Magnetic resonance imaging receiver coil decoupling using circumferential shielding structures

2016 ◽  
Author(s):  
Jhy-Neng Tasso Yeh ◽  
Fa-Hsuan Lin
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Receiver Coil ◽  
Resonance Imaging ◽  
Imaging Receiver

LOW-FIELD MAGNETIC RESONANCE IMAGING OF BEAGLE BRAIN WITH A DEDICATED RECEIVER COIL

1999 ◽  
Vol 40 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Marjatta Snellman ◽  
Judit Benczik ◽  
Raimo Joensuu ◽  
Usama Abo Ramadan ◽  
Jukka Tanttu ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Receiver Coil ◽  
Resonance Imaging ◽  
Low Field

A Flexible and Modular Receiver Coil Array for Magnetic Resonance Imaging

2019 ◽  
Vol 38 (3) ◽  
pp. 824-833 ◽  
Author(s):  
Jhy-Neng Tasso Yeh ◽  
Jo-Fu Lotus Lin ◽  
Yi-Tien Li ◽  
Fa-Hsuan Lin
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Receiver Coil ◽  
Resonance Imaging ◽  
Coil Array

scholarly journals Adaptive and Wireless Recordings of Electrophysiological Signals during Concurrent Magnetic Resonance Imaging

2018 ◽  
Author(s):  
Ranajay Mandal ◽  
Nishant Babaria ◽  
Jiayue Cao ◽  
Zhongming Liu ◽  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Speed ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Receiver Coil ◽  
Signal Acquisition ◽  
Resonance Imaging ◽  
Fmri Signal ◽  
Electrophysiological Signals

AbstractStrong electromagnetic fields that occur during functional magnetic resonance imaging (fMRI) presents a challenging environment for concurrent electrophysiological recordings. Here, we present a miniaturized, wireless platform – “MR-Link” (Multimodal Recording Link) that provides a hardware solution for simultaneous electrophysiological and fMRI signal acquisition. The device detects the changes in the electromagnetic field during fMRI to synchronize amplification and sampling of electrophysiological signals with minimal artifacts. It wirelessly transmits the recorded data at a frequency detectable by the MR-receiver coil. The transmitted data is readily separable from MRI in the frequency domain. To demonstrate its efficacy, we used this device to record electrocardiograms and somatosensory evoked potential during concurrent fMRI scans. The device minimized the fMRI-induced artifacts in electrophysiological data and wirelessly transmitted the data back to the receiver coil without compromising fMRI signal quality. The device is compact (22 mm dia., 2gms) and can be placed within the MR-bore to precisely synchronize with fMRI. Therefore, MR-Link offers an inexpensive system by eliminating the need for amplifiers with a high dynamic range, high-speed sampling, additional storage or synchronization hardware for electrophysiological signal acquisition. It is expected to enable a broader range of applications of simultaneous fMRI and electrophysiology in animals and humans.

scholarly journals Changes in magnetic resonance imaging relaxation time on postmortem magnetic resonance imaging of formalin-fixed human normal heart tissue

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kiyokadzu Ebata ◽  
Sakon Noriki ◽  
Kunihiro Inai ◽  
Hirohiko Kimura
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Formalin Fixation ◽  
Fixation Time ◽  
Receiver Coil ◽  
Resonance Imaging ◽  
Postmortem Magnetic Resonance Imaging ◽  
T1 And T2 ◽  
Formalin Fixed ◽  
Over Time

Abstract Background Postmortem magnetic resonance imaging (MRI) has been used to investigate the cause of death, but due to time constraints, it is not widely applied to the heart. Therefore, MRI analysis of the heart after formalin fixation was previously performed. However, the changes in MRI signal values based on the fixation time of formalin were not investigated. The objective was to investigate changes over time in the T1- and T2-values of MRI signals in normal areas of hearts removed during autopsy, hearts subsequently fixed in formalin, and heart specimens sliced for the preparation of pathological specimens. Methods The study subjects were 21 autopsy cases in our hospital between May 26, 2019 and February 16, 2020 whose hearts were removed and scanned by MRI. The male:female ratio was 14:7, and their ages at death ranged from 9 to 92 years (mean age 65.0 ± 19.7 years). Postmortem (PM)-MRI was conducted with a 0.3-Tesla (0.3-T) scanner containing a permanent magnet. A 4-channel QD head coil was used as the receiver coil. Scans were performed immediately after removal, post-formalin fixation, and after slicing; 7 cases were scanned at all three time points. Results The T1- and T2-values were calculated from the MRI signals of each sample organ at each scanning stage. Specimens were sliced from removed organs after formalin fixation, and the changes in T1- and T2-values over time were graphed to obtain an approximate curve. The median T1-values at each measurement time point tended to decrease from immediately after removal. The T2-values showed the same tendency to decrease, but this tendency was more pronounced for the T1-values. Conclusion MRI signal changes in images of heart specimens were investigated. Formalin fixation shortened both T1- and T2-values over time, and approximation formulae were derived to show these decreases over time. The shortening of T1- and T2-values can be understood as commensurate with the reduction in the water content (water molecules) of the formalin-fixed heart.

scholarly journals The Utility of Combined Target and Systematic Prostate Biopsies in the Diagnosis of Clinically Significant Prostate Cancer Using Prostate Imaging Reporting and Data System Version 2 Based on Biparametric Magnetic Resonance Imaging

2021 ◽  
Vol 28 (2) ◽  
pp. 1294-1301
Author(s):  
Daiki Kato ◽  
Kaori Ozawa ◽  
Shinichi Takeuchi ◽  
Makoto Kawase ◽  
Kota Kawase ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Prostate Cancer ◽  
Magnetic Resonance ◽  
Diagnostic Accuracy ◽  
Data System ◽  
Receiver Coil ◽  
Resonance Imaging ◽  
Prostate Imaging ◽  
Rate Of Increase ◽  
Clinically Significant

This study aimed to determine the predictive value of the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) based on biparametric magnetic resonance imaging (bpMRI) with combined target biopsy (TBx) and systematic biopsy (SBx) in patients with suspicion of having clinically significant prostate cancer (csPCa). In this retrospective study, we reviewed the clinical and pathological records of 184 consecutive patients who underwent bpMRI before prostate biopsy. We focused on patients with PI-RADS v2 scores ≥ 3. MRI was performed using a 3-Tesla clinical scanner with a 32-channel phased-array receiver coil. PI-RADS v2 was used to describe bpMRI findings based on T2-weighted imaging and diffusion-weighted imaging scores. The primary endpoint was the diagnostic accuracy rate of PI-RADS v2 based on bpMRI for patients with prostate cancer (PCa) who underwent combined TBx and SBx. A total of 104 patients were enrolled in this study. Combined TBx and SBx was significantly superior to either method alone for PCa detection in patients with suspicious lesions according to PI-RADS v2. TBx and SBx detected concordant csPCa in only 24.1% of the patients. In addition, the rate of increase in the Gleason score was similar between SBx (41.5%) and TBx (34.1%). The diagnostic accuracy of bpMRI is comparable to that of standard multiparametric MRI for the detection of csPCa. Moreover, combined TBx and SBx may be optimal for the accurate determination of csPCa diagnosis, the International Society of Urological Pathology grade, and risk classification.

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