Article

Diffusion tensor imaging of cingulum fibers in mild cognitive impairment and Alzheimer disease

Johns Hopkins University, Baltimore, Maryland, United States
Neurology (Impact Factor: 8.3). 02/2007; 68(1):13-9. DOI: 10.1212/01.wnl.0000250326.77323.01
Source: PubMed

ABSTRACT Neuroimaging in mild cognitive impairment (MCI) and Alzheimer disease (AD) generally shows medial temporal lobe atrophy and diminished glucose metabolism and cerebral blood flow in the posterior cingulate gyrus. However, it is unclear whether these abnormalities also impact the cingulum fibers, which connect the medial temporal lobe and the posterior cingulate regions.
To use diffusion tensor imaging (DTI), by measuring fractional anisotropy (FA), to test 1) if MCI and AD are associated with DTI abnormalities in the parahippocampal and posterior cingulate regions of the cingulum fibers; 2) if white matter abnormalities extend to the neocortical fiber connections in the corpus callosum (CC); 3) if DTI improves accuracy to separate AD and MCI from healthy aging vs structural MRI.
DTI and structural MRI were preformed on 17 patients with AD, 17 with MCI, and 18 cognitively normal (CN) subjects.
FA of the cingulum fibers was significantly reduced in MCI, and even more in AD. FA was also significantly reduced in the splenium of the CC in AD, but not in MCI. Adding DTI to hippocampal volume significantly improved the accuracy to separate MCI and AD from CN.
Assessment of the cingulum fibers using diffusion tensor imaging may aid early diagnosis of Alzheimer disease.

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Available from: Susanne G Mueller, May 05, 2014
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    • "Instead, we smoothed the image with a 2 mm kernel using FSLMATHS. To protect against Type I error we identified tracts previously reported to be associated with AD (Fig. 1) and divided them by hemisphere: the cingulum (CCG) (Xie et al. 2005; Zhang et al. 2007, 2014; Burzynska et al. 2010; Liu et al. 2011), the inferior fronto-occipital fasciculus (IFOF) (Gold et al. 2010; Teipel et al. 2010; Alves et al. 2012), the superior longitudinal fasciculus (SLF) (Liu et al. 2011; Sexton et al. 2011; Alves et al. 2012; Bosch et al. 2012), and the uncinate fasciculus (UF) (Liu et al. 2011; Sexton et al. 2011; Bosch et al. 2012). We created our white matter binary tract masks from the Johns Hopkins University (JHU) probabilistic atlas registered to the common MNI space (Mori et al. 2005; Hua et al. 2008). "
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    ABSTRACT: The objective of this study was to investigate the relationship between cardiorespiratory (CR) fitness and the brain's white matter tract integrity using diffusion tensor imaging (DTI) in the Alzheimer's disease (AD) population. We recruited older adults in the early stages of AD (n = 37; CDR = 0.5 and 1) and collected cross-sectional fitness and diffusion imaging data. We examined the association between CR fitness (peak oxygen consumption [VO2peak]) and fractional anisotropy (FA) in AD-related white matter tracts using two processing methodologies: a tract-of-interest approach and tract-based spatial statistic (TBSS). Subsequent diffusivity metrics (radial diffusivity [RD], mean diffusivity [MD], and axial diffusivity [A × D]) were also correlated with VO2peak. The tract-of-interest approach showed that higher VO2peak was associated with preserved white matter integrity as measured by increased FA in the right inferior fronto-occipital fasciculus (p = 0.035, r = 0.36). We did not find a significant correlation using TBSS, though there was a trend for a positive association between white matter integrity and higher VO2peak measures (p < 0.01 uncorrected). Our findings indicate that higher CR fitness levels in early AD participants may be related to preserved white matter integrity. However to draw stronger conclusions, further study on the relationship between fitness and white matter deterioration in AD is necessary.
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    • "AD-associated T 2 prolongation was also widespread in the white matter of the parietal and occipital lobes, with apparent confluence into the posterior portion of the cingulum. To the best of our knowledge, such T 2 prolongation in the cingulum has not been reported previously, though a number of DTI studies have shown disruption of diffusion anisotropy and mean diffusivity in the cingulum (especially in the posterior portion) of clinically diagnosed AD patients (Bozzali et al., 2012; Choo et al., 2010; Fellgiebel et al., 2005; Mielke et al., 2009; Takahashi et al., 2002; Zhang et al., 2007). Based on the findings of the present study and supporting DTI evidence from the literature, we surmise that the AD-associated T 2 prolongation in parietal and occipital white matter (including cingulum) is brought about by pathologic processes that ultimately lead to an increase in the tissue's free water content, possibly by the same mechanisms suspected in frontal white matter T 2 prolongation . "
    Radiological Society of North America 2014, Scientific Assembly and Annual Meeting;; 11/2014
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    • "Regardless of DTI sensitivity in assessing WM microstructural changes, differences in diffusion patterns across clinical groups may be challenging to interpret [1]. Several studies reported DTI changes in the parahippocampus, hippocampus , posterior cingulum, and splenium even at the MCI stage [9] [10] [11] [12] [13]. Widespread areas of DTI abnormalities may also be observed in AD. "
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