Computed Tomography Scanning Technology Research Articles

Applications of computed tomography (CT) scanning technology in forest research: a timely update and review

Organic materials of woody plants are complex and show internal, structural, and morphological variations due to genetic and environmental influences. Variability can be observed in stems, branches, leaves, and roots. Nondestructive and noninvasive technologies have been proposed to assess this variability. Computed tomography (CT) scanning, originally designed for medical diagnostics, permits the measurement of wood properties in situ (e.g., wood density, moisture content, internal defects, annual growth) and crown traits that characterize branching pattern geometry and canopy space occupancy for small-sized trees. Since Wei et al.’s (2011, Can. J. For. Res. 41(11): 2120–2140, doi: 10.1139/x11-111 ) review on the assessment of wood quality for optimized manufacturing processes using a CT scanner, several important developments have occurred, motivating the preparation of an update. We provide technical clarifications about the scales of observation and resolution; report on recent studies in which CT scanning was applied with research objectives beyond wood quality assessment for an optimized manufacturing of forest products; and stress the importance of analytical procedures for the graphical and quantitative analyses of CT scanning data (images and numbers) and the need for specialized algorithms and software. With this review, readers are expected to be well informed of the avenues offered by CT scanning technology in forest research in general.

Experimental and Numerical Study on CO2 Sweep Volume during CO2 Huff-n-Puff Enhanced Oil Recovery Process in Shale Oil Reservoirs

CO2 huff-n-puff has been proven to be the most effective enhanced oil recovery (EOR) method in shale oil reservoirs. The injected CO2 will replenish reservoir energy and penetrate the reservoir matrix to extract oil. However, the CO2 sweep volume during the huff-n-puff process has not been accurately evaluated by existing studies. In this paper, the CO2 sweep volume was investigated through experimental and numerical simulation methods. In the experimental study, the CO2 sweep areas were depicted by X-ray computed tomography scan technology. The results indicated that the ratio of the CO2 sweep area was 78.63% in the seventh huff-n-puff cycle, leading to a total oil recovery of 56.80%. The numerical simulation considered the mechanisms of molecular diffusion and nanopore confinement. The results showed that in the first huff-n-puff cycle, the gas sweep volume percentage was 9.47% after 100 days of huff period. In the gas swept volume, oil viscosity was reduced by 25.9% to 68.2%. After three cycles of CO2 ...

Characterization of the effects of detector angular misalignments and accuracy enhancement of X-ray CT dimensional measurements

Characterization of the effects of detector angular misalignments and accuracy enhancement of X-ray CT dimensional measurements

Analysis of Coal Swelling Deformation Caused by Carbon Dioxide Adsorption Based on X-Ray Computed Tomography

The geologic sequestration of carbon dioxide by coal beds leads to the swelling deformation of coal. In order to investigate the swelling deformation characteristics at the microscopic scale, X-ray computed tomography (CT) scanning technology was used. X-ray CT scanning technology detects the internal structure, deformation, and porosity of coal at different gas pressures. Results show that swelling deformation is nonuniform, which is caused by the heterogeneity of the coal structure. Through quantitative measurement of the distance between fractures and pseudocolor processing of CT images, we observed that fractures gradually close with the increase of adsorption pressure. As adsorption pressure increases, the porosity of coal decreases, and the density of coal increases.

A Description of the Skull of Eubaena Cephalica (Hay, 1904) and New Insights into the Cranial Circulation and Innervation of Baenid Turtles

ABSTRACT The internal carotid system has played an important role in the systematics of fossil turtles, including baenids. A new, almost perfectly preserved specimen of Eubaena cephalica provides an opportunity to explore for the first time the cranial circulation and innervation of this taxon using CT (computed tomography) scans. We here document that the skull possesses a well-developed, branching canalis nervus vidianus but lacks a canalis caroticus palatinum, which contradicts the previously reported circulation and innervation pattern for E. cephalica specifically and that of paracryptodires in general. Future investigation using CT scanning technology will be able to clarify if the pattern reported herein is unique to E. cephalica or is representative of paracryptodires in general. The latter conclusion will likely have considerable implications for the systematics of fossil turtles. Citation for this article: Rollot, Y., T. R. Lyson, and W. G. Joyce. 2018. A description of the skull of Eubaena cephalica (Hay, 1904) and new insights into the cranial circulation and innervation of baenid turtles. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1474886.

Estimation of the effects of medical diagnostic radiation exposure based on DNA damage

X-rays are widely applied in the medical field for the diagnosis and treatment of diseases. Among the uses of X-rays in diagnosis, computed tomography (CT) has been established as one of the most informative diagnostic radiology examinations. Moreover, recent advances in CT scan technology have made this examination much easier and more informative and increased its application, especially in Japan. However, the radiation dose of CT scans is higher than that of simple X-ray examinations. Therefore, the health risk of a CT scan has been discussed in various studies, but is still controversial. Consequently, the biological and cytogenetic effects of CT scans are being analyzed. Here, we summarize the recent findings concerning the biological and cytogenetic effects of ionizing radiation from a CT scan, by focusing on DNA damage and chromosome aberrations.

Effects of casein non-phosphopeptide on the development of rat muscle analyzed using computed tomography scanning technology.

The effects of casein non-phosphopeptide (CNPP) on the muscle development of healthy rats and selected blood hormones levels were investigated. CT technology and the ELISA kit were employed to detect the cross-sectional area of each muscle group and blood hormone levels, respectively. The cross-sectional area of the trunk and lower limb muscles of resistance exercise group (REG) rats that were administered a high daily dose of CNPP for 50 days increased more significantly than that of the blank group rats, no exercise group (NEG) rats administered with the same daily dose of CNPP, and REG rats administered with the same daily dose of lactalbumin (P < 0.05).The more enhanced development of trunk and lower limb muscles in CNPP-administered REG rats was associated with a higher blood level of insulin, while no clear trends in blood levels of growth hormone and testosterone were observed. The present results have demonstrated that a combination of physical exercise and diet supplementation with CNPP can synergistically improve muscle mass.

Modeling of rail head checks by X-ray computed tomography scan technology

To understand the internal characteristics of the Head Checks (HCs), X-ray computed tomography (CT) were applied to rail HCs inspection and modeling. Typical HCs at the rail shoulder and gauge corner in the high rail of a sharp curve of a heavy-haul railway were observed and sampled. Then, a suitable size and shape of the specimen, including several complete HCs, was designed to scan the internal HCs clearly and rapidly. Based on the CT scanning, the 3D internal information of the HC was extracted and digitized. It was found that the HCs at the rail shoulder and gauge corner propagated inside the rail in a nearly flat plane along a smooth and linear route without many large irregular fluctuations. The propagation rate along the HCs’ tip towards to the lateral and longitudinal of the rail was different. The HCs can be modeled by a series of methods like plane rotation projection, abnormal point elimination, shape fitting and spatial positioning, which kept the HCs close to reality. Here, we show that the spline curve, the ellipse and the cubic polynomial curve were suitable for the HC tip shape. The entire HC contour and its ratio of length/width was effected by HC propagation and rail wear. Comparing the length and space angles of the HCs by CT scanning and modeling, the modeled HCs showed high precision compared to the real ones.

Cardiac CT Scanner Technology: What Is New and What Is Next?

Technical specifications for multi-detector row computed tomography (CT) scanners from different manufacturers were very similar until the introduction of 64-slice scanners but then began to diverge with fundamental differences in the number of X-ray sources, detector geometry, gantry rotation time, and reconstruction algorithms. These hardware and software advancements were largely driven by clinical requirements for cardiac CT. This article provides an overview of technologies available on state-of-the-art CT systems and the clinical needs they seek to address.

On the damage constitutive model for hydrated shale using CT scanning technology

A novel characterization method for identifying hydrated shale damage characteristics is presented using X-ray CT (computed tomography) scanning technology and damage mechanics. Furthermore, a constitutive damage model was proposed based on the evolution equation of the damage variable for hydrated shale. On this basis, a theoretical method for quantitatively describing the mechanical effects caused by chemical reactions can be obtained via the integration of the aforementioned methods. X-ray CT scanning was conducted on shale samples from the Wufeng-Longmaxi Formation to investigate the internal damage and hydrated shale evolution laws. Uniaxial compression tests were utilized to investigate the complete stress–strain curves during the different hydration stages. The results indicated that the damage variable gradually increases with increasing immersion time. The damage variable growth rate is greater during the initial stage, but it slows with increased immersion time. The complete stress–strain curves simulated by the damage constitutive model are relatively consistent with the experimental results. The results suggest that this model accurately describes the mechanical effects induced by shale hydration. This method could help to improve research methods and chemically and mechanically coupled wellbore stability analyses.

The use of CT scan and stereo lithography apparatus technologies in a canine individualized rib prosthesis

ObjectiveTo design and fabricate canine rib prosthesis with full geometric shape using computed tomography (CT) scan combined with computer-aided design (CAD) and stereo lithographic (SLA) technologies and to evaluate the accuracy of this method. MethodsAfter scanned on 64 rows helical CT, the cortex part of the right 7th rib was selected as the prototype for design and manufacture of the rib prosthesis and image data were stored as DICOM format. Three-dimensional (3D) surface reconstruction was applied to produce 3D image of the 7th rib and results were outputted as STL format which were then modified by UG software for establishment of CAD model. ResultsThe rib prosthesis with full geometric shape was obtained based on CT scanning and SLA technique. About 30,000 point cloud data were acquired after 3D laser scan of the ribs. When comparing the rib prosthesis with the rib prototype, the maximum positive deviation, maximum negative deviation, average deviation and standard deviation were 1.764 mm, −2.126 mm, 0.183/−0.253 mm and 0.346 mm, respectively. There were about 88.17% of the point cloud data within the range of ±0.5 mm. ConclusionIt is feasible to design and fabricate rib prosthesis with full geometric shape by using CT scanning technology combined with CAD and SLA technologies. This method is fast, convenient and precise for manufacturing prosthesis. Optimization and improvement could be processed based on the deviation suggested by the scanning.

Water as a Contrast Medium: A Re-evaluation Using the Multidetector-row Computed Tomography

Water as an intraluminal negative contrast medium produces improved image quality with reduced artefact. However, rapid absorption of oral water in the bowel relative to speed and timing of image capturing has limited its clinical application. These findings predate advances in multidetector-row computed tomography (CT). To re-evaluate differences in image quality, we studied image clarity and luminal distention between the same group of patients who received both a pancreas protocol CT (PPCT) that uses oral water and a conventional positive oral contrast scan. We reviewed 66 patients who had previously undergone both a PPCT and an oral contrast abdominal CT. CT images were independently reviewed by two board-certified radiologists who scored degree of hollow viscus distention and visualization of mural detail using a Likert 5-point scale. Results were evaluated by using the Wilcoxon-signed rank test. Student's t test was applied to evaluate the differences in radiation dosage and Spearman's correlational test was used to evaluate interrater correlation between the radiologists. In comparing the mean radiation dosage, there was no statistical difference between the two protocols, and there was good interrater association with ratios of 0.595 and 0.51 achieved for the PPCT and conventional oral scan, respectively. The Wilcoxon signed-rank test showed statistical differences in the stomach (P < 0.001) for both clarity (P < 0.001) and distention (P < 0.001), the duodenum for both clarity (P < 0.001) and distention (P = 0.02), and the ileum for distention (P = 0.02) with the PPCT having a better median score for organ clarity in the stomach and duodenum and better luminal distention in the stomach, equal distention in the duodenum, and slightly worse distention in the ileum. For the remainder of the bowel and organs evaluated, there was no statistically significant difference in the ratings between the two protocols. Using present CT scan technology, water can be an effective contrast medium causing better or equal distention in the bowel and better or equal clarity than routine barium contrast. This calls for a need to reconsider the use of water as a contrast medium in clinical practice.

Current Computed Tomography Techniques Can Detect Duct of Bellini Plugging but Not Randall's Plaques

To assess the ability of noninvasive computed tomography (CT) scans to detect interstitial calcium phosphate deposits (Randall's plaques) and duct of Bellini plugs, which are possible stone precursor lesions. At time of percutaneous nephrolithotomy (PCNL) for stone removal, all accessible individual papillae of 105 patients were endoscopically visualized and video recorded. Image-processing software was used to estimate the percentage of papillary surface occupied by plaque or plug in each pole (upper, middle, lower). The location of stones was also recorded. A radiologist blinded to the mapping results scored presurgical (n = 98) and postsurgical (n = 105) abdominal CT scans for the presence or absence of calcification by pole. The cohort was a mean age of 56 years (range, 23-84 years). Maximum papillary surface area of each area of the kidney occupied by plug correlated with CT calcifications on pre- and postprocedure images by rank sum test. However, maximum plaque surface area did not correlate with radiographic findings (P = .10-.90 for each pole by rank sum test). Sensitivity was 81% and specificity was 69% of CT to detect plugs of at least 1% of the papillary surface area. Calcifications seen on current generation clinical CT scans correspond to ductal plugging involving at least 1% of the papillary surface area. Current clinical CT scan technology appears inadequate for detecting Randall's plaques.

Computed tomography scans and cancer risk: The latest findings

Computed tomography scans and cancer risk: The latest findings

Computed tomography of Crohn’s disease: The role of three dimensional technique

Crohn's disease, a transmural inflammatory bowel disease, remains a difficult entity to diagnose clinically. Over the last decade, multidetector computed tomography (CT) has become the method of choice for non-invasive evaluation of the small bowel, and has proved to be of significant value in the diagnosis of Crohn's disease. Advancements in CT enterography protocol design, three dimensional (3-D) post-processing software, and CT scanner technology have allowed increasing accuracy in diagnosis, and the acquisition of studies at a much lower radiation dose. The cases in this review will illustrate that the use of 3-D technique, proper enterography protocol design, and a detailed understanding of the different manifestations of Crohn's disease are all critical in properly diagnosing the full range of possible complications in Crohn's patients. In particular, CT enterography has proven to be effective in identifying involvement of the small and large bowel (including active inflammation, stigmata of chronic inflammation, and Crohn's-related bowel neoplasia) by Crohn's disease, as well as the extra-enteric manifestations of the disease, including fistulae, sinus tracts, abscesses, and urologic/hepatobiliary/osseous complications. Moreover, the proper use of 3-D technique (including volume rendering and maximum intensity projection) as a routine component of enterography interpretation can play a vital role in improving diagnostic accuracy.

Paediatric CT – The DRL challenge

Abstract: Recent publications and audits have highlighted the complexities associated with establishing dose reference levels (DRL's) in paediatric computed tomography (CT). National and international surveys are population based surveys in general and are broad stroke in nature therefore not sufficient for local DRL's in a paediatric context. Paediatric patients are all sizes and shapes with different physiology and metabolic systems influencing the effects of radiation and therefore dose1,2. Along with the nature of the patient the specific scanner plays an important role in determining the dose received by the patient. With the introduction of multi-slice CT scanner technology dose has been on the increase though lately with the worldwide emphasis on radiation dose reduction in CT3 that has been reversed, iterative reconstruction is also now being marketed as a major dose reduction (<1 mSv) technique. Following the outcome of the CT dose survey of 2010 the Medical Exposures Radiation Unit now requires CT DRL's to be established and audited annually. This is in line with the European Medical Exposures Directive (MED), introduced into Irish law by SI 478 (2002). Mandatory paediatric protocols which are age and size based are now required along with the recording of a dose parameter such as the DLP and CTDI, caveat these are usually based on adult phantoms. Following analysis of our system prior to completing the national audit we have established our own local DRL's which are age and size based. I will present our data over the last two years and compare them the national audit findings and international data4. The challenge for paediatric imaging is to establish meaningful local DRL's which are scanner and centre based.

Arecaceae Fossil Fruits from the Paleocene of Patagonia, Argentina

We describe fossil fruits collected from outcrops of the Salamanca Fm. (Paleocene, Danian, 63.3–61.9 Ma) at the Estancia Las Violetas locality, Chubut, Argentina that show affinities with members of the Subtribe Attaleinae, Tribe Cocoseae, Subfamily Arecoideae within the Arecaceae. The fossils are preserved as permineralizations, and were examined by longitudinal, tangential and cross-sections, as well as by the application of Computed Tomography Scanning technology (CT Scan). The fruits are ovoid drupes with 3 longitudinal grooves delimiting three valves; displaying apical stigmatic remains and a single apical germination pore. The exocarp and mesocarp are fused and anatomically indistinguishable one from another; they contain longitudinal fibrous bands with brachysclereids. A centrally placed seed occupies the single locule entirely; the seeds are deltoid with a basal hilum and acuminate tip while the endosperm is ruminate. The taxonomic position of the fossils was explored using phylogenetic analyses of molecular sequences combined with morphological data. Along with the suite of morphological characters that points to an affinity with the Subtribe Attaleinae, Tribe Cocoseae, subfamily Arecoideae, the results of the combined phylogenetic analyses confirm the taxonomic placement. This report constitutes the first confirmed record for the Subtribe Attaleinae worldwide and the first record of fossil palm fruits from Argentina.

Triaging patients with acute chest pain in the emergency department: implications of the CT-STAT trial

Evaluation of: Goldstein JA, Chinnaiyan KM, Abidov A et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J. Am. Coll. Cardiol. 58(14), 1414–1422 (2011).Rapid advancements in multidetector-row computed tomography scanner technology over the last decade have significantly improved the diagnostic performance of coronary computed tomography angiography (CTA), enabling it to potentially become the preferred imaging modality used in the rapid assessment of chest pain patients in the emergency department. There is a growing body of evidence suggesting coronary CTA can rule out coronary artery stenosis quickly and accurately, thereby reducing the number of hospitalizations and healthcare costs, without compromising quality of care. CT-STAT is the first multicenter trial to demonstrate the power of coronary CTA to streamline patient care in the acute setting and radically transform current treatment algorithms.

Applying multifractal spectrum combined with fractal discrete Brownian motion model to wood defects recognition

Wood nondestructive testing technology is a new and multidisciplinary industry scientific research. It has attained fast development and achievements in recent years. X-ray computed tomography (CT) scanning technology is a kind of wood nondestructive testing technology in practice. CT scanning technology has been applied to the detection of internal defects in the logs for the purpose of obtaining prior information, which can be used to reach better wood sawing decision. Fractal geometry and its extension multifractal are used for describing, modeling, analyzing, and processing of different complex shapes and images. A method in CT image edge detection using multifractal theory combined with fractal Brownian motion is applied in the paper. First, its multifractal spectrum is estimated. Then, different types of pixels are classified by the spectrum; they are smoothing edge points and singular edge points. From the images processed by multifractal spectrum theory and compared with each image by different spectrum values, it can be seen that the larger the range of threshold is set, the more exact the edge can be detected. The paper provides a new method to recognize the defect information and to saw it in the condition of nondestructive wood.

Patient dose considerations in computed tomography examinations.

Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable. However, the use of ionizing radiation also involves a certain risk since it may cause damage to tissues and organs and trigger carcinogenesis. Computed tomography (CT) is currently one of the major contributors to the collective population radiation dose both because it is a relatively high dose examination and an increasing number of people are subjected to CT examinations many times during their lifetime. The evolution of CT scanner technology has greatly increased the clinical applications of CT and its availability throughout the world and made it a routine rather than a specialized examination. With the modern multislice CT scanners, fast volume scanning of the whole human body within less than 1 min is now feasible. Two dimensional images of superb quality can be reconstructed in every possible plane with respect to the patient axis (e.g. axial, sagital and coronal). Furthermore, three-dimensional images of all anatomic structures and organs can be produced with only minimal additional effort (e.g. skeleton, tracheobronchial tree, gastrointestinal system and cardiovascular system). All these applications, which are diagnostically valuable, also involve a significant radiation risk. Therefore, all medical professionals involved with CT, either as referring or examining medical doctors must be aware of the risks involved before they decide to prescribe or perform CT examinations. Ultimately, the final decision concerning justification for a prescribed CT examination lies upon the radiologist. In this paper, we summarize the basic information concerning the detrimental effects of ionizing radiation, as well as the CT dosimetry background. Furthermore, after a brief summary of the evolution of CT scanning, the current CT scanner technology and its special features with respect to patient doses are given in detail. Some numerical data is also given in order to comprehend the magnitude of the potential radiation risk involved in comparison with risk from exposure to natural background radiation levels.