Artifact‐suppressed optimal three‐dimensional T1‐ and T2*‐weighted dual‐echo imaging. Issue 5 (5th November 2015)

• Record Type: Journal Article
• Authors: Do, Won‐Joon; Kim, Ki Hwan; Choi, Seung Hong; Park, Sung‐Hong
• Is Part Of: Magnetic resonance in medicine. Volume 76:Issue 5(2016)
• Page Start: 1504
• Page End: 1511
• Publication Date: 2015-11-05
• Subjects: T1 -- T2* -- dual echo sequence -- echo‐specific k‐space reordering -- CODEA; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26033
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To develop a new artifact‐suppressed optimal three‐dimensional (3D) T1 ‐ and T2 *‐weighted dual‐echo imaging. Methods: We optimized flip angles for 3D T1 ‐ and T2 *‐weighted imaging by conventional dual‐echo in vivo experiments and computer simulations, and then implemented a dual‐echo sequence with an echo‐specific k‐space reordering scheme to satisfy the optimal flip angles for both T1 and T2 * contrast. We also proposed two strategies to suppress ringing artifacts induced by the abrupt flip angle jumps in the proposed dual echo sequence: (i) implementing smooth transition regions and (ii) discarding the k‐space regions of the abrupt flip angle jumps as dummy phase‐encoding steps. Results: The optimal flip angles measured from experiments were different between T1 ‐ and T2 *‐weighted contrast, in agreement with simulations. The echo‐specific k‐space reordered dual‐echo sequence showed optimal T1 and T2 * contrast simultaneously, but also showed ringing artifacts because of high flip‐angle changes between k‐space regions. The two proposed strategies effectively suppressed the ringing artifacts. Conclusion: The proposed 3D dual‐echo sequence provided optimal T1 and T2 * contrast simultaneously with no artifacts and thus is potentially applicable to routine clinical applications for simultaneous high resolution T1 ‐ and T2 *‐weighted imaging. Magn Reson Med 76:1504–1511, 2016. © 2015 International Society for Magnetic Resonance in Medicine