The correlation coefficient is a common used statistic index in the management science, sociology, psychology and nursing. The meta-analysis based on data of correlation coefficients has increased nowadays. The meta package and metafor package are the two major packages in R for performing meta-analysis and can implement many types of meta-analysis, including the meta-analysis of correlation coefficients. This article gives a brief introduction of the process to perform meta-analysis of correlation coefficients using these two packages, and compares their statistical results and functions (such as plot drawing).
The metacor, which is developed based on the classical frequentist theory, is a specified package for performing meta-analysis of correlation coefficients in R software. This package was officially launched in 2011. Based on the DerSimonian-Laird method and Olkin-Pratt method, correlation coefficients can be directly pooled by using this package. The metacor package also can be used to draw the forest plot and is easy to use; however, it still needs to be improved. This paper briefly introduced how to perform a meta-analysis of correlation coefficients using the metacor package in R software through an example.
Ultrasound guided percutaneous interventional therapy has been widely used in clinic. Aiming at the problem of soft tissue deformation caused by probe contact force in robot-assisted ultrasound-guided therapy, a real-time non-reference ultrasound image evaluation method considering soft tissue deformation is proposed. On the basis of ultrasound image brightness and sharpness, a multi-dimensional ultrasound image evaluation index was designed, which incorporated the aggregation characteristics of the organization. In order to verify the effectiveness of the proposed method, ultrasound images of four different models were collected for experiments, including prostate phantom, phantom with cyst, pig liver tissue, and pig liver tissue with cyst. In addition, the correlation between subjective and objective evaluations was analyzed based on Spearman’s rank correlation coefficient. Experimental results showed that the average evaluation time of a single image was 68.8 milliseconds. The evaluation time could satisfy real-time applications. The proposed method realizes the effective evaluation of real-time ultrasound image quality in robot-assisted therapy, and has good consistency with the evaluation of supervisors.