dc.contributor.author | Leitão, D | |
dc.contributor.author | Tomi-Tricot, R | |
dc.contributor.author | Bridgen, P | |
dc.contributor.author | Wilkinson, T | |
dc.contributor.author | Liebig, P | |
dc.contributor.author | Gumbrecht, R | |
dc.contributor.author | Ritter, D | |
dc.contributor.author | Giles, SL | |
dc.contributor.author | Baburamani, A | |
dc.contributor.author | Sedlacik, J | |
dc.contributor.author | Hajnal, JV | |
dc.contributor.author | Malik, SJ | |
dc.date.accessioned | 2022-05-27T10:25:22Z | |
dc.date.available | 2022-05-27T10:25:22Z | |
dc.identifier.citation | Magnetic resonance in medicine, 2022, 88 (1), pp. 180 - 194 | |
dc.identifier.issn | 0740-3194 | |
dc.identifier.uri | https://repository.icr.ac.uk/handle/internal/5156 | |
dc.identifier.eissn | 1522-2594 | |
dc.identifier.doi | 10.1002/mrm.29199 | |
dc.description.abstract | <h4>Purpose</h4>This work proposes a novel RF pulse design for parallel transmit (pTx) systems to obtain uniform saturation of semisolid magnetization for magnetization transfer (MT) contrast in the presence of transmit field B1+ inhomogeneities. The semisolid magnetization is usually modeled as being purely longitudinal, with the applied B1+ field saturating but not rotating its magnetization; thus, standard pTx pulse design methods do not apply.<h4>Theory and methods</h4>Pulse design for saturation homogeneity (PUSH) optimizes pTx RF pulses by considering uniformity of root-mean squared B1+ , B1rms , which relates to the rate of semisolid saturation. Here we considered designs consisting of a small number of spatially non-selective sub-pulses optimized over either a single 2D plane or 3D. Simulations and in vivo experiments on a 7T Terra system with an 8-TX Nova head coil in five subjects were carried out to study the homogenization of B1rms and of the MT contrast by acquiring MT ratio maps.<h4>Results</h4>Simulations and in vivo experiments showed up to six and two times more uniform B1rms compared to circular polarized (CP) mode for 2D and 3D optimizations, respectively. This translated into 4 and 1.25 times more uniform MT contrast, consistently for all subjects, where two sub-pulses were enough for the implementation and coil used.<h4>Conclusion</h4>The proposed PUSH method obtains more uniform and higher MT contrast than CP mode within the same specific absorption rate (SAR) budget. | |
dc.format | Print-Electronic | |
dc.format.extent | 180 - 194 | |
dc.language | eng | |
dc.language.iso | eng | |
dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | |
dc.subject | Brain | |
dc.subject | Humans | |
dc.subject | Magnetic Resonance Imaging | |
dc.subject | Phantoms, Imaging | |
dc.subject | Algorithms | |
dc.subject | Radio Waves | |
dc.title | Parallel transmit pulse design for saturation homogeneity (PUSH) for magnetization transfer imaging at 7T. | |
dc.type | Journal Article | |
dcterms.dateAccepted | 2022-01-25 | |
rioxxterms.version | VoR | |
rioxxterms.versionofrecord | 10.1002/mrm.29199 | |
dc.relation.isPartOf | Magnetic resonance in medicine | |
pubs.issue | 1 | |
pubs.notes | Not known | |
pubs.organisational-group | /ICR | |
pubs.organisational-group | /ICR/Students | |
pubs.organisational-group | /ICR/Students/PhD and MPhil | |
pubs.organisational-group | /ICR/Students/PhD and MPhil/14/15 Starting Cohort | |
pubs.publication-status | Accepted | |
pubs.volume | 88 | |
pubs.embargo.terms | Not known | |
dc.contributor.icrauthor | Giles, Sharon | |