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We developed a reflectance continuous-wave near-infrared spectroscopy topography system with multi-source and multi-detector sensor head. A single wavelength (808 nm) laser diode is used as the original light source. With different-measurement approach, we can reconstruct images representing the variety of cerebral blood volume in clinical applications. Phantom experiments have been taken to verify...
Congenital heart defect is a leading cause of children mortality. Two-dimensional echocardiography is a safe and noninvasive diagnostic tool and two-dimensional images can be reconstructed to a three-dimensional model. However, for some complex congenital heart diseases, the visualization of three-dimensional cardiac tissue structure alone is not enough. Visualization of blood flow patterns in a human...
Blood oxygenation level dependent (BOLD) functional MRI and near infrared optical tomography have been widely used to investigate hemodynamic responses to functional stimulation in the human brain. In this paper, we present a complete methodology for integrating the two imaging modalities to study the underlying physiological mechanism of the hemodynamic response in primary visual cortex. Using a...
Parallel imaging using multiple phased-array coils and receiver channels has become an effective approach to high-speed magnetic resonance imaging (MRI). To obtain high spatiotemporal resolution, the k-space is subsampled and later interpolated using multiple channel data. Higher subsampling factors result in faster image acquisition. However, the subsampling factors are upper-bounded by the number...
Most technologies for tissue elasticity imaging are now based on measurement of stain distribution, since they are more suited to real-time processing than reconstruction of elastic modulus images. However, to obtain more quantitative information about tissue elastic properties, it is necessary to reconstruct tissue elastic modulus images. There, we developed a new method for reconstructing tissue...
As a differential diagnosis technique of living soft tissues, we are developing ultrasonic strain measurement-based shear modulus reconstruction methods. Previously, we reported a method utilizing the typical value of Poisson's ratio. However, as reconstruction errors were confirmed due to the difference between the original value and the set value, we proposed a method to reconstruct Poisson's ratio...
The approach to solve the inverse problem of electrocardiography presented here is using a computer model of the individual heart of a patient. It is based on a 3D-MRI dataset. Electrophysiologically important tissue classes are incorporated using rules. Source distributions inside the heart are simulated using a cellular automaton. Finite element method is used to calculate the corresponding body...
This paper derives and implements a method for recovering MRI signal losses caused by susceptibility-induced magnetic field gradients (SFGs) in regions with large static field inhomogeneities in echo-planar imaging (EPI). Factor to account for SFGs was added in a traditional EPI equation, which was a simple Fourier transform (FT) for expressing the actual k-space data of an EPI scan. The inverse calculation...
Parallel imaging using multiple receiver coils has emerged as an effective tool to reduce imaging time in various MRI applications. Although several different image reconstruction methods have been developed and demonstrated to be successful for Cartesian k-space trajectories, there is a lack of efficient reconstruction methods for arbitrary trajectories. In this paper, we formulate the reconstruction...
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...
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...
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...
Parallel magnetic resonance imaging (MRI) using multi-channel receiver coils has emerged as an effective tool to reduce imaging time in various MRI applications. However, there are still a number of image reconstruction issues that have not been fully addressed, thereby limited the level of speed enhancement achievable with the technology. This paper reformulates the image reconstruction problem as...
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...
The advent of partially parallel k-space data acquisition and reconstruction techniques has resulted in a drastic reduction in acquisition time. In this work, we have shown that the use of a new hybrid technique for reconstruction of partial k-space data can reduce acquisition time without loss of spatiotemporal resolution. The technique is termed hybrid k-t GRAPPA since it is a combination of k-t...
We investigated the source localization performance of the Laplacian weighted minimum norm (LWMN) estimate technique in a realistic geometry (RG) head model in the present study. We simulated current sources at different brain regions with various noise levels. The present results show there is no obvious depth dependency on the three-dimensional (3D) source estimation. The average source localization...
A new cryosection milling imaging system with high spatial resolution is developed to screen small laboratory animals such as mice and rats. The system hardware consists of cutting device, image capture and photography device, refrigerated storage and parallel data processing system. By this system high spatial resolution (no less than 20 mum) small laboratory animal atlas can be achieved. After image...
Fluorescence optical diffusion tomography (FODT) is considered as one of the most promising ways for non-invasive molecular-based imaging. Many reconstructed approaches to FODT utilize iterative methods for data inversion. However, they are regarded as being time-consuming and far from meeting the real-time imaging requests. In this work, a fast pre-iteration algorithm based on the generalized inverse...
In electrical impedance tomography (EIT), distribution of internal resistivity of an unknown object is estimated using measured boundary voltage induced by different current patterns. In this paper singular value decomposition is modified with a threshold to be used in the sensitivity theorem for reconstruction of EIT images. Two different parameters are added to the singular values according to a...
An image monitoring system using electrical impedance tomography (EIT) for intraperitoneal bleeding was designed (FMMU V3.5). It consists of a constant current driving source with frequency of 50 KHz, a high accuracy measurement module, a driving and measuring mode program-controlled circuits, a data acquisition card, an optoelectronic isolated digital I/O board, and a custom-specified linear power...
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