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Titolo:
Sampling and reconstruction effects due to motion in diffusion-weighted interleaved echo planar imaging
Autore:
Atkinson, D; Porter, DA; Hill, DLG; Calamante, F; Connelly, A;
Indirizzi:
Guys Hosp, Div Radiol Sci & Med Engn, Guys Kings & St Thomas Sch Med, London SE1 9RT, England Guys Hosp London England SE1 9RT Thomas Sch Med, London SE1 9RT, England Univ Coll London, Radiol & Phys Unit, Inst Child Hlth, London, England Univ Coll London London England Unit, Inst Child Hlth, London, England
Titolo Testata:
MAGNETIC RESONANCE IN MEDICINE
fascicolo: 1, volume: 44, anno: 2000,
pagine: 101 - 109
SICI:
0740-3194(200007)44:1<101:SAREDT>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
GRIDDING ALGORITHM; FOURIER INVERSION; NAVIGATOR ECHOES; IN-DIFFUSION; ACUTE STROKE; BRAIN; MRI; ARTIFACTS; PERFUSION; HUMANS;
Keywords:
irregular sampling; Nyquist; diffusion-weighted imaging; echo planar imaging; motion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Hill, DLG Guys Hosp, Div Radiol Sci & Med Engn, Guys Kings & St Thomas SchMed, London SE1 9RT, England Guys Hosp London England SE1 9RT Med, London SE1 9RT, England
Citazione:
D. Atkinson et al., "Sampling and reconstruction effects due to motion in diffusion-weighted interleaved echo planar imaging", MAGN RES M, 44(1), 2000, pp. 101-109

Abstract

Subject motion during diffusion-weighted interleaved echo-planar imaging causes k-space offsets which lead to irregular sampling in the phase-encode direction. For each image, the k-space shifts are monitored using 2D navigator echoes, and are shown to lead to a frequent violation of the Nyquist condition when an ungated sequence is used on seven subjects. Combining data from four repeat acquisitions allows the Nyquist condition to be satisfied in all but 1% of images. Reconstruction of the irregularly-sampled data canbe performed using a matrix inversion technique, The repeated acquisitionsmake the inversion more stable and additionally improve the signal-to-noise ratio. The resultant isotropic diffusion-weighted images and average apparent diffusion coefficient (ADC) maps show high resolution and enable clearlocalization of a stroke lesion, Residual ADC artifacts with a slow spatial variation are observed and assumed to originate from non-rigid pulsatile brain motion. (C) 2000 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 10:22:10