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[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...
While focusing at accurate 3D joint kinematics, this paper explores the problem of how to perform a robust rigid registration for a sequence of object surfaces observed using standard 3D medical imaging techniques. Each object instance is assumed to give access to a polyhedral encoding of its boundary. We consider the case where object instances are noised with significant truncations and segmentation...
In order to study the biomechanical mechanism properties of intervertebral disc herniation, combining the CT and MRI data-based anatomical structure of spine. A three-dimensional geometric model of the lumber disk was constructed. Based on the geometric model, a three-dimensional finite element modeling (FEM) for biomechanical analysis has been created. The FEM will represents a promising tool in...
The aim of this study was to optimize MRI conventional protocols for BMD measurements using MR-relaxometry in systems not facilitated with special multi echo protocols. Since, cortical and trabecular bone separation can not be performed in DEXA, so the results might lead to erroneous interpretation of BMD values. One method for bone quality determination is MR relaxometry that derives R2(=1/T2), R2*(=1/T2*)...
The FEM geometry modeling of realistic head is a key issue for the research on FEM-based EEG/MEG. In this paper, a methodology is developed to construct this kind of model. By using this method, a five -layer realistic head FEM model is obtained, and with its application in FEM-based EEG, a satisfying result shows the reliability of the model
This paper presents the identification and the study of the impact of a real-time MRI-based propulsion and tracking system constraints on the step response using a discrete PID controller. A simplified model for such a system accounts for these constraints such as the time delay, the sampling period, and the blood velocity. This application is intended for minimally invasive operations within the...
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...
Large arrays of RF coils with 16 or more channels are becoming commercially available. However, most MR scanners have eight or fewer receiver channels. In order for these scanners to achieve the SNR benefits of these large arrays, the signals from the array elements must be combined. In this paper, strategies for combining the array elements into 8 or fewer channels are discussed and an analysis of...
Despite deformable models' wide applicability in medical image segmentation, they are sometimes not adequate by themselves to achieve a desired degree of automation, a guaranteed level of accuracy, or an outcome beyond segmentation. In such situations, other methods may be combined with a deformable model to extend its abilities, overcome its shortcomings or increase the assurance of the segmentation...
This paper presents a unified variational framework for seamlessly integrating prior segmentation information into non-rigid registration procedures. Under this framework, in addition to the forces arises from the similarity measure in seeking for detailed correspondence, another set of forces generated by the prior segmentation contours can provide an extra guidance in assisting the alignment process...
We are involved in a comprehensive program to characterize atherosclerotic disease using multiple MR images having different contrast mechanisms (T1W, T2W, PDW, magnetization transfer, etc.) of human carotid and animal model arteries. We use specially designed intravascular and surface array coils that give high signal-to-noise but suffer from sensitivity inhomogeneity and significant noise. We present...
PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) MRI, proposed by J. G. Pipe, offers a novel and effective means for compensating motion. For the reconstruction of PROPLLER data, algorithms to reliably and accurately extract inter-strip motion from data in central overlapped area are crucial to motion artifacts suppression. When implemented on T1-weighted MR...
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
One way to reduce receiving coil noise in MRI scans is using non-resistive high-temperature superconducting (HTS) coils. They show advantages of much lower cost and easier fabrication over HTS thin film coils. In this work, we built a 200 mm in diameter Bi2Sr2Ca2Cu3Ox (Bi-2223) tape HTS RF coil and demonstrated that the SNR of using the HTS tape coil was 2.22 folds higher than that of the traditional...
In this paper we present an improved segmentation algorithm that recursively explores various thresholding levels until it reaches a termination criteria. This segmentation algorithm is based on earlier work adapting Otsu's thresholding approach to myelinated bundles of axons in cortical tissue. Experimentation using over 120 images has confirmed that this termination criteria provides visibly acceptable...
Functional imaging has played a significant role in bettering our understanding of mechanisms of brain function and dysfunctions. We review recent research on electrophysiological neuroimaging, multimodal neuroimaging integrating functional MRI with EEG, and our development of magnetoacoustic tomography with magnetic induction for high resolution impedance imaging. Examples from research of our group...
MRI and image quantitation play an expanding role in modern drug research, because MRI offers high resolution and non-invasive ability, and provides excellent soft tissue contrast. Moreover, with development of effective image segmentation and analysis methods, in-vivo and serial tissue growth measurements could be assessed. In the study, MR image acquisition and analysis protocol were established...
In this work, a new concept in high field RF head coil design for MRI applications is presented. An 8-element phased array head coil operating at 4T is designed based on a hybrid method combining reciprocity theorem and inverse method. Both circularly or linearly polarized head coils can be designed. A FDTD/MOM calculation method is used to model the phased array head coil and to accurately calculate...
This paper presents potential medical applications that an untethered microdevice in the cardiovascular system could perform within an MRI system. Recent developments and continuing evolution in micro/nano fabrication and design techniques will enable the development of functional microdevices able to explore the cardiovascular system. The magnetic resonance submarine (MR-Sub) project is a first step...
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