A NOVEL SATURATION-TRANSFER CONTRAST METHOD FOR 3D TIME-OF-FLIGHT MAGNETIC-RESONANCE ANGIOGRAPHY - A SLICE-SELECTIVE OFF-RESONANCE SINE PULSE (SORS) TECHNIQUE

Saturation transfer contrast (STC) techniques have been employed to de crease the signal intensity of observed water by saturating a broad pr oton component. The STC pulse, generally spatially nonselective, reduc es the signal of brain background tissues as well as inflowing blood i n 3D time-of-flight (TOF) angiography. We present a novel technique, a slice-selective off-resonance sine pulse (SORS), which is employed to enhance inflowing blood and to suppress the signal of stationary back ground tissues. The STC effects of the SORS and other spatially nonsel ective methods influencing inflowing blood is discussed in detail. Ang iograms using the SORS method are also presented to demonstrate improv ed vessel conspicuity. In addition, the SORS method is applicable to i magers with a whole-body RF transmitter system.