Search results for "Lumen"
showing 10 items of 149 documents
Functional Morphology of Human Arteries During Fetal and Postnatal Development
1980
The equilibrium between the distending force of the blood pressure and the arterial wall is determined essentially by a simple law of mechanics, the law of Laplace. According to this law, the total force or tension (T) in the vessel’s wall represents the product of the radius of the vessel (r) and the blood pressure (p), T = r.p. The law of Laplace may be used to estimate and compare the tension produced by blood pressure in vessels of different size and thereby determine the increase in functional load on arteries. Since tension increases not only with blood pressure but also with the radius of the vessel, the highest tension is presumably produced in the wall of the ascending aorta where …
Non-invasive visualisation of coronary atherosclerosis: state-of-art.
2007
Coronary artery disease remains the leading cause of death in the Western world. Non-invasive coronary artery imaging challenges any diagnostic modality because the coronary arteries are small and tortuous, whereas cardiac contraction and respiration cause motion artifacts. Therefore, non-invasive coronary imaging requires high spatial and temporal resolution. This review discusses the feasible applications in coronary imaging of magnetic resonance imaging and multi-slice computed tomography (MSCT), which are currently the only non-invasive diagnostic modalities for direct coronary atherosclerosis imaging. Particular attention and focus is devoted to the potential indications and clinical i…
The Association Between Quantitative Flow Ratio and Intravascular Imaging-defined Vulnerable Plaque Characteristics in Patients With Stable Angina an…
2021
Background: This study aimed to examine whether quantitative flow ratio (QFR), an angiography-based computation of fractional flow reserve, was associated with intravascular imaging-defined vulnerable plaque features, such as thin cap fibroatheroma (TCFA) in patients with stable angina, and non-ST-segment elevation acute coronary syndrome.Methods: Patients undergoing optical coherence tomography (OCT) or intravascular ultrasound (IVUS) examinations were identified from two prospective studies and their interrogated vessels were assessed with QFR. Lesions in the OCT cohort were classified into tertiles: QFR-T1 (QFR ≤ 0.85), QFR-T2 (0.85 < QFR ≤ 0.93), and QFR-T3 (QFR > 0.93). L…
Possible reason for preferential damage to renal tubular epithelial cells evoked by amphotericin B
1996
An important determinant of nephrotoxicity, which is the major complication of long-term amphotericin B treatment, is dysfunction of distal tubular epithelial cells. The underlying cause for this rather selective damage to the cells is unknown. In the present investigation, it was shown that kidney epithelial cells were initially damaged by amphotericin B at concentrations of 2.5 to 10 micrograms/ml, as demonstrable by a dramatic drop in cellular K+ levels. Cells could recover from the initial toxic action of the polyene if they were kept in medium of neutral pH, and cellular K+ levels returned to normal after 6 h. However, the recovery mechanisms failed at lower pHs of 5.6 to 6.0. At low p…
Comparison between Two Different Two-Stage Transperineal Approaches to Treat Urethral Strictures or Bladder Neck Contracture Associated with Severe U…
2012
Introduction.The recurrence of urethral/bladder neck stricture after multiple endoscopic procedures is a rare complication that can follow prostatic surgery and its treatment is still controversial.Material and Methods.We retrospectively analyzed our data on 17 patients, operated between September 2001 and January 2010, who presented severe urinary incontinence and urethral/bladder neck stricture after prostatic surgery and failure of at least four conservative endoscopic treatments. Six patients underwent a transperineal urethrovesical anastomosis and 11 patients a combined transperineal suprapubical (endoscopic) urethrovesical anastomosis. After six months the patients that presented comp…
Perkutan transhepatische Feinkaliber-Cholangioskopie
1988
Percutaneous transhepatic fine calibre cholangioscopy is described. A specially developed transparent instrument is used, which makes it unnecessary to have a steerable endoscope; visualisation of the biliary tree is of diagnostic value for assessing biliary stenoses due to tumours (choice of biopsy site, extent of intraductal radiation therapy) and for the assessment of anastomoses between the biliary system and the gut (condition of the mucosa, stenoses). In the presence of percutaneous biliary drainage, the method has little utility. Extension of the method for treating intraductal stones may be possible if in future a useful lumen can be added to the fine endoscope.
Dual lumen microcatheters for recanalisation of chronic total occlusions: A EuroCTO Club expert panel report
2021
Dual lumen microcatheters (DLMC) have become indispensable tools in the setting of percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). Other than allowing preservation and treatment of bifurcated coronary branches within or in the proximity of the CTO-body, they enable the use of modified parallel wiring, antegrade dissection and re-entry, collateral selection and retrograde negotiation of the distal CTO-cap. This Euro-CTO consensus document describes current DLMCs and suggests a practical guide to anatomies and techniques in which these devices are applicable.
Review of difficult airway management in thoracic surgery
2018
The management of difficult airway (DA) in thoracic surgery is more difficult due to the need for lung separation or isolation and frequent presence of associated upper and lower airway problems. We performed an article review analysing 818 papers published with clinical evidence indexed in Pubmed that allowed us to develop an algorithm. The best airway management in predicted DA is tracheal intubation and independent bronchial blockers guided by fibroscopy maintaining spontaneous ventilation. For unpredicted DA, the use of videolaryngoscopes is recommended initially, and adequate neuromuscular relaxation (rocuronium/sugammadex), among other maneuvers. In both cases, double lumen tubes shou…
Importance of calibration for diameter and area determination by intravascular ultrasound
1996
Intravascular ultrasound (IVUS) permits quantitative assessment of the lumen diameter and area of coronary arteries. The experimental study was performed to evaluate the accuracy of diameter and area measurements.Lumen quantitation (lumen diameter D and cross-sectional area A) in lucite tubes (lumen diameter 2.5 to 5.7 mm, Plexiglas) was performed using a mechanical IVUS system (HP console, 3.5 F catheter, Boston Scientific, 30 MHz). The influence of fluid type (blood, water and saline solution), fluid temperature (20 degrees C/37 degrees C), catheter to catheter variation, gain setting and ultrasound frequency (12, 20 and 30 MHz) was determined. In blood at 20 degrees C there was a constan…
Hepatic Sinusoidal Dilatation: A Review of Causes With Imaging-Pathologic Correlation.
2016
Hepatic sinusoids are vascular conduits connecting the portal triad with the central vein. Multiple conditions can lead to sinusoidal dilatation and congestion with resultant stasis of blood within the lumen. The altered hemodynamics associated with hepatic sinusoidal dilatation generally result in heterogeneous enhancement of the hepatic parenchyma on contrast-enhanced computed tomography and magnetic resonance imaging, a pattern often described as “mosaic” enhancement. In this article, we review the causes of hepatic sinusoidal dilatation and the imaging manifestations on contrast-enhanced computed tomography and magnetic resonance.