Covariates are factors which have significant impacts on the primary analysis prior to the subjects being treated. Covariates adjustment should be considered in the design and analysis stages of the clinical trial. Through controlling in the design stage is the optimal resolution; randomization, stratified randomization and restricted covariant values could be used to balance the covariates between comparative treatments. During data analysis stage, analysis of covariance, stratified analysis, linear or generalized linear model can be conducted for covariate adjustment according to different types of outcome and covariate. For confirmatory clinical trial, covariates should be defined in advance in the protocol and statistical analysis plan with the main statistical model.
Objective To observe the changes of the multifocal electr oretinograph (mf-ERG) in commotio retinae. Methods The affected eyes (traumatic group) and the fellow eyes (control group) of 31 patients with unilateral commotio retinae were examined by RETI scan 3.15 system. The responses of 61 retinal regions were recorded, and the average amplitude densities of the N1 (the first negative) wave and P1 (the first positive) wave in different regions of retinal were analyzed. Results The average amplitude densities of 1-4 rings in N1wave and 1-5 rings in P1wave were much lower in traumatic group than those in the control. Conclusions The average amplitude densities of N1wave and P1wave of mf-ERG in retin al affected regions decreases markedly in eyes with commotio retina; mf-ERG may provide the quantificational and orientational detection for the visual ability of the eyes with commotio retinae.(Chin J Ocul Fundus Dis，2004，20：226-228)
Taking advantages of the sparsity or compressibility inherent in real world signals, compressed sensing (CS) can collect compressed data at the sampling rate much lower than that needed in Shannon’s theorem. The combination of CS and low rank modeling is used to medical imaging techniques to increase the scanning speed of cardiac magnetic resonance (CMR), alleviate the patients’ suffering and improve the images quality. The alternating direction method of multipliers (ADMM) algorithm is proposed for multiscale low rank matrix decomposition of CMR images. The algorithm performance is evaluated quantitatively by the peak signal to noise ratio (PSNR) and relative l2 norm error (RLNE), with the human visual system and the local region magnification as the qualitative comparison. Compared to L + S, kt FOCUSS, k-t SPARSE SENSE algorithms, experimental results demonstrate that the proposed algorithm can achieve the best performance indices, and maintain the most detail features and edge contours. The proposed algorithm can encourage the development of fast imaging techniques, and improve the diagnoses values of CMR in clinical applications.
ObjectiveTo measure and analyze the tortuosity of retinal veins in neonatal and premature infants quantitatively. MethodsA retrospective clinical study. The fundus images of the left eyes were selected from 30 healthy neonates and 30 premature infants without retinopathy of prematurity underwent RetCam screening. There were 16 premature infants with a history of oxygen inspiration. The tortuosity of superior temporal veins, inferior temporal veins, superior nasal veins, inferior nasal veins was measured separately using a self-developed computer program. Pearson correlation analysis was used to analyze the relationship between tortuosity of retinal veins and birth weight, gestational age and correct gestational age. ResultsIn full-term neonatal infants, the vascular tortuosity of the nasal veins was significantly higher than the temporal veins (t=5.73, P < 0.01), while the superior veins and inferior veins showed no significant difference (t=0.39, P > 0.05). There was no correlation between vascular tortuosity of temporal (r=0.179, -0.175) or nasal veins (r=0.055, 0.345) with birth weight or gestational age (P > 0.05). In premature infants, the vascular tortuosity of the nasal veins was also significantly higher than the temporal veins (t=5.00, P < 0.01), no significant difference was found between the superior veins and inferior veins (t=0.39, P > 0.05). The vascular tortuosity of temporal veins of premature infants was negatively correlated with birth weight (r=-0.375, P < 0.05); however, no significant correlation was found with gestational age (r=-0.296, P > 0.05). The vascular tortuosity of the temporal retinal veins of premature infants with a history of oxygen inspiration was significantly higher than premature infants without a history of oxygen inspiration (t=2.517, P < 0.05), though no significant difference was found between the nasal veins (t=-0.261, P > 0.05). The vascular tortuosity of the temporal and nasal retinal veins of premature infants was both higher than neonate, but was not statistically significant (t=0.88, 1.50; P > 0.05). ConclusionsThe vascular tortuosity of the temporal veins was greater than the nasal veins in both full-term and premature infants, though no significant difference was found between superior and inferior veins. The vascular tortuosity of temporal veins of premature infants increased as birth weight decreased. The vascular tortuosity of the temporal retinal veins of premature infants with a history of oxygen inspiration was higher than premature infants without a history of oxygen inspiration.
ObjectiveThrough researching the "Automated Production Quality Management Specification 5th Edition" (GAMP5) promulgated by the International Society for Pharmaceutical Engineering, combined with domestic and foreign guidelines and regulatory requirements, to explore the practical methods for the verification of the central randomization system of clinical trials.MethodsThe GAMP5 verification process and specifications of the clinical trial central randomization system was established according to the GAMP5 guideline and domestic and foreign computerized system verification guidelines and regulations in combination with the characteristics of the clinical trial central randomization system, and the existing clinical trials central randomization system was used as an example to show the verification results.ResultsThe verification framework and process of the central randomization system met the requirements of the relevant regulations of clinical trials that had been constructed. For the existing system, a verification team was established, a verification plan was developed, and a computerized system verification was conducted in accordance with the V model to form a set of standardized verification documents.ConclusionsThe verification process of the central randomization system proposed by this research follows the GAMP5 specification and has high operability and reference value.
Objective To explore the value of laparoscopy combined with gastroscopy in treatment for gastric stromal tumors. Method The clinical data of 45 patients with gastric stromal tumors performed laparoscopy combined with gastroscopy resection from June 2008 to June 2012 in this hospital were analyzed retrospectively. Results Forty-five patients with gastric stromal tumors were successfully excised by laparoscopy combined with gastroscopy， and the tumors were completely resected and no residual tumor at the edge. The length of surgical incision was about 4-6 cm with an average of 5.1 cm. The mean operation time was 75 min. Postoperative recovery was smooth， no surgery-related comp-lications occurred. The mean hospital stay was 6.8 d. No recurrence or metastasis happened within the follow-up with an average of 16.5 months. The immunohistochemical examination results：43 cases of CD117 was positive， 32 cases of CD34 was positive， 28 cases of SMA was positive， 2 cases of Desmin was positive， 22 cases of S-100 was positive. Conclusions The treatment of gastric stromal tumors through laparoscopy combined with gastroscopy is safe and effective. The benefits include minimal invasiveness， shorter operation time， and rapid postoperative recovery. The laparoscopy combined with gastroscopy can make more precise resection range， and avoid residual tumor and resection of excessive normal gastric tissue.
Survival data were widely used in oncology clinical trials. The methods used, such as the log-rank test and Cox regression model, should meet the assumption of proportional hazards. However, the survival data with non-proportional hazard (NPH) are also quite usual, which will decrease the power of these methods and conceal the true treatment effect. Therefore, during the trial design, we need to test the proportional hazard assumption and plan different analysis methods for different testing results. This paper introduces some methods that are widely used for proportional hazard testing, and summarizes the application condition, advantages and disadvantages of analysis methods for non-proportional hazard survival data. When the non-proportional hazard occurs, we need to choose the suitable method case by case and to be cautious in the interpretation of the results.