Evaluation of white matter damage in patients with Alzheimer's Disease and in patients with mild cognitive impairment by using diffusion tensor imaging

Ukmar, Maja; Makuc, E.; Onor, Maria Luisa; Garbin, G.; Trevisiol, Marianna; Cova, Maria Assunta

doi:10.1016/j.clinimag.2009.04.008

Cited by 22 publications

(38 citation statements)

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“…Indeed, some studies reported changes in the anterior subregion (e.g. [20,21,46,82]), some in the posterior subregion [20,21,83,91], and some found no callosal changes [40,85,92]. This inconsistency in results may be the consequence of reduced sample size of studies considering discrete diagnostic categories of different clinical stages.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the findings of studies on more homogeneous patients, such as those with mild AD, are discrepant. For example, Xie et al [82] found a decrease of FA in the genu and left anterior body of the CC, whereas Ulkmar et al [83] found a decrease of FA in the genu and splenium of the CC; other studies [84][85][86][87] found no differences in the CC in patients with mild AD.…”

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 98%

“…At present, the DTI study results on MCI patients can be divided into two groups: 1) DTI studies on both amnesic and MCI "all subtypes" [23,40,41,84,85,88] that found no differences in MD and/or in FA in the CC compared with HC; and 2) the most recent studies [83,86,[89][90][91], which reported differences. One study on MCI "all subtypes" [89] found a significant change in MD and FA in the genu and the splenium of the CC in patients compared with HC.…”

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 99%

“…One study on MCI "all subtypes" [89] found a significant change in MD and FA in the genu and the splenium of the CC in patients compared with HC. Moreover, studies on amnesic MCI [83,86,90] mainly found a decreased FA and/or increased MD value in the splenium of the CC. Wang and colleagues [91] also reported a decreased FA value in the genu and the splenium and increased ADC in the genu of the CC (see Table 3 for technical details of the study).…”

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 99%

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In Vivo Structural Neuroanatomy of Corpus Callosum in Alzheimer's Disease and Mild Cognitive Impairment Using Different MRI Techniques: A Review

Paola

Spalletta

Caltagirone

2010

JAD

128

103

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Abstract. The corpus callosum (CC), which connects the two cerebral hemispheres, is the largest white matter fiber bundle in the human brain. This structure presents a peculiar myelination pattern: it has small diameter fibers, located in the genu, which myelinate much later in normal development, and large diameter fibers of the splenium, which myelinate early in development. Although the pathology of AD mainly involves the cerebral gray matter structure, there is evidence that white matter may also be involved. To illustrate callosal white matter changes in AD pathology, in this review we summarize in vivo imaging studies in humans, focusing on region of interest, voxel-based morphometry, diffusion-weighted imaging, and diffusion tensor imaging techniques. Our aims were to identify where in the CC, when in the different stages of AD, and how callosal changes can be detected with different MRI techniques. Results showed that changes in the anterior (genu and anterior body) as well as in the posterior (isthmus and splenum) portions of the CC might already be present in the early stages of AD. These findings support the hypothesis that two mechanisms, Wallerian degeneration and myelin breakdown, might be responsible for the region-specific changes detected in AD patients. Wallerian degeneration affects the posterior CC subregion, which receives axons directly from those brain areas (temporo-parietal lobe regions) primarily affected by the AD pathology. Instead, the myelin breakdown process affects the later-myelinating CC subregion and explains the earlier involvement of the genu in CC atrophy.

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Section: Discussionmentioning

confidence: 99%

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 98%

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 99%

Section: Diffusion-weighted Imaging and Diffusion Tensor Imaging Studiesmentioning

confidence: 99%

See 2 more Smart Citations

In Vivo Structural Neuroanatomy of Corpus Callosum in Alzheimer's Disease and Mild Cognitive Impairment Using Different MRI Techniques: A Review

Paola

Spalletta

Caltagirone

2010

JAD

128

103

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“…Similarly Wang et al (2009) and DiPaola et al (2010), using voxel based morphometry (VBM), identified a density reduction in the genu in aMCI patients compared with healthy controls. Other researchers like Ukmar et al (2008), Cho et al (2008) or Parente et al (2008) found an AF reduction in MCI patients in the CC splenium. The splenium of the corpus callosum, crux of the fornix (Zhuang et al, 2010) and the cingulum were sensitive discriminators to differentiante between aMCI and normal subjects (Chua et al, 2009).…”

Section: Diffusion Tensor Imaging (Dti)mentioning

confidence: 85%

Currently Available Neuroimaging Approaches in Alzheimer Disease (AD) Early Diagnosis

Ortiz-Terán¹,

Santos²,

Martín³

et al. 2011

The Clinical Spectrum of Alzheimer's Disease -the Charge Toward Comprehensive Diagnostic and Therapeutic Strategies

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Computerized Tomography (CT)Nowadays CT is not considered a standard technique for diagnosing AD, least of all in early stages. Its main usefulness is in differential diagnosis since it is less expensive, faster and more widely available than MRI. CT allows ruling out some clinical situations which lead to MEGMeasures magnetic fields and, indirectly, yields rather precise information about brain electrical activity CT = computerized tomography; MRI = magnetic resonance imaging; fMRI = functional magnetic resonance imaging; DTI = diffusion tensor imaging; SPECT = single-photon emission computed tomography; PET = positron emission tomography; MEG = magnetoencephalography; BOLD = blood oxygen level-dependent; NAA = N-acetyl aspartate; Cr = Creatinine; AD = Alzheimer's disease Table 1. Typical findings of different brain imaging methods used in AD and MCI diagnosis Magnetic Resonance Imaging (MRI) 1.2.1 Structural MRIThis technique provides the best possible spatial resolution. Given the fact the most robust neuroimaging finding in AD is the atrophy of mesial temporal structures, structural MRI is the most widely used approach. Hippocampal atrophy is another well known finding, but atrophy within other brain areas has also been described in entorrhinal cortex, amygdala, basal ganglia (nucleus basalis of Meynert), thalamus and bilateral parietal cortex. It is relevant to mention here that in terms of early diagnosis some consider the entorrhinal cortex as the earliest area affected by AD. Other researchers have stated that the nucleus basalis of Meynert is a key structure in AD early diagnosis (Herholz et al, 2004;Grothe et al, 2010). Functional MRI (fMRI)fMRI provides signal intensities images associated with a relative cerebral blood flow during cognitive tasks. Resting and activation functional MRI studies have showed a lesser coordinated activity in the hippocampus, inferior parietal lobes -both bilaterally-and cingulate cortex in patients with AD. This neuroimaging technique is nowadays used to monitor AD patients' treatment. Combining genetic risk with functional MRI memory task paradigms has shown to be a very accurate pre-symptomatic predictor of cognitive decline. Diffusion Tensor Imaging (DTI)DTI allows visualizing neuronal connectivity or, more precisely, local fiber orientation and white matter tracts integrity. Patients with AD show decreased fiber density in temporal white matter, probably related to the medial temporal grey matter atrophy, as well as in the splenium of the corpus callosum. www.intechopen.com Currently Available Neuroimaging Approaches in Alzheimer Disease (AD) Early Diagnosis 149In mild cognitive impairment (MCI), however, this decreased fiber density has been located in the anterior part of the corpus callosum. SpectroscopyIt provides information on tissue substrate or metabolite concentrations. Specifically the Nacetyl aspartate (NAA) has been used as a biomarker of neuronal death, and it has been demonstrated that in patients with MCI and AD is significantly reduced compared to hea...

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Callosal degeneration topographically correlated with cognitive function in amnestic mild cognitive impairment and alzheimer's disease dementia

Wang

Chou²,

Chang

et al. 2013

Human Brain Mapping

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Degeneration of the corpus callosum (CC) is evident in the pathogenesis of Alzheimer's disease (AD). However, the correlation of microstructural damage in the CC on the cognitive performance of patients with amnestic mild cognitive impairment (aMCI) and AD dementia is undetermined. We enrolled 26 normal controls, 24 patients with AD dementia, and 40 single-domain aMCI patients with at least grade 1 hippocampal atrophy and isolated memory impairment. Diffusion tensor imaging (DTI) with fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (DA), and radial diffusivity (DR) were measured. The entire CC was parcellated based on fiber trajectories to specific cortical Brodmann areas using a probabilistic tractography method. The relationship between the DTI measures in the subregions of the CC and cognitive performance was examined. Although the callosal degeneration in the patients with aMCI was less extended than in the patients with AD dementia, degeneration was already exhibited in several subregions of the CC at the aMCI stage. Scores of various neuropsychological tests were correlated to the severity of microstructural changes in the subregional CC connecting to functionally corresponding cortical regions. Our results confirm that CC degeneration is noticeable as early as the aMCI stage of AD and the disconnection of the CC subregional fibers to the corresponding Brodmann areas has an apparent impact on the related cognitive performance.

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Evaluation of white matter damage in patients with Alzheimer's Disease and in patients with mild cognitive impairment by using diffusion tensor imaging

Cited by 22 publications

References 0 publications

In Vivo Structural Neuroanatomy of Corpus Callosum in Alzheimer's Disease and Mild Cognitive Impairment Using Different MRI Techniques: A Review

In Vivo Structural Neuroanatomy of Corpus Callosum in Alzheimer's Disease and Mild Cognitive Impairment Using Different MRI Techniques: A Review

Currently Available Neuroimaging Approaches in Alzheimer Disease (AD) Early Diagnosis

Callosal degeneration topographically correlated with cognitive function in amnestic mild cognitive impairment and alzheimer's disease dementia

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