Search results for " angiography"

Atypical posterior circulation strokes: a case-based review of rare anatomical variations involved

2021

The circle of Willis is a very important vascular mechanism of protecting against cerebral ischemia, especially when circulation within the main arteries irrigating the brain is somehow impeded. As result of congenital malformation arising early in embryonic development, the fetal-type posterior circle of Willis remains as such during the rest of one's life. Consequently, the posterior cerebral artery (PCA) becomes a branch of the internal carotid artery (ICA), rather than of the basilar artery (BA). Furthermore, the rest of collateral circulation, between the anterior and the posterior regions of the brain, is also negatively affected (e.g., leptomeningeal vessels). The anatomical variant …

Optic pit syndrome

1986

In a study of 15 eyes with optic pits fluorescein angiography revealed that only pits associated with serous detachment of the macular retina showed fluorescence in the late venous phase, while the pits uncomplicated by detachment remained hypofluorescent throughout the test. This finding strongly supports the hypothesis that the subretinal fluid producing the macular detachment originates from leakage of vessels located in the floor of the pit. In addition a high incidence of anomalies was found to be associated with optic pits. Therefore the author suggests to call the association between optic pit and large optic disc, parapapillary chorioretinal changes, cilioretinal vessels, situs inve…

Tilted discs and central retinal vein occlusion.

1993

Area at Risk and Viability after Myocardial Ischemia and Reperfusion Can Be Determined by Contrast-Enhanced Cardiac Magnetic Resonance Imaging

2008

<i>Background/Aims:</i> Clinical differentiation between infarcted and viable myocardium in the ischemic area at risk is controversial. We investigated the potential of contrast-enhanced cardiac magnetic resonance imaging (ceCMRI) in determining the area at risk 24 h after ischemia. <i>Methods:</i> Myocardial ischemia was induced by percutaneous coronary intervention of the left anterior descending coronary artery in pigs. Coronary occlusion time was 30 min in group A, which caused little myocardial infarction and 45 min in group B, which led to irreversible damage. 24 h after reperfusion ceCMRI was performed at 2 and 15 min after administration of gadolinium-diethyl…

Assessment of coronary artery bypass grafts: value of different breath-hold MR imaging techniques.

1999

Our aim was to evaluate the patency of coronary artery bypass grafts and to detect graft stenosis using different breath-hold MR imaging techniques.Twenty-two patients with 59 grafts (14 internal mammary artery grafts and 45 saphenous vein grafts) and 76 distal anastomoses (singular and sequential grafts) were studied using a 1.5-T scanner. A two-dimensional T2-weighted breath-hold half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence and a three-dimensional breath-hold contrast-enhanced MR angiography sequence (fast imaging with steady-state free precession) were performed. For MR angiography, a bolus of 20 ml of gadopentetate dimeglumine was used. Time delay for contrast i…

Late gadolinium enhancement-cardiovascular magnetic resonance identifies coronary artery disease as the aetiology of left ventricular dysfunction in …

2009

Aims We evaluated the ability of late gadolinium enhancement (LGE) using cardiovascular magnetic resonance (CMR) to identify acute new-onset heart failure (HF) with left ventricular systolic dysfunction (LVSD), whether or not in relation to underlying coronary artery disease (CAD), in patients with no clinical evidence of associated ischaemic cardiomyopathy. Methods and results Hundred consecutive patients admitted with acute new-onset decompensated HF and EF ,40%, with no clinical or electrocardiographic data suggestive of CAD. The patients were classified according to the presence or absence of significant CAD (stenosis � 70% in at least one major vessel). Twenty-one patients (21%) had si…

Quantification of pulmonary blood flow (PBF): validation of perfusion MRI and nonlinear contrast agent (CA) dose correction with H(2)15O positron emi…

2009

Validation of quantification of pulmonary blood flow (PBF) with dynamic, contrast-enhanced MRI is still missing. A possible reason certainly lies in difficulties based on the nonlinear dependence of signal intensity (SI) from contrast agent (CA) concentration. Both aspects were addressed in this study. Nine healthy pigs were examined by first-pass perfusion MRI using gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and HO positron emission tomography (PET) imaging. Calculations of hemodynamic parameters were based on a one-compartment model (MR) and a two-compartment model (PET). Simulations showed a significant error when assuming a linear relation between MR SI and CA dose in the …

Irregular motion recovery in fluorescein angiograms

1997

Abstract Fluorescein angiography is a common procedure in ophthalmic practice, mainly to evaluate vascular retinopathies and choroidopathies from sequences of ocular fundus images. In order to compare the images, a reliable overlying is essential. This paper proposes some methods for the recovery of irregular motion in fluorescein angiograms (FA). The overlying is done by a three step procedure: detection of relevant points, matching points from different images and estimation of the assumed linear geometric transformation. A stochastic model (closely related to the general linear model) allows to fuse the second and third steps. Two different estimators of the geometric transformation are …

Relación entre exposición a corto plazo a dióxido de azufre atmosférico y lesiones obstructivas en el síndrome coronario agudo

2013

Resumen Fundamentos y objetivo Los contaminantes del aire urbano estan constituidos por una mezcla heterogenea de sustancias presentes en estado gaseoso y aerosoles. El objetivo del presente estudio fue comparar los efectos causados por la exposicion a contaminantes en fase gas y particulas atmosfericas en aire ambiente en pacientes que ingresan por un sindrome coronario agudo (SCA), en relacion con la presencia o no de lesiones obstructivas significativas (LOS) en arterias coronarias epicardicas. Pacientes y metodo Analizamos de forma prospectiva a un total de 2.110 pacientes con el diagnostico de SCA. Se determinaron las concentraciones medias de contaminantes en fase gas y particulas atm…

Prävention nach akutem Koronarsyndrom

2014

Das akute Koronarsyndrom hat eine erhohte Mortalitat auch im Verlauf nach erfolgreicher interventioneller Therapie. Entscheidend ist die Beurteilung, ob sich im Anschluss an das ACS eine Herzinsuffizienz entwickelt. In der Differenzierung des myokardialen Schadens als auch der Bestimmung des Verlustes an Funktion spielt die nichtinvasive Bildgebung eine besondere Bedeutung. Hinsichtlich der sekundaren Pravention richtet sich die nicht-medikamentose als auch medikamentose Therapie nach der myokardialen Funktion und dem Vorhandensein oder Fehlen einer Herzinsuffizienz. Ausdauerbelastung spielt bei den nicht-medikamentosen Masnahmen in der Rehabilitation je nach Schwere der Schadigung des Herz…