Quadrature Birdcage Coil with Distributed Capacitors for 7.0 T Magnetic Resonance Data Acquisition of Small Animals RICCARDO STARA, 1,2 GIANLUIGI TIBERI, 3,4 MATTEO GABRIELI, 1 GUIDO BUONINCONTRI, 2,5 NUNZIA FONTANA, 2,6 AGOSTINO MONORCHIO, 2,6 MAURO COSTAGLI, 3,4 MARK ROGER SYMMS, 7 ALESSANDRA RETICO, 2 MICHELA TOSETTI 3,4 1 Physics Department, University of Pisa, Pisa, Italy 2 National Institute of Nuclear Physics (INFN), Pisa, Italy 3 Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance, IRCCS Stella Maris Foundation, Pisa, Italy 4 Imago7 Foundation, Pisa, Italy 5 Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom 6 Department of Information Engineering, University of Pisa, Pisa, Italy 7 General Electric ASL (EMEA), Pisa, Italy ABSTRACT: High static magnetic field magnetic resonance imaging (MRI) is commonly used for preclinical studies in rodents. In this context, minimization of coil losses is man- datory to scan samples that are small compared to the radiofrequency wavelength in the medium. In this study we construct a radiofrequency (RF) birdcage probe with distrib- uted capacitors, operating in quadrature, tailored for 7.0T 1 H MRI of small animals. The design eliminates the need for extra electrical components on the probe structure and affords a high SNR, a uniform B 1 1 field (homogeneity of 93% in the axial plain of the phantom) and a coil sensitivity of 9.8 lT= ffiffiffiffi W p . Feasibility experiments of mouse imaging are conducted and the competitive capability of a 7.0 T human system equipped with the proposed coil is demonstrated in both body and brain preclinical imaging. V C 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 00B: 000000, 2015 KEY WORDS: RF volume coils; ultra high field magnetic resonance; small animal MR; distributed capacitance INTRODUCTION In high-resolution preclinical studies the use of Mag- netic Resonance Imaging (MRI) at high static field (>3T) provides substantial advantages in terms of spatial resolution and Signal to Noise Ratio (SNR). A dedicated small animal scanner can allow MRI with impressively high spatial resolution (beyond 100 lm) in combination with excellent soft tissue contrast, but major drawbacks of this dedicated equipment are its high costs and its limited availability. An increasing number of research groups use human scanners to perform small animal MRI featuring well-established human protocols (1). In this context, we investigated the potential of a human 7T scanner equipped with a tailored coil to perform small animal MRI. When dealing with samples that are small with respect to the radiofrequency (RF) wavelength, the Received 3 July 2014; revised 14 January 2015; accepted 4 February 2015 Correspondence to: Tiberi Gianluigi; E-mail: g.tiberi@iet.unipi.it Concepts in Magnetic Resonance Part B, Vol. 00B(00) 00–00 (2015) Published online in Wiley Online Library (wileyonlinelibrary. com). DOI: 10.1002/cmr.b.21271 Ó 2015 Wiley Periodicals, Inc. 1