نتایج جستجو برای: partial volume effects

تعداد نتایج: 2012014  

2002
Mohammad-Reza Siadat Hamid Soltanian-Zadeh

This paper presents a new method for partial volume estimation using standard eigenimage method and B-splines. The proposed method is applied on the multi-parameter volumetric images such as MRI. The proposed approach uses the B-spline bases (kernels) to interpolate a continuous 2D surface or 3D density function for a sampled image dataset. It uses the Fourier domain to calculate the interpolat...

2011
Gustav Brolin Michael Ljungberg Katarina Sjögreen Gleisner

Introduction and aim: In SPECT imaging, the finite spatial resolution of the imaging system leads to a blurring of the reconstructed image. Consequently, counts originating from each point in the source distribution will be spread out over a volume in the reconstructed image, leading to spill-over of counts between different structures and distortion of the apparent activity concentration. This...

Journal: :Physics in medicine and biology 2008
John P Chiverton Kevin Wells

Tomographic biomedical images are commonly affected by an imaging artefact known as the partial volume (PV) effect. The PV effect produces voxels composed of a mixture of tissues in anatomical magnetic resonance imaging (MRI) data resulting in a continuity of these tissue classes. Anatomical MRI data typically consist of a number of contiguous regions of tissues or even contiguous regions of PV...

Journal: :PET clinics 2007
Olivier Rousset Arman Rahmim Abass Alavi Habib Zaidi

In the early days of PET, the partial volume effect (PVE) was identified as a serious factor affecting image quality and limiting the accuracy of quantitative analysis. Because of the limited spatial resolution of clinical PET systems, the images are blurred by the system response so that smaller objects appear larger. Although the total number of counts is preserved, they are distributed over ...

2008
Alejandro Sánchez Crespo

In this thesis, a two-dimensional pixel-wise deconvolution method for partial volume correction (PVC) for combined Positron Emission Tomography and Computer Tomography (PET/CT) imaging has been developed. The method is based on Van Cittert's deconvolution algorithm and includes a noise reduction method based on adaptive smoothing and median filters. Furthermore, a technique to take into account...

Journal: :international journal of aquatic biology 0
seyed hossein hoseinifar department of fisheries, gorgan university of agricultural sciences and natural resources, p.o.box: 336, gorgan, iran parviz zare msc. graduated student from gorgan university of agricultural science and natural resources, iran

in this study, partial and complete replacement of live food ( artemia nauplii) with a microdiet was investigated in post-larval indian white shrimp, fenneropenaeus indicus . post-larvae (pl 1 ) were stocked into nine 20-l vessels (5-l water volume) at a density of 50 l -1 . shrimp were fed six times a day over 10 days. at the end of the feeding period, there was no significant difference in qu...

2006
Seth HUTCHINSON

and key words In this paper, we present a new approach for segmenting regions of bone in MRI volumes using a deformable model . Our method takes into account the partial volume effects that occur with MRI data, thus permitting a precise segmentation of these bone regions . Partial volume is estimated, in a narrow band around the deformable model, at each iteration of the propagation of the mode...

Journal: :Magnetic resonance in medicine 2009
Tolga Cukur Jin H Lee Neal K Bangerter Brian A Hargreaves Dwight G Nishimura

Flow-independent angiography is a non-contrast-enhanced technique that can generate vessel contrast even with reduced blood flow in the lower extremities. A method is presented for producing these angiograms with magnetization-prepared balanced steady-state free precession (bSSFP). Because bSSFP yields bright fat signal, robust fat suppression is essential for detailed depiction of the vasculat...

Journal: :AJNR. American journal of neuroradiology 1984
D W Chakeres

The effects of partial volume averaging on computed tomographic images of temporal bone structures were evaluated. The models chosen for study included a cadaver stapes, two metallic prosthetic stapes, and a formalin-fixed temporal bone. The studies measured the changes in apparent dimension and Hounsfield units with incremental filling of voxels with metallic densities, changes in the angle of...

Journal: :Alzheimer's & dementia : the journal of the Alzheimer's Association 2015
Klaus H Maier-Hein Carl-Fredrik Westin Martha E Shenton Michael W Weiner Ashish Raj Philipp Thomann Ron Kikinis Bram Stieltjes Ofer Pasternak

BACKGROUND Brain atrophy in subjects with mild cognitive impairment (MCI) introduces partial volume effects, limiting the sensitivity of diffusion tensor imaging to white matter microstructural degeneration. Appropriate correction isolates microstructural effects in MCI that might be precursors of Alzheimer's disease (AD). METHODS Forty-eight participants (18 MCI, 15 AD, and 15 healthy contro...

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