Cardiac cycle extraction from projection data using static signal suppression.

As an extension of the projection-data-based cardiac cycle extraction that we developed previously (W. S. Kim, K. J. Jung, K. D. Lee, J. B. Ra, and Z. H. Cho, "Proceedings, Seventh Annual Meeting of the Society of Magnetic Resonance in Medicine, 1988," p. 958; W. S. Kim, C. W. Mun, D. J. Kim, and Z. H. Cho, Magn. Reson. Med. 13, 25, 1990), a new technique with which one can extract the cardiac cycle by flow-based projection data measurements is described. Because the method uses flow-dependent projection data, it is possible to obtain the cardiac cycle even from regions such as the head, which has virtually no geometrically varying parts, unlike the cardiac region. The signal-to-noise of this flow (such as blood and CSF) based projection data acquisition is further enhanced by the use of the static sample signal suppression technique developed for angiography (J. H. Kim and Z. H. Cho, Magn. Reson. Med. 14, 554, 1990).