排序方式: 共有17条查询结果,搜索用时 15 毫秒
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Demir Sumeyra U Hakimzadeh Roya Hargraves Rosalyn Hobson Ward Kevin R Myer Eric V Najarian Kayvan 《BMC medical imaging》2012,12(1):1-13
Imaging of the human microcirculation in real-time has the potential to detect injuries and illnesses that disturb the microcirculation at earlier stages and may improve the efficacy of resuscitation. Despite advanced imaging techniques to monitor the microcirculation, there are currently no tools for the near real-time analysis of the videos produced by these imaging systems. An automated system tool that can extract microvasculature information and monitor changes in tissue perfusion quantitatively might be invaluable as a diagnostic and therapeutic endpoint for resuscitation. The experimental algorithm automatically extracts microvascular network and quantitatively measures changes in the microcirculation. There are two main parts in the algorithm: video processing and vessel segmentation. Microcirculatory videos are first stabilized in a video processing step to remove motion artifacts. In the vessel segmentation process, the microvascular network is extracted using multiple level thresholding and pixel verification techniques. Threshold levels are selected using histogram information of a set of training video recordings. Pixel-by-pixel differences are calculated throughout the frames to identify active blood vessels and capillaries with flow. Sublingual microcirculatory videos are recorded from anesthetized swine at baseline and during hemorrhage using a hand-held Side-stream Dark Field (SDF) imaging device to track changes in the microvasculature during hemorrhage. Automatically segmented vessels in the recordings are analyzed visually and the functional capillary density (FCD) values calculated by the algorithm are compared for both health baseline and hemorrhagic conditions. These results were compared to independently made FCD measurements using a well-known semi-automated method. Results of the fully automated algorithm demonstrated a significant decrease of FCD values. Similar, but more variable FCD values were calculated using a commercially available software program requiring manual editing. An entirely automated system for analyzing microcirculation videos to reduce human interaction and computation time is developed. The algorithm successfully stabilizes video recordings, segments blood vessels, identifies vessels without flow and calculates FCD in a fully automated process. The automated process provides an equal or better separation between healthy and hemorrhagic FCD values compared to currently available semi-automatic techniques. The proposed method shows promise for the quantitative measurement of changes occurring in microcirculation during injury. 相似文献
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Nazanin Hakimzadeh Hein J. Verberne Maria Siebes Jan J. Piek 《Current Cardiology Reviews》2014,10(1):73-86
In the event of obstructive coronary artery disease, collateral arteries have been deemed an alternative blood
source to preserve myocardial tissue perfusion and function. Monocytes play an important role in modulating this process,
by local secretion of growth factors and extracellular matrix degrading enzymes. Extensive efforts have focused on developing
compounds for augmenting the growth of collateral vessels (arteriogenesis). Nonetheless, clinical trials investigating
the therapeutic potential of these compounds resulted in disappointing outcomes. Previous studies focused on developing
compounds that stimulated collateral vessel growth by enhancing monocyte survival and activity. The limited success
of these compounds in clinical studies, led to a paradigm shift in arteriogenesis research. Recent studies have shown genetic
heterogeneity between CAD patients with sufficient and insufficient collateral vessels. The genetic predispositions in
patients with poorly developed collateral vessels include overexpression of arteriogenesis inhibiting signaling pathways.
New directions of arteriogenesis research focus on attempting to block such inhibitory pathways to ultimately promote arteriogenesis.
Methods to detect collateral vessel growth are also critical in realizing the therapeutic potential of newly developed
compounds. Traditional invasive measurements of intracoronary derived collateral flow index remain the gold
standard in quantifying functional capacity of collateral vessels. However, advancements made in hybrid diagnostic imaging
modalities will also prove to be advantageous in detecting the effects of pro-arteriogenic compounds. 相似文献
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