Slice-selective fat saturation in MR angiography using spatial-spectral selective prepulses.
Presaturation of fat signals by frequency-selective radiofrequency (RF) pulses is often applied in MR angiography to improve the visualization of the blood vessels. Unfortunately, standard fat saturation methods might cause a considerable reduction of the blood signal in the measured slices. This effect is caused by an attenuation of blood magnetization in remote tissue regions with water protons showing a similar Larmor frequency as the fat protons in the recorded slice. The affected blood water protons subsequently flow into the recorded slice and provide low signal intensity. Suitable spatial-spectral selective methods for slice-selective fat saturation were developed to avoid this unwanted effect. A spatial-spectral fat saturation technique was compared with a corresponding only spectrally selective approach. Both saturation techniques were included in a standard two-dimensional (2D) cine sequence and applied in angiographic examinations of the thighs. The results indicate that spatial-spectral saturation (acting slice selectively) leads to a clearly higher blood signal intensity in fat-suppressed MR angiography compared with standard techniques, especially in measurements performed during the systolic phase of the cardiac cycle.
Forster
J
J
Physikalisches Institut, Abteilung für Kinderkardiologie, Universität Tübingen, Germany.
Schick
F
F
Breuer
J
J
Sieverding
L
L
Lutz
O
O
D000273:Adipose Tissue; D000328:Adult; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D001808:Blood Vessels / Q000033:anatomy & histology; D003196:Computer Graphics; D003199:Computer Systems; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation; D008297:Male; D011673:Pulsatile Flow / Q000502:physiology; D012016:Reference Values; D013848:Thigh / Q000098:blood supply