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Radiofrequency bias...
Radiofrequency bias correction of magnetization prepared rapid gradient echo MRI at 7.0 Tesla using an external reference in a sequential protocol
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- Olsson, Hampus (författare)
- Lund University,Lunds universitet,Medicinsk strålningsfysik, Lund,Sektion V,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,MR Physics,Forskargrupper vid Lunds universitet,Medical Radiation Physics, Lund,Section V,Department of Clinical Sciences, Lund,Faculty of Medicine,Lund University Research Groups
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- Novén, Mikael (författare)
- Lund University,Lunds universitet,Allmän språkvetenskap,Avdelningen för lingvistik och kognitiv semiotik,Sektion 6,Språk- och litteraturcentrum,Institutioner,Humanistiska och teologiska fakulteterna,LAMiNATE (Language Acquisition, Multilingualism, and Teaching),Forskargrupper vid Lunds universitet,General Linguistics,Division of Linguistics and Cognitive Semiotics,Section 6,Centre for Languages and Literature,Departments,Joint Faculties of Humanities and Theology,LAMiNATE (Language Acquisition, Multilingualism, and Teaching),Lund University Research Groups
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- Lätt, Jimmy (författare)
- Skåne University Hospital
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- Wirestam, Ronnie (författare)
- Lund University,Lunds universitet,Medicinsk strålningsfysik, Lund,Sektion V,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,MR Physics,Forskargrupper vid Lunds universitet,Medical Radiation Physics, Lund,Section V,Department of Clinical Sciences, Lund,Faculty of Medicine,Lund University Research Groups
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- Helms, Gunther (författare)
- Lund University,Lunds universitet,Medicinsk strålningsfysik, Lund,Sektion V,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,MR Physics,Forskargrupper vid Lunds universitet,Medical Radiation Physics, Lund,Section V,Department of Clinical Sciences, Lund,Faculty of Medicine,Lund University Research Groups
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(creator_code:org_t)
- 2021
- 2021
- Engelska.
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Ingår i: Tomography : a journal for imaging research. - 2379-1381. ; 7:3, s. 434-451
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Abstract
Ämnesord
Stäng
- At field strengths of 7 T and above, T1-weighted imaging of human brain suffers increasingly from radiofrequency (RF) B1 inhomogeneities. The well-known MP2RAGE (magnetization prepared two rapid acquisition gradient echoes) sequence provides a solution but may not be readily available for all MR systems. Here, we describe the implementation and evaluation of a sequential protocol to obtain normalized magnetization prepared rapid gradient echo (MPRAGE) images at 0.7,0.8, or 0.9-mm isotropic spatial resolution. Optimization focused on the reference gradient-recalled echo (GRE) that was used for normalization of the MPRAGE. A good compromise between white-gray matter contrast and the signal-to-noise ratio (SNR) was reached at a flip angle of 3° and total scan time was reduced by increasing the reference voxel size by a factor of 8 relative to the MPRAGE resolution. The average intra-subject coefficient-of-variation (CV) in segmented white matter (WM) was 7.9 ±3.3% after normalization, compared to 20 ±8.4% before. The corresponding inter-subject average CV in WM as 7.6 ±7.6% and 13 ±7.8%. Maps of T1 derived from forward signal modelling showed no obvious bias after correction by a separately acquired flip angle map. To conclude, a non-interleaved acquisition for normalization of MPRAGE offers a simple alternative to MP2RAGE to obtain semi-quantitative purely T1-weighted images. These images can be converted to T1 maps, analogously to the established MP2RAGE approach. Scan time can be reduced by increasing the reference voxel size which has only a miniscule effect on image quality.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)
- NATURVETENSKAP -- Fysik -- Annan fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Other Physics Topics (hsv//eng)
Nyckelord
- Bias correction
- Intensity correction
- MPRAGE
- MP2RAGE
- B1
- 7T
- Ultra-high field
- Longitudinal relaxation
- T1
- T1-mapping
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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