Blind deblurring of spiral CT images Ming Jiang; Ge Wang; Skinner, M.W. ...
IEEE transactions on medical imaging,
07/2003, Volume:
22, Issue:
7
Journal Article
To discriminate fine anatomical features in the inner ear, it has been desirable that spiral computed tomography (CT) may perform beyond their current resolution limits with the aid of digital image ...processing techniques. In this paper, we develop a blind deblurring approach to enhance image resolution retrospectively without complete knowledge of the underlying point spread function (PSF). An oblique CT image can be approximated as the convolution of an isotropic Gaussian PSF and the actual cross section. Practically, the parameter of the PSF is often unavailable. Hence, estimation of the parameter for the underlying PSF is crucially important for blind image deblurring. Based on the iterative deblurring theory, we formulate an edge-to-noise ratio (ENR) to characterize the image quality change due to deblurring. Our blind deblurring algorithm estimates the parameter of the PSF by maximizing the ENR, and deblurs images. In the phantom studies, the blind deblurring algorithm reduces image blurring by about 24%, according to our blurring residual measure. Also, the blind deblurring algorithm works well in patient studies. After fully automatic blind deblurring, the conspicuity of the submillimeter features of the cochlea is substantially improved.
Aims.We investigate the origin of the ${\rm Br}\gamma$ emission of the Herbig Ae star HD 104237 on Astronomical Unit (AU) scales. Methods.Using AMBER/VLTI at a spectral resolution $\mathcal{R}=1500$ ...we spatially resolve the emission in both the ${\rm Br}\gamma$ line and the adjacent continuum. Results.The visibility does not vary between the continuum and the ${\rm Br}\gamma$ line, even though the line is strongly detected in the spectrum, with a peak intensity 35% above the continuum. This demonstrates that the line and continuum emission have similar size scales. We assume that the K-band continuum excess originates in a “puffed-up” inner rim of the circumstellar disk, and discuss the likely origin of ${\rm Br}\gamma$. Conclusions.We conclude that this emission most likely arises from a compact disk wind, launched from a region 0.2–0.5 AU from the star, with a spatial extent similar to that of the near infrared continuum emission region, i.e., very close to the inner rim location.
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► Mineral oil can significantly enhanced Entamoeba histolytica proliferation in microplates. ► Mineral oil covered medium-containing wells produced higher trophozoite numbers kept ...adherent and motile. ► Mineral oil addition reduces oxidative stress, down modulating reactive oxidative species production within trophozoites.
Entamoeba histolytica is among the most deadly parasites accounting for the second highest mortality rate among parasitic diseases. Nevertheless, contrary to trypanosomatids, this protozoan in hardly studied by parasitology groups. This astonishing discrepancy is largely due to the remarkable intricate conditions required for parasite proliferation in vitro, particularly whenever large cell numbers are required. The present study was undertaken in order to optimize E. histolytica culturing harvest, using mineral oil layers preventing culture medium-air contact to maintain anaerobic conditions in culture plate wells. 2×104 trophozoites were plated on each well in 2.0mL YI-S-33 medium, supplemented with bovine serum and 700μL mineral oil. Parasites were daily quantified by light microscopy counting for up to 96h and trophozoite motility was also assessed. We notice that E. histolytica cultures in 24-well plates reached several-fold higher cell densities, particularly whenever the mineral oil layer was placed on top of the medium surface, blocking the air interface.
At least 99% of the parasites were vigorously motile for 72h in oil-containing wells, whereas only less than 5% displayed significant motility in oil-devoid wells.
In order to determine whether such different growth responses were due at least in part to the oxidative stress, we used the reactive oxidant species fluorescent probe dihydroethidium (DHE).
The remarkably higher DHE parasite labeling in oil-devoid cultures indicate that oxidative stress reduction can play a significant role in elevated growth rates observed in oil supplemented cultures. Propidium iodide and Trypan blue dye-exclusion assays indicate that parasite necrosis resulted from the stressing conditions.
The present study indicates that E. histolytica culturing in oil-sealed wells may comprise a valuable tool for bioactivity of antiparasitic compounds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To test automated three-dimensional magnetic resonance (MR) imaging morphometry of the human hippocampus, to determine the potential gain in precision compared with conventional manual morphometry.
A ...canonical three-dimensional MR image atlas was used as a deformable template and automatically matched to three-dimensional MR images of 10 individuals (five healthy and five schizophrenic subjects). A subvolume containing the hippocampus was defined by using 16 landmarks that constrained the automated search for hippocampal boundaries. Transformation of the hippocampus template was automatically performed by using global pattern matching through a sequence of low-then high-dimensional translations, rotations, and scalings.
The average test-retest volume difference measured with the automatic method was 3.1%, compared with the manual test-retest difference of 7.1%. Correlation between automated and manually determined volumes demonstrated the validity of the automated technique (intraclass correlation coefficient = .86).
The automated method estimates hippocampal volumes with less variability (ie, lower variance) than that of manual out-lining.
Three-dimensional cochlear canal lengths, electrode array intracochlear insertion depths, and characteristic frequency ranges were estimated for 20 Nucleus implant recipients on the basis of in vivo ...computed tomography (CT) scans. Ultra-high resolution images were reconstructed from spiral CT data with 0.1-mm slicing and expanded attenuation scales. Canal length estimates (mean 33.01 mm; SD 2.31) were consistent with previous findings for normal human temporal bones. Intracochlear array insertion depths estimated by 3-dimensional (3-D) spiral calculations (mean 20.19 mm; SD 2.86) and by a computerized array tracking algorithm (mean 20.36 mm; SD 2.66) were not significantly different. Estimates from surgical observations were significantly longer (mean 21.03 mm; SD 2.31) because array compressions were not detectable. Characteristic frequencies at apical electrodes estimated from Greenwood's equations ranged from 387 Hz to 2,596 Hz. The results show that significant variations in cochlear anatomy and array distribution among implant patients that may impact implant performance can be reliably detected and quantified by using in vivo high-resolution CT and 3-D reconstructions.
Eckhart is often presented as the theologian of unity, and rightly so. In this he continued the work of Dionysius, but he also adopts a different perspective. In fact he develops three types of ...non-duality in his work : ontological, noetic and mystical non-duality. He starts with a classic viewpoint, first affirming ontological non-duality which then leads him to noetic non-duality, which is not only that of the Logos, but also that of the soul, before finally arriving at the mysical non-duality of essence without essence and of deity, which is a vital element throughout his work.
Eckhart est souvent présenté comme penseur de l'unité et c'est à juste titre. Il est, en cela, l'héritier de Denys, mais il adopte également une optique différente. En fait, il orchestre, dans son œuvre, une triple non-dualité : ontologique, noètique et mystique. Il part d'un point de vue classique : l'affirmation de la non-dualité ontologique pour en venir à la non-dualité noètique, qui est non seulement celle du Verbe, mais aussi celle de l'âme avant d'en venir à la non-dualité mystique du fond sans fond et de la déité, qui anime l'ensemble de son œuvre.
Gastrointestinal (GI) tract examination with spiral/helical computed tomography (CT) is currently performed by slice-based inspection of axial images. CT colography is a recent advance which allows ...an intraluminal visualization of the colon, similar to endoscopy. Various rendering algorithms have been developed with promising results, however navigation through the complex, tortuous anatomy of the colon can be time consuming in practice. In this paper, the authors propose an electrical-field-based method to unravel the convoluted colon, that is, to digitally straighten it with curved cross sections and flatten it over a plane. In the authors' method, electrical charges are simulated along the central colon path. Curved cross sections are defined by the electrical force lines, and lead to consistent unraveling. It is demonstrated with image volumes of two patients that this technique produces a global planar view of complicated colon features with a potential for detection of polyps.
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