STAR and STARFIRE for flow-dependent and flow-independent noncontrast carotid angiography.

Signal Targeting with Alternating Radiofrequency (STAR) and STAR and Flow-Independent Relaxation Enhancement (STARFIRE) are noncontrast methods for flow-dependent and flow-independent magnetic resonance angiography (MRA). The methods rely on the acquisition and complex subtraction of two image sets alternately labeled by spatially selective or spatially nonselective inversion radio frequency (RF) pulses. Experimental results show that the RF labeling period affects the extent of the carotid vessels seen with STAR imaging, and the conspicuity of cerebrospinal fluid (CSF) and fat in the STARFIRE images. Both methods were found to provide more detailed depiction of the carotid arteries than the alternative noncontrast MRA technique of time-of-flight (TOF) angiography.