Balanced steady-state free precession (b-SSFP) techniques (TrueFISP/FIESTA/bFFE) sequences are widely used for non-contrast enhanced (NCE) MRA of the chest, abdomen, and pelvis. TrueFISP/FIESTA are rapid gradient-echo sequences in which the free induction decay (FID) and spin/stimulated echo components are made to coincide in the middle of the TR interval. This structure allows a coherent transverse steady state to become established, whose maximum signal intensity depends on the ratio T2/T1 of the tissue being imaged. Small vessels such as the coronary, renal, or mesenteric arteries may be obscured by high signal from the nearby fat (high T2/T1 ratio such as blood and CSF) in which they are embedded. Commonly an adjuvant fat suppression method is used when performing b-SSFP MRA of these vessels. Figure shows a gated bSSFP coronary artery image with fat suppression.
