| 摘要 |
PURPOSE: To increase contrast of low spatial frequency image component from comparison with high spatial frequency image components and signal-to-noise ratio by changing controllable MR imaging parameters. CONSTITUTION: The maximum spatial frequency phase encoding of +Δis generated in between a sub-interval of data acquisitions. Continuous sub-intervals of data acquisitions reduce phase encoding by an increased quantity ofδup to the 128<th> data acquisition sub-intervals where zero space frequency by phase encoding is present. Afterwards, the phase encoding is gradually increased in the negative direction relating to the remainder of the 256<th> data acquisition. Especially, in order to improve a contrast and a signal-to-noise ratio relating to a lower spatial frequency within the last image, the 121-136<th> data acquisitions of central 16 pieces are obtained by using longer TR intervals. Similar last image can be obtained by reducing initial nutation angleθduring the central data acquisitions.
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