NMR functional imaging using a tailored RF gradient echo sequence: a true susceptibility measurement technique.
The tailored radio frequency gradient echo (TRFGE) technique that has been used in venography (Cho et al., Magn. Reson. Med. 28, 25-38, 1992; Ro, Cho, Magn. Reson. Med. 28, 237, 1992) is applied to functional imaging. The TRFGE technique has the advantage that it is sensitive to the field gradient created by the susceptibility effect, thereby enhancing only the signals from the regions with local field gradient. In addition, the method is insensitive to the in-flow effect, especially from the arterial blood. The latter further simplifies the functional MRI data analysis. The TRFGE sequence is, therefore, suitable for functional MR imaging for which true susceptibility effect measurements are of prime importance. To examine the TRFGE functional imaging systematically, experiments with various imaging parameters such as flip angle alpha, repetition time, and echo time were performed and the results were compared with the data obtained from the conventional gradient echo functional MR imaging. The experimental results shown were all obtained from human volunteers with a 2.0T whole body MRI system.
Cho
Z H
ZH
Department of Radiological Sciences, University of California, Irvine 92717, USA.
Ro
Y M
YM
Park
S T
ST
Chung
S C
SC
D001143:Arousal / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply*; D001931:Brain Mapping / Q000295:instrumentation; D003287:Contrast Media; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D009778:Occipital Lobe / Q000098:blood supply; D010101:Oxygen Consumption / Q000502:physiology*; D010775:Photic Stimulation; D012016:Reference Values
D003287:Contrast Media; D006454:Hemoglobins; C100003:deoxyhemoglobin