Reduction of Diffusion-Weighted Imaging Contrast of Acute Ischemic Stroke at Short Diffusion Times. Stroke 2015 Aug;46(8):2136-41
Date
07/15/2015Pubmed ID
26152297DOI
10.1161/STROKEAHA.115.008815Scopus ID
2-s2.0-84944707435 (requires institutional sign-in at Scopus site) 67 CitationsAbstract
BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) of tissue water is a sensitive and specific indicator of acute brain ischemia, where reductions of the diffusion of tissue water are observed acutely in the stroke lesion core. Although these diffusion changes have been long attributed to cell swelling, the precise nature of the biophysical mechanisms remains uncertain.
METHODS: The potential cause of diffusion reductions after stroke was investigated using an advanced DWI technique, oscillating gradient spin-echo DWI, that enables much shorter diffusion times and can improve specificity for alterations of structure at the micron level.
RESULTS: Diffusion measurements in the white matter lesions of patients with acute ischemic stroke were reduced by only 8% using oscillating gradient spin-echo DWI, in contrast to a 37% decrease using standard DWI. Neurite beading has recently been proposed as a mechanism for the diffusion changes after ischemic stroke with some ex vivo evidence. To explore whether beading could cause such differential results, simulations of beaded cylinders and axonal swelling were performed, yielding good agreement with experiment.
CONCLUSIONS: Short diffusion times result in dramatically reduced diffusion contrast of human stroke. Simulations implicate a combination of neuronal beading and axonal swelling as the key structural changes leading to the reduced apparent diffusion coefficient after stroke.
Author List
Baron CA, Kate M, Gioia L, Butcher K, Emery D, Budde M, Beaulieu CAuthor
Matthew Budde PhD Associate Professor in the Neurosurgery department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdultAged
Brain Ischemia
Diffusion
Diffusion Magnetic Resonance Imaging
Female
Humans
Male
Middle Aged
Monte Carlo Method
Stroke
Time Factors
