Image Quality and Clinical Usefulness of Ray-summation Image Reconstructed from CT Data, Compared with Digital Radiography.

Ray-summation (raysum) images reconstructed from computed tomography (CT) volume data resemble digital radiography (DR) images. Therefore, they have a potential to be used instead of DR images.The aim of this study was to compare the physical image quality evaluated by signal-difference-to-noise ratio (SDNR) and clinical usefulness between raysum and DR images. We employed an oval water phantom simulating adult abdomen for image quality measurement. Raysum images were reconstructed from CT volume data using an assumed x-ray quality of 70 keV. DR images were obtained using an indirect-type flat panel detector system. The normalized noise-power spectrum (NNPS) for various same dose indices (DR: entrance surface dose, CT: CT dose index volume) were measured from raysum and DR images. SDNRs were calculated from the results of NNPSs, modulation transfer function (MTF), and cartilage material contrast. Five experienced observers visually compared each pair of a clinical raysum image and a DR image for nine clinical cases (head, finger, pelvis, and foot). MTF of raysum was significantly lower than that of DR. SDNRs of DR were superior to those of raysum for each dose index, by an average factor of 1.24. For head and pelvis images, raysum images were comparable or a little superior compared with the DR images, because the radiation doses of raysum was much higher than those of DR. For finger and foot cases, the raysum images were inferior to DR images due to its lower resolution. Our results indicated a limited clinical usefulness of raysum compared with DR.

Do respiratory comorbidities limit the diagnostic usefulness of ultrasound-guided needle aspiration for subpleural lesions?

BACKGROUND: The usefulness of ultrasound-guided needle aspiration for subpleural lesions has been reported. However, no reports have evaluated its usefulness and safety in patients with respiratory comorbidities such as chronic obstructive pulmonary disease (COPD) and interstitial pneumonia (IP), which can increase the risk of iatrogenic pneumothorax. In this study, we evaluated the influence of chronic respiratory diseases (CRDs) on the usefulness and safety of ultrasound-guided needle aspiration for subpleural lesions. METHODS: Between January 2000 and September 2011, we examined 144 patients with intrapulmonary subpleural lesions. We retrospectively reviewed clinical data, including lesion size on thoracic computed tomography (CT), ultrasound findings, pathological findings obtained by ultrasound-guided needle aspiration, final diagnosis, and complications. RESULTS: A positive definitive diagnosis was obtained in 74.3% of all 144 patients; 84.7% patients with malignant diseases, including lung cancer; and 26.9% patients with benign diseases. Of the 144 patients, 64 belonged to the CRD group and 80 to the non-CRD group. The former included 31 patients with COPD, six with emphysematous changes on thoracic CT, 17 with IP, and 10 with other diseases. The positive rate of diagnosis for malignant diseases was 84.7% in the CRD group, which was the same as that in the non-CRD group. With regard to complications related to ultrasound-guided aspiration, there were only two cases of pneumothorax in the CRD group and one in the non-CRD group. CONCLUSION: Ultrasound-guided aspiration is safe and useful for subpleural lesions, particularly malignant lesions, even in patients with respiratory comorbidities such as COPD and IP.

Premelting phenomena in ionic crystals.

The theory of the premelting phenomena in ionic crystals has been developed on the basis of the concept of heterophase fluctuation in the vicinity of their melting points. The size of the liquid-like clusters is estimated by the theory using the experimental specific heat value. Molecular dynamics simulations are also performed in NaCl and AgBr crystals to examine the ionic configuration in the premelting region. The structural features are discussed using the Lindemann instability criterion.

A theory of transport properties in molten salts.

Expressions for diffusion constants in molten salts have been obtained in terms of the inter-ionic pair potentials and the pair distribution functions. Numerical attempts for diffusion constants in molten alkali halides are carried out and results agreed fairly with those obtained by molecular-dynamics simulation and with some experimental data. Based on the coupling of generalized Langevin equation and damped Einstein oscillator equation, ions' velocity autocorrelation functions have also been described and are numerically applied for molten potassium fluoride. The deviation from the Nernst-Einstein relation was also discussed in detail. In Appendixes A x B x C, the short-time expansion of velocity correlation functions in relation to the partial conductivities and the diffusion constants were obtained up to the term of t(4) and these were compared with a model function described by the form of cos(omegat)sech(ttau).

Recognition of individual genes in diverse microorganisms by cycling primed in situ amplification.

Cycling primed in situ amplification-fluorescent in situ hybridization (CPRINS-FISH) was developed to recognize individual genes in a single bacterial cell. In CPRINS, the amplicon was long single-stranded DNA and thus retained within the permeabilized microbial cells. FISH with a multiply labeled fluorescent probe set enabled significant reduction in nonspecific background while maintaining high fluorescence signals of target bacteria. The ampicillin resistance gene in Escherichia coli, chloramphenicol acetyltransferase gene in different gram-negative strains, and RNA polymerase sigma factor (rpoD) gene in Aeromonas spp. could be detected under identical permeabilization conditions. After concentration of environmental freshwater samples onto polycarbonate filters and subsequent coating of filters in gelatin, no decrease in bacterial cell numbers was observed with extensive permeabilization. The detection rates of bacterioplankton in river and pond water samples by CPRINS-FISH with a universal 16S rRNA gene primer and probe set ranged from 65 to 76% of total cell counts (mean, 71%). The concentrations of cells detected by CPRINS-FISH targeting of the rpoD genes of Aeromonas sobria and A. hydrophila in the water samples varied between 2.1 x 10(3) and 9.0 x 10(3) cells ml(-1) and between undetectable and 5.1 x 10(2) cells ml(-1), respectively. These results demonstrate that CPRINS-FISH provides a high sensitivity for microscopic detection of bacteria carrying a specific gene in natural aquatic samples.