title: Combined spin- and gradient-echo perfusion-weighted imaging.
abstract: In this study, a spin- and gradient-echo echo-planar imaging (SAGE EPI) MRI pulse sequence is presented that allows simultaneous measurements of gradient-echo and spin-echo dynamic susceptibility-contrast perfusion-weighted imaging data. Following signal excitation, five readout trains were acquired using spin- and gradient-echo echo-planar imaging, all of them with echo times of less than 100 ms. Contrast agent concentrations in brain tissue were determined based on absolute R2* and R(2) estimates rather than relative changes in the signals of individual echo trains, producing T(1)-independent dynamic susceptibility-contrast perfusion-weighted imaging data. Moreover, this acquisition technique enabled vessel size imaging through the simultaneous quantification of R2* and R(2), without an increase in acquisition time. In this work, the concepts of SAGE EPI pulse sequence and results in stroke and tumor imaging are presented. Overall, SAGE EPI combined the advantages of higher sensitivity to contrast agent passage of gradient-echo perfusion-weighted imaging with better microvascular selectivity of spin-echo perfusion-weighted imaging.
authors: Department of Radiology, Stanford University, Lucas Center, Stanford, California, USA.
authors: Heiko
authors: H
authors: Schmiedeskamp
authors: Matus
authors: M
authors: Straka
authors: Rexford D
authors: RD
authors: Newbould
authors: Greg
authors: G
authors: Zaharchuk
authors: Jalal B
authors: JB
authors: Andre
authors: Jean-Marc
authors: JM
authors: Olivot
authors: Michael E
authors: ME
authors: Moseley
authors: Gregory W
authors: GW
authors: Albers
authors: Roland
authors: R
authors: Bammer
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D019786:Gadolinium DTPA