Search results for "Enos"
showing 10 items of 1576 documents
Determination of myocardial perfusion and coronary flow reserve by densitometric measurements: a selective classification of regions of interest
2002
To evaluate the functional effect of a coronary artery stenosis on the dependent myocardium, digitized coronary angiograms (DCAs) were recorded. The DCAs, acquired during heart catheterization, provide information about myocardial perfusion and coronary flow reserve of areas supplied by this coronary artery. For each analysis the myocardium is separated into different regions of interest (ROIs); 16 ROIs in the distribution of the LCA and 8 ROIs for the RCA. In addition to that, the ROIs of the diseased vessels are divided into ROIs which are proximal, within and distal to the stenosis. Using a semiautomatic procedure, densograms are constructed from which the parameter rise time is calculat…
Resting myocardial blood flow quantification using contrast-enhanced magnetic resonance imaging in the presence of stenosis: A computational fluid dy…
2015
Purpose: The extent to which atherosclerotic plaques affect contrast agent (CA) transport in the coronary arteries and, hence, quantification of myocardial blood flow (MBF) using magnetic resonance imaging (MRI) is unclear. The purpose of this work was to evaluate the influence of plaque induced stenosis both on CA transport and on the accuracy of MBF quantification. Methods: Computational fluid dynamics simulations in a high-detailed realistic vascular model were employed to investigate CA bolus transport in the coronary arteries. The impact of atherosclerosis was analyzed by inserting various medium- to high-grade stenoses in the vascular model. The influence of stenosis morphology was ex…
Polycythemia Vera as a Predisposing Factor for Aortic Stenosis: Prevalence and Correlation with Blood Cells Count and Mutational Status
2008
Abstract The association between Polycythemia Vera (PV) and thrombosis is multi-factorial involving the complex interaction between activated leukocytes, platelets and endothelium. Recent reports have postulated that PV patients may over express adhesive molecules on red cell surface, likely by JAK2 mutation (Wautier M et al. Blood.2007;110(3):894–901). This process activates endothelium with production of vascular growth factors and other mechanisms leading to atherosclerosis. Aortic Stenosis (AS) is the commonest valvular heart disease in western countries; its pathogenesis is mainly related to a degenerative process sharing many characteristics with atherosclerosis. At the present is not…
Messung des Gefäßdurchmessers zur Bestimmung von Stent- und Ballongröße bei perkutanen Eingriffen an der Beckenstrombahn
1995
AIM Should the sizes of balloons and stents used in the pelvic circulation be determined by the size of the ipsilateral or contralateral vessel? STUDY DESIGN The angiographic findings in 31 patients were analysed; in 10 an occlusion and in 21 a high grade stenosis (greater than 75%) of the common iliac artery had been treated by stenting (26) or simple PTA (5). RESULTS In 26 of the 31 patients there was marked reduction in the lumen distal to the lesion up to 40%. In 17 patients this was reversed immediately after the procedure and in five others the lumen increased but a difference between the two sides remained. The changes on the two sides following treatment were statistically significa…
Evaluation von Nierenarterienstenosen: Vergleich von Angiographie mit invasiver Blutdruckmessung und Doppler-Sonographie
2000
Ziel: Der bei einer Nierenarterien-Angioplastie angiographisch gemessene Stenosegrad soll mit dem transstenotischen Blutdruck-Gradienten und dem prainterventionellen dopplersonographischen Befund verglichen werden. Methoden: Anhand von insgesamt 46 Nierenarterienstenosen bei 35 Patienten mit renovaskularer Hypertonie werden die angiographisch-morphologischen Befunde („linearer”, „geometrischer” und „densitometrischer” Stenosegrad) mit der invasiven transstenotischen Blutdruckmessung und den prainterventionellen Doppler-Befunden verglichen. Ergebnisse: Alle angiographisch bestimmten Stenosegrade korrelieren - masig - mit den transstenotischen Druckgradienten (Korrelationskoeffizienten: 0,67 …
Diagnostik der trachealen Instabilität: Spiral-CT in Inspiration und Exspiration und respiratorische cine-CT∗
2000
ry Spiral CT and Cine CT. Purpose: In tracheo- and broncho-malacia, localization and determination of collapse is necessary for planning a surgical procedure. We compared inspiratory and spiral CT, cine CT, and bronchoscopy and evaluated the relevance of each method. Methods: Seventeen patients with suspected or verified tracheal stonosis or collapse underwent paired inspiratory and exspiratory spiral CT and cine CT during continuous respiration (temporal increment 100 ms). The tracheal cross-sectional area was calculated and compared. Results : In addition to bronchoscopy, further information concerning localization, extent, collapse, stability of the tracheal wall, distal portions of the …
Significance of ultrasound for the diagnosis of hypertrophic pyloric stenosis
1986
The sonographic features of hypertrophic pyloric stenosis (HPS) were evaluated in a 5-year prospective study (1981–1985) at the University Clinic of Pediatric Surgery in Mainz. In 37 cases real-time ultrasound was performed preoperatively to measure muscle thickness, diameter, and length of the pylorus; the recorded values were compared with those of a control group. Muscular wall thickness proved to be the most reliable parameter, while pyloric canal length was the most difficult measurement to obtain. Diameter alone was not adequate to establish the sonographic diagnosis, which depends on the individually and functionally different luminal width and submucosal thickness. Significant sonog…
[CT-angiography in carotid stenosis].
1997
Purpose: Prospective evaluation of the accuracy of CT angiography (CTA) with different postprocessing for extracranial carotid artery in comparison with DSA. Method: one hundred patients were studied with standarized CTA. For postprocessing, MPR, MIP, and 3D reconstruction based on segmentation with upper and lower threshold were used. Intravascular density profiles were considered. All CTA studies were correlated with intra-arterial angiography. The degree and classification of stenoses was determined using the guidelines established by the NASCET collaborators. Results: Measurement of stenosis was possible by MPR in 82.5 %, by MIP in 85 %, and 3D in 100 %. Correct classification was found…
Coronary plaque imaging with multislice computed tomography: technique and clinical applications.
2006
The composition of an atherosclerotic lesion, rather than solely the degree of stenosis, is considered to be an important determinant of acute coronary events. Whereas until recently only invasive techniques have been able to provide clues about plaque composition with consistent reproducibility, several recent studies have revealed the potential of multislice computed tomography (MSCT) for noninvasive plaque imaging. Coronary MSCT has the potential to detect coronary plaques and to characterize their composition based on the X-ray attenuating features of each structure. MSCT may also reveal the total plaque burden (calcified and noncalcified components) for individual patients with coronar…
Effects of Ciprostene on Restenosis Rate during Therapeutic Transluminal Coronary Angioplasty
1992
Ciprostene, a chemically stable prostacyclin analog was studied for its effects on restenosis in patients with coronary artery disease undergoing therapeutic percutaneous transluminal coronary angioplasty (PTCA). In a double-blind, randomized trial 32 patients were randomized to receive either ciprostene or the respective placebo. The infusion started intracoronarily at a rate of 40 ng/kg/min 20 min before introduction of the balloon catheter into the coronary artery. Thereafter infusion was continued intravenously for 36 hours at a rate of 120 ng/kg/min and a tapering off period until 48 hours. The quantitative analyses of the degree of coronary artery stenoses on the angiographic films be…