Simultaneous two-contrast fast spin echo NMR imaging

Claim 1

An NMR system, the combination comprising: means for generating a polarizing magnetic field; excitation means for generating an RF excitation magnetic field which produces transverse magnetization in spins subjected to the polarizing magnetic field; receiver means for sensing the NMR signal produced by the transverse magnetization and producing digitized samples of the NMR signal; first gradient means for generating a first magnetic field gradient to phase encode the NMR signal; second gradient means for generating a second magnetic field gradient to frequency encode the NMR signal; pulse control means coupled to the excitation means, first gradient means, second gradient means, and receiver means, said pulse control means being operable to conduct a scan in which a series of pulse sequences are conducted to acquire digitized samples of NMR signals which enable a pair of images to be reconstructed; a pair of image array storage means each coupled to the receiver means and each storing digitized samples of the NMR signals required to reconstruct one of said images; wherein the pulse control means operates during the scan to perform a fast spin echo pulse sequence in which a set of RF refocusing pulses are produced by said excitation means, the second, gradient means generates a waveform which produces a pair of gradient recalled NMR echo signals between each successive pair of RF refocusing pulses, the first gradient means generates a waveform that separately phase encodes each gradient recalled NMR echo signal in each of said gradient, the first gradient recalled NMR echo signal in each of said pair is sensed by the receiver means and stored in the first of said pair of gradient recalled NMR echo signals of image array storage means, and the second gradient recalled NMR echo signal in each of said pairs is sensed by the receiver means and stored in the second of said pair of image array storage means.