نتایج جستجو برای: filtered backprojection contrast to noise ratio
تعداد نتایج: 10727429 فیلتر نتایج به سال:
conclusion various filters are needed to improve the image quality. in this study, seven different filters were implemented and investigated on both noisy and noise-free images. background developmental dysplasia of the hip (ddh) can be detected with ultrasonography (usg) images. however, the accuracy of this method is dependent on the skill of the radiologist. radiologists measure the hip join...
Iterative image reconstruction with the total-variation (TV) constraint has become an active research area in recent years, especially in x-ray CT and MRI. Based on Green's one-step-late algorithm, this paper develops a transmission noise weighted iterative algorithm with a TV prior. This paper compares the reconstructions from this iterative TV algorithm with reconstructions from our previousl...
UNLABELLED The high-resolution research tomograph (HRRT) is a dedicated human brain PET scanner. At present, iterative reconstruction methods are preferred for reconstructing HRRT studies. However, these iterative reconstruction algorithms show bias in short-duration frames. New algorithms such as the shifted Poisson ordered-subsets expectation maximization (SP-OSEM) and ordered-subsets weighte...
Contrast-enhanced MR angiography (CE-MRA) using steady-state free precession (SSFP) pulse sequences is described. Using SSFP, vascular structures can be visualized with high signal-to-noise ratio (SNR) at a substantial (delay) time after the initial arterial pass of contrast media. The peak blood SSFP signal was diminished by <20% 30 min after the initial administration of 0.2 mmol/kg of Gd-che...
A technique for rapid in-plane phase-contrast imaging with high signal-to-noise ratio (SNR) is described. Velocity-encoding is achieved by oscillating the readout gradient, such that each 2DFT phase-encode is acquired three times following a single RF slice-selective excitation. Three images are reconstructed, from which both flow velocity and local resonance offset are calculated. This techniq...
bstract. We present an adaptive contrast enhancement method ased on the generalized histogram, which is obtained by relaxing he restriction of using the integer count. For each pixel, the integer ount 1 allocated to a pixel is split into the fractional count and the emainder count. The generalized histogram is generated by accuulating the fractional count for each intensity level and distributi...
In the brain, results have been shown at 7T that are not achievable at lower field strengths. Cardiac imaging at 7T offers similar headline benefits to those images of the brain. More field strength gives more SNR, added to which more field strength increases the T1 and hence increases the effect of contrast agents. This simple idea is appealing in a grant application, but in reality 7T has som...
Introduction Quantitative susceptibility mapping (QSM) is a new contrast mechanism in magnetic resonance imaging (MRI). The images produced by the QSM enable researchers and clinicians to easily localize specific structures of the brain, such as deep brain nuclei. These nuclei are targets in many clinical applications and therefore their easy localization is a must. In this study, we aimed to i...
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