TY - GEN
T1 - Detecting fleeting MRI signals with frequency-modulated pulses
AU - Kobayashi, Naoharu
AU - Idiyatullin, Djaudat
AU - Corum, Curtis
AU - Moeller, Steen
AU - Chamberlain, Ryan
AU - O'Connell, Robert
AU - Nixdorf, Donald R.
AU - Garwood, Michael
PY - 2011
Y1 - 2011
N2 - We describe a fundamentally different approach to MRI referred to as SWIFT (sweep imaging with Fourier transformation). SWIFT exploits time-shared RF excitation and signal acquisition, allowing capture of signal from spins with extremely short transverse relaxation time, T2*. The MR signal is acquired in gaps inserted into a broadband frequency-swept excitation pulse, which results in acquisition delays of only 1-2 microseconds. In SWIFT, 3D k-space is sampled in a radial manner, whereby one projection of the object is acquired in the gaps of each frequency-swept pulse, allowing a repetition time (TR) on the order of the pulse length (typically 1 - 3 milliseconds). Since the orientation of consecutive projections varies in a smooth manner (i.e., only small increments in the values of the x, y, z gradients occur from view to view), SWIFT scanning is close to inaudible and is insensitive to gradient timing errors and eddy currents. SWIFT images can be acquired in scan times similar to and sometimes faster than conventional 3D gradient echo techniques. With its ability to capture signals from ultrashort T2* spins, SWIFT promises to expand the role of MRI in areas of research where MRI previously played no or negligible role. In this article, we show wood and tooth images obtained with SWIFT as examples of materials with ultrashort T 2*. Early experience suggests SWIFT can play a role in materials science and porous media research.
AB - We describe a fundamentally different approach to MRI referred to as SWIFT (sweep imaging with Fourier transformation). SWIFT exploits time-shared RF excitation and signal acquisition, allowing capture of signal from spins with extremely short transverse relaxation time, T2*. The MR signal is acquired in gaps inserted into a broadband frequency-swept excitation pulse, which results in acquisition delays of only 1-2 microseconds. In SWIFT, 3D k-space is sampled in a radial manner, whereby one projection of the object is acquired in the gaps of each frequency-swept pulse, allowing a repetition time (TR) on the order of the pulse length (typically 1 - 3 milliseconds). Since the orientation of consecutive projections varies in a smooth manner (i.e., only small increments in the values of the x, y, z gradients occur from view to view), SWIFT scanning is close to inaudible and is insensitive to gradient timing errors and eddy currents. SWIFT images can be acquired in scan times similar to and sometimes faster than conventional 3D gradient echo techniques. With its ability to capture signals from ultrashort T2* spins, SWIFT promises to expand the role of MRI in areas of research where MRI previously played no or negligible role. In this article, we show wood and tooth images obtained with SWIFT as examples of materials with ultrashort T 2*. Early experience suggests SWIFT can play a role in materials science and porous media research.
KW - MRI
KW - correlation spectroscopy
KW - frequency modulated pulse
KW - radial imaging
KW - ultrashort T
UR - http://www.scopus.com/inward/record.url?scp=79955066573&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955066573&partnerID=8YFLogxK
U2 - 10.1063/1.3579169
DO - 10.1063/1.3579169
M3 - Conference contribution
AN - SCOPUS:79955066573
SN - 9780735408852
T3 - AIP Conference Proceedings
SP - 23
EP - 26
BT - Magnetic Resonance in Porous Media - Proc. of the 10th Intl. Bologna Conference on Magnetic Resonance in Porous Media, MRPM10, including the 10th Colloquium on Mobile Magnetic Resonance, CMMR10
T2 - 10th International Bologna Conference on Magnetic Resonance in Porous Media, MRPM10, including the 10th Colloquium on Mobile Magnetic Resonance, CMMR10
Y2 - 12 September 2010 through 16 September 2010
ER -