Time-efficient interleaved human (23)Na and (1)H data acquisition at 7 T.
The aim of this study was to implement and evaluate a flexible and time-efficient interleaved imaging approach for the acquisition of proton and sodium images of the human knee at 7 T within a clinically relevant timescale. A flexible software framework was established which allowed the interleaving of multiple, different, fully specific absorption ratio (SAR)-validated scans. The system was able to switch between these different scans at flexible time points. The practical example presented consists of interleaved proton (Dixon imaging and T2* mapping) and sodium (mapping the sodium content and fluid-suppressed component separately) sequences with the key idea to perform proton MRI whilst the sodium nuclei relax towards thermal equilibrium, and vice versa. Comparisons were made between these four scans being acquired sequentially in the normal mode of scanner operation and those acquired in an interleaved fashion. Images acquired in the interleaved mode were very similar to those acquired in sequential scans with no image artifacts produced by the slight intra-sequence variation in steady-state magnetization. A reduction in scanning time of almost a factor of two was established using the interleaved scans, allowing such a protocol to be completed within 30 min. Phantom experiments and in vivo scans performed in healthy volunteers and in one patient proved the basic feasibility of this approach. This approach for the interleaving of multiple proton and sodium scans, each with different contrasts, is an efficient method for the design of new practical clinical protocols for sodium MRI.
Radiology Department, Leiden University Medical Center, the Netherlands.
Paul W
PW
de Bruin
Philips Research Laboratories, Hamburg, Germany.
Peter
P
Koken
Philips Healthcare Benelux, the Netherlands.
Maarten J
MJ
Versluis
Radiology Department, Leiden University Medical Center, the Netherlands.
Sebastian A
SA
Aussenhofer
Molecular Epidemiology, Leiden University Medical Center, the Netherlands.
Ingrid
I
Meulenbelt
Radiology Department, Leiden University Medical Center, the Netherlands.|Philips Research Laboratories, Hamburg, Germany.
Peter
P
Börnert
Radiology Department, Leiden University Medical Center, the Netherlands.
Andrew G
AG
Webb
D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007717:Knee / Q000033:anatomy & histology*; D008297:Male; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D019047:Phantoms, Imaging; D066244:Proton Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D011522:Protons; D012975:Sodium Isotopes; D012984:Software; D013997:Time Factors
D011522:Protons; D012975:Sodium Isotopes
Dixon; cartilage; fluid suppression; interleaved acquisition; sodium scanning