible of an adult were developed from a Computed Tomography scan images. Eight different TMJ implant designs and fixation screws were modeled. Three dimensional finite element models of eight implanted mandibles were analyzed. The forces assigned to the masticatory muscles for incisal clenching were applied consisting of nine important muscular loads. In chosen loading condition, The results indicated that the anatomical curvature contact surface design of TMJ implant can moderately improve the stability and the strain resulted in fixation screw holes in thinner TMJ implant was diminished in comparison with other thicknesses.

Investigation on the Yarn Squeezing Effect of Three Dimensional Full Five Directional Braided Composites

NASA Astrophysics Data System (ADS)

Hu, Long; Tao, Guoquan; Liu, Zhenguo; Wang, Yibo; Ya, Jixuan

2018-04-01

The influence of yarn squeezing effect on the geometric morphology and mechanical property of the three dimensional full five directional (3DF5D) braided composites is explored. Spatial path and cross-section shape of the yarns in the braided structure are characterized based on the micro computed tomography (micro CT) scanning images. The yarn distortion due to the squeezing effect is discussed and mathematical morphology of the yarn geometry is established. A new repeated unit cell (RUC) model of 3DF5D braided composites considering yarn squeezing effect is developed. Based on this model, mechanical properties of 3DF5D braided composites are analyzed. Good agreement is obtained between the predicted and experiment results. Moreover, the stress distribution of the new RUC model are compared with original RUC model, showing that the squeezing effect significantly increases the stress concentration level of the axial yarns.

Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature.

PubMed

Álvarez-Murga, M; Perrillat, J P; Le Godec, Y; Bergame, F; Philippe, J; King, A; Guignot, N; Mezouar, M; Hodeau, J L

2017-01-01

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris-Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C 60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure-temperature-stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

Spatial Modulation Improves Performance in CTIS

NASA Technical Reports Server (NTRS)

Bearman, Gregory H.; Wilson, Daniel W.; Johnson, William R.

2009-01-01

Suitably formulated spatial modulation of a scene imaged by a computed-tomography imaging spectrometer (CTIS) has been found to be useful as a means of improving the imaging performance of the CTIS. As used here, "spatial modulation" signifies the imposition of additional, artificial structure on a scene from within the CTIS optics. The basic principles of a CTIS were described in "Improvements in Computed- Tomography Imaging Spectrometry" (NPO-20561) NASA Tech Briefs, Vol. 24, No. 12 (December 2000), page 38 and "All-Reflective Computed-Tomography Imaging Spectrometers" (NPO-20836), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 7a. To recapitulate: A CTIS offers capabilities for imaging a scene with spatial, spectral, and temporal resolution. The spectral disperser in a CTIS is a two-dimensional diffraction grating. It is positioned between two relay lenses (or on one of two relay mirrors) in a video imaging system. If the disperser were removed, the system would produce ordinary images of the scene in its field of view. In the presence of the grating, the image on the focal plane of the system contains both spectral and spatial information because the multiple diffraction orders of the grating give rise to multiple, spectrally dispersed images of the scene. By use of algorithms adapted from computed tomography, the image on the focal plane can be processed into an image cube a three-dimensional collection of data on the image intensity as a function of the two spatial dimensions (x and y) in the scene and of wavelength (lambda). Thus, both spectrally and spatially resolved information on the scene at a given instant of time can be obtained, without scanning, from a single snapshot; this is what makes the CTIS such a potentially powerful tool for spatially, spectrally, and temporally resolved imaging. A CTIS performs poorly in imaging some types of scenes in particular, scenes that contain little spatial or spectral variation. The computed spectra of such scenes tend to approximate correct values to within acceptably small errors near the edges of the field of view but to be poor approximations away from the edges. The additional structure imposed on a scene according to the present method enables the CTIS algorithms to reconstruct acceptable approximations of the spectral data throughout the scene.

A comparative study of the deviation of the menton on posteroanterior cephalograms and three-dimensional computed tomography

PubMed Central

Lee, Hee Jin; Lee, Sungeun; Lee, Eun Joo; Song, In Ja; Kang, Byung-Cheol; Lee, Jae-Seo; Lim, Hoi-Jeong

2016-01-01

Purpose Facial asymmetry has been measured by the severity of deviation of the menton (Me) on posteroanterior (PA) cephalograms and three-dimensional (3D) computed tomography (CT). This study aimed to compare PA cephalograms and 3D CT regarding the severity of Me deviation and the direction of the Me. Materials and Methods PA cephalograms and 3D CT images of 35 patients who underwent orthognathic surgery (19 males and 16 females, with an average age of 22.1±3.3 years) were retrospectively reviewed in this study. By measuring the distance and direction of the Me from the midfacial reference line and the midsagittal plane in the cephalograms and 3D CT, respectively, the x-coordinates (x1 and x2) of the Me were obtained in each image. The difference between the x-coordinates was calculated and statistical analysis was performed to compare the severity of Me deviation and the direction of the Me in the two imaging modalities. Results A statistically significant difference in the severity of Me deviation was found between the two imaging modalities (Δx=2.45±2.03 mm, p<0.05) using the one-sample t-test. Statistically significant agreement was observed in the presence of deviation (k=0.64, p<0.05) and in the severity of Me deviation (k=0.27, p<0.05). A difference in the direction of the Me was detected in three patients (8.6%). The severity of the Me deviation was found to vary according to the imaging modality in 16 patients (45.7%). Conclusion The measurement of Me deviation may be different between PA cephalograms and 3D CT in some patients. PMID:27051637

Computed tomography arthrography with traction in the human hip for three-dimensional reconstruction of cartilage and the acetabular labrum

PubMed Central

Henak, C.R.; Abraham, C.L.; Peters, C.L.; Sanders, R.K.; Weiss, J.A.; Anderson, A.E.

2014-01-01

AIM To develop and demonstrate the efficacy of a computed tomography arthrography (CTA) protocol for the hip that enables accurate three-dimensional reconstructions of cartilage and excellent visualization of the acetabular labrum. MATERIALS AND METHODS Ninety-three subjects were imaged (104 scans); 68 subjects with abnormal anatomy, 11 patients after periacetabular osteotomy surgery, and 25 subjects with normal anatomy. Fifteen to 25 ml of contrast agent diluted with lidocaine was injected using a lateral oblique approach. A Hare traction splint applied traction during CT. The association between traction force and intra-articular joint space was assessed qualitatively under fluoroscopy. Cartilage geometry was reconstructed from the CTA images for 30 subjects; the maximum joint space under traction was measured. RESULTS Using the Hare traction splint, the intra-articular space and boundaries of cartilage could be clearly delineated throughout the joint; the acetabular labrum was also visible. Dysplastic hips required less traction (~5 kg) than normal and retroverted hips required (>10 kg) to separate the cartilage. An increase in traction force produced a corresponding widening of the intra-articular joint space. Under traction, the maximum width of the intra-articular joint space during CT ranged from 0.98–6.7 mm (2.46 ± 1.16 mm). CONCLUSIONS When applied to subjects with normal and abnormal hip anatomy, the CTA protocol presented yields clear delineation of the cartilage and the acetabular labrum. Use of a Hare traction splint provides a simple, cost-effective method to widen the intra-articular joint space during CT, and provides flexibility to vary the traction as required. PMID:25070373

Quantitative evaluation of native lung hyperinflation after single lung transplantation for emphysema using three-dimensional computed tomography volumetry.

PubMed

Motoyama, H; Chen, F; Ohsumi, A; Hijiya, K; Takahashi, M; Ohata, K; Yamada, T; Sato, M; Aoyama, A; Bando, T; Date, H

2014-04-01

Although double lung transplantation is performed more frequently for emphysema, single lung transplantation (SLT) continues to be performed owing to limited donor organ availability. Native lung hyperinflation (NLH) is a unique complication following SLT for emphysema. Three-dimensional computed tomography (3D-CT) volumetry has been introduced into the field of lung transplantation, which we used to assess NLH in emphysema patients undergoing SLT. The primary purpose of this study was to confirm the effectiveness of 3D-CT volumetry in the evaluation of NLH following SLT for emphysema. In 5 emphysema patients undergoing SLT at Kyoto University Hospital, 3D-CT volumetry data, pulmonary function test results, and clinical and radiological findings were retrospectively evaluated. Three patients did not develop a significant mediastinal shift, whereas the other 2 patients developed a mediastinal shift. In the 3 patients without a mediastinal shift, 3D-CT volumetry did not show a significant increase in native lung volume. These patients had a history of sternotomy prior to lung transplantation and firm adhesion on the mediastinal side was detected during lung transplantation. One of 2 patients with a mediastinal shift developed severe dyspnea with significantly decreased pulmonary function, and 3D-CT volumetry showed a significant increase in the native lung volume. However, the other patient did not show any dyspnea and his native lung volume decreased postoperatively (preoperatively to 6 months postoperatively: +981 mL and -348 mL, respectively). Although bilateral lung transplantation has become preferable for emphysema patients owing to postoperative NLH with SLT, patients with a history of sternotomy prior to lung transplantation might be good candidates for SLT. 3D-CT volumetry may be a useful method for detection of NLH. Copyright © 2014 Elsevier Inc. All rights reserved.

Three-dimensional reciprocal space x-ray coherent scattering tomography of two-dimensional object.

PubMed

Zhu, Zheyuan; Pang, Shuo

2018-04-01

X-ray coherent scattering tomography is a powerful tool in discriminating biological tissues and bio-compatible materials. Conventional x-ray scattering tomography framework can only resolve isotropic scattering profile under the assumption that the material is amorphous or in powder form, which is not true especially for biological samples with orientation-dependent structure. Previous tomography schemes based on x-ray coherent scattering failed to preserve the scattering pattern from samples with preferred orientations, or required elaborated data acquisition scheme, which could limit its application in practical settings. Here, we demonstrate a simple imaging modality to preserve the anisotropic scattering signal in three-dimensional reciprocal (momentum transfer) space of a two-dimensional sample layer. By incorporating detector movement along the direction of x-ray beam, combined with a tomographic data acquisition scheme, we match the five dimensions of the measurements with the five dimensions (three in momentum transfer domain, and two in spatial domain) of the object. We employed a collimated pencil beam of a table-top copper-anode x-ray tube, along with a panel detector to investigate the feasibility of our method. We have demonstrated x-ray coherent scattering tomographic imaging at a spatial resolution ~2 mm and momentum transfer resolution 0.01 Å -1 for the rotation-invariant scattering direction. For any arbitrary, non-rotation-invariant direction, the same spatial and momentum transfer resolution can be achieved based on the spatial information from the rotation-invariant direction. The reconstructed scattering profile of each pixel from the experiment is consistent with the x-ray diffraction profile of each material. The three-dimensional scattering pattern recovered from the measurement reveals the partially ordered molecular structure of Teflon wrap in our sample. We extend the applicability of conventional x-ray coherent scattering tomography to the reconstruction of two-dimensional samples with anisotropic scattering profile by introducing additional degree of freedom on the detector. The presented method has the potential to achieve low-cost, high-specificity material discrimination based on x-ray coherent scattering. © 2018 American Association of Physicists in Medicine.

Visualisation of the temporary cavity by computed tomography using contrast material.

PubMed

Schyma, Christian; Hagemeier, Lars; Greschus, Susanne; Schild, Hans; Madea, Burkhard

2012-01-01

The temporary cavity of a missile produces radial tears in ordnance gelatine, which correlate to the energy transfer. Computed tomography is a useful and non-destructive method to examine gelatine blocks. However, the tears give only few radiocontrast by air filling, which decreases with the time past shooting. Therefore, systematically, a radiocontrast material was searched to enhance the contrast. Different contrast materials were amalgamated to acryl paint, and about 7 g was sealed in a foil bag, which was integrated in the front of a standard 10% gelatine cylinder. Shots with Action-5 expanding bullets were performed from a 5-m distance. Gelatine was scanned by multi-slice computed tomography. The multiplanar reconstructed images were compared to mechanically cut slices of 1 cm thickness. It was shown experimentally that iodine containing water-soluble contrast material did not give sufficient contrast and caused diffusion artefacts. Best results were obtained by barium sulphate emulsion. The amount of acryl paint was sufficient to colour the tears for optical scanning. The radiocontrast of barium leads to satisfying imaging of tears and allowed the creation of a three-dimensional reconstruction of the temporary cavity. Comparison of optical and radiological results showed an excellent correlation, but absolute measures in computed tomographic (CT) images remained lower compared with optically gathered values in the gelatine slices. Combination of paint and contrast material for CT examination will facilitate the evaluation of complex ballistic models and increase accuracy.

A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation

PubMed Central

Manning, Phillip Lars; Lowe, Tristan; Withers, Philip J.

2017-01-01

This paper uses X-ray computed tomography to track the mechanical response of a vertebrate (Barnacle goose) long bone subjected to an axial compressive load, which is increased gradually until failure. A loading rig was mounted in an X-ray computed tomography system so that a time-lapse sequence of three-dimensional (3D) images of the bone’s internal (cancellous or trabecular) structure could be recorded during loading. Five distinct types of deformation mechanism were observed in the cancellous part of the bone. These were (i) cracking, (ii) thinning (iii) tearing of cell walls and struts, (iv) notch formation, (v) necking and (vi) buckling. The results highlight that bone experiences brittle (notch formation and cracking), ductile (thinning, tearing and necking) and elastic (buckling) modes of deformation. Progressive deformation, leading to cracking was studied in detail using digital image correlation. The resulting strain maps were consistent with mechanisms occurring at a finer-length scale. This paper is the first to capture time-lapse 3D images of a whole long bone subject to loading until failure. The results serve as a unique reference for researchers interested in how bone responds to loading. For those using computer modelling, the study not only provides qualitative information for verification and validation of their simulations but also highlights that constitutive models for bone need to take into account a number of different deformation mechanisms. PMID:28652932

A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation.

PubMed

Mustansar, Zartasha; McDonald, Samuel A; Sellers, William Irvin; Manning, Phillip Lars; Lowe, Tristan; Withers, Philip J; Margetts, Lee

2017-01-01

This paper uses X-ray computed tomography to track the mechanical response of a vertebrate (Barnacle goose) long bone subjected to an axial compressive load, which is increased gradually until failure. A loading rig was mounted in an X-ray computed tomography system so that a time-lapse sequence of three-dimensional (3D) images of the bone's internal (cancellous or trabecular) structure could be recorded during loading. Five distinct types of deformation mechanism were observed in the cancellous part of the bone. These were (i) cracking, (ii) thinning (iii) tearing of cell walls and struts, (iv) notch formation, (v) necking and (vi) buckling. The results highlight that bone experiences brittle (notch formation and cracking), ductile (thinning, tearing and necking) and elastic (buckling) modes of deformation. Progressive deformation, leading to cracking was studied in detail using digital image correlation. The resulting strain maps were consistent with mechanisms occurring at a finer-length scale. This paper is the first to capture time-lapse 3D images of a whole long bone subject to loading until failure. The results serve as a unique reference for researchers interested in how bone responds to loading. For those using computer modelling, the study not only provides qualitative information for verification and validation of their simulations but also highlights that constitutive models for bone need to take into account a number of different deformation mechanisms.

Development of AN Innovative Three-Dimensional Complete Body Screening Device - 3D-CBS

NASA Astrophysics Data System (ADS)

Crosetto, D. B.

2004-07-01

This article describes an innovative technological approach that increases the efficiency with which a large number of particles (photons) can be detected and analyzed. The three-dimensional complete body screening (3D-CBS) combines the functional imaging capability of the Positron Emission Tomography (PET) with those of the anatomical imaging capability of Computed Tomography (CT). The novel techniques provide better images in a shorter time with less radiation to the patient. A primary means of accomplishing this is the use of a larger solid angle, but this requires a new electronic technique capable of handling the increased data rate. This technique, combined with an improved and simplified detector assembly, enables executing complex real-time algorithms and allows more efficiently use of economical crystals. These are the principal features of this invention. A good synergy of advanced techniques in particle detection, together with technological progress in industry (latest FPGA technology) and simple, but cost-effective ideas provide a revolutionary invention. This technology enables over 400 times PET efficiency improvement at once compared to two to three times improvements achieved every five years during the past decades. Details of the electronics are provided, including an IBM PC board with a parallel-processing architecture implemented in FPGA, enabling the execution of a programmable complex real-time algorithm for best detection of photons.

Imaging cellular and subcellular structure of human brain tissue using micro computed tomography

NASA Astrophysics Data System (ADS)

Khimchenko, Anna; Bikis, Christos; Schweighauser, Gabriel; Hench, Jürgen; Joita-Pacureanu, Alexandra-Teodora; Thalmann, Peter; Deyhle, Hans; Osmani, Bekim; Chicherova, Natalia; Hieber, Simone E.; Cloetens, Peter; Müller-Gerbl, Magdalena; Schulz, Georg; Müller, Bert

2017-09-01

Brain tissues have been an attractive subject for investigations in neuropathology, neuroscience, and neurobiol- ogy. Nevertheless, existing imaging methodologies have intrinsic limitations in three-dimensional (3D) label-free visualisation of extended tissue samples down to (sub)cellular level. For a long time, these morphological features were visualised by electron or light microscopies. In addition to being time-consuming, microscopic investigation includes specimen fixation, embedding, sectioning, staining, and imaging with the associated artefacts. More- over, optical microscopy remains hampered by a fundamental limit in the spatial resolution that is imposed by the diffraction of visible light wavefront. In contrast, various tomography approaches do not require a complex specimen preparation and can now reach a true (sub)cellular resolution. Even laboratory-based micro computed tomography in the absorption-contrast mode of formalin-fixed paraffin-embedded (FFPE) human cerebellum yields an image contrast comparable to conventional histological sections. Data of a superior image quality was obtained by means of synchrotron radiation-based single-distance X-ray phase-contrast tomography enabling the visualisation of non-stained Purkinje cells down to the subcellular level and automated cell counting. The question arises, whether the data quality of the hard X-ray tomography can be superior to optical microscopy. Herein, we discuss the label-free investigation of the human brain ultramorphology be means of synchrotron radiation-based hard X-ray magnified phase-contrast in-line tomography at the nano-imaging beamline ID16A (ESRF, Grenoble, France). As an example, we present images of FFPE human cerebellum block. Hard X-ray tomography can provide detailed information on human tissues in health and disease with a spatial resolution below the optical limit, improving understanding of the neuro-degenerative diseases.

The effect of in situ/in vitro three-dimensional quantitative computed tomography image voxel size on the finite element model of human vertebral cancellous bone.

PubMed

Lu, Yongtao; Engelke, Klaus; Glueer, Claus-C; Morlock, Michael M; Huber, Gerd

2014-11-01

Quantitative computed tomography-based finite element modeling technique is a promising clinical tool for the prediction of bone strength. However, quantitative computed tomography-based finite element models were created from image datasets with different image voxel sizes. The aim of this study was to investigate whether there is an influence of image voxel size on the finite element models. In all 12 thoracolumbar vertebrae were scanned prior to autopsy (in situ) using two different quantitative computed tomography scan protocols, which resulted in image datasets with two different voxel sizes (0.29 × 0.29 × 1.3 mm(3) vs 0.18 × 0.18 × 0.6 mm(3)). Eight of them were scanned after autopsy (in vitro) and the datasets were reconstructed with two voxel sizes (0.32 × 0.32 × 0.6 mm(3) vs. 0.18 × 0.18 × 0.3 mm(3)). Finite element models with cuboid volume of interest extracted from the vertebral cancellous part were created and inhomogeneous bilinear bone properties were defined. Axial compression was simulated. No effect of voxel size was detected on the apparent bone mineral density for both the in situ and in vitro cases. However, the apparent modulus and yield strength showed significant differences in the two voxel size group pairs (in situ and in vitro). In conclusion, the image voxel size may have to be considered when the finite element voxel modeling technique is used in clinical applications. © IMechE 2014.

Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

PubMed Central

Wong, Ka-Kit; Gandhi, Arpit; Viglianti, Benjamin L; Fig, Lorraine M; Rubello, Domenico; Gross, Milton D

2016-01-01

AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders. METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology. RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for 99mTc-sestamibi parathyroid scintigraphy and 99mTc-pertechnetate thyroid scintigraphy, 123I- or 131I-radioiodine for staging of differentiated thyroid carcinoma, 111In- and 99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, 131I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and 123I- or 131I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma. CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy from CT, translating to improved diagnostic accuracy and meaningful impact on patient care. PMID:27358692

Three-dimensional distribution of polymorphs and magnesium in a calcified underwater attachment system by diffraction tomography

PubMed Central

Leemreize, Hanna; Almer, Jonathan D.; Stock, Stuart R.; Birkedal, Henrik

2013-01-01

Biological materials display complicated three-dimensional hierarchical structures. Determining these structures is essential in understanding the link between material design and properties. Herein, we show how diffraction tomography can be used to determine the relative placement of the calcium carbonate polymorphs calcite and aragonite in the highly mineralized holdfast system of the bivalve Anomia simplex. In addition to high fidelity and non-destructive mapping of polymorphs, we use detailed analysis of X-ray diffraction peak positions in reconstructed powder diffraction data to determine the local degree of Mg substitution in the calcite phase. These data show how diffraction tomography can provide detailed multi-length scale information on complex materials in general and of biomineralized tissues in particular. PMID:23804437

Three-dimensional structural analysis of eukaryotic flagella/cilia by electron cryo-tomography

PubMed Central

Bui, Khanh Huy; Pigino, Gaia; Ishikawa, Takashi

2011-01-01

Electron cryo-tomography is a potential approach to analyzing the three-dimensional conformation of frozen hydrated biological macromolecules using electron microscopy. Since projections of each individual object illuminated from different orientations are merged, electron tomography is capable of structural analysis of such heterogeneous environments as in vivo or with polymorphism, although radiation damage and the missing wedge are severe problems. Here, recent results on the structure of eukaryotic flagella, which is an ATP-driven bending organelle, from green algae Chlamydomonas are presented. Tomographic analysis reveals asymmetric molecular arrangements, especially that of the dynein motor proteins, in flagella, giving insight into the mechanism of planar asymmetric bending motion. Methodological challenges to obtaining higher-resolution structures from this technique are also discussed. PMID:21169680

[Establishment and validation of normal human L1-L5 lumbar three-dimensional finite element model].

PubMed

Zhu, Zhenqi; Liu, Chenjun; Wang, Jiefu; Wang, Kaifeng; Huang, Zhixin; Wang, Weida; Liu, Haiying

2014-10-14

To create and validate a L1-L5 lumbar three-dimensional finite element model. The L1-L5 lumbar spines of a male healthy volunteer were scanned with computed tomography (CT). And a L1-L5 lumbar three-dimensional finite element model was created with the aid of software packages of Mimics, Geomagic and Ansys. Then border conditions were set, unit type was determined, finite element mesh was divided and a model was established for loading and calculating. Average model stiffness under the conditions of flexion, extension, lateral bending and axial rotation was calculated and compared with the outcomes of former articles for validation. A normal human L1-L5 lumbar three-dimensional finite element model was established to include 459 340 elements and 661 938 nodes. After constraining the inferior endplate of L5 vertebral body, 500 kg × m × s⁻² compressive loading was imposed averagely on the superior endplate of L1 vertebral body. Then 10 kg × m² × s⁻² moment simulating flexion, extension, lateral bending and axial rotation were imposed on the superior endplate of L1 vertebral body. Eventually the average stiffness of all directions was calculated and it was similar to the outcomes of former articles. The L1-L5 lumbar three-dimensional finite element model is validated so that it may used with biomechanical simulation and analysis of normal or surgical models.

[Three dimensional finite element model of a modified posterior cervical single open-door laminoplasty].

PubMed

Wang, Q; Yang, Y; Fei, Q; Li, D; Li, J J; Meng, H; Su, N; Fan, Z H; Wang, B Q

2017-06-06

Objective: To build a three-dimensional finite element models of a modified posterior cervical single open-door laminoplasty with short-segmental lateral mass screws fusion. Methods: The C(2)-C(7) segmental data were obtained from computed tomography (CT) scans of a male patient with cervical spondylotic myelopathy and spinal stenosis.Three-dimensional finite element models of a modified cervical single open-door laminoplasty (before and after surgery) were constructed by the combination of software package MIMICS, Geomagic and ABAQUS.The models were composed of bony vertebrae, articulating facets, intervertebral disc and associated ligaments.The loads of moments 1.5Nm at different directions (flexion, extension, lateral bending and axial rotation)were applied at preoperative model to calculate intersegmental ranges of motion.The results were compared with the previous studies to verify the validation of the models. Results: Three-dimensional finite element models of the modified cervical single open- door laminoplasty had 102258 elements (preoperative model) and 161 892 elements (postoperative model) respectively, including C(2-7) six bony vertebraes, C(2-3)-C(6-7) five intervertebral disc, main ligaments and lateral mass screws.The intersegmental responses at the preoperative model under the loads of moments 1.5 Nm at different directions were similar to the previous published data. Conclusion: Three-dimensional finite element models of the modified cervical single open- door laminoplasty were successfully established and had a good biological fidelity, which can be used for further study.

Three-dimensional photography for the evaluation of facial profiles in obstructive sleep apnoea.

PubMed

Lin, Shih-Wei; Sutherland, Kate; Liao, Yu-Fang; Cistulli, Peter A; Chuang, Li-Pang; Chou, Yu-Ting; Chang, Chih-Hao; Lee, Chung-Shu; Li, Li-Fu; Chen, Ning-Hung

2018-06-01

Craniofacial structure is an important determinant of obstructive sleep apnoea (OSA) syndrome risk. Three-dimensional stereo-photogrammetry (3dMD) is a novel technique which allows quantification of the craniofacial profile. This study compares the facial images of OSA patients captured by 3dMD to three-dimensional computed tomography (3-D CT) and two-dimensional (2-D) digital photogrammetry. Measurements were correlated with indices of OSA severity. Thirty-eight patients diagnosed with OSA were included, and digital photogrammetry, 3dMD and 3-D CT were performed. Distances, areas, angles and volumes from the images captured by three methods were analysed. Almost all measurements captured by 3dMD showed strong agreement with 3-D CT measurements. Results from 2-D digital photogrammetry showed poor agreement with 3-D CT. Mandibular width, neck perimeter size and maxillary volume measurements correlated well with the severity of OSA using all three imaging methods. Mandibular length, facial width, binocular width, neck width, cranial base triangle area, cranial base area 1 and middle cranial fossa volume correlated well with OSA severity using 3dMD and 3-D CT, but not with 2-D digital photogrammetry. 3dMD provided accurate craniofacial measurements of OSA patients, which were highly concordant with those obtained by CT, while avoiding the radiation associated with CT. © 2018 Asian Pacific Society of Respirology.

Three-dimensional analysis of cervical spine segmental motion in rotation.

PubMed

Zhao, Xiong; Wu, Zi-Xiang; Han, Bao-Jun; Yan, Ya-Bo; Zhang, Yang; Lei, Wei

2013-06-20

The movements of the cervical spine during head rotation are too complicated to measure using conventional radiography or computed tomography (CT) techniques. In this study, we measure three-dimensional segmental motion of cervical spine rotation in vivo using a non-invasive measurement technique. Sixteen healthy volunteers underwent three-dimensional CT of the cervical spine during head rotation. Occiput (Oc) - T1 reconstructions were created of volunteers in each of 3 positions: supine and maximum left and right rotations of the head with respect to the bosom. Segmental motions were calculated using Euler angles and volume merge methods in three major planes. Mean maximum axial rotation of the cervical spine to one side was 1.6° to 38.5° at each level. Coupled lateral bending opposite to lateral bending was observed in the upper cervical levels, while in the subaxial cervical levels, it was observed in the same direction as axial rotation. Coupled extension was observed in the cervical levels of C5-T1, while coupled flexion was observed in the cervical levels of Oc-C5. The three-dimensional cervical segmental motions in rotation were accurately measured with the non-invasive measure. These findings will be helpful as the basis for understanding cervical spine movement in rotation and abnormal conditions. The presented data also provide baseline segmental motions for the design of prostheses for the cervical spine.

Evaluating the Amount of Tooth Movement and Root Resorption during Canine Retraction with Friction versus Frictionless Mechanics Using Cone Beam Computed Tomography

PubMed Central

Makhlouf, Mohamed; Aboul–Ezz, Amr; Fayed, Mona Salah; Hafez, Hend

2018-01-01

BACKGROUND: The current study was carried out to compare the amount of tooth movement during canine retraction comparing two different retraction mechanics; friction mechanics represented by a NiTi closed coil spring versus frictionless mechanics represented by T - loop, and their effect on root resorption using Cone Beam Computed Tomography (CBCT). METHOD: Ten patients were selected in a split-mouth study design that had a malocclusion that necessitates the extraction of maxillary first premolars and retraction of maxillary canines. The right maxillary canines were retracted using T - loops fabricated from 0.017 X 0.025 TMA wires. The left maxillary canines received NiTi coil spring with 150 gm of retraction force. Pre retraction and post retraction Cone Beam Computed Tomography were taken to evaluate the amount of tooth movement and root resorption using three-dimensional planes. RESULTS: T - loop side showed statistically significant higher mean anteroposterior measurement than NiTi coil spring side, indicating a lower amount of canine movement pre and post a canine retraction. Concerning the root resorption, there was no statistically significant change in the mean measurements of canine root length post retraction. CONCLUSION: The NiTi coil spring side showed more distal movement more than the T-loop side. Both retraction mechanics with controlled retraction force, do not cause root resorption. PMID:29531610

Evaluating the Amount of Tooth Movement and Root Resorption during Canine Retraction with Friction versus Frictionless Mechanics Using Cone Beam Computed Tomography.

PubMed

Makhlouf, Mohamed; Aboul-Ezz, Amr; Fayed, Mona Salah; Hafez, Hend

2018-02-15

The current study was carried out to compare the amount of tooth movement during canine retraction comparing two different retraction mechanics; friction mechanics represented by a NiTi closed coil spring versus frictionless mechanics represented by T - loop, and their effect on root resorption using Cone Beam Computed Tomography (CBCT). Ten patients were selected in a split-mouth study design that had a malocclusion that necessitates the extraction of maxillary first premolars and retraction of maxillary canines. The right maxillary canines were retracted using T - loops fabricated from 0.017 X 0.025 TMA wires. The left maxillary canines received NiTi coil spring with 150 gm of retraction force. Pre retraction and post retraction Cone Beam Computed Tomography were taken to evaluate the amount of tooth movement and root resorption using three-dimensional planes. T - loop side showed statistically significant higher mean anteroposterior measurement than NiTi coil spring side, indicating a lower amount of canine movement pre and post a canine retraction. Concerning the root resorption, there was no statistically significant change in the mean measurements of canine root length post retraction. The NiTi coil spring side showed more distal movement more than the T-loop side. Both retraction mechanics with controlled retraction force, do not cause root resorption.

Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer.

PubMed

Ale, Angelique; Ermolayev, Vladimir; Deliolanis, Nikolaos C; Ntziachristos, Vasilis

2013-05-01

The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method. Despite this progress, the detection sensitivity of targeted fluorescence agents remains limited by nonspecific background accumulation of the fluorochrome employed, which complicates early detection of murine cancers. Therefore we examine whether x-ray CT information and bulk fluorescence detection can be combined to increase detection sensitivity. Correspondingly, we research the performance of a data-driven fluorescence background estimator employed for subtraction of background fluorescence from acquisition data. Using mice containing known fluorochromes ex vivo, we demonstrate the reduction of background signals from reconstructed images and sensitivity improvements. Finally, by applying the method to in vivo data from K-ras transgenic mice developing lung cancer, we find small tumors at an early stage compared with reconstructions performed using raw data. We conclude with the benefits of employing fluorescence subtraction in hybrid FMT-XCT for early detection studies.

Three-dimensional visualization of the craniofacial patient: volume segmentation, data integration and animation.

PubMed

Enciso, R; Memon, A; Mah, J

2003-01-01

The research goal at the Craniofacial Virtual Reality Laboratory of the School of Dentistry in conjunction with the Integrated Media Systems Center, School of Engineering, University of Southern California, is to develop computer methods to accurately visualize patients in three dimensions using advanced imaging and data acquisition devices such as cone-beam computerized tomography (CT) and mandibular motion capture. Data from these devices were integrated for three-dimensional (3D) patient-specific visualization, modeling and animation. Generic methods are in development that can be used with common CT image format (DICOM), mesh format (STL) and motion data (3D position over time). This paper presents preliminary descriptive studies on: 1) segmentation of the lower and upper jaws with two types of CT data--(a) traditional whole head CT data and (b) the new dental Newtom CT; 2) manual integration of accurate 3D tooth crowns with the segmented lower jaw 3D model; 3) realistic patient-specific 3D animation of the lower jaw.

Casting Simulation of an Austrian Bronze Age Sword Hilt

NASA Astrophysics Data System (ADS)

Pola, Annalisa; Mödlinger, Marianne; Piccardo, Paolo; Montesano, Lorenzo

2015-07-01

Bronze Age swords with a metal hilt can be considered the peak of Bronze Age casting technologies. To reconstruct the casting techniques used more than 3000 years ago, a metal hilted sword of the Schalenknauf type from Lower Austria was studied with the aid of macroscopic analyses and simulation of mold filling and casting solidification. A three-dimensional model of the hilt was created based on optical scanner measurements performed on a hilt recently discovered during archaeological excavations. Three different configurations of the gating system were considered, two on the pommel disk and one on the knob, and the effect of its location on the formation of casting defects was investigated. Three-dimensional computed tomography was used to detect internal defects, such as gas and shrinkage porosity, which were then compared with those calculated by simulation. The best match between actual and predicted hilt quality demonstrated the location of the gating system, which turned out to be on the pommel disk.

Three-dimensional computed tomographic volumetry precisely predicts the postoperative pulmonary function.

PubMed

Kobayashi, Keisuke; Saeki, Yusuke; Kitazawa, Shinsuke; Kobayashi, Naohiro; Kikuchi, Shinji; Goto, Yukinobu; Sakai, Mitsuaki; Sato, Yukio

2017-11-01

It is important to accurately predict the patient's postoperative pulmonary function. The aim of this study was to compare the accuracy of predictions of the postoperative residual pulmonary function obtained with three-dimensional computed tomographic (3D-CT) volumetry with that of predictions obtained with the conventional segment-counting method. Fifty-three patients scheduled to undergo lung cancer resection, pulmonary function tests, and computed tomography were enrolled in this study. The postoperative residual pulmonary function was predicted based on the segment-counting and 3D-CT volumetry methods. The predicted postoperative values were compared with the results of postoperative pulmonary function tests. Regarding the linear correlation coefficients between the predicted postoperative values and the measured values, those obtained using the 3D-CT volumetry method tended to be higher than those acquired using the segment-counting method. In addition, the variations between the predicted and measured values were smaller with the 3D-CT volumetry method than with the segment-counting method. These results were more obvious in COPD patients than in non-COPD patients. Our findings suggested that the 3D-CT volumetry was able to predict the residual pulmonary function more accurately than the segment-counting method, especially in patients with COPD. This method might lead to the selection of appropriate candidates for surgery among patients with a marginal pulmonary function.

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages.

PubMed

Carlton, Holly D; Elmer, John W; Li, Yan; Pacheco, Mario; Goyal, Deepak; Parkinson, Dilworth Y; MacDowell, Alastair A

2016-04-13

Synchrotron radiation micro-tomography (SRµT) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm(2), but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample's properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 µm all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

Lumbo-Pelvic-Hip Complex Pain in a Competitive Basketball Player

PubMed Central

Reiman, Michael P.; Cox, Kara D.; Jones, Kay S.; Byrd, J. W.

2011-01-01

Establishing the cause of lumbo-pelvic-hip complex pain is a challenge for many clinicians. This case report describes the mechanism of injury, diagnostic process, surgical management, and rehabilitation of a female high school basketball athlete who sustained an injury when falling on her right side. Diagnostics included clinical examination, radiography of the spine and hip joint, magnetic resonance imaging arthrogram, 3-dimensional computed tomography scan, and computed tomography of the hip joint. A systematic multidisciplinary clinical approach resulted in the patient’s return to previous functional levels. PMID:23015993

Electromagnetic Navigational Bronchoscopy Reduces the Time Required for Localization and Resection of Lung Nodules.

PubMed

Bolton, William David; Cochran, Thomas; Ben-Or, Sharon; Stephenson, James E; Ellis, William; Hale, Allyson L; Binks, Andrew P

The aims of the study were to evaluate electromagnetic navigational bronchoscopy (ENB) and computed tomography-guided placement as localization techniques for minimally invasive resection of small pulmonary nodules and determine whether electromagnetic navigational bronchoscopy is a safer and more effective method than computed tomography-guided localization. We performed a retrospective review of our thoracic surgery database to identify patients who underwent minimally invasive resection for a pulmonary mass and used either electromagnetic navigational bronchoscopy or computed tomography-guided localization techniques between July 2011 and May 2015. Three hundred eighty-three patients had a minimally invasive resection during our study period, 117 of whom underwent electromagnetic navigational bronchoscopy or computed tomography localization (electromagnetic navigational bronchoscopy = 81; computed tomography = 36). There was no significant difference between computed tomography and electromagnetic navigational bronchoscopy patient groups with regard to age, sex, race, pathology, nodule size, or location. Both computed tomography and electromagnetic navigational bronchoscopy were 100% successful at localizing the mass, and there was no difference in the type of definitive surgical resection (wedge, segmentectomy, or lobectomy) (P = 0.320). Postoperative complications occurred in 36% of all patients, but there were no complications related to the localization procedures. In terms of localization time and surgical time, there was no difference between groups. However, the down/wait time between localization and resection was significant (computed tomography = 189 minutes; electromagnetic navigational bronchoscopy = 27 minutes); this explains why the difference in total time (sum of localization, down, and surgery) was significant (P < 0.001). We found electromagnetic navigational bronchoscopy to be as safe and effective as computed tomography-guided wire placement and to provide a significantly decreased down time between localization and surgical resection.

The efficacy of 320-detector row computed tomography for the assessment of preoperative pulmonary vasculature of candidates for pulmonary segmentectomy.

PubMed

Tane, Shinya; Ohno, Yoshiharu; Hokka, Daisuke; Ogawa, Hiroyuki; Tauchi, Shunsuke; Nishio, Wataru; Yoshimura, Masahiro; Okita, Yutaka; Maniwa, Yoshimasa

2013-12-01

The purpose of this study was to compare the efficacy of 320-detector row computed tomography (CT) with that of 64-detector row CT for three-dimensional assessment of pulmonary vasculature of candidates for pulmonary segmentectomy. We included 32 patients who underwent both 320- and 64-detector CT before pulmonary segmentectomy, which was performed by cutting the pulmonary artery and bronchi of the affected segment followed by dissection of the intersegmental plane along the intersegmental vein. Before the operation, three-dimensional pulmonary vasculature images were obtained for each patient, and the arteries and intersegmental veins of the affected segments were identified. Two thoracic surgeons independently assessed the vessels with visual scoring systems, and kappa analysis was used to determine interobserver agreement. The Wilcoxon signed-rank test was used to compare the visual scores for the assessment of the visualization capabilities of the two methods. In addition, the final determination of pulmonary vasculature at a given site was made by consensus from thoracic surgeons during operation, and receiver operating characteristic analysis was performed to compare their efficacy of pulmonary vasculature assessment. Sensitivity, specificity and accuracy of either method were also compared by means of McNemar's test. Of the 32 cases, there were no operative complications, but 1 patient died of postoperative idiopathic interstitial pneumonia. Visualization scores for the pulmonary vessels were significantly higher for 320- than those for 64-detector CT (P < 0.0001 for the affected arteries and P < 0.0001 for the intersegmental veins). As for pulmonary vasculature assessment, the areas under the curve showed no statistically significant differences in between the two methods, while the specificity and accuracy of intersegemental vein assessment were significantly better for 320- than those for 64-detector row CT (P < 0.05). Interobserver agreement for the assessment yielded by either method was almost perfect for all cases. Three hundred and twenty-detector row CT is more useful than conventional 64-detector row CT for preoperative three-dimensional assessment of pulmonary vasculature, especially when we identify the intersegmental veins, in candidates for pulmonary segmentectomy.

Three-dimensional planning and use of patient-specific guides improve glenoid component position: an in vitro study.

PubMed

Walch, Gilles; Vezeridis, Peter S; Boileau, Pascal; Deransart, Pierric; Chaoui, Jean

2015-02-01

Glenoid component positioning is a key factor for success in total shoulder arthroplasty. Three-dimensional (3D) measurements of glenoid retroversion, inclination, and humeral head subluxation are helpful tools for preoperative planning. The purpose of this study was to assess the reliability and precision of a novel surgical method for placing the glenoid component with use of patient-specific templates created by preoperative surgical planning and 3D modeling. A preoperative computed tomography examination of cadaveric scapulae (N = 18) was performed. The glenoid implants were virtually placed, and patient-specific guides were created to direct the guide pin into the desired orientation and position in the glenoid. The 3D orientation and position of the guide pin were evaluated by performing a postoperative computed tomography scan for each scapula. The differences between the preoperative planning and the achieved result were analyzed. The mean error in 3D orientation of the guide pin was 2.39°, the mean entry point position error was 1.05 mm, and the mean inclination angle error was 1.42°. The average error in the version angle was 1.64°. There were no technical difficulties or complications related to use of patient-specific guides for guide pin placement. Quantitative analysis of guide pin positioning demonstrated a good correlation between preoperative planning and the achieved position of the guide pin. This study demonstrates the reliability and precision of preoperative planning software and patient-specific guides for glenoid component placement in total shoulder arthroplasty. Copyright © 2015. Published by Elsevier Inc.

Diffuse skull base/cervical fusion syndromes in two siblings with spondylocostal dysostosis syndrome: analysis via three dimensional computed tomography scanning.

PubMed

Al Kaissi, Ali; Ben Chehida, Farid; Ben Ghachem, Maher; Klaushofer, Klaus; Grill, Franz

2008-06-01

A study on a pair of male sibs to reach for the etiological understanding of unusual skull base/spine maldevelopment. Previously, radiographs alone were used to formulate this diagnosis. Here, three-dimensional computed tomography (3D CT) studies further clarified the typical diagnostic findings associated with spondylocostal dysostosis (SCD). Interestingly, patients with SCD are at increased risk for diffuse skull base/cervical fusion syndromes and can result in severe neurologic deficits associated with any degree of trauma. Classically SCD is defined as a skeletal dysplasia with clinical and radiologic manifestations, consisting of short neck and trunk, nonprogressive scoliosis and abnormalities of vertebral segmentation and of the ribs. Radiograms have been adopted as the only modality for the classification and prognostication of patients with SCD. Detailed clinical and radiographic examinations were undertaken with emphasis on the significance of the 3D CT scanning. We observed extensive fusion of the clivus with the cervical/entire spine, resulting in a remarkable solid, immobile, and fixed bony ankylosis of extremely serious outcome. Patients with spondylcostal dysostosis are predisposed to develop extensive skull-base-cervical spine fusion. The latter might lead to the development of a solid, immobile, and fixed bony ankylosis. In children/adults trivial injuries and/or high-energy trauma can lead to serious intracranial and spinal cord injury. Comprehensive orthopedic and neurosurgeons management must follow the recognition of these anomalies. To the best of our knowledge, no previous CT studies of the spine have been published in patients with SCD.

Anatomy of the larynx and pharynx: effects of age, gender and height revealed by multidetector computed tomography.

PubMed

Inamoto, Y; Saitoh, E; Okada, S; Kagaya, H; Shibata, S; Baba, M; Onogi, K; Hashimoto, S; Katada, K; Wattanapan, P; Palmer, J B

2015-09-01

Although oropharyngeal and laryngeal structures are essential for swallowing, the three-dimensional (3D) anatomy is not well understood, due in part to limitations of available measuring techniques. This study uses 3D images acquired by 320-row area detector computed tomography ('320-ADCT'), to measure the pharynx and larynx and to investigate the effects of age, gender and height. Fifty-four healthy volunteers (30 male, 24 female, 23-77 years) underwent one single-phase volume scan (0.35 s) with 320-ADCT during resting tidal breathing. Six measurements of the pharynx and two of larynx were performed. Bivariate statistical methods were used to analyse the effects of gender, age and height on these measurements. Length and volume were significantly larger for men than for women for every measurement (P < 0.05) and increased with height (P < 0.05). Multiple regression analysis was performed to understand the interactions of gender, height and age. Gender, height and age each had significant effects on certain values. The volume of the larynx and hypopharynx was significantly affected by height and age. The length of pharynx was associated with gender and age. Length of the vocal folds and distance from the valleculae to the vocal folds were significantly affected by gender (P < 0.05). These results suggest that age, gender and height have independent and interacting effects on the morphology of the pharynx and larynx. Three-dimensional imaging and morphometrics using 320-ADCT are powerful tools for efficiently and reliably observing and measuring the pharynx and larynx. © 2015 John Wiley & Sons Ltd.

Virtual Reality Model of the Three-Dimensional Anatomy of the Cavernous Sinus Based on a Cadaveric Image and Dissection.

PubMed

Qian, Zeng-Hui; Feng, Xu; Li, Yang; Tang, Ke

2018-01-01

Studying the three-dimensional (3D) anatomy of the cavernous sinus is essential for treating lesions in this region with skull base surgeries. Cadaver dissection is a conventional method that has insurmountable flaws with regard to understanding spatial anatomy. The authors' research aimed to build an image model of the cavernous sinus region in a virtual reality system to precisely, individually and objectively elucidate the complete and local stereo-anatomy. Computed tomography and magnetic resonance imaging scans were performed on 5 adult cadaver heads. Latex mixed with contrast agent was injected into the arterial system and then into the venous system. Computed tomography scans were performed again following the 2 injections. Magnetic resonance imaging scans were performed again after the cranial nerves were exposed. Image data were input into a virtual reality system to establish a model of the cavernous sinus. Observation results of the image models were compared with those of the cadaver heads. Visualization of the cavernous sinus region models built using the virtual reality system was good for all the cadavers. High resolutions were achieved for the images of different tissues. The observed results were consistent with those of the cadaver head. The spatial architecture and modality of the cavernous sinus were clearly displayed in the 3D model by rotating the model and conveniently changing its transparency. A 3D virtual reality model of the cavernous sinus region is helpful for globally and objectively understanding anatomy. The observation procedure was accurate, convenient, noninvasive, and time and specimen saving.

Material Characterization and Geometric Segmentation of a Composite Structure Using Microfocus X-Ray Computed Tomography Image-Based Finite Element Modeling

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Roth, D. J.; Cotton, R.; Studor, George F.; Christiansen, Eric; Young, P. C.

2011-01-01

This study utilizes microfocus x-ray computed tomography (CT) slice sets to model and characterize the damage locations and sizes in thermal protection system materials that underwent impact testing. ScanIP/FE software is used to visualize and process the slice sets, followed by mesh generation on the segmented volumetric rendering. Then, the local stress fields around several of the damaged regions are calculated for realistic mission profiles that subject the sample to extreme temperature and other severe environmental conditions. The resulting stress fields are used to quantify damage severity and make an assessment as to whether damage that did not penetrate to the base material can still result in catastrophic failure of the structure. It is expected that this study will demonstrate that finite element modeling based on an accurate three-dimensional rendered model from a series of CT slices is an essential tool to quantify the internal macroscopic defects and damage of a complex system made out of thermal protection material. Results obtained showing details of segmented images; three-dimensional volume-rendered models, finite element meshes generated, and the resulting thermomechanical stress state due to impact loading for the material are presented and discussed. Further, this study is conducted to exhibit certain high-caliber capabilities that the nondestructive evaluation (NDE) group at NASA Glenn Research Center can offer to assist in assessing the structural durability of such highly specialized materials so improvements in their performance and capacities to handle harsh operating conditions can be made.

Evaluation of Teeth Development in Unilateral Cleft Lip and Palate Patients in Mixed Dentition by Using Medical Image Control Systems.

PubMed

Gezgin, O; Botsali, M S

2018-02-01

The aim of this study was to evaluate the crown and root development in patients with cleft lip and palate using medical software programmes. In our study, 25 patients with mixed dentition unilateral cleft lip and palate were examined with cone-beam computed tomography (CBCT). The tomography images obtained as high resolution medical images on the computer control system (MIMICS 15.0, Materialise, Leuven, Belgium and SOLIDWORKS 2014 Premium, Concord, Massachusetts) were converted to three-dimensional volumetric images. These three-dimensional images of the cleft on the sides of the teeth in the crown and root growth were measured by mesiodistal length and crown/root rate with volume and area. These measurements were compared with a control group of healthy individuals. There were no statistically significant differences in the volume, surface area and MD size, crown/root ratio of central incisor, canine, first premolar and second premolar teeth within defect, and healthy teeth. However, it was found that there was a significant difference between the volume, surface area and MD size, and crown/root ratio of the lateral teeth in each group. In particular, among patients with cleft lip and palate, on obtaining a solid model of the tooth structure by using these programs, tooth development can be examined in more detail, diagnosis can be made more reliable, as well as in treatment planning. We believe that these programs can be used to resolve certain limitations such as a lack of an application to be used in routine dental treatment and in particular the need to do more study.

Optical computed tomography for spatially isotropic four-dimensional imaging of live single cells

PubMed Central

Kelbauskas, Laimonas; Shetty, Rishabh; Cao, Bin; Wang, Kuo-Chen; Smith, Dean; Wang, Hong; Chao, Shi-Hui; Gangaraju, Sandhya; Ashcroft, Brian; Kritzer, Margaret; Glenn, Honor; Johnson, Roger H.; Meldrum, Deirdre R.

2017-01-01

Quantitative three-dimensional (3D) computed tomography (CT) imaging of living single cells enables orientation-independent morphometric analysis of the intricacies of cellular physiology. Since its invention, x-ray CT has become indispensable in the clinic for diagnostic and prognostic purposes due to its quantitative absorption-based imaging in true 3D that allows objects of interest to be viewed and measured from any orientation. However, x-ray CT has not been useful at the level of single cells because there is insufficient contrast to form an image. Recently, optical CT has been developed successfully for fixed cells, but this technology called Cell-CT is incompatible with live-cell imaging due to the use of stains, such as hematoxylin, that are not compatible with cell viability. We present a novel development of optical CT for quantitative, multispectral functional 4D (three spatial + one spectral dimension) imaging of living single cells. The method applied to immune system cells offers truly isotropic 3D spatial resolution and enables time-resolved imaging studies of cells suspended in aqueous medium. Using live-cell optical CT, we found a heterogeneous response to mitochondrial fission inhibition in mouse macrophages and differential basal remodeling of small (0.1 to 1 fl) and large (1 to 20 fl) nuclear and mitochondrial structures on a 20- to 30-s time scale in human myelogenous leukemia cells. Because of its robust 3D measurement capabilities, live-cell optical CT represents a powerful new tool in the biomedical research field. PMID:29226240

The free descending branch muscle-sparing latissimus dorsi flap: vascular anatomy and clinical applications.

PubMed

Colohan, Shannon; Wong, Corrine; Lakhiani, Chrisovalantis; Cheng, Angela; Maia, Munique; Arbique, Gary; Saint-Cyr, Michel

2012-12-01

Increasing focus on reducing morbidity from latissimus dorsi flaps has led to the evolution of muscle-sparing variants and perforator-based flaps. This study aimed to investigate the vascular anatomy of the muscle-sparing variant and to describe its application as a free flap based on the descending branch of the thoracodorsal artery. Twelve fresh cadavers underwent anatomical dissection and angiographic injection studies of the thoracodorsal arterial system. The musculocutaneous territories of the descending and transverse branches to the latissimus dorsi muscle were identified and assessed using three-dimensional reconstruction software of computed tomography imaging results. In the clinical study, five patients underwent reconstruction of a variety of defects using the free descending branch muscle-sparing latissimus dorsi flap. Three- and four-dimensional (computed tomography) angiography demonstrated perfusion of the latissimus dorsi muscle by the transverse and descending branches, with overlap of vascular territories via cross-linking vessels. The descending branch supplied a slightly greater cutaneous area overlying the muscle, although differences between both branches were not significant (p = 0.76). In the clinical study, the free muscle-sparing latissimus dorsi flap provided excellent coverage with no flap complications or seroma. The free muscle-sparing latissimus dorsi flap based on the descending branch of the thoracodorsal artery is a viable reconstructive option. Significant collateral flow between vessels allows for larger flap harvest than would be expected. The flap is technically simple to harvest, provides a large perfusion area, and is a reliable variant of the full latissimus dorsi flap. Therapeutic, V.

Effect of the High-Pitch Mode in Dual-Source Computed Tomography on the Accuracy of Three-Dimensional Volumetry of Solid Pulmonary Nodules: A Phantom Study

PubMed Central

Hwang, Sung Ho; Ham, Soo-Youn; Kang, Eun-Young; Lee, Ki Yeol

2015-01-01

Objective To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. Materials and Methods A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. Results In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 ± 5.3%), with an IVV of 13.1 ± 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. Conclusion The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule. PMID:25995695

Analysis of high-pitched phonation using three-dimensional computed tomography.

PubMed

Hiramatsu, Hiroyuki; Tokashiki, Ryoji; Nakamura, Hirokazu; Motohashi, Ray; Sakurai, Eriko; Nomoto, Masaki; Toyomura, Fumimasa; Suzuki, Mamoru

2012-09-01

Our aim was to use three-dimensional computed tomography (3DCT) to examine arytenoid cartilage movement during a high-pitched tone task. This was a prospective study. This study included 14 patients with male-to-female gender identity disorder who had undergone 3DCT imaging for surgical simulation between January 2007 and May 2008. First, to prove that the phonation condition was indeed one of the high-pitched phonation, we confirmed the rotational movement of the thyroid cartilage, horizontal gliding movement of the inferior horn, and vocal fold elongation on a high-pitched tone task. Next, we detected the arytenoid cartilage positions of the joint during a comparison of comfortable and high-pitched phonations. We measured the movement direction and movement distance of the arytenoid cartilage. In all cases, the cricothyroid space became narrower (rotation movement), and we observed anterior gliding movement of the inferior horn. In all cases, elongation of the vocal folds by the high-pitched phonation was confirmed and the arytenoid cartilages were displaced both anteriorly and caudally from the position during comfortable phonation by the high-pitched tone task. The arytenoid cartilages did not move posteriorly to elongate the vocal folds during high-pitched phonation. The arytenoid cartilages were pulled anteriorly and moved caudally because of tension associated with vocal fold elongation because of the task of high-pitched phonation. These results suggest that there are no movements at the cricoarytenoid joint that directly control the length of the vocal folds in accordance with pitch. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

A new method for mapping the three-dimensional atomic distribution within nanoparticles by atom probe tomography (APT).

PubMed

Kim, Se-Ho; Kang, Phil Woong; Park, O Ok; Seol, Jae-Bok; Ahn, Jae-Pyoung; Lee, Ji Yeong; Choi, Pyuck-Pa

2018-07-01

We present a new method of preparing needle-shaped specimens for atom probe tomography from freestanding Pd and C-supported Pt nanoparticles. The method consists of two steps, namely electrophoresis of nanoparticles on a flat Cu substrate followed by electrodeposition of a Ni film acting as an embedding matrix for the nanoparticles. Atom probe specimen preparation can be subsequently carried out by means of focused-ion-beam milling. Using this approach, we have been able to perform correlative atom probe tomography and transmission electron microscopy analyses on both nanoparticle systems. Reliable mass spectra and three-dimensional atom maps could be obtained for Pd nanoparticle specimens. In contrast, atom probe samples prepared from C-supported Pt nanoparticles showed uneven field evaporation and hence artifacts in the reconstructed atom maps. Our developed method is a viable means of mapping the three-dimensional atomic distribution within nanoparticles and is expected to contribute to an improved understanding of the structure-composition-property relationships of various nanoparticle systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Integrating three-dimensional digital technologies for comprehensive implant dentistry.

PubMed

Patel, Neal

2010-06-01

The increase in the popularity of and the demand for the use of dental implants to replace teeth has encouraged advancement in clinical technology and materials to improve patients' acceptance and clinical outcomes. Recent advances such as three-dimensional dental radiography with cone-beam computed tomography (CBCT), precision dental implant planning software and clinical execution with guided surgery all play a role in the success of implant dentistry. The author illustrates the technique of comprehensive implant dentistry planning through integration of computer-aided design/computer-aided manufacturing (CAD/CAM) and CBCT data. The technique includes clinical treatment with guided surgery, including the creation of a final restoration with a high-strength ceramic (IPS e.max CAD, Ivoclar Vivadent, Amherst, N.Y.). The author also introduces a technique involving CAD/CAM for fabricating custom implant abutments. The release of software integrating CEREC Acquisition Center with Bluecam (Sirona Dental Systems, Charlotte, N.C.) chairside CAD/CAM and Galileos CBCT imaging (Sirona Dental Systems) allows dentists to plan implant placement, perform implant dentistry with increased precision and provide predictable restorative results by using chairside IPS e.max CAD. The precision of clinical treatment provided by the integration of CAD/CAM and CBCT allows dentists to plan for ideal surgical placement and the appropriate thickness of restorative modalities before placing implants.

A three-dimensional thermal and electromagnetic model of whole limb heating with a MAPA.

PubMed

Charny, C K; Levin, R L

1991-10-01

Previous studies by the authors have shown that if properly implemented, the Pennes assumptions can be applied to quantify bioheat transfer during extremity heating. Given its relative numerical simplicity and its ability to predict temperatures in thermoregulated tissue, the Pennes model of bioheat transfer was utilized in a three-dimensional thermal model of limb heating. While the arterial blood temperature was assumed to be radially uniform within a cross section of the limb, axial gradients in the arterial and venous blood temperatures were computed with this three-dimensional model. A realistically shaped, three-dimensional finite element model of a tumor-bearing human lower leg was constructed and was "attached" mathematically to the whole body thermal model of man described in previous studies by the authors. The central as well as local thermoregulatory feedback control mechanisms which determine blood perfusion to the various tissues and rate of evaporation by sweating were input into the limb model. In addition, the temperature of the arterial blood which feeds into the most proximal section of the lower leg was computed by the whole body thermal model. The variations in the shape of the tissues which comprise the limb were obtained from computerized tomography scans. Axial variations in the energy deposition patterns along the length of the limb exposed to a miniannular phased array (MAPA) applicator were also input into this model of limb heating. Results indicate that proper positioning of the limb relative to the MAPA is a significant factor in determining the effectiveness of the treatment. A patient-specific hyperthermia protocol can be designed using this coupled electromagnetic and thermal model.

Image matrix processor for fast multi-dimensional computations

DOEpatents

Roberson, G.P.; Skeate, M.F.

1996-10-15

An apparatus for multi-dimensional computation is disclosed which comprises a computation engine, including a plurality of processing modules. The processing modules are configured in parallel and compute respective contributions to a computed multi-dimensional image of respective two dimensional data sets. A high-speed, parallel access storage system is provided which stores the multi-dimensional data sets, and a switching circuit routes the data among the processing modules in the computation engine and the storage system. A data acquisition port receives the two dimensional data sets representing projections through an image, for reconstruction algorithms such as encountered in computerized tomography. The processing modules include a programmable local host, by which they may be configured to execute a plurality of different types of multi-dimensional algorithms. The processing modules thus include an image manipulation processor, which includes a source cache, a target cache, a coefficient table, and control software for executing image transformation routines using data in the source cache and the coefficient table and loading resulting data in the target cache. The local host processor operates to load the source cache with a two dimensional data set, loads the coefficient table, and transfers resulting data out of the target cache to the storage system, or to another destination. 10 figs.

CFD and PTV steady flow investigation in an anatomically accurate abdominal aortic aneurysm.

PubMed

Boutsianis, Evangelos; Guala, Michele; Olgac, Ufuk; Wildermuth, Simon; Hoyer, Klaus; Ventikos, Yiannis; Poulikakos, Dimos

2009-01-01

There is considerable interest in computational and experimental flow investigations within abdominal aortic aneurysms (AAAs). This task stipulates advanced grid generation techniques and cross-validation because of the anatomical complexity. The purpose of this study is to examine the feasibility of velocity measurements by particle tracking velocimetry (PTV) in realistic AAA models. Computed tomography and rapid prototyping were combined to digitize and construct a silicone replica of a patient-specific AAA. Three-dimensional velocity measurements were acquired using PTV under steady averaged resting boundary conditions. Computational fluid dynamics (CFD) simulations were subsequently carried out with identical boundary conditions. The computational grid was created by splitting the luminal volume into manifold and nonmanifold subsections. They were filled with tetrahedral and hexahedral elements, respectively. Grid independency was tested on three successively refined meshes. Velocity differences of about 1% in all three directions existed mainly within the AAA sack. Pressure revealed similar variations, with the sparser mesh predicting larger values. PTV velocity measurements were taken along the abdominal aorta and showed good agreement with the numerical data. The results within the aneurysm neck and sack showed average velocity variations of about 5% of the mean inlet velocity. The corresponding average differences increased for all velocity components downstream the iliac bifurcation to as much as 15%. The two domains differed slightly due to flow-induced forces acting on the silicone model. Velocity quantification through narrow branches was problematic due to decreased signal to noise ratio at the larger local velocities. Computational wall pressure and shear fields are also presented. The agreement between CFD simulations and the PTV experimental data was confirmed by three-dimensional velocity comparisons at several locations within the investigated AAA anatomy indicating the feasibility of this approach.

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

PubMed Central

Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

2016-01-01

Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

An evaluation of clinical, radiological and three-dimensional dental tomography findings in ectodermal dysplasia cases

PubMed Central

Doğan, Mehmet-Sinan; Callea, Michele; Aksoy, Orhan; Clarich, Gabriella; Günay, Ayşe; Günay, Ahmet; Güven, Sedat; Maglione, Michele; Akkuş, Zeki

2015-01-01

Background This study aimed to review the results related to head and jaw disorders in cases of ectodermal dysplasia. The evaluation of ectodermal dysplasia cases was made by clincal examination and examination of the jaw and facial areas radiologically and on cone-beam 3-dimensional dental tomography (CBCT) images. Material and Methods In the 36 cases evaluated in the study, typical clinical findings of pure hypohidrotic ectodermal displasia (HED) were seen, such as missing teeth, dry skin, hair and nail disorders. CBCT images were obtained from 12 of the 36 cases, aged 1.5- 45 years, and orthodontic analyses were made on these images. Results The clinical and radiological evaluations determined, hypodontia or oligodontia, breathing problems, sweating problems, a history of fever, sparse hair, saddle nose, skin peeling, hypopigmentation, hyperpigmentation, finger and nail deformities, conical teeth anomalies, abnormal tooth root formation, tooth resorption in the root, gingivitis, history of epilepsy, absent lachrymal canals and vision problems in the cases which included to the study. Conclusions Ectodermal dysplasia cases have a particular place in dentistry and require a professional, multi-disciplinary approach in respect of the chewing function, orthognathic problems, growth, oral and dental health. It has been understood that with data obtained from modern technologies such as three-dimensional dental tomography and the treatments applied, the quality of life of these cases can be improved. Key words: Ectodermal dysplasia, three-dimensional dental tomography. PMID:25662550

Axial Tomography from Digitized Real Time Radiography

DOE R&D Accomplishments Database

Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

1985-01-18

Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

Creation of three-dimensional craniofacial standards from CBCT images

NASA Astrophysics Data System (ADS)

Subramanyan, Krishna; Palomo, Martin; Hans, Mark

2006-03-01

Low-dose three-dimensional Cone Beam Computed Tomography (CBCT) is becoming increasingly popular in the clinical practice of dental medicine. Two-dimensional Bolton Standards of dentofacial development are routinely used to identify deviations from normal craniofacial anatomy. With the advent of CBCT three dimensional imaging, we propose a set of methods to extend these 2D Bolton Standards to anatomically correct surface based 3D standards to allow analysis of morphometric changes seen in craniofacial complex. To create 3D surface standards, we have implemented series of steps. 1) Converting bi-plane 2D tracings into set of splines 2) Converting the 2D splines curves from bi-plane projection into 3D space curves 3) Creating labeled template of facial and skeletal shapes and 4) Creating 3D average surface Bolton standards. We have used datasets from patients scanned with Hitachi MercuRay CBCT scanner providing high resolution and isotropic CT volume images, digitized Bolton Standards from age 3 to 18 years of lateral and frontal male, female and average tracings and converted them into facial and skeletal 3D space curves. This new 3D standard will help in assessing shape variations due to aging in young population and provide reference to correct facial anomalies in dental medicine.

Three-Dimensional Cone Beam Computed Tomography Volumetric Outcomes of rhBMP-2/Demineralized Bone Matrix versus Iliac Crest Bone Graft for Alveolar Cleft Reconstruction.

PubMed

Liang, Fan; Yen, Stephen L-K; Imahiyerobo, Thomas; Sanborn, Luke; Yen, Leia; Yen, Daniel; Nazarian, Sheila; Jedrzejewski, Breanna; Urata, Mark; Hammoudeh, Jeffrey

2017-10-01

Recent studies indicate that recombinant human bone morphogenetic protein-2 (rhBMP-2) in a demineralized bone matrix scaffold is a comparable alternative to iliac bone autograft in the setting of secondary alveolar cleft repair. Postreconstruction occlusal radiographs demonstrate improved bone stock when rhBMP-2/demineralized bone matrix (DBM) scaffold is used but lack the capacity to evaluate bone growth in three dimensions. This study uses cone beam computed tomography to provide the first clinical evaluation of volumetric and density comparisons between these two treatment modalities. A prospective study was conducted with 31 patients and 36 repairs of the alveolar cleft over a 2-year period. Twenty-one repairs used rhBMP-2/DBM scaffold and 14 repairs used iliac bone grafting. Postoperatively, occlusal radiographs were obtained at 3 months to evaluate bone fill; cone beam computed tomographic images were obtained at 6 to 9 months to compare volumetric and density data. At 3 months, postoperative occlusal radiographs demonstrated that 67 percent of patients receiving rhBMP-2/DBM scaffold had complete bone fill of the alveolus, versus 56 percent of patients in the autologous group. In contrast, cone beam computed tomographic data showed 31.6 percent (95 percent CI, 24.2 to 38.5 percent) fill in the rhBMP-2 group compared with 32.5 percent (95 percent CI, 22.1 to 42.9 percent) in the autologous population. Density analysis demonstrated identical average values between the groups (1.38 g/cc). These data demonstrate comparable bone regrowth and density values following secondary alveolar cleft repair using rhBMP-2/DBM scaffold versus autologous iliac bone graft. Cone beam computed tomography provides a more nuanced understanding of true bone regeneration within the alveolar cleft that may contribute to the information provided by occlusal radiographs alone. Therapeutic, II.

68Ga-PSMA PET/CT in prostate cancer.

PubMed

García Garzón, J R; de Arcocha Torres, M; Delgado-Bolton, R; Ceci, F; Alvarez Ruiz, S; Orcajo Rincón, J; Caresia Aróztegui, A P; García Velloso, M J; García Vicente, A M

Positron emission tomography/computed tomography (PET/CT) with 68 Ga-PSMA is a non-invasive diagnostic technique to image prostate cancer with increased prostate-specific membrane antigen (PSMA) expression. PSMA is a transmembrane protein present in all prostatic tissues. Increased PSMA expression is seen in several malignancies, although prostate cancer is the tumour where it presents higher concentrations. Almost all prostate adenocarcinomas show PSMA expression in most of lesions, primary and metastatic. Immunohistochemistry has demonstrated that the expression of PSMA increases in patients with de-differentiated, metastatic or hormone-refractory tumours. Moreover, the expression level of PSMA has a prognostic value for disease outcome. PET measures the three-dimensional distribution of 68 Ga-PSMA, producing semi-quantitative images that allow for non-invasive assessment of PSMA expression. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Partially coherent lensfree tomographic microscopy⋄

PubMed Central

Isikman, Serhan O.; Bishara, Waheb; Ozcan, Aydogan

2012-01-01

Optical sectioning of biological specimens provides detailed volumetric information regarding their internal structure. To provide a complementary approach to existing three-dimensional (3D) microscopy modalities, we have recently demonstrated lensfree optical tomography that offers high-throughput imaging within a compact and simple platform. In this approach, in-line holograms of objects at different angles of partially coherent illumination are recorded using a digital sensor-array, which enables computing pixel super-resolved tomographic images of the specimen. This imaging modality, which forms the focus of this review, offers micrometer-scale 3D resolution over large imaging volumes of, for example, 10–15 mm3, and can be assembled in light weight and compact architectures. Therefore, lensfree optical tomography might be particularly useful for lab-on-a-chip applications as well as for microscopy needs in resource-limited settings. PMID:22193016

Computed tomography imaging spectrometer (CTIS) with 2D reflective grating for ultraviolet to long-wave infrared detection especially useful for surveying transient events

NASA Technical Reports Server (NTRS)

Muller, Richard E. (Inventor); Mouroulis, Pantazis Z. (Inventor); Maker, Paul D. (Inventor); Wilson, Daniel W. (Inventor)

2003-01-01

The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for rapidly occurring events it is also useful for investigation of some slow moving phenomena as in the life sciences.

The female knee: anatomic variations.

PubMed

Conley, Sheryl; Rosenberg, Aaron; Crowninshield, Roy

2007-01-01

Traditional knee implants have been designed "down the middle,"based on the combined average size and shape of male and female knee anatomy.Sex-based research in the field of orthopaedics has led to new understanding of the anatomic differences between the sexes and the associated implications for women undergoing total knee arthroplasty. Through the use of a comprehensive bone morphology atlas that utilizes novel three-dimensional computed tomography analysis technology, significant anatomic differences have been documented in the shape and size of female knees compared with male knees. This research identifies three notable anatomic differences in the female population: a less prominent anterior condyle, an increased Q angle, and a reduced medial-lateral:anterior-posterior aspect ratio.

Morphometric analysis of the proximal ulna using three-dimensional computed tomography and computer-aided design: varus, dorsal, and torsion angulation.

PubMed

Yong, Woon Jae; Tan, Jun; Adikrishna, Arnold; Lee, Hyun Joo; Jung, Jin Woo; Cho, Dong-Woo; Jeon, In-Ho

2014-10-01

The proximal ulna, particularly the course of the posterior border, has a complex three-dimensional (3D) morphology which has been highlighted recently due to its clinical relevance in relation to surgical treatments. 3D computed tomography (CT) reconstruction and computer-aided design (CAD) based software can help to visualize the complex anatomy and thus aid the investigation of the more detailed morphology of the proximal ulna. In our current study, 3D CT reconstruction images of 20 cadavers were imported into the 3D CAD program. Three morphologic angle parameters of the proximal ulna were measured including the dorsal, varus and torsion angulation. The torsion angulation was measured using the flat spot of olecranon dorsal aspect. We measured the total length of the ulna and the distance between the olecranon tip and the apex of dorsal and varus angulation. Furthermore, the thickness of olecranon was also measured for all the specimens. The results showed that the mean dorsal, varus, and torsion angulation was 4.3° (range 2.6°-5.9°), 12.1° (range 7.9°-17.6°), and 22.5° (range 16.6°-30.5°), respectively. The average length ratio of the dorsal and varus angulation apex to the total ulnar length was 26.4 % (range 19.8-30.7 %) and 32.7 % (range 27.5-37.5 %), respectively. The average of olecranon thickness at the proximal tip, mid-olecranon fossa, and at coronoid tip level was 17.8 mm (range 14.1-22.8 mm), 19.7 mm (range 15.8-23.1 mm), and 35.1 mm (range 27.9-41.8 mm), respectively. In conclusion, variations in the proximal ulna have to be considered when anatomically contoured dorsal plates are applied. Knowledge of the 3D morphologic anatomy of the proximal ulna would provide important information on fracture reductions, and the design of a precontoured dorsal plate or a prosthetic ulnar stem.

Correlation of quantitative computed tomographic subchondral bone density and ash density in horses.

PubMed

Drum, M G; Les, C M; Park, R D; Norrdin, R W; McIlwraith, C W; Kawcak, C E

2009-02-01

The purpose of this study was to compare subchondral bone density obtained using quantitative computed tomography with ash density values from intact equine joints, and to determine if there are measurable anatomic variations in mean subchondral bone density. Five adult equine metacarpophalangeal joints were scanned with computed tomography (CT), disarticulated, and four 1-cm(3) regions of interest (ROI) cut from the distal third metacarpal bone. Bone cubes were ashed, and percent mineralization and ash density were recorded. Three-dimensional models were created of the distal third metacarpal bone from CT images. Four ROIs were measured on the distal aspect of the third metacarpal bone at axial and abaxial sites of the medial and lateral condyles for correlation with ash samples. Overall correlations of mean quantitative CT (QCT) density with ash density (r=0.82) and percent mineralization (r=0.93) were strong. There were significant differences between abaxial and axial ROIs for mean QCT density, percent bone mineralization and ash density (p<0.05). QCT appears to be a good measure of bone density in equine subchondral bone. Additionally, differences existed between axial and abaxial subchondral bone density in the equine distal third metacarpal bone.

Evaluation of the Diagnostic Accuracy of Conventional 2-Dimensional and 3-Dimensional Computed Tomography for Assessing Canine Sacral and Pelvic Fractures by Radiologists, Orthopedic Surgeons, and Veterinary Medical Students.

PubMed

Stieger-Vanegas, Susanne M; Senthirajah, Sri Kumar Jamie; Nemanic, Sarah; Baltzer, Wendy; Warnock, Jennifer; Hollars, Katelyn; Lee, Scott S; Bobe, Gerd

2015-08-01

To determine, using 3 groups of evaluators of varying experience reading orthopedic CT studies, if 3-dimensional computed tomography (3D-CT) provides a more accurate and time efficient method for diagnosis of canine sacral and pelvic fractures, and displacements of the sacroiliac and coxofemoral joints compared with 2-dimensional computed tomography (2D-CT). Retrospective clinical and prospective study. Dogs (n = 23): 12 dogs with traumatic pelvic fractures, 11 canine cadavers with pelvic trauma induced by a lateral impactor. All dogs had a 2D-CT exam of the pelvis and subsequent 3D-CT reconstructions from the 2D-CT images. Both 2D-CT and 3D-CT studies were anonymized and randomly presented to 2 veterinary radiologists, 2 veterinary orthopedic surgeons, and 2 veterinary medical students. Evaluators classified fractures using a confidence scale and recorded the duration of evaluation for each modality and case. 3D-CT was a more time-efficient technique for evaluation of traumatic sacral and pelvic injuries compared with 2D-CT in all evaluator groups irrespective of experience level reading orthopedic CT studies. However, for radiologists and surgeons, 2D-CT was the more accurate technique for evaluating sacral and pelvic fractures. 3D-CT improves sacral and pelvic fracture diagnosis when added to 2D-CT; however, 3D-CT has a reduced accuracy for evaluation of sacral and pelvic fractures if used without concurrent evaluation of 2D-CT images. © Copyright 2014 by The American College of Veterinary Surgeons.

Reply to comment by X. X. Zhang et al. on "Three-dimensional quantification of soil hydraulic properties using X-ray computed tomography and image-based modeling"

NASA Astrophysics Data System (ADS)

Tracy, Saoirse R.; Daly, Keith R.; Sturrock, Craig J.; Crout, Neil M. J.; Mooney, Sacha J.; Roose, Tiina

2016-07-01

In response to the comment raised by Zhang et al. (2016, doi: 10.1002/2015WR018432) we explore the differences in average velocity computed using slip and no-slip boundary conditions at the air water interface. We consider a porous medium in which the air phase acts to impede the movement of water rather than to lubricate it, a case closer to the observed distribution of water in our CT images. We find that, whilst the slip boundary condition may be a more accurate approximation, in cases where the air phase is seen to impede water movement the differences between the two approaches are negligible.

[The clinical and X-ray classification of osteonecrosis of the low jaw].

PubMed

Medvedev, Iu A; Basin, E M; Sokolina, I A

2013-01-01

To elaborate a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction. Ninety-two patients with drug addiction who had undergone orthopantomography, direct frontal X-ray of the skull, and multislice computed tomography, followed by multiplanar and three-dimensional imaging reconstruction were examined. One hundred thirty four X-ray films and 74 computed tomographic images were analyzed. The authors proposed a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction and elaborated recommendations for surgical interventions on the basis of the developed classification. The developed clinical and X-ray classification and recommendations for surgical interventions may be used to treat osteonecroses of various etiology.

Validation of a computer modelled forensic facial reconstruction technique using CT data from live subjects: a pilot study.

PubMed

Short, Laura J; Khambay, Balvinder; Ayoub, Ashraf; Erolin, Caroline; Rynn, Chris; Wilkinson, Caroline

2014-04-01

Human forensic facial soft tissue reconstructions are used when post-mortem deterioration makes identification difficult by usual means. The aim is to trigger recognition of the in vivo countenance of the individual by a friend or family member. A further use is in the field of archaeology. There are a number of different methods that can be applied to complete the facial reconstruction, ranging from two dimensional drawings, three dimensional clay models and now, with the advances of three dimensional technology, three dimensional computerised modelling. Studies carried out to assess the accuracy of facial reconstructions have produced variable results over the years. Advances in three dimensional imaging techniques in the field of oral and maxillofacial surgery, particularly cone beam computed tomography (CBCT), now provides an opportunity to utilise the data of live subjects and assess the accuracy of the three dimensional computerised facial reconstruction technique. The aim of this study was to assess the accuracy of a computer modelled facial reconstruction technique using CBCT data from live subjects. This retrospective pilot study was carried out at the Glasgow Dental Hospital Orthodontic Department and the Centre of Anatomy and Human Identification, Dundee University School of Life Sciences. Ten patients (5 male and 5 female; mean age 23 years) with mild skeletal discrepancies with pre-surgical cone beam CT data (CBCT) were included in this study. The actual and forensic reconstruction soft tissues were analysed using 3D software to look at differences between landmarks, linear and angular measurements and surface meshes. There were no statistical differences for 18 out of the 23 linear and 7 out of 8 angular measurements between the reconstruction and the target (p<0.05). The use of Procrustes superimposition has highlighted potential problems with soft tissue depth and anatomical landmarks' position. Surface mesh analysis showed that this virtual sculpture technique can be objectively assessed using the distance between the meshes. This study found that the percentage of faces with less than ±2.5mm error ranged from 56% to 90%. This may be improved if Procrustes superimposition could be applied to all the mesh points rather than specific landmarks. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Micro-CT Characterization on the Meso-Structure of Three-Dimensional Full Five-Directional Braided Composite

NASA Astrophysics Data System (ADS)

Ya, Jixuan; Liu, Zhenguo; Wang, Yuanhang

2017-06-01

The meso-structure is important in predicting mechanical properties of the three-dimensional (3D) braided composite. In this paper, the internal structure and porosity of three-dimensional full five-directional (3DF5D) braided composite is characterized at mesoscopic scale (the scale of the yarns) using micro-computed tomography (micro-CT) non-destructively. Glass fiber yarns as tracer are added into the sample made of carbon fiber to enhance the contrast in the sectional images. The model of tracer yarns is established with 3D reconstruction method to analyze the cross-section and path of yarns. The porosities are reconstructed and characterized in the end. The results demonstrate that the cross sections of braiding yarns and axial yarns change with the regions and the heights in one pitch of 3DF5D braided composites. The path of braiding yarns are various in the different regions while the axial yarns are always straight. Helical indentations appear on the surfaces of the axial yarns because of the squeeze from braiding yarns. Moreover, the porosities in different shapes and sizes are almost located in the matrix and between the yarns.

Three-dimensional printing in cardiology: Current applications and future challenges.

PubMed

Luo, Hongxing; Meyer-Szary, Jarosław; Wang, Zhongmin; Sabiniewicz, Robert; Liu, Yuhao

2017-01-01

Three-dimensional (3D) printing has attracted a huge interest in recent years. Broadly speaking, it refers to the technology which converts a predesigned virtual model to a touchable object. In clinical medicine, it usually converts a series of two-dimensional medical images acquired through computed tomography, magnetic resonance imaging or 3D echocardiography into a physical model. Medical 3D printing consists of three main steps: image acquisition, virtual reconstruction and 3D manufacturing. It is a promising tool for preoperative evaluation, medical device design, hemodynamic simulation and medical education, it is also likely to reduce operative risk and increase operative success. However, the most relevant studies are case reports or series which are underpowered in testing its actual effect on patient outcomes. The decision of making a 3D cardiac model may seem arbitrary since it is mostly based on a cardiologist's perceived difficulty in performing an interventional procedure. A uniform consensus is urgently necessary to standardize the key steps of 3D printing from imaging acquisition to final production. In the future, more clinical trials of rigorous design are possible to further validate the effect of 3D printing on the treatment of cardiovascular diseases. (Cardiol J 2017; 24, 4: 436-444).

Three-dimensional gas exchange pathways in pome fruit characterized by synchrotron x-ray computed tomography.

PubMed

Verboven, Pieter; Kerckhofs, Greet; Mebatsion, Hibru Kelemu; Ho, Quang Tri; Temst, Kristiaan; Wevers, Martine; Cloetens, Peter; Nicolaï, Bart M

2008-06-01

Our understanding of the gas exchange mechanisms in plant organs critically depends on insights in the three-dimensional (3-D) structural arrangement of cells and voids. Using synchrotron radiation x-ray tomography, we obtained for the first time high-contrast 3-D absorption images of in vivo fruit tissues of high moisture content at 1.4-microm resolution and 3-D phase contrast images of cell assemblies at a resolution as low as 0.7 microm, enabling visualization of individual cell morphology, cell walls, and entire void networks that were previously unknown. Intercellular spaces were always clear of water. The apple (Malus domestica) cortex contains considerably larger parenchyma cells and voids than pear (Pyrus communis) parenchyma. Voids in apple often are larger than the surrounding cells and some cells are not connected to void spaces. The main voids in apple stretch hundreds of micrometers but are disconnected. Voids in pear cortex tissue are always smaller than parenchyma cells, but each cell is surrounded by a tight and continuous network of voids, except near brachyssclereid groups. Vascular and dermal tissues were also measured. The visualized network architecture was consistent over different picking dates and shelf life. The differences in void fraction (5.1% for pear cortex and 23.0% for apple cortex) and in gas network architecture helps explain the ability of tissues to facilitate or impede gas exchange. Structural changes and anisotropy of tissues may eventually lead to physiological disorders. A combined tomography and internal gas analysis during growth are needed to make progress on the understanding of void formation in fruit.

Computational Flow Modeling of Human Upper Airway Breathing

NASA Astrophysics Data System (ADS)

Mylavarapu, Goutham

Computational modeling of biological systems have gained a lot of interest in biomedical research, in the recent past. This thesis focuses on the application of computational simulations to study airflow dynamics in human upper respiratory tract. With advancements in medical imaging, patient specific geometries of anatomically accurate respiratory tracts can now be reconstructed from Magnetic Resonance Images (MRI) or Computed Tomography (CT) scans, with better and accurate details than traditional cadaver cast models. Computational studies using these individualized geometrical models have advantages of non-invasiveness, ease, minimum patient interaction, improved accuracy over experimental and clinical studies. Numerical simulations can provide detailed flow fields including velocities, flow rates, airway wall pressure, shear stresses, turbulence in an airway. Interpretation of these physical quantities will enable to develop efficient treatment procedures, medical devices, targeted drug delivery etc. The hypothesis for this research is that computational modeling can predict the outcomes of a surgical intervention or a treatment plan prior to its application and will guide the physician in providing better treatment to the patients. In the current work, three different computational approaches Computational Fluid Dynamics (CFD), Flow-Structure Interaction (FSI) and Particle Flow simulations were used to investigate flow in airway geometries. CFD approach assumes airway wall as rigid, and relatively easy to simulate, compared to the more challenging FSI approach, where interactions of airway wall deformations with flow are also accounted. The CFD methodology using different turbulence models is validated against experimental measurements in an airway phantom. Two case-studies using CFD, to quantify a pre and post-operative airway and another, to perform virtual surgery to determine the best possible surgery in a constricted airway is demonstrated. The unsteady Large Eddy simulations (LES) and a steady Reynolds Averaged Navier Stokes (RANS) approaches in CFD modeling are discussed. The more challenging FSI approach is modeled first in simple two-dimensional anatomical geometry and then extended to simplified three dimensional geometry and finally in three dimensionally accurate geometries. The concepts of virtual surgery and the differences to CFD are discussed. Finally, the influence of various drug delivery parameters on particle deposition efficiency in airway anatomy are investigated through particle-flow simulations in a nasal airway model.

Comparison of digital intraoral scanners by single-image capture system and full-color movie system.

PubMed

Yamamoto, Meguru; Kataoka, Yu; Manabe, Atsufumi

2017-01-01

The use of dental computer-aided design/computer-aided manufacturing (CAD/CAM) restoration is rapidly increasing. This study was performed to evaluate the marginal and internal cement thickness and the adhesive gap of internal cavities comprising CAD/CAM materials using two digital impression acquisition methods and micro-computed tomography. Images obtained by a single-image acquisition system (Bluecam Ver. 4.0) and a full-color video acquisition system (Omnicam Ver. 4.2) were divided into the BL and OM groups, respectively. Silicone impressions were prepared from an ISO-standard metal mold, and CEREC Stone BC and New Fuji Rock IMP were used to create working models (n=20) in the BL and OM groups (n=10 per group), respectively. Individual inlays were designed in a conventional manner using designated software, and all restorations were prepared using CEREC inLab MC XL. These were assembled with the corresponding working models used for measurement, and the level of fit was examined by three-dimensional analysis based on micro-computed tomography. Significant differences in the marginal and internal cement thickness and adhesive gap spacing were found between the OM and BL groups. The full-color movie capture system appears to be a more optimal restoration system than the single-image capture system.

Potential advantage of studying the lymphatic drainage by sentinel node technique and SPECT-CT image fusion for pelvic irradiation of prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krengli, Marco; Ballare, Andrea; Cannillo, Barbara

2006-11-15

Purpose: This study aims to investigate the in vivo drainage of lymphatic spread by using the sentinel node (SN) technique and single-photon emission computed tomography (SPECT)-computed tomography (CT) image fusion, and to analyze the impact of such information on conformal pelvic irradiation. Methods and Materials: Twenty-three prostate cancer patients, candidates for radical prostatectomy already included in a trial studying the SN technique, were enrolled. CT and SPECT images were obtained after intraprostate injection of 115 MBq of {sup 99m}Tc-nanocolloid, allowing identification of SN and other pelvic lymph nodes. Target and nontarget structures, including lymph nodes identified by SPECT, were drawnmore » on SPECT-CT fusion images. A three-dimensional conformal treatment plan was performed for each patient. Results: Single-photon emission computed tomography lymph nodal uptake was detected in 20 of 23 cases (87%). The SN was inside the pelvic clinical target volume (CTV{sub 2}) in 16 of 20 cases (80%) and received no less than the prescribed dose in 17 of 20 cases (85%). The most frequent locations of SN outside the CTV{sub 2} were the common iliac and presacral lymph nodes. Sixteen of the 32 other lymph nodes (50%) identified by SPECT were found outside the CTV{sub 2}. Overall, the SN and other intrapelvic lymph nodes identified by SPECT were not included in the CTV{sub 2} in 5 of 20 (25%) patients. Conclusions: The study of lymphatic drainage can contribute to a better knowledge of the in vivo potential pattern of lymph node metastasis in prostate cancer and can lead to a modification of treatment volume with consequent optimization of pelvic irradiation.« less

[Quantitative assessment on artifacts of dental restorative materials in cone beam computed tomography].

PubMed

Yuan, Fu-song; Sun, Yu-chun; Xie, Xiao-yan; Wang, Yong; Lv, Pei-jun

2013-12-18

To quantitatively evaluate the artifacts appearance of eight kinds of common dental restorative materials, such as zirconia. For the full-crown tooth preparation of mandibular first molar, eight kinds of full-crowns, such as zirconia all-ceramic crown, glass ceramic crown, ceramage crown, Au-Pt based porcelain-fused-metal (PFM) crown, Pure Titanium PFM crown, Co-Cr PFM crown, Ni-Cr PFM crown, and Au-Pd metal crown were fabricated. And natural teeth in vitro were used as controls. These full-crown and natural teeth in vitro were mounted an ultraviolet-curable resin fixed plate. High resolution cone beam computed tomography (CBCT) was used to scan all of the crowns and natural teeth in vitro, and their DICOM data were imported into software MIMICS 10.0. Then, the number of stripes and the maximum diameters of artifacts around the full-crowns were evaluated quantitatively in two-dimensional tomography images. In the two-dimensional tomography images,the artifacts did not appear around the natural teeth in vitro, glass ceramic crown, and ceramage crown. But thr artifacts appeared around the zirconia all-ceramic and metal crown. The number of stripes of artifacts was five to nine per one crown. The maximum diameters of the artifacts were 2.4 to 2.6 cm and 2.2 to 2.7 cm. In the two-dimensional tomography images of CBCT, stripe-like and radical artifacts were caused around the zirconia all-ceramic crown and metal based porcelain-fused-metal crowns. These artifacts could lower the imaging quality of the full crown shape greatly. The artifact was not caused around the natural teeth in vitro, glass ceramic crown, and ceramage crown.

Computational high-resolution optical imaging of the living human retina

NASA Astrophysics Data System (ADS)

Shemonski, Nathan D.; South, Fredrick A.; Liu, Yuan-Zhi; Adie, Steven G.; Scott Carney, P.; Boppart, Stephen A.

2015-07-01

High-resolution in vivo imaging is of great importance for the fields of biology and medicine. The introduction of hardware-based adaptive optics (HAO) has pushed the limits of optical imaging, enabling high-resolution near diffraction-limited imaging of previously unresolvable structures. In ophthalmology, when combined with optical coherence tomography, HAO has enabled a detailed three-dimensional visualization of photoreceptor distributions and individual nerve fibre bundles in the living human retina. However, the introduction of HAO hardware and supporting software adds considerable complexity and cost to an imaging system, limiting the number of researchers and medical professionals who could benefit from the technology. Here we demonstrate a fully automated computational approach that enables high-resolution in vivo ophthalmic imaging without the need for HAO. The results demonstrate that computational methods in coherent microscopy are applicable in highly dynamic living systems.

A new approach for solving seismic tomography problems and assessing the uncertainty through the use of graph theory and direct methods

NASA Astrophysics Data System (ADS)

Bogiatzis, P.; Ishii, M.; Davis, T. A.

2016-12-01

Seismic tomography inverse problems are among the largest high-dimensional parameter estimation tasks in Earth science. We show how combinatorics and graph theory can be used to analyze the structure of such problems, and to effectively decompose them into smaller ones that can be solved efficiently by means of the least squares method. In combination with recent high performance direct sparse algorithms, this reduction in dimensionality allows for an efficient computation of the model resolution and covariance matrices using limited resources. Furthermore, we show that a new sparse singular value decomposition method can be used to obtain the complete spectrum of the singular values. This procedure provides the means for more objective regularization and further dimensionality reduction of the problem. We apply this methodology to a moderate size, non-linear seismic tomography problem to image the structure of the crust and the upper mantle beneath Japan using local deep earthquakes recorded by the High Sensitivity Seismograph Network stations.

Prospective study comparing three-dimensional computed tomography and magnetic resonance imaging for evaluating the renal vascular anatomy in potential living renal donors.

PubMed

Bhatti, Aftab A; Chugtai, Aamir; Haslam, Philip; Talbot, David; Rix, David A; Soomro, Naeem A

2005-11-01

To prospectively compare the accuracy of multislice spiral computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) in evaluating the renal vascular anatomy in potential living renal donors. Thirty-one donors underwent multislice spiral CTA and gadolinium-enhanced MRA. In addition to axial images, multiplanar reconstruction and maximum intensity projections were used to display the renal vascular anatomy. Twenty-four donors had a left laparoscopic donor nephrectomy (LDN), whereas seven had right open donor nephrectomy (ODN); LDN was only considered if the renal vascular anatomy was favourable on the left. CTA and MRA images were analysed by two radiologists independently. The radiological and surgical findings were correlated after the surgery. CTA showed 33 arteries and 32 veins (100% sensitivity) whereas MRA showed 32 arteries and 31 veins (97% sensitivity). CTA detected all five accessory renal arteries whereas MRA only detected one. CTA also identified all three accessory renal veins whereas MRA identified two. CTA had a sensitivity of 97% and 47% for left lumbar and left gonadal veins, whereas MRA had a sensitivity of 74% and 46%, respectively. Multislice spiral CTA with three-dimensional reconstruction was more accurate than MRA for both renal arterial and venous anatomy.

CT Scans of Cores Metadata, Barrow, Alaska 2015

DOE Data Explorer

Katie McKnight; Tim Kneafsey; Craig Ulrich

2015-03-11

Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

Soft Tissue Structure Modelling for Use in Orthopaedic Applications and Musculoskeletal Biomechanics

NASA Astrophysics Data System (ADS)

Audenaert, E. A.; Mahieu, P.; van Hoof, T.; Pattyn, C.

2009-12-01

We present our methodology for the three-dimensional anatomical and geometrical description of soft tissues, relevant for orthopaedic surgical applications and musculoskeletal biomechanics. The technique involves the segmentation and geometrical description of muscles and neurovascular structures from high-resolution computer tomography scanning for the reconstruction of generic anatomical models. These models can be used for quantitative interpretation of anatomical and biomechanical aspects of different soft tissue structures. This approach should allow the use of these data in other application fields, such as musculoskeletal modelling, simulations for radiation therapy, and databases for use in minimally invasive, navigated and robotic surgery.

Correlated Light and Electron Microscopy/Electron Tomography of Mitochondria In Situ

PubMed Central

Perkins, Guy A.; Sun, Mei G.; Frey, Terrence G.

2009-01-01

Three-dimensional light microscopy and three-dimensional electron microscopy (electron tomography) separately provide very powerful tools to study cellular structure and physiology, including the structure and physiology of mitochondria. Fluorescence microscopy allows one to study processes in live cells with specific labels and stains that follow the movement of labeled proteins and changes within cellular compartments but does not have sufficient resolution to define the ultrastructure of intracellular organelles such as mitochondria. Electron microscopy and electron tomography provide the highest resolution currently available to study mitochondrial ultrastructure but cannot follow processes in living cells. We describe the combination of these two techniques in which fluorescence confocal microscopy is used to study structural and physiologic changes in mitochondria within apoptotic HeLa cells to define the apoptotic timeframe. Cells can then be selected at various stages of the apoptotic timeframe for examination at higher resolution by electron microscopy and electron tomography. This is a form of “virtual” 4-dimensional electron microscopy that has revealed interesting structural changes in the mitochondria of HeLa cells during apoptosis. The same techniques can be applied, with modification, to study other dynamic processes within cells in other experimental contexts. PMID:19348881

The Influence of Surgical Stabilization on Glenohumeral Abduction Using 3-Dimensional Computed Tomography in Patients With Shoulder Instability.

PubMed

Bakshi, Neil K; Jameel, Omar F; Merrill, Zachary F; Debski, Richard E; Sekiya, Jon K

2016-08-01

This study compared the amount of glenohumeral abduction during arm abduction in the affected and unaffected shoulders of 3 groups of patients with shoulder instability: failed surgical stabilization, successful surgical stabilization, and unstable shoulder with no prior surgical intervention. All patients underwent bilateral shoulder computed tomography scans in 3 positions: 0° of abduction and 0° of external rotation (0-0 position), 30° of abduction and 30° of external rotation (30-30 position), and arms maximally abducted (overhead position). Three-dimensional computed tomography reconstruction was performed for both shoulders in all 3 positions. A specialized coordinate system marked specific points and directions on the humerus and glenoid of each model. These coordinates were used to calculate the glenohumeral abduction for the normal and affected sides in the 0-0, 30-30, and overhead positions. Thirty-nine patients with shoulder instability were included, of whom 14 had failed surgical repairs, 10 had successful surgical repairs, and 15 had unstable shoulders with no prior surgical intervention. In the overhead position, patients with failed surgical intervention had significantly less glenohumeral abduction in the failed shoulder (95.6° ± 12.7°) compared with the normal shoulder (101.5° ± 12.4°, P = .02). Patients with successfully stabilized shoulders had significantly less glenohumeral abduction in the successfully stabilized shoulder (93.6° ± 10.8°) compared with the normal shoulder (102.1° ± 12.5°, P = .03). Unstable shoulders with no prior surgical intervention (102.1° ± 10.3°) did not differ when compared with the normal shoulders (101.9° ± 10.9°, P = .95). Surgical intervention, regardless of its success, limits the amount of abduction at the glenohumeral joint. Level III, retrospective comparative study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Ideal-observer analysis of lesion detectability in planar, conventional SPECT, and dedicated SPECT scintimammography using effective multi-dimensional smoothing

NASA Astrophysics Data System (ADS)

La Riviere, P. J.; Pan, X.; Penney, B. C.

1998-06-01

Scintimammography, a nuclear-medicine imaging technique that relies on the preferential uptake of Tc-99m-sestamibi and other radionuclides in breast malignancies, has the potential to provide differentiation of mammographically suspicious lesions, as well as outright detection of malignancies in women with radiographically dense breasts. In this work we use the ideal-observer framework to quantify the detectability of a 1-cm lesion using three different imaging geometries: the planar technique that is the current clinical standard, conventional single-photon emission computed tomography (SPECT), in which the scintillation cameras rotate around the entire torso, and dedicated breast SPECT, in which the cameras rotate around the breast alone. We also introduce an adaptive smoothing technique for the processing of planar images and of sinograms that exploits Fourier transforms to achieve effective multidimensional smoothing at a reasonable computational cost. For the detection of a 1-cm lesion with a clinically typical 6:1 tumor-background ratio, we find ideal-observer signal-to-noise ratios (SNR) that suggest that the dedicated breast SPECT geometry is the most effective of the three, and that the adaptive, two-dimensional smoothing technique should enhance lesion detectability in the tomographic reconstructions.