The effect of iron in MRI and transverse relaxation of amyloid-beta plaques in Alzheimer's disease

Mark Meadowcroft, Douglas G. Peters, Rahul P. Dewal, James Connor, Qing Yang

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Dysregulation of neural iron is known to occur during the progression of Alzheimer's disease. The visualization of amyloid-beta (Aβ) plaques with MRI has largely been credited to rapid proton relaxation in the vicinity of plaques as a result of focal iron deposition. The goal of this work was to determine the relationship between local relaxation and related focal iron content associated with Aβ plaques. Alzheimer's disease (n=5) and control tissue (n=3) sample slices from the entorhinal cortex were treated overnight with the iron chelator deferoxamine or saline, and microscopic gradient-echo MRI datasets were taken. Subsequent to imaging, the same slices were stained for Aβ and iron, and then compared with regard to parametric R2* relaxation maps and gradient-echo-weighted MR images. Aβ plaques in both chelated and unchelated tissue generated MR hypo-intensities and showed relaxation rates significantly greater than the surrounding tissue. The transverse relaxation rate associated with amyloid plaques was determined not to be solely a result of iron load, as much of the relaxation associated with Aβ plaques remained following iron chelation. The data indicate a dual relaxation mechanism associated with Aβ plaques, such that iron and plaque composition synergistically produce transverse relaxation.

Original languageEnglish (US)
Pages (from-to)297-305
Number of pages9
JournalNMR in Biomedicine
Volume28
Issue number3
DOIs
StatePublished - Mar 1 2015

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy

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