Ladder-Like Low Iodine Delivery Rate Injection Protocols Based on BMI at 70 KV by Automated Tube Voltage Selection in Coronary CTA.

Objective: To evaluate the feasibility of reducing the injection velocity and volume of contrast agent according to BMI, and the effect of body weight (BW), body surface area（BSA）, body mass index（BMI），and blood volume (BV) on aortic contrast enhancement when the voltage of third-generation dual-source CT is selected at 70 KV. Methods: A total of 280 patients selected at 70 KV were randomly divided into an experimental group and a control group. Each group was divided into 7 subgroups according to BMI ≤20, 20-21, 21-22, 22-23, 23-24, 24-25, and 25-26. The experimental group uses 2.3/2.4/2.5/2.6/2.7/2.8/2.9 ml/s injection speed with 350 mgI/ml contrast agents according to the subgroups; injection time was fixed at 10 s. In the control group, the fixed injection flow rate was 3.5 ml/s, time was 12 s with a total of 42 ml. Subjects in both groups were inspected to adaptive prospective ECG-gating sequence scanning, and subjective and objective image quality of the two groups were compared using Student's t-test. BMI, BSA, and BV were calculated from the patient's body weight and height. We assess the relationship between aortic attenuation and BW, BMI, BV, and BSA using regression analysis or correlation analysis. Results: Significant differences exist in vascular enhancement between the two groups; SNR and CNR of objective image quality in the experimental group were lower than those in the control group (P < 0.05). Both groups had the same subjective image scores (P > 0.05). The number of vessels in the optimal enhancement range counts more in the experimental group than in the control group (χ2 value = 334.25, P ＜ 0.05). In the control group, a weak to medium correlation was seen between vascular enhancement and BMI (r = -0.20), BW (r = -0.42), BSA (r = -0.46), and BV (r = -0.48) (P ＜ 0.05 for all). Conclusions: Compared to BW, BSA, and BV, a weaker negative correlation exists between vascular enhancement and BMI when ATVS selects 70 KV. However, as a much easier way to operate, the stepped low flow and low-contrast agent injection based on BMI was feasible, and the image quality was more homogenized than that of the control group.

Hexabromocyclododecane diastereoisomers in surface sediments from river drainage basins of Shanghai, China: occurrence, distribution, and mass inventory.

Concentrations of hexabromocyclododecanes (HBCDs) were determined in surface sediments of Shanghai, China. The concentrations of total HBCD diastereoisomers (ΣHBCD) ranged from 0.01 to 13.70 ng g(-1) dry weight (dw) with a mean value of 3.41 ng g(-1) dw, which was up to several orders of magnitude lower than those reported for sediments from European countries. The ΣHBCD concentrations in sediments from chemical/textile industrial or densely populated areas were generally higher than those from rural or less chemical/textile industrialized areas in Shanghai. A high proportion of α-HBCD was observed in sediment samples and was significantly higher than that of commercial HBCD products. This might be due to thermal isomerization from γ-HBCD to α-HBCD and slower degradation rate of α-HBCD compared to γ-HBCD in anaerobic conditions. The mass inventory of ΣHBCD in surface sediments of Shanghai was estimated at 164.4 kg, representing a significant source of HBCDs to the Shanghai environment. This indicates that further study on potential transfer of HBCDs from sediments to aquatic organisms and ecological risk assessments is required.

Hexabromocyclododecanes in surface sediments from Shanghai, China: spatial distribution, seasonal variation and diastereoisomer-specific profiles.

The concentrations, spatial distribution, diastereoisomer-specific profiles of hexabromocyclododecanes (HBCDs) in surface sediments from three major rivers in Shanghai as well as the seasonal variation of HBCDs were investigated. The concentrations of total HBCD diastereoisomers ranged from 0.05 to 6.87ngg(-1)dw. Significant spatial distribution of total HBCDs concentrations were observed. The mean concentration of total HBCDs followed the order of Suzhou Creek (2.00ngg(-1))>Huangpu River (1.59ngg(-1))>Yunzao Creek (0.77ngg(-1)). The concentration was a relatively low HBCDs level compared to levels measured in domestic and other parts of the world. The proportions of α-HBCD in sediment samples were generally higher than that of commercial formulations. This might be due to thermal isomerization from γ-HBCD to α-HBCD and slower degradation rate of α-HBCD compared to γ-HBCD in anaerobic conditions. The concentrations of ΣHBCD in the summer were significantly higher than those in the winter (paired t test, p<0.01). This seasonal variation could probably be attributed to a combined effect of temperature and wet deposition. Moreover, a poor and no significant correlation between ΣHBCD levels and TOC content in sediments was observed, suggesting that the spatial distributions of HBCDs were not constrained by the TOC in sediments of Shanghai.