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Cheng B. Saw Ph.D. Hungcheng Chen M.S. Ron E. Beatty M.Engr. Henry Wagner Jr. M.D. 《Medical Dosimetry》2008,33(2):149-155
Image-guided radiation therapy (IGRT) relies on the quality of fused images to yield accurate and reproducible patient setup prior to dose delivery. The registration of 2 image datasets can be characterized as hardware-based or software-based image fusion. Hardware-based image fusion is performed by hybrid scanners that combine 2 distinct medical imaging modalities such as positron emission tomography (PET) and computed tomography (CT) into a single device. In hybrid scanners, the patient maintains the same position during both studies making the fusion of image data sets simple. However, it cannot perform temporal image registration where image datasets are acquired at different times. On the other hand, software-based image fusion technique can merge image datasets taken at different times or with different medical imaging modalities. Software-based image fusion can be performed either manually, using landmarks, or automatically. In the automatic image fusion method, the best fit is evaluated using mutual information coefficient. Manual image fusion is typically performed at dose planning and for patient setup prior to dose delivery for IGRT. The fusion of orthogonal live radiographic images taken prior to dose delivery to digitally reconstructed radiographs will be presented. Although manual image fusion has been routinely used, the use of fiducial markers has shortened the fusion time. Automated image fusion should be possible for IGRT because the image datasets are derived basically from the same imaging modality, resulting in further shortening the fusion time. The advantages and limitations of both hardware-based and software-based image fusion methodologies are discussed. 相似文献
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Micropipette aspiration of human platelets: influence of microtubules and actin filaments on deformability 总被引:6,自引:0,他引:6
The deformability of human platelets has been evaluated by micropipette aspiration. Control discoid platelets were about ten times as resistant to deformation in the micropipette as red blood cells. Under a constant negative pressure of 10 cm H2O, control platelets developed extension lengths of 0.74 +/- 0.1 micron. Prior treatment with vincristine, colchicine, or low temperature, all of which remove platelet microtubules, was associated with marked increases in lengths of aspirated segments. Taxol or heavy water, which stabilize microtubules, prevented the increased deformability caused by agents that dissolve microtubules. Cytochalasin B, an agent that inhibits assembly of actin microfilaments, also caused an increase in lengths of aspirated segments that could not be prevented by taxol. Vincristine and cytochalasin B, together, caused a greater increase in deformability than either agent alone. These results indicate important roles for microtubules and microfilaments in platelet deformability. 相似文献
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Ahmed N. Mahmoud Siva Sagar Taduru Amgad Mentias Dhruv Mahtta Amr F. Barakat Marwan Saad Akram Y. Elgendy Mohammad K. Mojadidi Mohamed Omer Ahmed Abuzaid Nayan Agarwal Islam Y. Elgendy R. David Anderson Jacqueline Saw 《JACC: Cardiovascular Interventions》2018,11(1):80-90
Objectives
The authors sought to determine the clinical characteristics and in-hospital survival of women presenting with acute myocardial infarction (AMI) and spontaneous coronary artery dissection (SCAD).Background
The clinical presentation and in-hospital survival of women with AMI and SCAD remains unclear.Methods
The National Inpatient Sample (2009 to 2014) was queried for all women with a primary diagnosis of AMI and concomitant SCAD. Iatrogenic coronary dissection was excluded. The main outcome was in-hospital mortality. Propensity score matching and multivariable logistic regression analyses were performed.Results
Among 752,352 eligible women with AMI, 7,347 had a SCAD diagnosis. Women with SCAD were younger (61.7 vs. 67.1 years of age) with less comorbidity. SCAD was associated with higher incidence of in-hospital mortality (6.8% vs. 3.4%). In SCAD patients, a decrease in in-hospital mortality was evident with time (11.4% in 2009 vs. 5.0% in 2014) and concurred with less percutaneous coronary intervention (PCI) (82.5% vs. 69.1%). Propensity score yielded 7,332 SCAD and 14,352 patients without SCAD. The odds ratio (OR) of in-hospital mortality remained higher with SCAD after propensity matching (OR: 1.87, 95% confidence interval [CI]: 1.65 to 2.11) and on multivariable regression analyses (OR: 2.41, 95% CI: 2.07 to 2.80). PCI was associated with higher mortality in SCAD patients presenting with non–ST-segment elevation myocardial infarction (OR: 2.01; 95% CI: 1.00 to 4.47), but not with STEMI (OR: 0.62; 95% CI: 0.41 to 0.96).Conclusions
Women presenting with AMI and SCAD appear to be at higher risk of in-hospital mortality. Lower rates of PCI were associated with improved survival, with evidence of worse outcomes when PCI was performed for SCAD in the setting of non with ST-segment elevation myocardial infarction. 相似文献997.
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Carolina Un Lam Chin-Ying Stephen Hsu Robert Yee David Koh Yung Seng Lee Mary Foong-Fong Chong Meijin Cai Kenneth Kwek Seang Mei Saw Keith Godfrey Peter Gluckman Yap Seng Chong 《Clinical oral investigations》2016,20(8):1871-1879