Home About us Contact
|
Home About us Contact | ||
|
|
||
Vessel Segments (vessel + segment)
Selected AbstractsVolumetric flow mapping for microvascular networks by bimodality imaging with light microscope and laser doppler imagerMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2004Ying Sun Abstract A method was developed to produce a composite image of microvascular networks with grayscales proportional to volumetric flows. Velocities in arterioles and venules were assessed with a high-resolution laser Doppler imager (LDI). The vascular structures were quantified from the micrograph with a computerized vessel detection algorithm. After registering the detected vascular network with the LDI scan, volumetric flows were calculated along the centerlines of the vessels. In vivo data were obtained from the hamster cheek pouch in 6 studies. Flow continuity of the flow map was evaluated by comparing the main flow (Q) with the sum of branch flows (Qs), averaging over the respective vessel segments incident to each bifurcation. The method was reproducible across the 6 studies with the correlation coefficient (r) between Qs and Q ranging from 0.913 to 0.986. In all, over 20,000 flow estimates from 360 vessel segments (24,160 ,m in diameter) at 166 bifurcations were analyzed. With flow normalized between 0 and 1, the linear regression yielded: Qs = 1.03 Q + 0.006; r = 0.952, n = 166, P < 0.0005. The bimodality imaging method exploits a large amount of velocity and diameter data, and therefore should be useful for studying heterogeneous flows in the microvasculature. Microsc. Res. Tech. 65:130,138, 2004. © 2004 Wiley-Liss, Inc. [source] Bimodal Oscillation Frequencies of Blood Flow in the Inflammatory Colon MicrocirculationTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2009Akira Tsuda Abstract Rhythmic changes in blood flow direction have been described in the mucosal plexus of mice with acute colitis. In this report, we studied mice with acute colitis induced either by dextran sodium sulfate or by trinitrobenzenesulfonic acid. Both forms of colitis were associated with blood flow oscillations as documented by fluorescence intravital videomicroscopy. The complex oscillation patterns suggested more than one mechanism for these changes in blood flow. By tracking fluorescent nanoparticles in the inflamed mucosal plexus, we identified two forms of blood flow oscillations within the inflammatory mouse colon. Stable oscillations were associated with a base frequency of approximately 2 cycles/sec. Velocity measurements in the upstream and downstream vessel segments indicated that stable oscillations were the result of regional flow occlusion within the mucosal plexus. In contrast, metastable oscillations demonstrated a lower frequency (0.2,0.4 cycles/sec) and appeared to be the result of flow dynamics in vessels linked by the bridging mucosal vessels. These blood flow oscillations were not directly associated with cardiopulmonary movement. We conclude that both the stable and metasable oscillating patterns reflect flow adaptations to inflammatory changes in the mucosal plexus. Anat Rec, 2009. © 2008 Wiley-Liss, Inc. [source] Clinical assessment of a new real time 3D quantitative coronary angiography system: Evaluation in stented vessel segmentsCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2006Rainer Gradaus MD Abstract Background: Foreshortening is a recognized problem that is present in angiography and results from views that are not perpendicular to coronary lesions. This limits visual coronary analysis as well as 2D quantitative coronary angiography systems (QCA). The CardiOp-B System® is a 3D image acquisition and processing software system designed as an add-on to conventional X-ray angiography system. CardiOp-B's features include real time and off line analysis with comprehensive 3D reconstruction integrating all of the available information of two 2D vessel angiographies into one 3D image. It was the aim of the study to analyze the accuracy of this new 3D QCA system. Methods: 3D QCA was performed in 50 patients (age 64 ± 10.9; 84% male; LV-EF 63 ± 16%) measuring 61 stents during high-pressure inflation (diameter: 2.25,4 mm; length: 8,32 mm). The obtained values (proximal and distal stent diameter, stent length) were correlated with the predefined size of the stents at the used inflation pressure. Results: The linear correlation for the proximal stent diameter was Stentprox= 0.03 + 0.93 × real stent size (r2 = 0.85). The linear correlation for the distal stent diameter was Stentdistal= ,0.03 + 0.89 × real stent size (r2 = 0.81). The linear correlation for the stent length was Stentlength= ,0.61 + 1.02 × real stent length (r2 = 0.98). Conclusions: The CardiOp-B System® is a new 3D QCA system with a high linear correlation between the real vessel size and the obtained vessel dimension. It provides real time or off line accurate and comprehensive diagnostic information to the interventional cardiologist without changing the basic coronary angiography procedure. © 2006 Wiley-Liss, Inc. [source] 2325: Dynamic retinal vessel analysis , how different parameters create the whole pictureACTA OPHTHALMOLOGICA, Issue 2010I LANZL Purpose Dynamic vessel analysis is usually associated with the observation of the reaction of retinal vessels to a defined stimulus. The data which is generated this way may be further analysed with respect to the dynamic unstimulated and stimulated vessel behaviour. Assessment of different parameters may highlight different aspects of the underlying disease. Methods Vessel diameters of retinal vessel segments were assessed by Dynamic Vessel Analyzer (DVA) in healthy volunteers of different age groups and patients with diabetes, glaucoma and systemic hypertension. Mathematical analysis of unstimulated vessels was used to describe vessel wall characteristics. Methods of signal analysis including Fourier Transformation, spectral filtration, auto- and cross correlation were applied to evaluate characteristic oscillations and pulse wave propagation along the vessel. Results Characteristic different vessel behaviour and vessel wall conformation are obtained by dynamic quantitative evaluations from the unstimulated vessels in physiologic aging and disease. Conclusion Dynamic vessel analysis includes information which may lead to further understanding of the vascular status and underlying disease pathology. It is also feasible to assess pulse wave velocities in retinal arterioles und thus clinically characterize the elasticity of the upstream vasculature in health and disease. [source] Does internal longitudinal microstructure of retinal veins change with age in medically healthy persons?ACTA OPHTHALMOLOGICA, Issue 2009KE KOTLIAR Purpose We demonstrated previously that roughness of the retinal arterial blood column measured along the vessel axis, termed longitudinal arterial profile (LAP) increases significantly in anamnesticly healthy volunteers with increasing age. Recently we have demonstrated age related changes in LAP of medically healthy persons. Whether longitudinal retinal venous profiles (LVP) are altered with age in this group is investigated. Methods 83 medically healthy volunteers were examined by Dynamic Vessel Analyzer (IMEDOS, Jena, Germany) using stimulation with flickering light. 3 age groups were formed: young (N=28, 30,2±4,3 years), middle age (N=28, 42,3±3,3 years) and seniors (N=27, 64,0±5,0 years). Included in the analysis were volunteers without medical vascular risk factors defined as: blood pressure < 140/90 mmHg, HDL > 35 mg/dl, LDL < 190 mg/dl and glucose levels < 110 mg/dl. Retinal venous diameters were measured along 1 mm vessel segments to obtain LVP. Differences were analyzed using Fourier transformation. Results In all age groups power spectra of LVP do not change during all stages of the venous response to the stimulation. There were no significant differences in LVP between the age groups. Venous diameters in middle-age group were reduced in comparison to the young group at all stages of vessel reaction (p<0,05). Conclusion Our results indicate that in contrast to retinal arteries retinal veins of validated healthy volunteers do not undergo age related microstructural changes. Hence previously reported age related decrease of retinal venous diameter might have physiologic origin due to reduced blood flow in retinal microcirculation with age, not because of structural changes of venous wall. [source] Microstructural alterations of the retinal arterial blood column along the vessel axis in healthy volunteers with ageACTA OPHTHALMOLOGICA, Issue 2009IM LANZL Purpose We demonstrated previously that roughness of the retinal arterial blood column measured along the vessel axis increases in anamnestically healthy volunteers with increasing age. We termed it longitudinal retinal arterial profile (LAP). Whether LAP is altered with age in medically supervised healthy persons is investigated. Methods 82 medically healthy volunteers were examined by Dynamic Vessel Analyzer (IMEDOS, Jena, Germany) using stimulation with flickering light. 3 age groups were formed: young (N=27, 30,5±4,3 years), middle age (N=28, 42,3±3,3 years) and seniors (N=27, 64,0±5,0 years). Included in the analysis were volunteers without medical vascular risk factors defined as: blood pressure < 140/90 mmHg, HDL > 35 mg/dl, LDL < 190 mg/dl and glucose levels < 110 mg/dl. Retinal arterial diameters were measured along 1 mm vessel segments to obtain LAP. Differences were analyzed using Fourier transformation. Results In all age groups LAP do not change during all stages of the arterial response. Arterial diameters in the senior group were reduced in comparison to the young group at all stages of the vessel reaction (p<0,05). There are differences in LAP between the age groups. Compared to young persons, seniors showed significantly diminished waves with a period of 417 µm at all stages of the arterial reaction, whereas young volunteers showed less pronounced waves with a period of 208 µm (p<0,05). Conclusion Our results represent the healthy aging process in retinal vasculature. Age related microstructural changes in longitudinal profiles of retinal arteries in medically healthy persons might be an indication for alterations in the vascular endothelium and smooth musculature. [source] | ||||||||||