Could iron accumulation be an etiology of the white matter change in Alzheimer's disease: using phase imaging to detect white matter iron deposition based on diffusion tensor imaging

Abstract

Background/aims: To investigate if and where abnormal iron accumulation in white matter fibers occurs in patients with Alzheimer's disease (AD) by phase imaging and to relate these findings to white matter tract degeneration assessed by diffusion tensor imaging.

Methods: Twenty-five patients with AD and 20 normal controls underwent phase imaging and diffusion tensor imaging with a 3.0-tesla system. White matter fibers including fornix (Fx), genu of corpus callosum (GCC), splenium of corpus callosum (SCC), bilateral posterior cingulum (PC), superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF) and frontal occipital fasciculus (IOF) were measured on a fractional anisotropy (FA) map, mean diffusivity (MD) map and phase map.

Results: Significantly decreased phase values and FA values in the Fx and PC regions were found in the AD group. The phase value in Fx had a moderately positive correlation with the FA value (r = 0.666, p = 0.000) in the AD group. Meanwhile, phase values in PC showed positive correlation with FA values (right side: r = 0.436, p = 0.033; left side: r = 0.458, p = 0.022, respectively).

Conclusion: Iron accumulation of Fx and PC regions was significantly positively correlated with FA value, indicating that abnormal iron deposition may be one of the causes of white matter disruption in AD.