Peripheral nerve stimulation characteristics of an asymmetric head‐only gradient coil compatible with a high‐channel‐count receiver array. Issue 6 (2nd December 2015)

• Record Type: Journal Article
• Authors: Lee, Seung‐Kyun; Mathieu, Jean‐Baptiste; Graziani, Dominic; Piel, Joseph; Budesheim, Eric; Fiveland, Eric; Hardy, Christopher J.; Tan, Ek Tsoon; Amm, Bruce; Foo, Thomas K.‐F.; Bernstein, Matt A.; Huston, John; Shu, Yunhong; Schenck, John F.
• Is Part Of: Magnetic resonance in medicine. Volume 76:Issue 6(2016)
• Page Start: 1939
• Page End: 1950
• Publication Date: 2015-12-02
• Subjects: peripheral nerve stimulation -- PNS -- head‐only gradient coil -- EPI -- neuroimaging; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26044
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To characterize peripheral nerve stimulation (PNS) of an asymmetric head‐only gradient coil that is compatible with a commercial high–channel‐count receive‐only array. Methods: Two prototypes of an asymmetric head‐only gradient coil set with a 42‐cm inner diameter were constructed for brain imaging at 3T with maximum performance specifications of up to 85 mT/m and 708 T/m/s. Tests were performed in 24 volunteers to measure PNS thresholds with the transverse (x = left–right; y = anterior–posterior [A/P]) gradient coils of both prototypes. Fourteen of these 24 volunteers were also tested for the z‐gradient PNS in the second prototype and were scanned with high–slew‐rate echo planar imaging (EPI) immediately after the PNS tests. Results: For both prototypes, the y‐gradient PNS threshold was markedly higher than the x‐gradient threshold. The z‐gradient threshold was intermediate between those for the x‐ and y‐coils. Of the 24 volunteers, only two experienced y‐gradient PNS at 80 mT/m and 500 T/m/s. All volunteers underwent the EPI scan without PNS when the readout direction was set to A/P. Conclusion: Measured PNS characteristics of asymmetric head‐only gradient coil prototypes indicate that such coils, especially in the A/P direction, can be used for fast EPI readout in high‐performance neuroimaging scans with substantially reduced PNS concerns compared with conventional whole body gradient coils. Magn Reson Med 76:1939–1950, 2016. © 2015 International Society for Magnetic Resonance in Medicine