title: Eight-channel phased array coil and detunable TEM volume coil for 7 T brain imaging.
abstract: An eight-channel receive-only brain coil and table-top detunable volume transmit coil were developed and tested at 7 T for human imaging. Optimization of this device required attention to sources of interaction between the array elements, between the transmit and receive coils and minimization of common mode currents on the coaxial cables. Circular receive coils (85 mm dia.) were designed on a flexible former to fit tightly around the head and within a 270-mm diameter TEM transmit volume coil. In the near cortex, the array provided a fivefold increase in SNR compared to a TEM transmit-receive coil, a gain larger than that seen in comparable coils at 3 T. The higher SNR gain is likely due to strong dielectric effects, which cause the volume coil to perform poorly in the cortex compared to centrally. The sensitivity and coverage of the array is demonstrated with high-resolution images of the brain cortex.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, A. A. Martinos Center, Charlestown, Massachusetts 02129, USA. gwiggins@nmr.mgh.harvard.edu
authors.forename: G C
authors.initials: GC
authors.lastname: Wiggins
authors.forename: A
authors.initials: A
authors.lastname: Potthast
authors.forename: C
authors.initials: C
authors.lastname: Triantafyllou
authors.forename: C J
authors.initials: CJ
authors.lastname: Wiggins
authors.forename: L L
authors.initials: LL
authors.lastname: Wald
mesh_terms: D001921:Brain / Q000033:anatomy & histology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008280:Magnetics / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers