Cryogenic receive coil and low noise preamplifier for MRI at 0.01 T

Frank Resmer, Hugh Seton, James Hutchison

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We have investigated the design and Construction of liquid nitrogen cooled surface coils made from stranded (litz) copper wire for low field MRI applications If designed correctly, cooled litz coils can provide a competitive alternative to high temperature Superconducting (HTS) coils without the complications associated with flux trapping Litz coils can also be produced with a wider range of shapes and sizes, and at lower cost Existing models were verified experimentally for flat spiral coils wound from solid and litz wires, operated at room temperature and 77 K. and then used to design and optimise a cooled receive coil for MRI at 0 0 1 T (425 kHz) The Q-factor reached 1022 when the coil was cooled to 77 K, giving a bandwidth Of Just 0 42 kHz, so a low noise JFET preamplifier was developed to provide active damping of the coil resonance and thus minimise image intensity artefacts The noise Contribution of the preamplifier was determined using a method based oil resistive Sources and image noise analysis The voltage and Current noise were measured to be 1 25 nV/Hz(1/2) and 51 fA/Hz(1/2), respectively, and these values were used to estimate a noise figure ON 32 dB at the resonant frequency of the cooled coil The coil was used to acquire 001 T spin echo images, first at room temperature and then cooled to 77 K in a low noise liquid nitrogen cryostat The measured SNR improvement on cooling, by a factor of 3 0, was found to correspond well with theoretical predictions.
Original languageEnglish
Pages (from-to)57-65
Number of pages9
JournalJournal of Magnetic Resonance
Volume203
Issue number1
Early online date3 Dec 2009
DOIs
Publication statusPublished - Mar 2010

Fingerprint

preamplifiers
Magnetic resonance imaging
Cryogenics
low noise
cryogenics
Noise
coils
Liquid nitrogen
Wire
Temperature
Junction gate field effect transistors
Flux pinning
Cryostats
Nitrogen
Noise figure
Copper
Natural frequencies
Oils
Damping
Artifacts

Keywords

  • low field
  • cooled
  • Litz
  • low noise
  • active damping

Cite this

Cryogenic receive coil and low noise preamplifier for MRI at 0.01 T. / Resmer, Frank; Seton, Hugh; Hutchison, James.

In: Journal of Magnetic Resonance, Vol. 203, No. 1, 03.2010, p. 57-65.

Research output: Contribution to journalArticle

Resmer, Frank ; Seton, Hugh ; Hutchison, James. / Cryogenic receive coil and low noise preamplifier for MRI at 0.01 T. In: Journal of Magnetic Resonance. 2010 ; Vol. 203, No. 1. pp. 57-65.
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