In this article, an introduction is given on the structure of RF subsystem, its main parameters and impact on the performance of MRI and RF techniques and its development. Furthermore, pivotal parameters provided by different suppliers are quoted and compared in functionality aspect.
Magnetic Resonance Imaging ; instrumentation ; methods ; Radio Waves

Calculation methods of coil sensitivity in parallel MRI were elaborated, compared and analyzed.
Algorithms ; Magnetic Resonance Imaging ; instrumentation ; methods

To optimize the configuration of the conventional SE and FSE sequence parameters in low field MRI. With the combination of larger vision, relatively thinner slice thickness, small number of excitation (NEX = 1 or 2), the signal-to-noise ration and the spatial resolution on follow-up images are moderate, the scan time is significantly shorter along with fewer motion artifacts, the check success rate is improved.
Equipment Design ; Magnetic Resonance Imaging ; instrumentation ; methods

Grounding technique is very important to ensure the human safety, imaging devices' safety and the devices' reliable running. This paper expatriates the principles of the grounding safety, interference rejection earth, and the grounding modes and the mode selection for each imaging devices and equipments, and related grounding requirements.
Equipment Safety ; methods ; Magnetic Resonance Imaging ; instrumentation

It has been several decades since the Magnetic Resonance Imaging was introduced to the public as a measure of clinical imaging diagnosis in the 1980's. Time has witnessed increasingly advanced structure and imaging technique. Now, fiber is used as the media to transmit signals of MRI. Manufacturers are competing to release new and creative imaging technique to customers, which has made it faster, more accurate and more convenient for MR imaging. This article briefly introduces latest MR devices with fiber transmission and summarizes their hardwares and softwares so as to provide reference to hospitals that will purchase these devices.
Magnetic Resonance Imaging ; instrumentation ; methods ; Software

A mechanical shimming method and device for permanent magnet of MRI system has been developed to meet its stringent homogeneity requirement without time-consuming passive shimming on site, installation and adjustment efficiency has been increased.
Magnetic Resonance Imaging ; instrumentation ; methods ; Magnets

With the development of magnetic resonance (MR) technology, the concern is focused on molecular and physiological imaging besides structural information. Ultra high field MR scanner shows great superiority. 3. 0-T MR scanners provide almost two-fold signal-to-noise ratio (SNR) compared with a standard 1. 5-T MR scanner. The higher baseline SNR can be converted into a variety of alternative benefits. There are still some other changes brought about by 3. 0-T, such as higher sensitivity to motion, susceptibility effect, more difference in resonant frequency among different metabolites, and so on. These features may be a double-edged sword in structural and functional imaging. But with the ceaseless progress of the technology and gains in experience, 3. 0-T systems will provide more information and show more advantages.
Animals ; Humans ; Image Enhancement ; methods ; Magnetic Resonance Imaging ; instrumentation ; methods ; Magnetic Resonance Spectroscopy ; instrumentation ; Sensitivity and Specificity

Traditional manual shimming measures and records data by highly accurate Tesla meters, then analyzes the data and puts small shimming magnet pieces to those are needed, and finally completes the shimming by repeating the above mentioned process. Because using Tesla meter to measure and record data takes much time, the efficiency of manual shimming is quite low. This article puts up an assisting way to shimming by using medical MRI shimming software designed and realized based on COM communications, thus enhances shimming efficiency greatly.
Magnetic Resonance Imaging ; instrumentation ; methods ; Magnets ; Software ; Software Design

In this paper, ACR single image method and NEMA dual-image method were measured SNR using two types of phased-array coils. The correlation equation of the two methods was obtained and substitutability of two methods was analyzed. The results showed that the two methods are replaceable in the evaluation of coils, but the later method gets higher SNR than the first method because structure noise is eliminated.
Algorithms ; Magnetic Resonance Imaging ; instrumentation ; methods ; Signal-To-Noise Ratio

Imaging objects are spatially encoded by gradient magnetic fields in magnetic resonance imaging systems. The eddy current caused by rapid switches of gradient fields will result in artifacts in the images. A method of eddy current compensation based on pre-emphasis of gradient current is presented in this thesis. The compensation parameters are acquired rapidly utilizing Faraday's induction theorem and data fitting method. The experiments prove that the method is efficient for reduction of the debugging time and for the improvement of the image quality.
Artifacts ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; instrumentation ; methods