A statistical approach was investigated to estimate the concentration of compounds lacking authentic standards/surrogates (CLASS). As a means to assess the reliability of this approach, the response factor (RF) of CLASS is derived by predictive equations based on a linear regression (LR) analysis between the actual RF (by external calibration) of 18 reference volatile organic compounds (VOCs) consisting of six original functional groups and their physicochemical parameters ((1) carbon number (CN), (2) molecular weight (MW), and (3) boiling point (BP)). If the experimental bias is estimated in terms of percent difference (PD) between the actual and projected RF, the least bias for 18 VOCs is found from CN (17.9 ± 19.0%). In contrast, the PD values against MW and BP are 40.6% and 81.5%, respectively. Predictive equations were hence derived via an LR analysis between the actual RF and CN for 29 groups: (1) one group consisting of all 18 reference VOCs, (2) three out of six original functional groups, and (3) 25 groups formed randomly from the six functional groups. The applicability of this method was tested by fitting these 29 equations into each of the six original functional groups. According to this approach, the mean PD for 18 compounds dropped as low as 5.60 ± 5.63%. This approach can thus be used as a practical tool to assess the quantitative data for CLASS.
In this study, we have examined the patterns of VOCs released from used Tedlar bags that were once used for the collection under strong source activities. In this way, we attempted to account for the possible bias associated with the repetitive use of Tedlar bags. To this end, we selected the bags that were never heated. All of these target bags were used in ambient temperature (typically at or below 30°C). These bags were also dealt carefully to avoid any mechanical abrasion. This study will provide the essential information regarding the interaction between VOCs and Tedlar bag materials as a potential source of bias in bag sampling approaches.
volatile organic compounds; tedlar bag; sampling bias; polar; nonpolar
The emission rates of volatile organic compounds (VOCs) were measured to investigate the emission characteristics of five types of common furniture products using a 5 m3 size chamber at 25°C and 50% humidity. The results indicated that toluene and α-pinene are the most dominant components. The emission rates of individual components decreased constantly through time, approaching the equilibrium emission level. The relative ordering of their emission rates, if assessed in terms of total VOC (TVOC), can be arranged as follows: dining table > sofa > desk chair > bedside table > cabinet. If the emission rates of VOCs are examined between different chemical groups, they can also be arranged in the following order: aromatic (AR) > terpenes (TER) > carbonyl (CBN) > others > paraffin (PR) > olefin (HOL) > halogenated paraffin (HPR). In addition, if emission strengths are compared between coated and uncoated furniture, there is no significant difference in terms of emission magnitude. Our results indicate that the emission characteristics of VOC are greatly distinguished between different furniture products in terms of relative dominance between different chemicals.
volatile organic compounds (VOCs); total volatile organic compound (TVOC); furniture products; chamber test; emission rate; health hazard
Soil samples were collected over a year-long period along a background–urban–rural transect in Delhi, India for the analysis of polycyclic aromatic hydrocarbons (PAHs), black carbon (BC), and total organic carbon (TOC) in five grain size fractions, x, in μm of 0≤x<53 (I), 53≤x<250 (II), 250≤x<500 (III), 500≤x<2000 (IV), and their sum (total: T). Maximum concentrations of PAH, BC, and TOC were observed in the smallest fraction (I) comprising silt and clay, irrespective of site or season. Results of the molecular diagnostic ratios and principal component analysis (PCA) identified coal, wood, biomass burning, and vehicular emissions as major sources of PAHs at all the three sites, while BC/TOC ratios pointed toward biomass combustion as the chief source of carbonaceous species. This work presents the first such rural-urban transect study considering PAH, BC, and TOC in soil.
black carbon (BC); grain size; polycyclic aromatic hydrocarbons (PAHs); soil; source apportionment; transect
Liver fibrosis occurs as a wound-healing response to chronic hepatic injuries irrespective of the underlying etiology and may progress to life-threatening cirrhosis. Here we show that CCN1, a matricellular protein of the CCN (CYR61/CTGF/NOV) family, is accumulated in hepatocytes of human cirrhotic livers. CCN1 is not required for liver development or regeneration, since these processes are normal in mice with hepatocyte-specific Ccn1 deletion. However, Ccn1 expression is upregulated upon liver injuries and functions to inhibit liver fibrogenesis induced by either carbon tetrachloride intoxication or bile duct ligation and promote fibrosis regression. CCN1 acts by triggering cellular senescence in activated hepatic stellate cells and portal fibroblasts by engaging integrin α6β1 to induce reactive oxygen species accumulation through the RAC1-NADPH oxidase 1 enzyme complex, whereupon the senescent cells express an antifibrosis genetic program. Mice with hepatocyte-specific Ccn1 deletion suffer exacerbated fibrosis with a concomitant deficit in cellular senescence, whereas overexpression of hepatic Ccn1 reduces liver fibrosis with enhanced senescence. Furthermore, tail vein delivery of purified CCN1 protein accelerates fibrosis regression in mice with established fibrosis. These findings reveal a novel integrin-dependent mechanism of fibrosis resolution in chronic liver injury and identify the CCN1 signaling pathway as a potential target for therapeutic intervention.
To investigate the environmental behavior of volatile organic compounds (VOCs) in urban areas, their concentrations were measured at four urban monitoring sites (namely, N, S, E, and W) in Seoul, Korea (February to December 2009). A total of 27 compounds were quantified that consist of four chemical groups: aromatic (AR), halogenated aromatic, halogenated paraffin, and halogenated olefin. Results were evaluated by focusing on these four functional groups just mentioned and their summation term as total VOC (TVOC) along with several individual species (mainly AR species, that is, benzene, toluene, ethylbenzene, and xylene). The highest concentration of chemical groups was found from AR (71.1±42.1 ppbC), while that for individual species confirmed the dominance of toluene (7.48±3.88 ppb). The analysis of spatial distribution indicated that high TVOC levels were recorded at sites N and W, while it was not so significant such as S and E in terms of TVOC budget. Seasonal variation of these VOCs was characterized by the peak values in December to reflect the combined effects of pronounced source activities and meteorological conditions. Analysis of spatial variations in VOC levels between the four urban sites indicated that their distributions are tightly affected by local source processes in each area.
volatile organic compounds (VOCs); total volatile organic compound (TVOC); spatial; seasonal; urban area; Seoul
In this study, volatile urinary components were collected using three different types of samples from patients suffering from urinary incontinence (UI): (1) urine (A); (2) urine + non-used pad (B); and (3) urine + used pad (C). In addition, urine + non-used pad (D) samples from non-patients were also collected as a reference. The collection of urinary volatiles was conducted with the aid of a glass impinger-based mini-chamber method. Each of the four sample types (A through D) was placed in a glass impinger and incubated for 4 hours at 37 °C. Ultra pure air was then passed through the chamber, and volatile urine gas components were collected into Tedlar bags at the other end. These bag samples were then analyzed for a wide range of VOCs and major offensive odorants (e.g., reduced sulfur compounds (RSCs), carbonyls, trimethylamine (TMA), ammonia, etc.). Among the various odorants, sulfur compounds (methanethiol and hydrogen sulfide) and aldehydes (acetaldehyde, butylaldehyde, and isovaleraldehyde) were detected above odor threshold and predicted to contribute most effectively to odor intensity of urine incontinence.
incontinence; urinary; volatiles; GC; HPLC; incontinence pads; sample collection; glass impinger
The classes and concentrations of volatile organic compounds (VOC) released from fresh and decaying strawberries were investigated and compared. In this study, a total of 147 strawberry volatiles were quantified before and after nine days of storage to explore differences in the aroma profile between fresh strawberries (storage days (SRD) of 0, 1, and 3) and those that had started to decay (SRD = 6 and 9). In terms of concentration, seven compounds dominated the aroma profile of fresh strawberries (relative composition (RC) up to 97.4% by mass, sum concentration): (1) ethyl acetate = 518 mg·m−3, (2) methyl acetate = 239 mg·m−3, (3) ethyl butyrate = 13.5 mg·m−3, (4) methyl butyrate = 11.1 mg·m−3, (5) acetaldehyde = 24.9 mg·m−3, (6) acetic acid = 15.2 mg·m−3, and (7) acetone = 13.9 mg·m−3. In contrast, two alcohols dominated the aroma profile of decayed samples (RC up to 98.6%): (1) ethyl alcohol = 94.2 mg·m−3 and (2) isobutyl alcohol = 289 mg·m−3. Alternatively; if the aroma profiles are re-evaluated by summing odor activity values (ΣOAV); four ester compounds ((1) ethyl butyrate (6,160); (2) ethyl hexanoate (3,608); (3) ethyl isovalerate (1,592); and (4) ethyl 2-methylbutyrate (942)) were identified as the key constituents of fresh strawberry aroma (SRD-0). As the strawberries began to decay; isobutyl alcohol recorded the maximum OAV of 114 (relative proportion (RP) (SRD = 6) = 58.3%). However, as the decay process continued, the total OAV dropped further by 3 to 4 orders of magnitude—decreasing to 196 on SRD = 6 to 7.37 on SRD = 9. The overall results of this study confirm dramatic changes in the aroma profile of strawberries over time, especially with the onset of decay.
fresh and decaying strawberry; strawberry fragrances; mass concentration; threshold; odor activity value (OAV)
In an effort to reduce the experimental bias involved in the analysis of gaseous elemental mercury (Hgo), the blank response from gold-coated adsorption tubes has been investigated using cold vapor atomic absorption spectrometry (CVAAS). Our study has been compared with our recent investigation on memory effect in a cold vapour atomic fluorescence spectrometry (CVAFS). The pattern of blank responses was quantified after loading different amounts of mercury and after different time intervals of 1, 14, and 45 days. In case of the one day interval, the result of five to six instant blank heating cycles confirmed successful liberation of mercury following the second and third blank heating cycles. The results of 14 or 45 days generally suggest that liberation of excess mercury is affected by both the initial loading amount and the length of storage time prior to analysis. We have demonstrated a possibly effective way to reduce memory effects. Some similarities of these results with those from CVAFS experiment suggests that the blank response is caused by a combination of mercury absorbed within the bulk gold and micro- and nanoparticles liberated during heating and not from coabsorbing interfering gaseous species.
In an effort to study the possible effects of climate change on the behavior of atmospheric mercury (Hg), we built a temperature–controlled microchamber system to measure its emission from top soils. To this end, mercury vapour emission rates were investigated in the laboratory using top soil samples collected from an urban area. The emissions of Hg, when measured as a function of soil temperature (from ambient levels up to 70°C at increments of 10°C), showed a positive correlation with rising temperature. According to the continuous analyses of the Hg vapor given off by the identical soil samples, evasion rate diminished noticeably with increasing number of repetitions. The experimental results, if examined in terms of activation energy (Ea), showed highly contrasting patterns between the single and repetitive runs. Although the results of the former exhibited Ea values smaller than the vaporization energy of Hg (i.e., <14 Kcal mol−1), those of the latter increased systematically with increasing number of repetitions. As such, it is proposed that changes in the magnitude of Ea values can be used as a highly sensitive criterion to discriminate the important role of vaporization from other diverse (biotic/abiotic) processes occurring in the soil layer.
A hepatitis B virus (HBV) vaccine has been developed using a new adjuvant and HBV surface antigens produced from a CHO cell line. The purified HBV surface antigens are composed of L protein, M protein, and S protein in a mixture of 20- and 40-nm-diameter particles and filamentous forms. This HBV surface antigen, formulated with L-pampo, a proprietary adjuvant, induced 10 times more antibody than the same antigen with alum and was capable of inducing strong immune responses in three different HBV transgenic mice. In spite of the presence of a large amount of HBV antigen in the blood, no antibody against HBV surface antigen was normally detected in these transgenic mice. After immunization, the HBV antigen was also cleared from the blood.
Background: Numerous studies have linked fine particles [≤ 2.5 µm in aerodynamic diameter (PM2.5)] and health. Most studies focused on the total mass of the particles, although the chemical composition of the particles varies substantially. Which chemical components of fine particles that are the most harmful is not well understood, and research on the chemical composition of PM2.5 and the components that are the most harmful is particularly limited in Asia.
Objectives: We characterized PM2.5 chemical composition and estimated the effects of cause-specific mortality of PM2.5 mass and constituents in Seoul, Korea. We compared the chemical composition of particles to those of the eastern and western United States.
Methods: We examined temporal variability of PM2.5 mass and its composition using hourly data. We applied an overdispersed Poisson generalized linear model, adjusting for time, day of week, temperature, and relative humidity to investigate the association between risk of mortality and PM2.5 mass and its constituents in Seoul, Korea, for August 2008 through October 2009.
Results: PM2.5 and chemical components exhibited temporal patterns by time of day and season. The chemical characteristics of Seoul’s PM2.5 were more similar to PM2.5 found in the western United States than in the eastern United States. Seoul’s PM2.5 had lower sulfate (SO4) contributions and higher nitrate (NO3) contributions than that of the eastern United States, although overall PM2.5 levels in Seoul were higher than in the United States. An interquartile range (IQR) increase in magnesium (Mg) (0.05 μg/m3) was associated with a 1.4% increase (95% confidence interval: 0.2%, 2.6%) in total mortality on the following day. Several components that were among the largest contributors to PM2.5 total mass—NO3, SO4, and ammonium (NH4)—were moderately associated with same-day cardiovascular mortality at the p < 0.10 level. Other components with smaller mass contributions [Mg and chlorine (Cl)] exhibited moderate associations with respiratory mortality on the following day (p < 0.10).
Conclusions: Our findings link PM2.5 constituents with mortality and have implications for policy making on sources of PM2.5 and on the relevance of PM2.5 health studies from other areas to this region.
chemical constituents; mortality; PM2.5; time-series
There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (Igeo), calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution.
Commercial standard gas generators are often complex and expensive devices. The objective of this research was to assess the performance of a simplified glass impinger system for standard gas generation from a permeation tube (PT) device. The performance of the impinger standard gas generation system was assessed for four aromatic VOCs (benzene, toluene, ethylbenzene, and m-xylene; BTEX) at varying flow rates (FR) of 50 to 800 mL·min−1. Because actual permeation rate (APR) values deviated from those computed by the manufacturer's formula (MPR), new empirical relationships were developed to derive the predicted PR (PPR) of the target components. Experimental results corrected by such a formula indicate that the compatibility between the APR and MPR generally increased with low FR, while the reproducibility was generally reduced with decreasing flow rate. Although compatibility between different PRs is at a relatively small and narrow FR range, the use of correction formula is recommendable for the accurate use of PT.
impinge; permeation; benzene; toluene; ethylbenzene; xylene
To learn more about the effects of mixing different odorants, a series of air dilution sensory (ADS) tests were conducted using four reduced sulfur compounds [RSC: hydrogen sulfide (H2S), methanethiol (CH3SH), dimethylsulfide (DMS), and dimethyldisulfide (DMDS)] at varying concentration levels. The tests were initially conducted by analyzing samples containing single individual RSCs at a wide range of concentrations. The resulting data were then evaluated to define the empirical relationship for each RSC between the dilution-to-threshold (D/T) ratio and odor intensity (OI) scaling. Based on the relationships defined for each individual RSC, the D/T ratios were estimated for a synthetic mixture of four RSCs. The effect of mixing was then examined by assessing the relative contribution of each RSC to those estimates with the aid of the actually measured D/T values. This stepwise test confirmed that the odor intensity of the synthetic mixture is not governed by the common theoretical basis (e.g., rule of additivity, synergism, or a stronger component model) but is best represented by the averaged contribution of all RSC components. The overall results of this study thus suggest that the mixing phenomenon between odorants with similar chemical properties (like RSC family) can be characterized by the averaging effect of all participants.
human sensing; odor mixing; threshold; hydrogen sulfide; methanethiol; dilution-to-threshold (D/T) ratio
The forkhead box M1b (FoxM1b) transcription factor is over-expressed in human cancers, and its expression often correlates with poor prognosis. Previously, using conditional knockout strains, we showed that FoxM1b is essential for hepatocellular carcinoma (HCC) development. However, over-expression of FoxM1b had only marginal effects on HCC progression. Here we investigated the effect of FoxM1b expression in the absence of its inhibitor Arf. We show that transgenic expression of FoxM1b in an Arf-null background drives hepatic fibrosis and metastasis of HCC. We identify novel mechanisms of FoxM1b that are involved in epithelial–mesenchymal transition, cell motility, invasion and a pre-metastatic niche formation. FoxM1b activates the Akt-Snail1 pathway and stimulates expression of Stathmin, lysyl oxidase, lysyl oxidase like-2 and several other genes involved in metastasis. Furthermore, we show that an Arf-derived peptide, which inhibits FoxM1b, impedes metastasis of the FoxM1b-expressing HCC cells. The observations indicate that FoxM1b is a potent activator of tumour metastasis and that the Arf-mediated inhibition of FoxM1b is a critical mechanism for suppression of tumour metastasis.
Arf; FoxM1; metastasis
We identified a gene for β-1,3-glucan synthesis (GBG1), a nonessential gene whose disruption alters cell wall synthesis enzyme activities and cell wall composition. This gene was cloned by functional complementation of defects in β-1,3-glucan synthase activity of the the previously isolated Saccharomyces cerevisiae mutant LP0353, which displays a number of cell wall defects at restrictive temperature. Disruption of the GBG1 gene did not affect cell viability or growth rate, but did cause alterations in cell wall synthesis enzyme activities: reduction of β-1,3-glucan synthase and chitin synthase III activities as well as increased chitin synthase I and II activities. GBG1 disruption also showed altered cell wall composition as well as susceptibility toward cell wall inhibitors such as Zymolyase, Calcofluor white, and Nikkomycin Z. These results indicate that GBG1 plays a role in cell wall biogenesis in S. cerevisiae
β-1,3-glucan synthase; Cell wall composition; Chitin synthase; GBG1/AYR1; Saccharomyces cerevisiae
To simulate the occurrence of masking phenomena with the aid of an air dilution sensory (ADS) test, two types of odorant mixtures were prepared: (1) M2 with two individual odorants [H2S and acetaldehyde (AA)] and (2) M6 with six individual odorants (H2S and five aldehydes). The test results derived for samples containing single individual odorants at a wide range of concentrations are initially used to define the empirical relationship between the dilution-to-threshold (D/T) ratio and odor intensity (OI) scaling. Based on these relationships, the D/T ratios were estimated for each odorant with the same intensity as the synthetic mixture. The relative contribution of each odorant to such mixture is then assessed by comparing the estimated and measured D/T values. This stepwise test confirmed the dominance of certain compounds at a given OI rating. In the case of M2, H2S showed sensitive detection at high OI range, while AA did so at low end. The pattern of a competing relationship is also seen consistently from M6 between AA (low) and iso-valeraldehyde (IA: high OI range). The overall results thus suggest that the masking phenomena between strong odorants should proceed under competing relationships, if released at the same time.
human sensing; odor masking; threshold; hydrogen sulfide; acetaldehyde; dilution-to-threshold (D/T) ratio
β-Thalassemia is a genetic disorder caused by mutations in the β-globin gene. Triplex-forming oligonucleotides and triplex-forming peptide nucleic acids (PNAs) have been shown to stimulate recombination in mammalian cells via site-specific binding and creation of altered helical structures that provoke DNA repair. However, the use of these molecules for gene targeting requires homopurine tracts to facilitate triple helix formation. Alternatively, to achieve binding to mixed-sequence target sites for the induced gene correction, we have used pseudo-complementary PNAs (pcPNAs). Due to steric hindrance, pcPNAs are unable to form pcPNA–pcPNA duplexes but can bind to complementary DNA sequences via double duplex-invasion complexes. We demonstrate here that pcPNAs, when co-transfected with donor DNA fragments, can promote single base pair modification at the start of the second intron of the beta-globin gene. This was detected by the restoration of proper splicing of transcripts produced from a green fluorescent protein-beta globin fusion gene. We also demonstrate that pcPNAs are effective in stimulating recombination in human fibroblast cells in a manner dependent on the nucleotide excision repair factor, XPA. These results suggest that pcPNAs can be effective tools to induce heritable, site-specific modification of disease-related genes in human cells without purine sequence restriction.
Cardiovascular mortality is associated with vascular calcification (VC) in hemodialysis (HD) patients. The present study was designed to find factors related with medial artery calcification on the plain radiography of feet by comparing C-reactive protein (CRP), plasminogen activator inhibitor type 1 (PAI-1) and lipid profile including oxidized low density lipoprotein (ox-LDL) and to elucidate associations among these factors in HD patients. Forty-eight HD patients were recruited for this study. VC in the feet was detected in 18 patients (37.5%) among total patients and 12 patients (85.7%) among diabetic patients. Diabetes, cardiovascular disease (CVD), pulse pressure, ox-LDL/LDL were higher and high density lipoprotein (HDL) was lower in patients with VC than in patients without VC. Negative associations were found between HDL and CRP, PAI-1. PAI-1 had positive association with ox-LDL/LDL. History of CVD was the only determinant of vascular calcification on the plain radiography of feet. Ox-LDL/LDL, HDL, CRP, and PAI-1 were closely related with one another in HD patients. History of CVD is the most important factor associated with the presence of VC and low HDL and relatively high oxidized LDL/LDL ratio may affect VC formation on the plain radiography in the feet of HD patients.
Vascular Calcification; Oxidized Low Density Lipoprotein; High Density Lipoproteins; Hemodialysis
Leucine-rich Repeat Containing protein 10 (LRRC10) has recently been identified as a cardiac-specific factor in mice. However, the function of this factor remains to be elucidated. In this study, we investigated the developmental roles of Lrrc10 using zebrafish as an animal model. Knockdown of Lrrc10 in zebrafish embryos (morphants) using morpholinos caused severe cardiac morphogenic defects including a cardiac looping failure accompanied by a large pericardial edema, and embryonic lethality between day 6 and 7 post fertilization. The Lrrc10 morphants exhibited cardiac functional defects as evidenced by a decrease in ejection fraction and cardiac output. Further investigations into the underlying mechanisms of the cardiac defects revealed that the number of cardiomyocyte was reduced in the morphants. Expression of two cardiac genes was deregulated in the morphants including an increase in atrial natriuretic factor, a hallmark for cardiac hypertrophy and failure, and a decrease in cardiac myosin light chain 2, an essential protein for cardiac contractility in zebrafish. Moreover, a reduced fluorescence intensity from NADH in the morphant heart was observed in live zebrafish embryos as compared to control. Taken together, the present study demonstrates that Lrrc10 is necessary for normal cardiac development and cardiac function in zebrafish embryos, which will enhance our understanding of congenital heart defects and heart disease.
Leucine-rich Repeat Containing protein 10; Heart development; Cardiac function; Zebrafish embryos; Cardiac looping defects; Pericardial edema
This study is to identify the spectrum of Epstein-Barr virus (EBV)-positive lymphoproliferative diseases (LPD) and relationships between these diseases in Korea. The EBV status and clinicopathology of 764 patients, including acute EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), chronic active EBV (CAEBV) infections, B-LPD arising in chronic latent EBV infection, T & natural killer (NK) cell non-Hodgkin's lymphomas (NHL), B-NHLs, and Hodgkin's lymphomas (HD), were analyzed. T or NK cell NHLs were the most common forms of EBV-positive NHLs (107/167, 64%); among these, nasal-type NK/T cell lymphomas were the most common (89/107, 83%). According to the age, Burkitt's lymphoma was the most common in early childhood; in teenagers, chronic (active) EBV infection-associated LPD was the most common type. The incidence of NK/T cell lymphoma began to increase from the twenties and formed the major type of EBV-associated tumor throughout life. Diffuse large B cell lymphoma formed the major type in the sixties and seventies. In conclusion, primary infections in early childhood are complicated by the development of CAEBV infections that are main predisposing factors for EBV-associated T or NK cell malignancies in young adults. In old patients, decreased immunity associated with old age and environmental cofactors may provoke the development of peripheral T cell lymphoma, unspecified, and diffuse large B cell lymphoma.
Lymphoma; Epstein-Barr Virus; Lymphohistiocytosis, Hemophagocytic
To reduce beam hardening artifacts caused by the shoulder joint, we explored new and unique methods to improve the quality of images, such as varying the injection site and changing the position of patients (swimmers position).
Materials and Methods
Fifth-four patients underwent neck CT examinations performed in routine and swimmers position and with a 64-slice MDCT scanner in spiral scanning. To examine the difference due to the injection sites of contrast material, subjects were divided into right- and left-side groups. For the evaluation of images, we carried out a subjective and objective assessment based on radiologists' ratings and noise measurement.
Images of the lower neck in the swimmers position exhibited less hardening and streak artifacts. The subjective and objective evaluations showed that the swimmers position received higher rating by radiologists and had lower noise level than that of routine position. The swimmers position was the most effective for the diagnosis of the cervico-thoracic junction area. As for the injection site, we obtained better images by an injection of contrast material in the right arm than in the left.
CT examination of the lower neck in the swimmers position may improve the quality of image and the effectiveness of diagnosis. The injection of a contrast material to the right side rather than the left side reduced foreign body artifacts.
Cervico-thoracic junction; computed tomography; artifacts; swimmers position