Description: Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment

This title appears in the Scientific Report : 2018

Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifact...

Personal Name(s):	Huang, Xiaolei
	Dong, Hui (Corresponding author) / Qiu, Yang / Li, Bo / Tao, Quan / Zhang, Yi / Krause, Hans-Joachim (Corresponding author) / Offenhäusser, Andreas / Xie, Xiaoming
Contributing Institute:	JARA-FIT; JARA-FIT Bioelektronik; ICS-8
Published in:	Journal of magnetic resonance, 286 (2018) S. 52 - 59
Imprint:	Amsterdam [u.a.] Elsevier 2018
DOI:	10.1016/j.jmr.2017.11.009
PubMed ID:	29183004
Document Type:	Journal Article
Research Program:	Physical Basis of Diseases Engineering Cell Function
Link:	OpenAccess Restricted OpenAccess Restricted
	Publikationsportal JuSER

Please use the identifier: http://hdl.handle.net/2128/16436 in citations.
Please use the identifier: http://dx.doi.org/10.1016/j.jmr.2017.11.009 in citations.

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel (s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room.