Latest simultaneous multi-slice (SMS) methods greatly benefit MR efficiency for recent studies using parallel imaging technique. However, these methods are limited by the requirement of array coils. The proposed Coherent Wideband method, which employs an extended field of view to separate multiple excited slices, can be applied to any existing MRI instrument, even those without array coils.
View Article and Find Full Text PDFJ Clin Sleep Med
October 2019
Study Objectives: Reliable sleep staging is difficult to obtain from home sleep testing for diagnosis of obstructive sleep apnea (OSA), especially when it is self-applied. Hence, the current study aimed to develop a single frontal electroencephalography-based automatic sleep staging system (ASSS).
Methods: The ASSS system was developed on a clinical dataset, with a high percentage of participants with OSA.
Rev Sci Instrum
April 2017
This study proposes a modified Shinnar-Le Roux method to synthesize the excitation radio frequency (RF) pulse for a 2D gradient echo (GRE) based simultaneous multi-slice (SMS) magnetic resonance imaging (MRI) with features of low specific absorption rate (SAR) and small out-of-slice ripple. This synthesis method for SMS RF pulses employs thinner slice bandwidth and lower multislice offset frequencies to reduce SAR values and adopts a weighted Parks-McClellan algorithm to reduce sidelobes. Formulas for estimating relative SAR values of the SMS pulses are also introduced.
View Article and Find Full Text PDFPurpose: In this study, single-frequency excitation wideband magnetic resonance imaging (MRI) (SE-WMRI) was proposed to obtain high-quality accelerated images by reducing phase-encoding steps while applying separation gradients.
Methods: A zig-zag k-space trajectory with reduced phase-encoding steps and an increased readout sampling rate was proposed. A unique gradient design with buffer intervals near the trajectory turns was employed to avoid undersampling and image artifacts.
Purpose: In this study multiple-frequency excitation wideband MRI (ME-WMRI), a technique designed to acquire simultaneously excited images without blurring was proposed.
Methods: ME-WMRI consists of (a) a coherent acquisition sequence that applies refocusing gradient during readout to mitigate signal dephasing, and (b) a signal enhancement procedure that further reduces image blurring. This two-step method was tested on phantom imaging andin vivo imaging with up to 3.
This paper presents hardware implementation of an efficient solution to recovering gray-scale data pixels of images that have undergone interpixel interference in holographic data storage systems. The adopted algorithm, called the turbo receiver using interference-aware dual-list (TRIDL) detection, enjoys benefits of low error rate performance and low complexity. To verify the functionality and feasibility, this paper implements TRIDL detection with some circuit design techniques such as resource sharing on a field-programmable gate array.
View Article and Find Full Text PDFThis paper presents an efficient solution to recovering data pixels of images that have undergone optical and electrical channel impairments in holographic data storage systems. The channel impairments considered include interpixel interference, three types of misalignment, and noise. The proposed misalignment-compensation scheme, consisting of realignment and rate conversion, can effectively eliminate misalignment with more than 84% reduction in additions and 74% reduction in multiplications.
View Article and Find Full Text PDFAnnu Int Conf IEEE Eng Med Biol Soc
May 2008
Whole-brain images were acquired with a 2X acceleration factor by using Simultaneous Multi-slice Acquisition (SMA). Utilizing a Sinc pulse modulated by cosine/sine functions combined with an extra gradient along the slice-selection direction during acquisition, we are able to take multiple magnetic resonance images of different slice simultaneously. 2-slice and 4-slice SMA experiments were also conducted to demonstrate the feasibility of this method; also a volumetric image of the phantom was taken, achieving an overall 3X acceleration.
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