Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Default user image.

Ronnie Wirestam

Professor

Default user image.

Quantitative diffusion coefficient maps using fast spin-echo MRI

Författare

  • Sara Brockstedt
  • C Thomsen
  • Ronnie Wirestam
  • Stig Holtås
  • Freddy Ståhlberg

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