A spiral volume coil for improved RF field homogeneity at high static magnetic field strength.
Biological samples have a high dielectric constant that can shorten RF wavelengths by a factor of 8 relative to the vacuum. At high field strengths, finite wavelength effects within larger samples are the dominant cause of RF field nonuniformity. A coil design is presented that can reduce and even eliminate this inhomogeneity; 4-T images in phantoms and in the head of a normal volunteer are presented, which demonstrate improved homogeneity relative to a standard coil. This coil design should aid in realizing the potential advantages of imaging large samples at high field strengths.
Alsop
D C
DC
Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA.
Connick
T J
TJ
Mizsei
G
G
D019412:Anatomy, Cross-Sectional; D001921:Brain / Q000033:anatomy & histology*; D004574:Electromagnetic Fields; D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D012016:Reference Values; D012680:Sensitivity and Specificity