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Photon emission computed tomography (SPECT) images suffer from poor resolution and low contrast, which make it difficult for physicians to put an accurate interpretation for diagnosis, in particular, early diagnosis. Although the Wiener filter is a simple and powerful tool to restore degraded images, the requirement for a priori information limits its application. In this paper, we present a new 3D...
[Gd(TTDA-BOM)]2- is a newly developed paramagnetic contrast agent. The ligand, TTDA-BOM, bears a benzyloxymethyl group so that the lipophilicity is increased. The water exchange rate for [Gd(TTDA-BOM)]2- is significantly higher than that of [Gd(DTPA)]2- and [Gd(BOPTA)]2-. In addition, the bound relaxivity of this Gd (III) complex has a remarkably high value with HSA. Therefore, it has potential to...
In magnetic resonance imaging (MRI), surface coils have the advantage of higher signal to noise ratio (SNR) but suffer from image inhomogeneity due to the non-uniform sensitivity profile. To remove bright spots caused by non-uniform sensitivity profiles, a gradient weighted smoothing method is discussed in this work. A partial differential equations (PDE) based model is applied for this locally adaptive...
The coil separation of phased-array coils is an important issue if a wide area of interest is to be imaged. An equivalent circuit of two circular-shaped coils was used to compute the optimal distance in a two phased-array coil. This circuit included the mutual inductance of two circular coils. An expression for the mutual inductance was derived and the resulting values included in the circuit. With...
Diffusion tensor magnetic resonance imaging (DTI) has the ability to provide non-invasive information on tissue microstructure not available in routine clinical MRI images. This includes information regarding the degree of anisotropy as well as the direction of the diffusion of water molecules within the tissues. Since white matter areas of the brain have an ordered structure (due to the myelination...
Arterial spin labeling (ASL) has been developed into a useful tool for measuring local tissue perfusion with magnetic resonance imaging (MRI). Velocity-selective ASL (VS-ASL) tags spins on a basis of flow velocity, instead of the spatial distribution that is commonly used by conventional ASL techniques. Using a 90deg-180deg-90deg radiofrequency pulse train in combination with flow-sensitive gradients,...
A new method for the propulsion of a spherical ferromagnetic device along a given path in a water filled phantom with no human interaction is presented using an 1.5 T magnetic resonance imaging (MRI) clinical system. A special real time loop is implemented and presented that feeds the scanner with the appropriate gradients amplitudes and directions based on a pre-determined path. This paper studies...
The diagnosis of cardiovascular disease requires precise assessment of both morphology and function of the heart. Currently, magnetic resonance imaging (MRI) provides a useful tool for accurate and reproducible assessment of regional function of the left ventricle noninvasively. MR tagging produces images of the heart that can be analyzed using harmonic phase (HARP) method to describe the regional...
This work presents the application of a quantitative magnetic resonance imaging (MRI) technique in stereotactic deep-brain neurosurgery planning procedures. The high spatial resolution T1 and T2 maps acquired using this imaging method have been normalized to the standard CJH-27 brain coordinate system and integrated into a neurosurgical visualization and navigation system to improve the accuracy...
Small animal imaging systems now allow researchers to non-invasively monitor the progression of diseases in living small animals and study the efficacy of drugs and treatment protocols. Magnetic resonance imaging (MRI) is an established imaging modality capable of obtaining high resolution anatomical images which are sensitive to blood volume, blood flow, and metabolic rate of oxygen. Optical tomography,...
One of the most common artifacts for echo planar imaging is the ghost artifact, typically overcome with the aid of a reference scan preceding the actual image acquisition. In this work, we describe an automated free-scan-reference method for reducing ghost artifact using image-based correction. The two dimensional Fourier transformation of an entire data of image matrix is used to reconstruct two...
An exact formula has been derived to calculate the required RF (B1) peak power for 2D arbitrary shape excitation in MRI with rectilinear K-space trajectory. An approximate formula has also been derived for spiral trajectory
In magnetic resonance imaging, multi-channel phased array coils enjoy a high signal to noise ratio (SNR) and better parallel imaging performance. But with the increase in number of channels, the reconstruction time and requirement for computer memory become inevitable problems. In this work, principle component analysis is applied to reduce the size of data and protect the performance of parallel...
In magnetic resonance imaging, a finite number of k-space data are often collected in order to decrease the acquisition time. The partial k-space data lead to the famous Gibbs ringing artifact with Fourier transform method. The Gegenbauer reconstruction method has been shown to effectively eliminate the Gibbs ringing artifact and restore high resolution. However, the disadvantages of using the Gegenbauer...
A natural magnetic resonance imaging (MRI) contrast based on the pulp of a fruit "Euterpe Oleracea", popularly known as Acai, was investigated. T1 and T2 contrasted images shown the effects of the contrast agent increasing the ability to visualize the contour of segments of the gastrointestinal tract
Dynamic contrast-enhanced (DCE) MR cardiac imaging has been recognized as a unique and powerful tool for assessing both cardiac functions and physiological conditions of the heart tissues (e.g., tissue rejection following heart transplantation). However, because of cardiac motion and the limited data acquisition speed of existing MRI techniques, it has been very difficult to acquire dynamic images...
The data from the Visible Human Project (VHP) and the Chinese Visible Human (CVH), which are the serially sectioned images of the entire cadaver, are being used to produce three-dimensional (3D) images and software. The purpose of our research, the Visible Korean Human (VKH), is to produce an enhanced version of the serially sectioned images of an entire cadaver that can be used to upgrade the 3D...
The goal of the project is to investigate new computational tools for understanding normal upper airway mechanics and the pathophysiology of obstructive sleep apnea (OSA), a disorder characterized by repetitive pharyngeal collapse and occlusion during sleep. To relate the airway mechanical parameters to anatomy, and explore the roles of primary muscle properties, airway shape and structure, a new...
In vivo small animal imaging provides a powerful tool for the study of a variety of diseases. Magnetic resonance imaging (MRI) has become an established technology for the assessment of therapies. In this study, we used high-resolution MRI to evaluate polycystic kidney disease (PKD) in transgenic mice. We used a customized mouse coil to acquire serial MR images from both wide-type and transgenic PKD...
Based on software radio theory, this paper focuses on researching a direct conversion structure for the radio frequency (RF) receiver front-end and tries to apply this flexible receiver front-end in MRI receiving system. In particular, we look at the conventional architecture of RF receiver front-ends of MRI; present architecture of a direct conversion for RF receiver front-end of MRI; outline the...
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