ObjectiveTo discuss the value of dual-source CT Flash scanning in reducing the dose of radiation in 3D cardiac imaging. MethodWe collected 60 patients from March to August 2014 who should undergo cardiac 3D CT scanning before radiofrequency ablation. They were randomly divided into group A and B with 30 in each. Patients in group A underwent flash technology scanning, while those in group B accepted conventional retrospective electrocardiography-gated scanning. CARE Dose techniques were used to collect data. Scanning parameters were the same for both groups:collimation was 128×0.6 mm, reconstruction thickness was 0.75 mm, reconstruction interval was 0.7 mm, and field of view was 180-200 mm. After image acquisition, we measured the CT values and noise of left atrium and various branches of the pulmonary veins (upper left, lower left, upper right, and lower right). Statistical software was used for the two groups of images to analyze the carrier noise ratio (CNR), signal noise ratio (SNR), blinded scores, computed tomography dose index (CTDIvol), and dose-length product (DLP) of the left atrium and pulmonary vein. ResultsCNR and SNR of the left atrium and various pulmonary veins between the two groups had no significant differences (P>0.05) . Blinded scores between the two groups were not significantly different (P>0.05) . CTDIvol in group A and group B was respectively (2.92±0.38) and (20.15±12.09) mGy, with a significant difference (t=?7.803, P<0.001) . DLP of group A was (59.30±6.67) mGy·cm, significantly lower than that in group B [(334.43±216.71) mGy·cm] (t=?6.591, P<0.001) . Flash-efficient radiation dose was (0.83±0.94) mSv in group A, far below that in group B [(4.53±3.03) msv], and the difference was statistically significant (t=?6.684, P<0.001) . ConclusionsDual-source CT Flash technology applied in 3D cardiac scanning can reduce radiation dose as well as meet the needs of image diagnosis.
Dose-response meta-analysis, as a subset of meta-analysis, plays an important role in dealing with the relationship between exposure level and risk of diseases. Traditional models limited in linear regression between the independent variables and the dependent variable. With the development of methodology and functional model, Nonlinear regression method was applied to dose-response meta-analysis, such as restricted cubic spline regression, quadratic B-spline regression. However, in these methods, the term and order of the independent variables have been assigned that may not suit for any trend distribution and it may lead to over fitting. Flexible fraction polynomial regression is a good method to solve this problem, which modelling a flexible fraction polynomial and choosing the best fitting model by using the likelihood-ratio test for a more accurate evaluation. In this article, we will discuss how to conduct a dose-response meta-analysis by flexible fraction polynomial.
ObjectiveTo evaluate the predictive value of mini-fluid challenge for volume responsiveness in patients under shock.MethodsSixty patients diagnosed as shock were included in the study. A 50 mL infusion of physiological saline over 10 seconds and a further 450 mL over 15 minutes were conducted through the central venous catheter. Cardiac output (CO), global end-diastolic volume index (GEDVI), central venous pressure (CVP) and extravascular pulmonary water index (EVLWI) were monitored by the pulse indicator continuous cardiac output monitoring. If the increase of CO after 500 mL volume expansion (ΔCO500) ≥10%, the patient was considered to be with volume responsiveness. The relevance between ΔCO50 and ΔCO500 was analyzed, and the sensitivity and specificity of the ΔCO50 were analyzed by receiver operating characteristic (ROC) curve.ResultsAfter 50 mL volume injection, the heart rate and systolic blood pressure of the two groups did not change obviously. The CVP of non-responders changed slightly higher than that of responders, but neither of them had obviously difference (P>0.05). The CO of responders had increased significantly (P<0.05) which was in accord with that after a further 450 mL volume injection. GEDVI and EVLWI did not change significantly (P>0.05). ΔCO50 and ΔCO500 were strongly correlated (r=0.706, 95%CI 0.677 - 0.891, P>0.05). The area under ROC curve for ΔCO50 was 0.814 (95%CI 0.707 - 0.922).ConclusionThe volume responsiveness of patients under shock can be predicted by mini-fluid challenge study which is related to normal volume expansion and it does not increase the risk of pulmonary edema.
Objective Influence factors of the stable warfarin dose in the early period after mechanical prosthetic valve replacement were analyzed to guide the anticoagulation therapy for these patients. Methods A total of 288 patients within 6 months after mechanical prosthetic valve replacement in West China Hospital were followed up and registered at outpatient department from July 2012 to April 2014, including basic information (name, sex, age, height, weight, etc.), general clinical data (cardiac function, heart rate, surgery pattern, etc.) and related data about anticoagulation therapy. The target international standardized ratio (INR) range was 1.60 to 2.20 and the acceptable INR was 1.50 to 2.30. The sex, age, height, body weight, body mass index (BMI), body surface area (BSA) and related clinical factors were analyzed to find the relationship with the dose of warfarin. Results Sex was found to have a significant effect on the stable warfarin dose (P<0.05). Women needed a lower stable warfarin dose than men during the early anticoagulation therapy. There was no significant difference in the stable warfarin dose of patients with different ages, rhythms, NYHA classification, surgery pattern and diseases before operation; but the stable warfarin dose was lower in the patients with radiofrequency ablation during valve replacement procedures than the patients with single valve replacement (P<0.05). There was an association between age, height, weight, BMI, BSA and the stable warfarin dose withR2 of 1.2%, 3.2%, 3.5%, 1.1%, 4.2%, respectively and they could explain 6.1% of variability in warfarin dose. Conclusion During early anticoagulation therapy in patients with mechanical prosthetic valve replacement, it is necessary to consider the effects of various preoperative factors, drug factors and demographic factors on warfarin dose. Even though there is an association between age, height, weight, BMI, BSA and the stable warfarin dose, which can only explain 6.1% of variability in warfarin dose, thus cannot guide the postoperative anticoagulation of these patients.
Objective To systematically review the dose-response relationship between cadmium exposure and the risk of stroke onset. Methods The PubMed, Web of Science, Cochrane Library, Embase, CNKI, VIP, WanFang Data, and CBM databases were electronically searched to collect studies related to objectives from inception to June 2024. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Meta-analysis was then performed using Stata 15.1 software. Results There were 10 studies that involved 28 250 participants, and 7 of them were prospective cohort studies and 3 were case-control studies. Meta-analysis results showed that cadmium exposure significantly increased the risk of stroke (RR=1.39, 95%CI 1.20 to 1.59, P<0.01), blood cadmium exposure significantly increased the risk of stroke (RR=1.79, 95%CI 1.34 to 2.25, P<0.01), urinary cadmium exposure significantly increased the risk of stroke (RR=1.30, 95%CI 1.09 to 1.52, P<0.01). Blood cadmium exposure had a significantly nonlinear dose-response relationship associated with an increased risk of stroke (χ2=8.56, P<0.05). The risk of stroke increased by 15% with the blood cadmium exposure concentration of 0.8 μg/L (RR=1.15, 95%CI 0.98 to 1.36), and 51% with the blood cadmium exposure concentration of 1.2 μg/L (RR=1.51, 95%CI 1.14 to 2.01) than those without blood cadmium exposure. Urinary cadmium exposure had significantly linear dose-response relationship associated with an increased risk of stroke (χ2=2.47, P=0.12). The risk of stroke increased by 26% with the urinary cadmium exposure concentration of 0.8 μg/g (RR=1.26, 95%CI 1.20 to 1.31), and 31% with the urinary cadmium exposure concentration of 1.2 μg/g (RR=1.31, 95%CI 1.27 to 1.36) than those without urinary cadmium exposure. Conclusion Cadmium exposure increases the risk of stroke. There was a significant dose-response relationship between cadmium exposure and the risk of stroke.
Objective To investigate the effect of doxycycline on the proliferation and vasculogenic mimicry in retinoblastoma (RB) cell line in vitro. Methods RB cell line were tested for their ability to form perfusable tubular networks in 3D culture with doxycycline in the concentrations ranging from 5 to 20 mg/L, and CoCl2 was used as chemical hypoxia-inducing reagent to mimic tumor hypoxic microenvironment. The effect of doxycycline on proliferation were detected by MTT assay in vitro, and the effect on tube formation of RB cells were detected by tube-like structure formation assay and PAS staining. The mRNA levels of MMP2 and MMP9 at different hypoxic culture and different doxycycline concentrations were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Results The micrograph showed that RB cells linked each other to form cavity and network tructure in 3D culture. the number of tubules in doxycycline group were significantly lower than which in the control group in the concentrations ranging from 5 to 20 mg/L (Plt;0.001).OD of doxycycline group was significantly lower than which in the control group (t=15.320，Plt;0.01) , The proliferation of RB cells had a negative correlation with the concentration of doxycycline (r =-0924, Plt;001). The levels of MMP2 and MMP9 mRNA of RB cells under hypoxia were significantly higher than which in the control group (t=16.469，Plt;0.01). As the concentration of doxycycline increased, the expression of MMP-2 and MMP-9 decreased. The result of double staining also showed that VM, formed by CD34negative and PASpositive tumor cells, existed in 12 simples of retinoblastoma. Conclusion RB cells have the capacity of selfmetamorphosing and vasculorizing in 3D culture. Doxycycline can inhibit their proliferation and vasculogenic mimicry formation in vitro by downregulating the expression of MMP-2 and MMP-9 .
When investing the relationship between independent and dependent variables in dose-response meta-analysis, the common method is to fit a regression function. A well-established model should take both linear and non-linear relationship into consideration. Traditional linear dose-response meta-analysis model showed poor applicability since it was based on simple linear function. We introduced a piecewise linear function into dose-response meta-analysis model which overcame this problem. In this paper, we will give a detailed discussion on traditional linear and piecewise linear regression model in dose-response meta-analysis.