Reducing contamination while closing the gap: BASSI RF pulses in PASL

Autor: G. Bruce Pike, Jan M. Warnking
Přispěvatelé: McConnell Brain Imaging Centre (MNI), Montreal Neurological Institute and Hospital, McGill University = Université McGill [Montréal, Canada]-McGill University = Université McGill [Montréal, Canada], Dojat, Michel
Rok vydání: 2006
Předmět:
Adult
Radio Waves
[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging
MESH: Bayes Theorem
MESH: Radio Waves
Imaging phantom
MESH: Magnetic Resonance Imaging
030218 nuclear medicine & medical imaging
Amplitude modulation
03 medical and health sciences
0302 clinical medicine
Optics
Nuclear magnetic resonance
Flip angle
MESH: Spin Labels
Humans
Frequency offset
Radiology
Nuclear Medicine and imaging
[SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]
Saturation (magnetic)
MESH: Brain Mapping
Brain Mapping
MESH: Humans
Spins
Sinc function
Phantoms
Imaging
business.industry
Chemistry
Bayes Theorem
MESH: Adult
MESH: Blood Flow Velocity
MESH: Cerebrovascular Circulation
Magnetic Resonance Imaging
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging
MESH: Phantoms
Imaging
Cerebrovascular Circulation
Spin Labels
[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]
Radio frequency
business
Blood Flow Velocity
030217 neurology & neurosurgery
Zdroj: Magnetic Resonance in Medicine
Magnetic Resonance in Medicine, Wiley, 2006, 55 (4), pp.865-73. ⟨10.1002/mrm.20843⟩
ISSN: 1522-2594
0740-3194
DOI: 10.1002/mrm.20843
Popis: International audience; Bandwidth-modulated selective saturation and inversion (BASSI) pulses are a class of frequency- and gradient-modulated radiofrequency (RF) pulses, derived from the hyperbolic secant pulse by temporal variation of the bandwidth parameter. These pulses afford optimal amplitude modulation, achieving uniform and highly selective profiles at any effective flip angle. In this paper, BASSI pulses are parameterized to obtain low RF energy pulsed arterial spin labeling (PASL) label pulses with minimal contamination of static spins outside the label region and highly selective PICORE/QUIPSS II saturation pulses allowing for small label gaps. They are compared to frequency offset corrected inversion (FOCI) label pulses and sinc saturation pulses in simulations and a phantom experiment. Drawing on the outstanding selectivity of bandwidth-modulated saturation pulses, a new noninvasive method to measure in vivo the contamination effects due to direct and indirect saturation of static spins by the label pulse is presented. In an in vivo study on four subjects, contamination effects in a QUIPSS II PASL implementation based on BASSI pulses are compared to those present in a state-of-the-art Q2TIPS sequence employing a FOCI label pulse. Residual contamination in the QUIPSS II/BASSI sequence is shown to be reduced by a factor of 3, compared to the Q2TIPS/FOCI sequence. In vivo human perfusion images obtained with a label gap of only 2 mm are presented.
Databáze: OpenAIRE
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