Due to the high spatiotemporal resolution , cardiac cine magnetic resonance imaging (CCMRI) has been widely used to evaluate the cardiac function of cardiovascular diseases such as myocardial ischemia and so on. Segmentation-based motion tracking of left myocardium is very important for comprehensive evaluation of cardiac function in the diagnosis and treatment of cardiovascular diseases. However, it is a challenge to track motion of left myocardium, which is homogeneous and cannot provide effective motion information. In this paper, CCMRI imaging techniques for myocardial motion tracking are introduced firstly. Then approaches for motion tracking of left myocardium based on CCMRI image are described in details and are summarized and prospected at the end, which not only helps beginners to have a quick and comprehensive understanding on this topic, but also provides theoretical reference to related researchers for further optimization of approaches for motion tracking of left myocardium. From the current study, motion tracking approaches for left myocardium based on CCMRI image make comprehensive use of the spatiotemporal motion characteristics of CCMRI image, the motion and structures of myocardium of left ventricle and so on, which can make up for the shortcomings of sparse motion information of CCMRI image. However, it still needs improved constraint framework, verification methods and so on.
Objective The changes of the aquaporins 1 (AQP-1) expression may be related to the chondrocyte apoptosis. To explore the correlation between the expression of AQP-1 and chondrocyte apoptosis by observing the expression of the AQP-1 and the Caspase-3, so as to provide experimental evidence for the further study in the pathogenesis of osteoarthritis (OA). Methods Seventy-two 8-week-old clean grade male Sprague Dawley rats, weighing 286-320 g (mean, 300 g), were randomly divided into the operated group (n=24), the sham-operated group (n=24), and the control group (n=24).OA models were made by amputating the anterior cruciate l igament and medial collateral l igament, and partial excision of medial meniscus in operated group; the articular cavity was exposed only in sham-operated group; and no treatment was given in control group. The general condition of the rat was observed after model was establ ished. At 1, 2, 4, and 8 weeks, the specimens of knee joints were harvested to perform the gross and histological observations; the mRNA expressions of AQP-1 and Caspase-3 were determined by real-time fluorescent quantitative PCR; and the activity of the Caspase-3 protease was detected. The correlations between the expression of AQP-1 mRNA and the expressions of Caspase-3 mRNA and protease were analyzed. Results Totally 6 rats died after operation, and the rats were suppl ied immediately; the other rats survived to the end of experiment. The appearance and structure of knee articular cartilage were normal in control group and sham-operated group. While in operated group, the cartilage had a rough surface with fissure and vegetation, and fibrosis and irregular cell arrangement were seen on the surface of cartilage. There were significant differences in the Mankin score between the operated group and sham-operated group, control group at 2, 4, and 8 weeks (P lt; 0.05). There was no significant difference in expressions of the AQP-1 mRNA and Caspase-3 mRNA, and the activity of the Caspase-3 protease among 3 groups at 1 week after operation (P gt; 0.05); while the expressions of the AQP-1 mRNA, Caspase-3 mRNA, and the activity of the Caspase-3 protease in operated group were significantly higher than those in sham-operated group and control group at 2, 4, and 8 weeks after operation (P lt; 0.05), andthere was an increased trend over time. There was significantly positive correlation (r=0.817, P=0.000) between the expressions of AQP-1 mRNA and Caspase-3 mRNA, and the regression equation was y=0.426 7x2+0.051 5x; meanwhile, there was also significantly positive correlation (r=0.945, P=0.000) between the expression of AQP-1 mRNA and the activity of Caspase-3 protease, and the regression equation was y=15.423 0x+4.392 8. Conclusion The up-regulation of AQP-1 expression in OA cartilage may be related to the chondrocyte apoptosis, and the changes of AQP-1 expression may involve in the pathogenesis of OA.