Seminars and Colloquia

M.Alecci (Univ. de L'Aquila),"Radio Frequency Coils (Sensors) for High Field MRI/MRS"

131 (INFN sez di Pisa, edificio C)


INFN sez di Pisa, edificio C

In recent years, the need for higher sensitivity and spectral resolution has pushed current Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) research towards high field (3 to 9.4 Tesla) whole-body systems. These MR scanners are proving to be very useful for a number of applications, including quantitative proton (1H) and other NMR detectable nuclei (sodium 23Na; phosphorous 31P, etc) measurements in clinical studies, such as stroke and brain tumours. A very critical hardware component is the radiofrequency (RF) coil (sensor) used to provide RF pulses and to detect the signal of the proton and other low gamma nuclei. We review the strategies for single and double-tuned RF coils design that are suitable for high field MRI/MRS applications (1-6). In particular, we report about the design of novel Double-Tuned (DT) volume and surface TEM resonators based on microstrip technology (7-9). Theoretical Multi-Transmission-Line simulation and workbench experimental data are used to prove the DT TEM concept for 4T and 9.4T 1H/23Na applications. Preliminary 1H/23Na MR images were acquired in the calf of healthy volunteers at 4T using a DT surface TEM prototype. The prospective use of single and double-tuned RF coils as elements for parallel imaging modalities are also discussed. (1) Vaughan JT et al, MRM 32:206 (1994). (2) Zhang X et al, Proc ISMRM 423 (2003). (3) Avdievich NI, USP 2005/0253581A1 (2005). (4) Avdievich NI et al, Proc ISMRM 239 (2007). (5) Avdievich NI et al, MRM 57:1190 (2007). (6) Alecci M et al, JMR 181:203 (2006) (7) Vitacolonna et al, Italian Patent RM2007A000584 (2007). (8) Alecci M et al, Italian Patent RM2007A000585 (2007). (9) Vitacolonna A et al, Proc. ISMRM 4751 (2009).