True FISP/ FIESTA / Balanced SARGE / BASG / True SSFP / STERF
MRI image appearance of True FISP/ FIESTA
The easiest way to identify TrueFISP images is to look for blood vessels and fluid-filled spaces in the body (e.g., cerebrospinal fluid in the brain ventricles and spinal canal, free fluid in the abdomen, fluid in the gall bladder and common bile duct, synovial fluid in joints, fluid in the urinary tract and urinary bladder, edema, or any other pathological fluid collection in the body). Fluids and blood vessels normally appear bright in TrueFISP images. TrueFISP images are usually more prone to chemical shift artifacts.
True fast imaging with steady state precession (TrueFISP) is a coherent technique that utilizes a fully balanced gradient waveform. The image contrast is a function of T1/T2 ratios. However, when using a short TR and a short TE, the T1 component remains constant, resulting in primarily T2-weighted images. TrueFISP is highly sensitive to inhomogeneities in the magnetic field, which can lead to the presence of interference stripes in the images. To mitigate this, it is advisable to keep the TR as short as possible and to perform a shim prior to acquisition. The rapid acquisition speed and minimal sensitivity to motion contribute to the reliability of this technique, even in patients who struggle with breath-holding.
Tissues and their TrueFISP appearance
Bone marrow : – equal to or higher than that of muscle (fatty marrow is usually bright)
White matter : – slightly darker than gray
Liver : darker than gray (darker than spleen)
Moving blood : – bright
Gray matter : – gray
Spleen : gray
Muscles :- gray
Fluids : – bright
Bone : – dark
Fat : – bright
Air : – dark