Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Mitchio Mitomi

Hirokazu Suzuki

Fumitoshi Kojima

Satoshi Sugiura

Selective excitation is used to excite to resonance nuclear spins in a predetermined planar slice of a target. The received NMR signals are then used to correct non-homogenity of a static magnetic field based upon the calculated spin-spin relaxation time T.sub.2 * of the observed NMR signal.

Field gradient correction apparatus for compensating static field

Apparatus is provided in an NMR diagnostic apparatus for reducing or eliminating low frequency cyclic noise. The NMR signals are phase demodulated using reference signals having the same frequency as the excitation signals. A provision is made to change the phases of the output reference signals by 180.degree.. These signals are selectively used to demodulate the received NMR signals which are first divided into two signals of the same phase. The demodulated signals, which are 180.degree. apart, are added thereby eliminating the cyclic noise component.

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Otawara, Japan

Mitchio Mitomi