TY  - JOUR
A1  - Martin, Conrad
A1  - Frauenrath, Tobias
A1  - Özerdem, Celal
A1  - Renz, Wolfgang
A1  - Niendorf, Thoralf
T1  - Development and evaluation of a small and mobile Magneto Alert Sensor (MALSE) to support safety requirements for magnetic resonance imaging
JF  - European Radiology
N2  - Objective
The purpose of this study is to (i) design a small and mobile Magnetic field ALert SEnsor (MALSE), (ii) to carefully evaluate its sensors to their consistency of activation/deactivation and sensitivity to magnetic fields, and (iii) to demonstrate the applicability of MALSE in 1.5 T, 3.0 T and 7.0 T MR fringe field environments.

Methods
MALSE comprises a set of reed sensors, which activate in response to their exposure to a magnetic field. The activation/deactivation of reed sensors was examined by moving them in/out of the fringe field generated by 7TMR.

Results
The consistency with which individual reed sensors would activate at the same field strength was found to be 100% for the setup used. All of the reed switches investigated required a substantial drop in ambient magnetic field strength before they deactivated.

Conclusions
MALSE is a simple concept for alerting MRI staff to a ferromagnetic object being brought into fringe magnetic fields which exceeds MALSEs activation magnetic field. MALSE can easily be attached to ferromagnetic objects within the vicinity of a scanner, thus creating a barrier for hazardous situations induced by ferromagnetic parts which should not enter the vicinity of an MR-system to occur.
KW  - MRI
KW  - MR safety
KW  - Magneto alert sensor
KW  - High field MRI
KW  - Uktrahigh field MRI
Y1  - 2011
U6  - https://doi.org/10.1007/s00330-011-2153-z
SN  - 1432-1084
VL  - 21
SP  - 2187
EP  - 2192
PB  - Springer
CY  - Berlin, Heidelberg
ER  - 
TY  - JOUR
A1  - Dieringer, Matthias A.
A1  - Renz, Wolfgang
A1  - Lindel, Tomasz D.
A1  - Seifert, Frank
A1  - Frauenrath, Tobias
A1  - von Knobelsdorf-Brenkenhoff, Florian
A1  - Waiczies, Helmar
A1  - Hoffmann, Werner
A1  - Rieger, Jan
A1  - Pfeiffer, Harald
A1  - Ittermann, Bernd
A1  - Schulz-Menger, Jeanette
A1  - Niendorf, Thoralf
T1  - Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T
JF  - Journal of Magnetic Resonance Imaging
N2  - Purpose
To design and evaluate a four-channel cardiac transceiver coil array for functional cardiac imaging at 7T.

Materials and Methods
A four-element cardiac transceiver surface coil array was developed with two rectangular loops mounted on an anterior former and two rectangular loops on a posterior former. specific absorption rate (SAR) simulations were performed and a Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-1 calibration method was applied prior to obtain 2D FLASH CINE (mSENSE, R = 2) images from nine healthy volunteers with a spatial resolution of up to 1 × 1 × 2.5 mm3.

Results
Tuning and matching was found to be better than 10 dB for all subjects. The decoupling (S21) was measured to be >18 dB between neighboring loops, >20 dB for opposite loops, and >30 dB for other loop combinations. SAR values were well within the limits provided by the IEC. Imaging provided clinically acceptable signal homogeneity with an excellent blood-myocardium contrast applying the Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-2 calibration approach.

Conclusion
A four-channel cardiac transceiver coil array for 7T was built, allowing for cardiac imaging with clinically acceptable signal homogeneity and an excellent blood-myocardium contrast. Minor anatomic structures, such as pericardium, mitral, and tricuspid valves and their apparatus, as well as trabeculae, were accurately delineated.
Y1  - 2011
U6  - https://doi.org/10.1002/jmri.22451
SN  - 1522-2586
VL  - 33
IS  - 3
SP  - 736
EP  - 741
PB  - Wiley-Liss
CY  - New York
ER  -