Premium
Rapid dark‐blood carotid vessel‐wall imaging with random bipolar gradients in a radial SSFP acquisition
Author(s) -
Lin HungYu,
Flask Chris A.,
Dale Brian M.,
Duerk Jeffrey L.
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20821
Subject(s) - steady state free precession imaging , physics , nuclear magnetic resonance , imaging phantom , signal (programming language) , blood flow , spins , precession , magnetic resonance imaging , optics , medicine , radiology , computer science , programming language , condensed matter physics , astronomy
Abstract Purpose To investigate and evaluate a new rapid dark‐blood vessel‐wall imaging method using random bipolar gradients with a radial steady‐state free precession (SSFP) acquisition in carotid applications. Materials and Methods The carotid artery bifurcations of four asymptomatic volunteers (28–37 years old, mean age = 31 years) were included in this study. Dark‐blood contrast was achieved through the use of random bipolar gradients applied prior to the signal acquisition of each radial projection in a balanced SSFP acquisition. The resulting phase variation for moving spins established significant destructive interference in the low‐frequency region of k ‐space. This phase variation resulted in a net nulling of the signal from flowing spins, while the bipolar gradients had a minimal effect on the static spins. The net effect was that the regular SSFP signal amplitude (SA) in stationary tissues was preserved while dark‐blood contrast was achieved for moving spins. In this implementation, application of the random bipolar gradient pulses along all three spatial directions nulled the signal from both in‐plane and through‐plane flow in phantom and in vivo studies. Results In vivo imaging trials confirmed that dark‐blood contrast can be achieved with the radial random bipolar SSFP method, thereby substantially reversing the vessel‐to‐lumen contrast‐to‐noise ratio (CNR) of a conventional rectilinear SSFP “bright‐blood” acquisition from bright blood to dark blood with only a modest increase in TR (∼4 msec) to accommodate the additional bipolar gradients. Conclusion Overall, this sequence offers a simple and effective dark‐blood contrast mechanism for high‐SNR SSFP acquisitions in vessel wall imaging within a short acquisition time. J. Magn. Reson. Imaging 2007;25:1299–1304. © 2007 Wiley‐Liss, Inc.