In this paper, we propose a new active contour algorithm, i.e. hierarchical contextual active contour (HCAC), and apply it to automatic liver segmentation from three-dimensional CT (3D-CT) images. HCAC is a learning-based method and can be divided into two stages. At the first stage, i.e. the training stage, given a set of abdominal 3D-CT training images and the corresponding manual liver labels, we tried to establish a mapping between automatic segmentations (in each round) and manual reference segmentations via context features, and obtained a series of self-correcting classifiers. At the second stage, i.e. the segmentation stage, we firstly used the basic active contour to segment the image and subsequently used the contextual active contour (CAC) iteratively, which combines the image information and the current shape model, to improve the segmentation result. The current shape model is produced by the corresponding self-correcting classifier (the input is the previous automatic segmentation result). The proposed method was evaluated on the datasets of MICCAI 2007 liver segmentation challenge. The experimental results showed that we would get more and more accurate segmentation results by the iterative steps and the satisfied results would be obtained after about six rounds of iterations.
Medical image registration is very challenging due to the various imaging modality, image quality, wide inter-patients variability, and intra-patient variability with disease progressing of medical images, with strict requirement for robustness. Inspired by semantic model, especially the recent tremendous progress in computer vision tasks under bag-of-visual-word framework, we set up a novel semantic model to match medical images. Since most of medical images have poor contrast, small dynamic range, and involving only intensities and so on, the traditional visual word models do not perform very well. To benefit from the advantages from the relative works, we proposed a novel visual word model named directional visual words, which performs better on medical images. Then we applied this model to do medical registration. In our experiment, the critical anatomical structures were first manually specified by experts. Then we adopted the directional visual word, the strategy of spatial pyramid searching from coarse to fine, and the k-means algorithm to help us locating the positions of the key structures accurately. Sequentially, we shall register corresponding images by the areas around these positions. The results of the experiments which were performed on real cardiac images showed that our method could achieve high registration accuracy in some specific areas.
ObjectiveTo investigate the influence of sepsis on the expression of apoptotic protease caspase-3 in hippocampus neurons of rats. MethodsModels of rats with sepsis were established by the cecal ligation and puncture (CLP) method. Eighty 30-day-old male Wistar rats were randomly divided into CLP group (n=50) and control group (n=30). In the CLP group, only CLP was performed on the rats. Ten rats in the CLP group and another 10 in the control group were taken at 6, 12, and 24 hours after operation, respectively. Five of them in each group were taken for neurobehavioral score, and the other five were killed and their brains were removed. Then the Western blot and immunohistochemistry staining were used to detect the expression changes of apoptosis protein caspase-3. ResultsIn the control group, there were very low expression of apoptotic protease caspase-3 and high scores of neurological behavior. In the CLP group, the expression of apoptotic protease caspase-3 started to increase at the 6th hour, and reached the peak at the 24th hour after CLP, both of which were significantly higher than the control group (P<0.05). The scores of neurological behavior of the CLP group began to decline at 6h after CLP, and decreased gradually along with the time, and the scores were significantly lower at various time points after CLP in the CLP group than those in the control group (P<0.05). ConclusionThe scores of neurological behavior decrease and the expression of apoptosis protease caspase-3 increase in the rat hippocampus with sepsis, and fluctuate with time change.
Optometry has become the second class course under the allied health professions since 2012, and has been the National undergraduate enrollment directory. According to the definition of optometry provided by the World Council of Optometry, the jobs of optometrist in China include the basic eye care, basic optometry, contact lens fitting, binocular vision anomaly treatment, strabismus and amblyopia treatment, low vision treatment, special ocular examination, maintenance of equipment related to optometry, operation and sales management. At present, the demand of professional optometrist is great. However, the development of optometrical education is limited by the lack of professional ranks. The professional ranks and titles for optometrist, corresponding registration and examination system should be established by the Ministry of Health as soon as possible, in order for the development of optometrical education and human resource management.
ObjectiveTo explore the teaching effects of case-based learning (CBL) as an educational strategy in digestive diseases module teaching. MethodsSixty-three oral and dental medical senior students were randomly divided into two groups during February to June 2012. Among them, 31 students were enrolled in the CBL group accepting CBL teaching method based on certain cases, while the other 32 students were designated into the control group receiving traditional teaching method. Their scores in practice skill examination, analytical ability of medical records, module test scores and behavior observation results were compared. Questionnaire survey was performed for students in the CBL group. ResultsThere were no significant difference in scores of clinical practice skill examination and behavior observation results between the two groups (P>0.05). Students in the CBL group did significantly better in case analysis and module test scores (P<0.05). Questionnaire survey revealed that CBL method could significantly improve the learning interest, cultivate the ability to combine theory and practice, strengthen analytical skills and promote problem-solving abilities. The students were generally satisfied with the CBL teaching method. ConclusionCBL method has an obvious advantage in digestive diseases teaching.
ObjectiveTo systematically review the efficacy and safety of respiratory fluoroquinolones monotherapy versus β-lactams plus macrolides combination therapy for non-ICU hospitalized community acquired pneumonia (CAP) patients. MethodsWe searched databases including PubMed, the Cochrane Library (Issue 3, 2015), EMbase, CNKI, WanFang Data, VIP and CBM to identify randomized controlled trials (RCTs) involving the comparison of fluoroquinolones monotherapy with β-lactams plus macrolides combination treatment for the non-ICU hospitalized patients with CAP up to April 2015. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, assessed the risk bias of included studies, and then meta-analysis was performed using the RevMan 5.0 software. ResultsA total of 17 RCTs involving 5 423 patients were included. The results of meta-analysis showed that there was no significant difference between the two therapy groups on the mortality. For the clinical treatment success rates, no significant differences between the two groups were found based on the data of intention-to-treat (ITT) and per-protocol (PP) analyses. However, respiratory fluoroquinolones monotherapy was associated with higher clinical treatment success rates based on the data that it was unclear whether ITT or PP analysis was used (RR=1.08, 95% CI 1.01 to 1.18, P=0.02), especially in Asians (RR=1.10, 95%CI 1.02 to 1.18, P=0.01). Additionally, respiratory fluoroquinolones monotherapy was associated with less adverse events (RR=0.81, 95%CI 0.73 to 0.90, P<0.000 1), especially in Caucasians (RR=0.64, 95%CI 0.36 to 1.14, P=0.13). ConclusionCurrent evidence shows that the efficacy of respiratory fluoroquinolones monotherapy may be similar to β-lactams plus macrolides combination treatment for non-ICU hospitalized CAP patients. Since the limitation of quantity and quality of included studies, large-scale high-quality RCTs are needed to verify the above conclusion.