Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
VELOCITY SENSITIVITY OF SLICE-SELECTIVE EXCITATION
Autore:
LEWIS DP; TSUI BMW; MORAN PR;
Indirizzi:
UNIV N CAROLINA,DEPT BIOMED ENGN,151 MACNIDER HALL CHAPEL HILL NC 27599
Titolo Testata:
Magnetic resonance imaging
fascicolo: 8, volume: 16, anno: 1998,
pagine: 907 - 916
SICI:
0730-725X(1998)16:8<907:VSOSE>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
INVERSION-RECOVERY; RADIOFREQUENCY PULSES; NMR SIGNAL; BLOOD-FLOW; SPINS; DEPENDENCE; SEQUENCES; DESIGN;
Keywords:
RADIOFREQUENCY (RF) PULSE; FLOW; SELECTIVE EXCITATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
D.P. Lewis et al., "VELOCITY SENSITIVITY OF SLICE-SELECTIVE EXCITATION", Magnetic resonance imaging, 16(8), 1998, pp. 907-916

Abstract

The purpose of this study was to investigate how flow affects slice-selective excitation, particularly for radiofrequency (rf) pulses optimized for slice-selective excitation of stationary material. Simulationmethods were used to calculate the slice profiles for material flowing at different velocities, using optimal flow compensation when appropriate, Four rf pulses of very different shapes were used in the simulation study: a 90 degrees linear-phase Shinnar-LeRoux pulse; a 90 degrees self-refocusing pulse; a minimum-phase Shinnar-LeRoux inversion pulse; and a SPINCALC inversion pulse. Slice profiles from simulations with a laminar how model were compared with experimental studies for twodifferent rf pulses using a clinical magnetic resonance imaging (MRI)system. We found that, for a given rf pulse, the effect of flow on slice-selective excitation depends on the product of the selection gradient amplitude, the component of velocity in the slice selection direction, and the square of the rf pulse duration, The shapes of the slice profiles from the Shinnar-LeRoux pulses were relatively insensitive tovelocity. However, the slice profiles from the self-refocusing pulse and the SPINCALC pulse were significantly degraded by velocity. Experimental slice profiles showed excellent agreement with simulation. In conclusion, our study demonstrates that slice-selective excitation can be significantly degraded by dow depending on the velocity, the gradient amplitude, and characteristics of the rf excitation pulse used. Theresults can aid in the design of rf pulses for slice-selective excitation of flowing material. (C) 1998 Elsevier Science Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 01:18:08