Ronnie Wirestam
Professor
Quantitative diffusion coefficient maps using fast spin-echo MRI
Författare
Summary, in English
In this work, we have evaluated the performance of a diffusion-sensitive fast spin-echo (FSE) pulse sequence. The proposed pulse sequence utilises velocity-compensating diffusion-encoding gradients and includes the collection of navigator echoes. Spoiler gradients were inserted in the slice-selecting direction to minimise effects from stimulated echoes. Calculations of the b values showed that cross-terms between imaging gradients and diffusion gradients only led to a marginal increase of b values. Pixel-wise calculation of apparent diffusion coefficient (ADC) maps was performed numerically, considering cross-terms between diffusion-encoding and imaging gradients. The sequences investigated used echo train lengths of 16, 8 and 4 echoes and were encoded in either the slice-, frequency- or phase-encoding direction. In order to allow for higher b values a pulse-sequence version using non-motion compensating diffusion-encoding gradients was written. Phantom measurements were performed and the diffusion coefficients of water and acetone were reasonable. Seven healthy volunteers (age 28-50 years) were examined and apparent diffusion coefficient values agreed well with expected values. Diffusion-weighted images, apparent diffusion coefficient maps and images corresponding to the trace of the diffusion tensor of good quality were retrieved in vivo.
Avdelning/ar
- Medicinsk strålningsfysik, Lund
- Diagnostisk radiologi, Lund
Publiceringsår
1998
Språk
Engelska
Sidor
877-886
Publikation/Tidskrift/Serie
Magnetic Resonance Imaging
Volym
16
Issue
8
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Radiology, Nuclear Medicine and Medical Imaging
Nyckelord
- Navigator echoes Article Outline
- Phase correction
- Motion-compensating gradients
- Diffusion
- Fast spin-echo
Aktiv
Published
ISBN/ISSN/Övrigt
- ISSN: 1873-5894