نتایج جستجو برای: misregistration artifact
تعداد نتایج: 19385 فیلتر نتایج به سال:
To evaluate the limitations of intravenous carotid digital subtraction angiography (DSA) in the diagnosis of carotid disease, studies of 130 patients were reviewed. Factors that resulted in a nondiagnostic study included: (1) misregistration larynx artifact overlying the carotid bifurcation; (2) external carotid or vertebral artery overlying the internal carotid artery; and (3) poor arterial co...
Introduction: Integration of single photon emission computed tomography (SPECT) and computed tomography (CT) scanners into SPECT/CT hybrid systems permit detection of coronary artery disease in myocardial perfusion imaging (MPI). Misregistration between CT and emission data can produce some errors in uptake value of SPECT images. The aim of this study was evaluate the influence...
Interleaved echo-planar imaging (EPI) is an ultrafast imaging technique important for applications that require high time resolution or short total acquisition times. Unfortunately, EPI is prone to significant ghosting artifacts, resulting primarily from system time delays that cause data matrix misregistration. In this work, it is shown mathematically and experimentally that system time delays...
Background T1 mapping of the left ventricle is routinely performed using Modified Look-Locker Inversion Recovery (MOLLI) [1] in a variety of disease settings [2]. MOLLI requires relatively long breathholds, and consequently sequences of MOLLI images may be misregistered due to respiratory drift. We sought to develop a T1 mapping sequence that would not require breathholding and would not have m...
Introduction Cardiac arrhythmias, whether ventricular or supraventricular, initially presented a challenge for coronary computed tomography angiography (CCTA) because they could result in motion artifact during image acquisition, increased acquisition times, and increased radiation dose. Cardiac motion and misregistration artifacts in a scan performed during premature ventricular contractions c...
Dynamic sequential computed tomographic scanning with automatic table incrementation uses low milliampere-second technique to eliminate tube cooling delays between scanning slices and, thus, markedly shortens examination times. A total of 25 patients with spinal column trauma involving 28 levels were studied with dynamic scans and retrospectively reviewed. Dynamic studies were considerably fast...
Image misregistration has become one of the significant bottlenecks for improving the accuracy of multisource data analysis, such as data fusion and change detection. In this paper, the effects of misregistration on the accuracy of remotely sensed change detection were systematically investigated and quantitatively evaluated. This simulation research focused on two interconnected components. In...
Spatial normalisation is a key element of statistical parametric mapping and related techniques for analysing cohort statistics on voxel arrays and surfaces. The normalisation process involves aligning each individual specimen to a template using some sort of registration algorithm. Any misregistration will result in data being mapped onto the template at the wrong location. At best, this will ...
Hyperspectral imaging sensors suffer from spectral and spatial misregistration. Optical-system aberrations and misalignments cause these artifacts mainly due to pushbroom systems, where crosstrack and spectral pixels are continuously recorded at the same time using a two-dimensional detector array. The spectral misregistration, also known as“ smile”or“ frown”curve, is a shift in wavelength in t...
Magnetic resonance (MR) imaging is finding an ever-growing role in the evaluation of a wide range of conditions in the abdomen. No longer confined to problem solving regarding abnormalities in solid organs, such as the liver and kidneys, MR imaging is increasingly being applied to the evaluation of the pancreatic and biliary ductal systems and even the bowel. Recent technical advances in hardwa...
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