title: Fast CPMG-based Bloch-Siegert B(1)+ mapping.
abstract: A novel method for B(1)+ mapping based on the Bloch-Siegert (BS) shift was recently presented. This method applies off-resonant pulses before signal acquisition to encode B(1) information into the signal phase. BS-based methods possess significant advantages in measurement time and accuracy compared to magnitude-based B(1)+ methods. This study extends the idea of BS B(1)+ mapping to Carr, Purcell, Meiboom, Gill (CPMG)-based multi-spin-echo (BS-CPMG-MSE) and turbo-spin-echo (BS-CPMG-TSE) imaging. Compared to BS-based spin echo imaging (BS-SE), faster acquisition of the B(1)+ information was possible using the BS-CPMG-TSE sequence. Furthermore, signal loss by T(2)* effects could be minimized using these spin echo-based techniques. These effects are critical for gradient echo-based BS methods at high field strengths. However, multi-spin-echo-based BS B(1) methods inherently possess high specific absorption rates. Thus, the relative specific absorption rate of BS-CPMG-TSE sequences was estimated and compared with the specific absorption rate produced by BS-SE sequences.
authors.affiliation: Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany. thomas.basse-luesebrink@physik.uni-wuerzburg.de
authors.forename: T C
authors.initials: TC
authors.lastname: Basse-Lüsebrink
authors.forename: V J F
authors.initials: VJ
authors.lastname: Sturm
authors.forename: T
authors.initials: T
authors.lastname: Kampf
authors.forename: G
authors.initials: G
authors.lastname: Stoll
authors.forename: P M
authors.initials: PM
authors.lastname: Jakob
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D051379:Mice; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D012985:Software Design