نتایج جستجو برای: Signal Intensity
تعداد نتایج: 582563 فیلتر نتایج به سال:
introduction contrast-enhanced fluid-attenuated inversion recovery (flair) is one of the mri sequences that can be used for detection and evaluation of pathological changes in the brain. in this work, we have studied the effect of different echo times (te) on the maximum relationship between signal intensity and concentration of the contrast agent using the flair sequence. materials and methods...
Background and Aims: Disc displacement is the most common temporomandibular joint disorder and magnetic resonance imaging (MRI) is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of magnetic resonance (MR). The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior ...
background: intervertebral disc herniation has two common types, extrusion and protrusion, which may affect the adjacent vertebrae.in addition, it is associated with significant signal changes in t1 mri (short tr/te) and t2 mri (long tr/te). methods: the present study is a cross-sectional analytic one, in which sampling was performed retrospectively. cases were randomly selected from the pati...
using a new numerical model, the pump-to-signal relative intensity noise (rin) transfer in singlepumpfiber optical parametric amplifiers for low modulation frequencies is investigated. the model includesfiber loss, pump depletion, as well as the gain saturation, and therefore, it can describe the practicalcircumstances associated with various applications of fiber optical parametric amplifiers....
The true MR signal intensity extracted from noisy MR magnitude images is biased with the Rician noise caused by noise rectification in the magnitude calculation for low intensity pixels. This noise is more problematic when a quantitative analysis is performed based on the magnitude images with low SNR(<3.0). In such cases, the received signal for both the real and imaginary components will fluc...
Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to det...
The patient was a nine-year-old girl with prolonged focal seizure admitted to the pediatric ward of Rasoul-e-Akram Hospital. The child seemed to be depressed, and in physical examination the only abnormal finding was pink discoid rashes on the cheeks. Brain Ct-Scan performed at the emergency department yielded no specific findings. In order to investigate the precise cause of focal seizure,...
Background: Intervertebral disc herniation has two common types, extrusion and protrusion, which may affect the adjacent vertebrae.In addition, it is associated with significant signal changes in T1 MRI (short TR/TE) and T2 MRI (long TR/TE). Methods: The present study is a cross-sectional analytic one, in which sampling was performed retrospectively. Cases were randomly selected from the pa...
background :inversion recovery (ir) pulse sequences can generate t1-weighted images with a different range of inversion time (ti) to suppress or null the signal intensity (si) for a specified tissue. in this study, we aimed to investigate the effect of ti values on the concentration of the contrast agent, which leads to a minimum signal intensity, using an inversion recovery t1-weighted 3-dimen...
background: since tumors located in thorax region of body mainly move due to respiration, in the modern radiotherapy, there have been many attempts such as; external markers, strain gage and spirometer represent for monitoring patients’ breathing signal. with the advent of fluoroscopy technique, indirect methods were proposed as an alternative approach to extract patients’ breathing signals. ma...
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