Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and aco...Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and acoustic shadow are present A novel approach for hard plaque recognition and media-adventitia border detection of IVUS images is presented in this paper. The IVUS images were first enhanced by a spatial-frequency domain filter that was constructed by the directional filter and histogram equalization. Then, the hard plaque was recognized based on the intensity variation within different regions that were obtained using the k-means algorithm. In the next step, a cost matrix representing the probability of the media-adventitia border was generated by combining image gradient, plaque location and image intensity. A heuristic graph-searching was applied to find the media-adventitia border from the cost matrix.Experiment results showed that the accuracy of hard plaque recognition and media-adventitia border detection was 89.94% and 95.57%, respectively. In conclusion,using hard plaques recognition could improve media-adventitia border detection in IVUS images.展开更多
Enhance extemal counterpulsation （ECP） procedure has exhbited itself to be an effective therapy for the m anagem entof ischem ic card iovascu lar diseases, However, considering that EECP significantly increases the...Enhance extemal counterpulsation （ECP） procedure has exhbited itself to be an effective therapy for the m anagem entof ischem ic card iovascu lar diseases, However, considering that EECP significantly increases the acute diastolic pressure, whether it will intervene in the chronic progression of advanced plaque causing great concern in clilical applkation, but yet rein ains elusive presently. In the current paper, a flu id-structure interface （FSI） num erical model of artery with p iaque corn ponent w as developed based on in vivo hem odynam ic m easurem entperfotm ed h a porcine model, to caku late the m echanical stresses of the plaque before and during EECP, and h lum to assess the potential effects of long-term EECP treatm ent on plaque progression. The resu Its show that E E C P augm ented the wall shear stress （WSS） and plaque w all stress （PWS） over the card lac cycles, aswell as the spacial oscillatory of W SS （WSSG ）. Durhg EECP treatm ent, the PW S level respectively raised 6.82% and 6.07% in two simulation cases. The currentpilot study suggests that E E C P treatm entre ay p lay a positive effect on inh biting the conthued plaque progression by hcreashg the PW S level over the card iac cycles. Meanwhile, the plaque morphology should be taken into consideration while m aking patient- specific plan for Ion g- term E E C P treatment in clinic.展开更多
Bodies of plants are modularly organized. Development proceeds by adding new modules to open endings with a potential for branching. Each module is autonomous to some extent. Development relies on the self-organized p...Bodies of plants are modularly organized. Development proceeds by adding new modules to open endings with a potential for branching. Each module is autonomous to some extent. Development relies on the self-organized patterns that emerge from the interactions of individual modules. Interactions include both competition and cooperation,and several types of positive and negative feedback loops are involved. Development can be open to external influences, thus enabling the plant to adjust its form to the environment,for example, to the spatial distribution of ecological resources. This paper provides a review on adaptive plasticity in plants.展开更多
文摘Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and acoustic shadow are present A novel approach for hard plaque recognition and media-adventitia border detection of IVUS images is presented in this paper. The IVUS images were first enhanced by a spatial-frequency domain filter that was constructed by the directional filter and histogram equalization. Then, the hard plaque was recognized based on the intensity variation within different regions that were obtained using the k-means algorithm. In the next step, a cost matrix representing the probability of the media-adventitia border was generated by combining image gradient, plaque location and image intensity. A heuristic graph-searching was applied to find the media-adventitia border from the cost matrix.Experiment results showed that the accuracy of hard plaque recognition and media-adventitia border detection was 89.94% and 95.57%, respectively. In conclusion,using hard plaques recognition could improve media-adventitia border detection in IVUS images.
基金Key Clinical Project from the Ministry of Heatthgrant number:25400+1 种基金National Natural Science Foundation of Chinagrant number:81170272
文摘Enhance extemal counterpulsation （ECP） procedure has exhbited itself to be an effective therapy for the m anagem entof ischem ic card iovascu lar diseases, However, considering that EECP significantly increases the acute diastolic pressure, whether it will intervene in the chronic progression of advanced plaque causing great concern in clilical applkation, but yet rein ains elusive presently. In the current paper, a flu id-structure interface （FSI） num erical model of artery with p iaque corn ponent w as developed based on in vivo hem odynam ic m easurem entperfotm ed h a porcine model, to caku late the m echanical stresses of the plaque before and during EECP, and h lum to assess the potential effects of long-term EECP treatm ent on plaque progression. The resu Its show that E E C P augm ented the wall shear stress （WSS） and plaque w all stress （PWS） over the card lac cycles, aswell as the spacial oscillatory of W SS （WSSG ）. Durhg EECP treatm ent, the PW S level respectively raised 6.82% and 6.07% in two simulation cases. The currentpilot study suggests that E E C P treatm entre ay p lay a positive effect on inh biting the conthued plaque progression by hcreashg the PW S level over the card iac cycles. Meanwhile, the plaque morphology should be taken into consideration while m aking patient- specific plan for Ion g- term E E C P treatment in clinic.
基金This research was subsidized by the Hungarian National Research Fund(OTKA T35009,and NWOOTKA N34028),the Hungarian Ministry of Education(FKFP 0187/1990,Istvn Szchenyi Scolarship),and the International Program of the Santa Fe Institute,NM,USA.
文摘Bodies of plants are modularly organized. Development proceeds by adding new modules to open endings with a potential for branching. Each module is autonomous to some extent. Development relies on the self-organized patterns that emerge from the interactions of individual modules. Interactions include both competition and cooperation,and several types of positive and negative feedback loops are involved. Development can be open to external influences, thus enabling the plant to adjust its form to the environment,for example, to the spatial distribution of ecological resources. This paper provides a review on adaptive plasticity in plants.
