Search results for "CONTRAST"
showing 10 items of 1162 documents
Changes in Pupil Area during Low-energy Femtosecond Laser-assisted Cataract Surgery
2018
Purpose: To study the potential changes in pupil area within low-energy femtosecond-laser assisted cataract surgery (FLACS). Methods: A retrospective assessment of the pupil size was performed in the eyes undergoing FLACS using the Ziemer LDV Z8. We measured the pupil diameters as part of the images taken preoperatively and at the completion of laser pretreatment (after releasing the suction). We calculated the pupil area in 40 eyes of 40 patients (14 right and 26 left eyes). The mean ± standard deviation (SD) of age of the patients was 74 ± 7.4 years (range: 51-87). Paired t-test was used for statistical analyses. Subgroups were built with reference to age and preoperative pupil area (smal…
Detection of liver metastases in cancer patients with geographic fatty infiltration of the liver: the added value of contrast-enhanced sonography
2017
Purpose The aim of this study is to assess the role of contrast-enhanced ultrasonography (CEUS) in the detection of liver metastases in cancer patients with geographic liver fatty deposition on greyscale ultrasonography (US). Methods Thirty-seven consecutive cancer patients (24 women and 13 men; age, 33 to 80 years; mean, 58.1 years) with geographic liver fatty deposition, but without any detectable focal liver lesion on greyscale US, underwent sulphur hexafluoride-enhanced US. Two readers reported by consensus the presence, size, and location of any detected lesion. All patients underwent magnetic resonance imaging (MRI) as a confirmatory study. Sensitivity, specificity, positive and negat…
Advances in detection and characterization of atherosclerosis using contrast agents targeting the macrophage
2006
With advances in imaging technology and our understanding of the role of inflammation in atherosclerosis, the macrophage appears to be an excellent target for imaging the progression of disease. In addition to imaging the macrophage with only 1 modality, contrast agents can be created that can be imaged with multiple modalities. This seems extremely attractive, as lesion morphology and characteristics can be determined with modalities that provide high picture resolution, such as CT or MRI, whereas macrophage quantity can be accurately determined through the creation of a radiolabeled contrast agent such as FDG via PET. Although this combination of imaging technologies may yield clinically …
New frontiers in liver ultrasound: From mono to multi parametricity
2021
Modern liver ultrasonography (US) has become a "one-stop shop " able to provide not only anatomic and morphologic but also functional information about vascularity, stiffness and other various liver tissue properties. Modern US techniques allow a quantitative assessment of various liver diseases. US scanning is no more limited to the visualized plane, but three-dimensional, volumetric acquisition and consequent post-processing are also possible. Further, US scan can be consistently merged and visualized in real time with Computed Tomography and Magnetic Resonance Imaging examinations. Effective and safe microbubble-based contrast agents allow a real time, dynamic study of contrast kinetic f…
The use of contrast echocardiography: a matter of clinical judgement
2005
In their editorial, Buck and Erbel1 raise the important question in which settings application of contrast agents to an echocardiographic examination is appropriate. There is no doubt that the beauty of echocardiography relates to its ease of use. We should acknowledge that highest accuracy in the determination of left ventricular function is not necessary in most patients referred for an echocardiographic evaluation. Thus, contrast echocardiography will not be a technique to be used in all patients for mere evaluation of left ventricular function as cardiac magnetic resonance imaging will not be used in routine clinical practice only for its known superb accuracy. However, there are patien…
Analysis of Regional Left Ventricular Function by Cineventriculography, Cardiac Magnetic Resonance Imaging, and Unenhanced and Contrast-Enhanced Echo…
2006
OBJECTIVES To define the use of cineventriculography, cardiac magnetic resonance imaging (cMRI), and unenhanced and contrast-enhanced echocardiography for detection of left ventricular (LV) regional wall motion abnormalities (RWMA). BACKGROUND Detection of RWMA is integral to the evaluation of LV function. METHODS In 100 patients, cineventriculography and unenhanced and contrast-enhanced echocardiography were performed. Fifty-six of the patients underwent additional cMRI. RWMA were assessed referring to a 16-segment model for cMRI, unenhanced and contrast echocardiography. Cineventriculography was evaluated on a 7-segment model. Hypokinesia in one or more segments defined presence of RWMA. …
Focal liver lesions hyperintense on T1-weighted magnetic resonance images.
2009
This article reviews focal liver lesions hyperintense on T1-weighted magnetic resonance (MR) images and describes the underlying etiologies associated with their T1 signal intensity. Although focal liver lesions are commonly detected because of their iso- or hypointensity on T1-weighted images, lesions (benign or malignant) may present with T1 hyperintensity when they contain T1 shortening elements--such as fat, hemorrhage, copper, melanin, and highly concentrated proteins. Our discussion includes the description of state-of-the-art T1-weighted MR sequences and the imaging features of lesions on pre- and postcontrast MR images that are characteristic for lesion composition and useful for ma…
Lung ventilation- and perfusion-weighted Fourier decomposition magnetic resonance imaging: In vivo validation with hyperpolarized3He and dynamic cont…
2012
The purpose of this work was to validate ventilation-weighted (VW) and perfusion-weighted (QW) Fourier decomposition (FD) magnetic resonance imaging (MRI) with hyperpolarized (3)He MRI and dynamic contrast-enhanced perfusion (DCE) MRI in a controlled animal experiment. Three healthy pigs were studied on 1.5-T MR scanner. For FD MRI, the VW and QW images were obtained by postprocessing of time-resolved lung image sets. DCE acquisitions were performed immediately after contrast agent injection. (3)He MRI data were acquired following the administration of hyperpolarized helium and nitrogen mixture. After baseline MR scans, pulmonary embolism was artificially produced. FD MRI and DCE MRI perfus…
Assessment of Skeletal Muscle Microperfusion Using MRI
2013
Blood oxygenation level-dependent (BOLD) MRI, arterial spin labeling (ASL) and dynamic contrast enhancement (DCE) are current magnetic resonance imaging (MRI) techniques allowing the non-invasive functional assessment of peripheral microvasculature in healthy and diseased individuals. The functional imaging of skeletal muscle microvasculature helps to understand muscular and vascular physiology and alterations of microcirculation under certain pathological conditions such as peripheral arterial occlusive disease, diabetes mellitus, chronic compartment syndrome and rheumatic disorders. BOLD MRI uses blood as an endogenous contrast agent provided by the different magnetic properties of oxy- a…
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…