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Ronnie Wirestam

Professor

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Wavelet-based noise reduction for improved deconvolution of time-series data in dynamic susceptibility-contrast MRI.

Författare

  • Ronnie Wirestam
  • Freddy Ståhlberg

Summary, in English

Dynamic susceptibility-contrast (DSC) MRI requires deconvolution to retrieve the tissue residue function R(t) and the cerebral blood flow (CBF). In this study, deconvolution of time-series data was performed by wavelet-transform-based denoising combined with the Fourier transform (FT). Traditional FT-based deconvolution of noisy data requires frequency-domain filtering, often leading to excessive smoothing of the recovered signal. In the present approach, only a low degree of regularisation was employed while the major noise reduction was accomplished by wavelet transformation of data and Wiener-like filtering in the wavelet space. After inverse wavelet transform, the estimate of CBF.R(t) was obtained. DSC-MRI signal-versus-time curves (signal-to-noise ratios 40 and 100) were simulated, corresponding to CBF values in the range 10-60 ml/(min 100 g). Three shapes of the tissue residue function were investigated. The technique was also applied to six volunteers. Simulations showed CBF estimates with acceptable accuracy and precision, as well as independence of any time shift between the arterial input function and the tissue concentration curve. The grey-matter to white-matter CBF ratio in volunteers was 2.4 +/- 0.2. The proposed wavelet/FT deconvolution is robust and can be implemented into existing perfusion software. CBF maps from healthy volunteers showed high quality.

Avdelning/ar

  • Medicinsk strålningsfysik, Lund
  • Diagnostisk radiologi, Lund

Publiceringsår

2005

Språk

Engelska

Sidor

113-118

Publikation/Tidskrift/Serie

Magma

Volym

18

Issue

3

Dokumenttyp

Artikel i tidskrift

Förlag

Springer

Ämne

  • Radiology, Nuclear Medicine and Medical Imaging

Nyckelord

  • wavelets
  • noise
  • cerebral blood flow
  • imaging
  • perfusion
  • magnetic resonance
  • deconvolution
  • dynamic susceptibility contrast

Aktiv

Published

Projekt

  • Optimisation and Validation of Dynamic Susceptibility Contrast MRI

ISBN/ISSN/Övrigt

  • ISSN: 1352-8661