title: Stripline resonator and preamplifier for preclinical magnetic resonance imaging at 4.7 T.
abstract: OBJECTIVE
  To design and evaluate a fully shielded, λ/4 stripline resonator as a receive-only surface coil for preclinical MRI at 4.7 T.
  
  
  METHODS
  A 20 mm diameter stripline surface coil was fabricated from double-sided Duroid 5880 PCB material and was directly coupled to the input of a MOSFET preamplifier, without requiring a matching network. The new coil was compared with a conventional 20 mm, wire loop, receive-only surface coil in imaging experiments with a separate transmit-only saddle coil.
  
  
  RESULTS
  The stripline surface coil exhibits a loaded Q-factor of 132 at 200 MHz, compared to 138 for a conventional wire loop coil and its resonant frequency drops by 0.2 MHz under loading, rather than 0.5 MHz for the wire loop. The stripline coil displays a more symmetrical B1 map compared to the wire loop, but the SNR falls off more rapidly with depth so it is 30% poorer 8 mm from the coil plane. It should be possible, however, to reduce this difference by using a thicker dielectric in future versions of the stripline coil.
  
  
  CONCLUSIONS
  Compared to a conventional surface coil, the stripline coil is easy to manufacture, requires shorter set-up times and shows reduced dielectric interaction with conductive samples.
authors.affiliation: Comprehensive Cancer Imaging Centre (CCIC), Imperial College MRC Cyclotron Building, Hammersmith Hospital, DuCane Road, London, W12 0NN, UK. ilavdas@imperial.ac.uk
authors.forename: Ioannis
authors.initials: I
authors.lastname: Lavdas
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Seton
authors.forename: Charles R
authors.initials: CR
authors.lastname: Harrington
authors.forename: Claude M
authors.initials: CM
authors.lastname: Wischik
mesh_terms: D000669:Amplifiers, Electronic; D017097:Electric Impedance; D004867:Equipment Design; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio