DOUBLE-QUANTUM-FILTERED SODIUM IMAGING

Double-quantum-filtered (DQ) images of 23Na at 7.05 T are reported for phantoms containing concentric volumes of 145 mM sodium chloride and 145 mM sodium chloride entrapped in a 4% (w/v) agarose gel. Excellent single-quantum suppression was obtained. DQ image profiles are also reported for 46 and 4.6 mM sodium chloride in agarose gels. The sensitivity of the DQ-filtered signal to magnetic field inhomogeneity and to susceptibility effects is explicitly demonstrated. The DQ filter can be used to introduce an additional source of contrast into Na images. We describe the considerations necessary for obtaining DQ-filtered images with good signal-to-noise in short imaging times and quantify the losses encountered when using a DQ filter. Possible extensions to in vivo and in vitro biological specimens and to nonbiological materials are discussed. © 1990.